The black soldier fly (Hermetia illucens) is a common saprophytic insect, its larvae have a short reproductive cycle, high conversion rate and low cost, can be efficiently converted organic waste into high-quality insect proteins, oils and other products through resource utilization. At present, the research and application of black soldier fly mainly focus on aquaculture, poultry and pig feed, due to the domestic regulatory restrictions, its use in ruminant animal feed has been limited. Currently limited studies suggest that black soldier fly larvae demonstrate significant potential on improving the growth performance of ruminants, affecting the rumen fermentation and reducing the methane emissions. This review summarizes the research progress of biological characteristics, nutritional value of black soldier fly and its applications in animal feed, and discusse the feasibility of its application in ruminant animal feed, to provide the reference for the feed application of black soldier fly.

Intestinal tract is the main digestion and absorption site of nutrients, and a healthy intestinal tract can improve the feed conversion rate of pigs and promote their growth and development, therefore, maintaining intestinal health is crucial for healthy pig breeding. Plant polyphenols are secondary metabolites widely present in plant tissues, with biological properties such as antioxidant, anti-inflammatory, antibacterial and antitumour. Many studies have shown that plant polyphenols can maintain the intestinal health of pigs by regulating intestinal oxidative stress, improving intestinal morphology and structure, and enhancing the intestinal barrier function, etc. They have been widely used as green and safe feed additives in pig production. This paper reviews the physicochemical properties and composition of plant polyphenols, as well as their regulation and mechanism of action on the state of oxidative balance, intestinal morphology and intestinal mucosal barrier integrity of the pig intestinal tract, with a view to providing theoretical basis for the rational application of plant polyphenols in healthy pig breeding.

Eleutheroside (ELU) is one of the main extracts of Chinese herbal medicine Acanthopanax senticosus, which has the function of relieving biofilm damage caused by oxidative stress and protecting intestinal health. The intestinal development of weaned piglets is incomplete, and the intestinal health and growth performance are easily affected by the external environment. Taking weaned piglets and rats as examples, this paper summarizes the reasons and manifestations of young monogastric mammals susceptible to weaning stress, the research status of ELU in relieving intestinal oxidative stress and inflammation in weaning stage, and the ways of ELU in regulating oxidative stress and inflammation, so as to provide reference for the application of Acanthopanax senticosus and its extracts as feed additives in relieving weaning stress and make suggestions on the application mode of ELU.

T cells are an important line of defence to protect the health of the organism, which plays a key role in anti-infection, anti-tumor and autoimmune diseases by recognizing and killing pathogens and protecting the organism from aggression, while avoiding damage to its own tissues. However, there are fewer systematic studies on porcine T cell development and immune homeostasis, so this article comprehensively analyses the development and differentiation of porcine T cells, immune homeostasis and its regulatory mechanisms, with a view to providing reference for the prevention and control of porcine diseases and the precise regulation of porcine T cell immune homeostasis.

The microbial fermentation in the rumen of ruminants produces methane (CH₄), a potent greenhouse gas, which not only accelerates global warming but also reduces feed utilization efficiency and decreases livestock product output. Therefore, it is imperative to mitigate CH₄ emissions from ruminants. Exploring CH₄ mitigation measures through the CH₄ production process or CH₄ substrates represents the most direct and effective approach to addressing CH₄ emissions from ruminants. Hydrogenases, a broad class of metalloenzymes widely distributed within rumen microorganisms of ruminants, play a crucial role in the CH₄ production process and substrate generation. Hydrogenases may emerge as novel targets for inhibiting CH₄ production. Consequently, this paper delved into the distribution of hydrogenases in rumen microbes (bacteria, fungi and protozoa) and their role in the CH₄ production process, aiming to provide a theoretical foundation for the development of innovative CH₄ mitigation strategies.

Intestinal health of aquatic animals are very crucial in aquaculture. As essential amino acids of aquatic animals, branched-chain amino acids play an important role in their growth, intestinal immunity, intestinal flora. Especially under the background of the development of novel protein sources and the development of low protein and low fishmeal feed, the research on branched-chain amino acid nutrition of aquatic animals has gradually attracted attention. However, both deficiency and excess of single branched-chain amino acid can affect intestinal health of aquatic animals. In this paper, the physicochemical properties of branched-chain amino acids and their effects on intestinal health were reviewed in order to provide theoretical basis and reference for the application of branched-chain amino acids in aquaculture.

Sesamol (SEM) is a phenolic compound present in sesame, which has the effects of anti-oxidation, anti-inflammation, anti-obesity, bacteriostasis, anti-tumor, and protection of intestinal barrier, etc. As a natural plant extract, SEM holds great potential for application in livestock and poultry production. This review summarizes the physicochemical properties, main physiological functions and application of SEM in livestock and poultry production, providing a reference for the rational application of SEM in livestock and poultry production.

Since the ban of the usage of antibiotics in the feed, it has been one of the important tasks in current livestock and poultry production to looking for effective breeding scheme. 5-hydroxytryptophan and its metabolites, such as 5-hydroxytryptamine and melatonin, have a variety of biological functions such as enhancing body immunity, anti-inflammatory, antioxidant, improving sleep, which show great potential for application in livestock and poultry production. Appropriate supplementation of 5-hydroxytryptophan can enhance the growth performance of livestock and poultry, improve gut health, and by promoting melatonin synthesis, optimize reproductive performance and circadian rhythms, thereby improving overall animal health. This article reviews the synthetic secretion and metabolic mechanisms, biological functions and applications in livestock and poultry production of 5-hydroxytryptophan and its metabolites, with the aim of providing a feasible reference for the in-depth development and application of melatonin and promoting green and healthy breeding practices in livestock and poultry.

α-lipoic acid depends on the synthesis of mitochondrial fatty acid synthesis pathway Ⅱ (mtFAS Ⅱ) in mitochondria, and can act as a cofactor for lipid acylation modification of mitochondrial metabolic enzymes and regulation of mitochondrial biogenesis. In this article, the structure, source and biological functions of α-lipoic acid were reviewed, and the mechanism of α-lipoic acid regulating skeletal muscle fibers was summarized from the aspects of skeletal muscle fiber type conversion, antioxidant and lipid metabolism, and further exploration was conducted on the effects of α-lipoic acid on meat quality indicators such as pH, color, water holding capacity,and tenderness, aiming to provide a scientific basis for the development of high-quality, high edible, and high safety meat.

Flaxseed and its by-product, flaxseed meal, serve as a novel unconventional feed resource rich in high-quality protein, which is of great significance in alleviating the current shortage of protein feed resources in China and promoting the implementation of a soybean meal reduction and substitution strategy. However, the high content of antinutritional factors and low nutrient digestibility in flaxseed and its by-product greatly limit their application in livestock and poultry production. Extrusion technology, as an efficient processing strategy, holds great potential in reducing the contents of antinutritional factors such as cyanogenic glycosides and phytic acid in raw materials, improving nutrient digestibility, and enhancing the feeding value of raw materials. This paper systematically reviewed the progress in the application of extrusion technology to improve the nutritional value of flaxseed and its by-product, and delved into their effects on the growth performance of livestock and poultry. It provides a theoretical basis for the application of extrusion technology, as well as flaxseed and its by-product, in livestock and poultry production.

In recent years, the incidence of cardiovascular diseases has continued to increase, becoming the first cause of death in China and even in the world. The increase in cholesterol level caused by the increase in intaking of red meat and eggs is a major cause of cardiovascular disease,dietary guidelines advocate reducing cholesterol intake while ensuring health. Therefore, controlling cholesterol level in red meat such as beef is significant for human and animal health. More and more studies have shown that gastrointestinal microbiota not only participates in host digestion and absorption, but also plays a key role in regulating lipid metabolism, including the maintenance of cholesterol homeostasis. In this paper, the effects of gastrointestinal microbiota and its metabolites in lowering cholesterol levels and their mechanisms were reviewed, in order to provide a reference for reducing cholesterol levels and improving animal health and production by targeting gastrointestinal microbiota.

Intestinal absorption serves as the primary pathways for nutrients and drugs to enter the bloodstream, involving multiple complex processes such as epithelial barrier permeability, transporter protein activities, and intestinal metabolism. Developing an efficient, safe, convenient, and reliable in vitro absorption prediction model to study the absorption and metabolism of active substances in the intestine has been a challenge and a hotspot topic in research. Intestinal organoids, as an important type of intestinal absorption model, are composed of various intestinal cells, capable of expressing multiple transporters, and forming intestinal structures with absorption and metabolic functions, making them an ideal tool for predicting the absorption and metabolism of active substances. This review summarized the absorption function and cellular composition of the intestine, the biological characteristics of intestinal organoids, construction methods, and their application in the study of active substance absorption and metabolism, aiming to provide new insights for the development of efficient, low-toxicity substances that promote animal growth.

This experiment was conducted to investigate the effects of different dietary crude protein levels on growth performance, serum biochemical indices, nutrient apparent digestibility and fecal microbial composition of Duhua piglets. A total of 360 healthy piglets (Duroc×Guangdong small-spotted pigs) at 32 days of age were divided into 6 groups according to body weight with 6 replicates per group and 10 piglets (half male and half female) per replicate. The piglets in the six groups were fed corn-soybean meal diets with crude protein levels of 15.00%, 16.00%, 17.00%, 18.00%, 19.00% and 20.00%, respectively, and the proportion of essential amino acids such as lysine was consistent with that of crude protein. The experimental period was 28 days. On days 1, 14 and 28 of the experiment, the body weight was weighed by fasting, and the diarrhea was recorded daily. The results showed as follows: 1) with the increase of dietary crude protein level, the body weight of piglets on day 28 increased linearly (P<0.05), and showed a quadratic curve change (P<0.05). The average daily gain (ADG) of piglets from days 1 to 28 increased linearly (P<0.05) and showed a quadratic curve change (P<0.05). From days 15 to 28, the average daily feed intake (ADFI)of piglets increased linearly (P<0.05). From days 1 to 28, the feed/gain (F/G)of piglets decreased linearly (P<0.05) and showed a quadratic curve change (P<0.05). Broken-line analysis recommended optimal crude protein levels of 17.92%, 20.13%, and 17.33% based on ADG, ADFI, and F/G, respectively. 2) Higher crude protein levels tended to linearly increase diarrhea rates during days 1 to 14 (P=0.052) and days 1 to 28 (P=0.084), with quadratic trends (P=0.057). 3) With the increase of dietary crude protein level, serum creatinine and triglycerides contents increased linearly (P<0.05) and quadratically (P<0.05), while total cholesterol content decreased linearly (P<0.05) and quadratically (P<0.05). No significant effects were observed on low-density lipoprotein and high-density lipoprotein contents, aspartate aminotransferase and alkaline phosphatase activities, or albumin content in serum (P>0.05). 4) With the increase of dietary crude protein level, the apparent digestibility of crude protein increased linearly (P<0.05) and showed a quadratic curve change (P<0.05). The apparent digestibility of crude fat decreased linearly (P<0.05), and showed a quadratic curve change (P<0.05). The apparent digestibility of crude ash had no significant effect (P>0.05). 5) Analysis of the microbial composition in feces by 16S rRNA sequencing showed that with the increase of dietary crude protein level, Chao index, Richness index and ACE index in the feces of piglets showed a significant quadratic curve change (P<0.05). The relative abundances of Prevotella and Faecalibacterium decreased linearly (P<0.05) and quadratically (P<0.05), while those of Limosilactobacillus and Lactobacillus increased linearly (P<0.05),with that of Lactobacillus showing additional quadratic effects (P<0.05). In summary, increasing dietary crude protein level can significantly improve the growth performance, apparent digestibility of crude protein and intestinal microecology of Duhua piglets, but if the dietary crude protein level is too high, it will increase the diarrhea rate. Considering the growth performance and diarrhea rate of piglets, the recommended dietary crude protein level for Duhua piglets is 18.00%.

The experiment was conducted to investigate the effects of corn starch and pea starch on growth performance, intestinal microbiota and liver metabolism of piglets under different dietary protein levels. A total of 56 Duroc×Landrace×Yorkshine hybrid piglets with a body weight of (9.88±1.45) kg were selected and randomly divided into 4 groups according to a 2×2 (the two factors were starch source and protein level, respectively) factorial assay design, with 7 replicates in each group and 2 pigs in each replicate. The dietary treatments of each group were pea starch+16% crude protein (CP) (PSLP group), pea starch+20% CP (PSHP group), corn starch+16% CP (CSLP group), and corn starch+20% CP (CSHP group), respectively. The experiment lasted for 21 days. The results showed as follows: 1) compared with pea starch, corn starch significantly increased the average daily gain (ADG) and average daily feed intake (ADFI) of piglets (P<0.05); compared with 16% CP, 20% CP had a tendency to increase ADG and ADFI (0.05≤P<0.10); the starch source and protein level had a significant interaction on the feed to weight ratio (P<0.05). 2) Compared with 16% CP, 20% CP significantly increased the total protein content in serum of piglets (P<0.05), and tended to increase the globulin content in serum (0.05≤P<0.10). 3) Compared with corn starch, pea starch significantly increased the contents of lysine, methionine, threonine, histidine and arginine in serum of piglets (P<0.05); compared with 20% CP, 16% CP significantly increased the contents of lysine, methionine, histidine, glutamic acid and arginine in serum (P<0.05); the starch source and protein level had a significant interaction on the contents of methionine and histidine in serum (P<0.05). 4) Compared with pea starch, corn starch significantly increased the Prevotella relative abundance in cecum and colon of piglets (P<0.05), and significantly decreased the Flavonifractor relative abundance in cecum and colon (P<0.05); compared with 20% CP, 16% CP significantly decreased the relative abundances of Clostridium_sensu_stricto_1 and Terrisporobacter in cecum and colon (P<0.05); the starch source and protein level had a significant interaction on the relative abundances of Prevotellaceae_NK3B31_group and Coprococcus (P<0.05). 5) The functional annotations of Kyoto Encyclopedia of Genes and Genomes (KEGG) for liver differential metabolites were mainly enriched in the amino acid metabolism and fatty acid metabolism pathways. Compared with corn starch, the amino acids and their precursors L-glutamate, L-histidinol and ascorbate were significantly enriched in liver in pea starch group (P<0.05); compared with pea starch, the 15-keto-prostaglandin E2, glycochenodeoxycholate and eicosadienoic acid were significantly enriched in liver in corn starch group (P<0.05). Increasing dietary protein level significantly enhanced the enrichment of 15(S)-hydroperoxyeicosatetraenoic acid, 8(S)-hydroxyeicosatetraenoic acid, 15-keto-prostaglandin E2 and coenzyme A in liver (P<0.05). In conclusion, corn starch can promote the enrichment of beneficial bacteria in intestine of piglets and the lipid metabolism process in liver, thereby improving their growth performance. Pea starch can effectively promote the process of amino acid synthesis in the body. Increasing the dietary protein level can promote the synthesis of fatty acids in liver and the digestion and absorption of lipid, and there is a tendency to improve the growth performance of piglets.

This experiment established an oxidative stress model in weaned piglets induced by enterotoxigenic Escherichia coli (ETEC) with fimbriae K88, aiming to investigate the effects of ellagic acid (EA) on growth performance, antioxidant function, and nuclear factor E2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathway of weaned piglets challenged with ETEC K88. Twenty-four 21-day-old Duroc×Landrace×Yorkshire weaned piglets with consistent genetic background and similar body weight [(7.83±0.09) kg] were randomly divided into 3 groups, with 8 replicates per group and 1 pig per replicate. Piglets in the control group (CON group) and diarrhea model group (ETEC group) were fed the basal diet, while those in the EA-diarrhea model group (EA-ETEC group) were fed the basal diet supplemented with 500 mg/kg EA. The pre-trial period was 3 days, and the formal trial period was 18 days. From day 16 to 18 of the formal trial, each weaned piglet in the ETEC group and EA-ETEC group was orally administered 10 mL of ETEC K88 bacterial solution at a concentration of 2×10⁹ CFU/mL daily, while those in the CON group were administered the same volume of sterile LB medium. The results showed as follows: 1) before challenge, compared with the ETEC group, the average daily feed intake (ADFI) and average daily gain (ADG) of weaned piglets in the EA-ETEC group were significantly increased (P<0.05), and the body weight on day 15 showed a trend of increase (P=0.083); there was no significant difference in diarrhea rate between the CON group and ETEC group or between the ETEC group and EA-ETEC group (P>0.05). During the challenge period, compared with the CON group, the body weight on day 18, ADFI and ADG of weaned piglets in the ETEC group were significantly decreased (P<0.05), and the diarrhea rate was significantly increased (P<0.05); compared with the ETEC group, the body weight on day 18 and ADFI of weaned piglets in the EA-ETEC group were significantly increased (P<0.05), and the diarrhea rate was significantly decreased (P<0.05). During the whole experimental period, compared with the CON group, the ADFI and ADG of weaned piglets in the ETEC group were significantly decreased (P<0.05), and the feed to gain ratio (F/G) was significantly increased (P<0.05); compared with the ETEC group, the ADFI and ADG of weaned piglets in the EA-ETEC group were significantly increased (P<0.05), and the F/G was significantly decreased (P<0.05). 2) After challenge, compared with the CON group, the spleen index of weaned piglets in the ETEC group was significantly decreased (P<0.05), and the lung index was significantly increased (P<0.05); compared with the ETEC group, the spleen index of weaned piglets in the EA-ETEC group was significantly increased (P<0.05), and the stomach index showed a trend of increase (P=0.065). 3) After challenge, compared with the CON group, the superoxide dismutase (SOD) activity and total antioxidant capacity (T-AOC) in jejunal mucosa of weaned piglets in the ETEC group were significantly decreased (P<0.05), and the malondialdehyde (MDA) content in jejunal mucosa was significantly increased (P<0.05); compared with the ETEC group, the SOD activity and T-AOC in jejunal mucosa of weaned piglets in the EA-ETEC group were significantly increased (P<0.05), and the MDA content in jejunal mucosa was significantly decreased (P<0.05). 4) After challenge, compared with the CON group, the mRNA relative expression levels of SOD1, SOD2 and glutathione peroxidase 1 (GSH-Px1) in jejunal mucosa of weaned piglets in the ETEC group were significantly decreased (P<0.05); compared with the ETEC group, the mRNA relative expression levels of SOD2 and GSH-Px1 in jejunal mucosa of weaned piglets in the EA-ETEC group were significantly increased (P<0.05), and the relative mRNA expression level of SOD1 in jejunal mucosa showed a trend of increase (P=0.083). 5) After challenge, compared with the CON group, the mRNA relative expression level of Keap1 in jejunal mucosa of weaned piglets in the ETEC group was significantly increased (P<0.05), and the mRNA relative expression level of Nrf2 in jejunal mucosa was significantly decreased (P<0.05); compared with the ETEC group, the mRNA relative expression level of Keap1 in jejunal mucosa of weaned piglets in the EA-ETEC group was significantly decreased (P<0.05), and the mRNA relative expression level of Nrf2 in jejunal mucosa was significantly increased (P<0.05). In conclusion, dietary supplementation with 500 mg/kg EA can alleviate the decline in growth performance and intestinal damage of weaned piglets challenged with ETEC K88. Meanwhile, EA can effectively alleviate the oxidative stress induced by ETEC K88 challenge by regulating the antioxidant signaling pathway, modulating the expression of antioxidant genes, antioxidant enzyme activities and peroxide content in jejunal mucosa.

This experiment was conducted to investigate the effects of glutathione (GSH) on muscle free amino acid contents, expression of genes related to muscle fiber development and lipid metabolism of weaned piglets under immune stress. Thirty-five healthy 28-day-old “Duroc×Landrace×Yrokshire” weaned piglets were selected. After a 5-day pre-feeding with a basal diet, they were randomly divided into 5 groups according to the principle of similar body weight [(9.52±0.20) kg], with 7 replicates per group and 1 piglet per replicate. The control group (CON group) and immune stress group (PQ group) were fed a basal diet, while the 0.01%GSH+immune stress group (LGSH+PQ group), 0.03%GSH+immune stress group (MGSH+PQ group) and 0.06%GSH+immune stress group (HGSH+PQ group) were fed diets supplemented with 0.01%, 0.03% and 0.06% GSH in the basal diet, respectively. The formal trial period was 28 days. The piglets in PQ group and each GSH+PQ group were intraperitoneally injected with 8 mg/kg BW of paraquat (PQ) on days 23, 25 and 27 of the formal trial period, while the piglets in CON group were injected with the same amount of 0.9% normal saline. Slaughter and sampling were conducted on day 28. The results showed as follows: 1) compared with the CON group, the glycine content and the ratio of flavor amino acids to total amino acids in longissimus dorsi, biceps femoris and psoas major of the PQ group and each GSH+PQ group were significantly decreased (P<0.05), while the ratio of essential amino acids to total amino acids in longissimus dorsi and psoas major was significantly increased (P<0.05). The cysteine content in biceps femoris and psoas major of the PQ group was significantly increased (P<0.05). Compared with the PQ group, the cysteine content in biceps femoris and psoas major of the MGSH+PQ group was significantly decreased (P<0.05). 2) PQ treatment did not cause obvious inflammatory responses in muscles of various sites. 3) Compared with the CON group, the mRNA relative expression level of myogenic determination factor (MyoD) in longissimus dorsi and biceps femoris of the PQ group was significantly decreased (P<0.05), while the mRNA relative expression level of myosin heavy chain Ⅱx (MyHC Ⅱx) in psoas major was significantly increased (P<0.05). Compared with the PQ group, the mRNA relative expression level of MyoD in longissimus dorsi of the LGSH+PQ group was significantly increased (P<0.05); the mRNA relative expression level of myogenic regulatory factor 5 (Myf5) in biceps femoris and psoas major of the MGSH+PQ and HGSH+PQ groups was significantly increased (P<0.05). 4) Compared with the CON group, the mRNA relative expression level of hormone-sensitive lipase (HSL) in longissimus dorsi of each GSH+PQ group was significantly increased (P<0.05); while the mRNA relative expression level of HSL in psoas major of the PQ group was significantly decreased (P<0.05). Compared with the PQ group, the mRNA relative expression level of fatty acid transport protein 1 (FATP1) in longissimus dorsi of the MGSH+PQ group was significantly increased (P<0.05); the mRNA relative expression level of FATP1 in biceps femoris of the MGSH+PQ and HGSH+PQ groups was significantly increased (P<0.05); the mRNA relative expression levels of both HSL and FATP1 in psoas major of each GSH+PQ group were significantly increased (P<0.05). In conclusion, immune stress did not induce obvious inflammatory responses in muscles of weaned piglets. However, it led to a reduction in flavor amino acid content, impaired muscle fiber development, transformation of muscle fiber types and abnormal lipid metabolism. Dietary supplementation with GSH can alleviate these negative effects on weaned piglets to some extent, with the optimal alleviating effect observed at a supplementation level of 0.03%.

This experiment was designed to conduct in-depth mining and analysis of the data on the nutritional requirements of Rongchang sows during late gestation and lactation through comprehensive evaluation methods, and to construct a comprehensive evaluation method based on the measured index data to scientifically determine the nutritional requirements of sows. Based on the experimental data from the previous research on the effects of different dietary net energy (NE) and standard ileal digestible lysine (SID Lys) levels on the reproductive performance of Rongchang sows during late gestation and lactation, the entropy weight method and the analytic hierarchy process were applied to determine the weights of indicators. The technique for order preference by similarity to an ideal solution (TOPSIS) method and grey relational degree analysis were utilized to construct comprehensive evaluation index. The nutrient requirements of sows were identified based on the above methods. The results showed as follows: 1) different dietary NE and SID Lys levels had significant effects on different reproductive performance indicators of Rongchang sows during late gestation and lactation. 2) Through the entropy weight method, it was discovered that the variation coefficient of backfat increase data was the largest, while the variation coefficients of the remaining indicators were relatively small during late gestation. Moreover, the variation coefficients of all indicators were similar, and the entropy weights were also comparable during lactation. 3) By combining the weight methods of the analytic hierarchy process and the entropy weight method and conducting a comprehensive evaluation using the TOPSIS method, it was found that when the NE level was 10.04 MJ/kg and the SID Lys level was 0.52% for Rongchang sows during late gestation, the best reproductive performance could be achieved. In addition, when the NE level was 10.21 MJ/kg and the SID Lys level was 0.85% for Rongchang sows during lactating, the best reproductive performance could be achieved. 4) Taking the comprehensive evaluation score as the reference sequence and conducting grey relational degree analysis on different indicators, it was found that the piglet weight at birth and the live litter size had a higher correlation with the reference sequence and made a greater contribution to the comprehensive evaluation score, while the average daily gain and backfat increase had a relatively lower correlation with the reference sequence during late gestation. Moreover, during lactating, except for the pre-weaning mortality, which had a lower correlation with the reference sequence, the relational degrees of the remaining indicators exceeded 0.8, indicating a relatively high correlation. In conclusion, the optimal dietary nutritional levels for Rongchang sows are defined as 10.04 MJ/kg NE and 0.52% SID Lys during late gestation and 10.21 MJ/kg NE and 0.85% SID Lys during lactation. The comprehensive evaluation method developed in this study can be used to determine the nutrient requirements of Rongchang sows during late gestation and lactation, and can draw more accurate conclusions than traditional method considering the existing of more indicators.

This experiment was conducted to study the effects of Enteromorpha prolifera polysaccharides-calcium (EPP-Ca) on growth performance, serum biochemical indexes and slaughter performance of yellow-feathered broilers. A total of 360 one-day-old yellow-feathered male broilers with similar body weight [(29.60±0.02) g] and good health were randomly divided into 4 groups: control group, Enteromorpha prolifera polysaccharides (EPP) group, LEPP-Ca group, HEPP-Ca group, with 6 replicates in each group and 15 broilers in each replicate. The control group was fed a corn-soybean meal basal diet, and the diets of EPP group, LEPP-Ca group and HEPP-Ca group were supplemented with 200 mg/kg EPP, 200mg/kg EPP-Ca and 400 mg/kg EPP-Ca on the basis of the basal diet, respectively. The experiment lasted for 70 days. The results showed as follows: 1) during the whole experiment, the average daily feed intake of HEPP-Ca group was significantly lower than that of the other three groups (P<0.05); the average daily gain of LEPP-Ca group was significantly higher than that of the other three groups (P<0.05). Compared with the control group, the feed-to-gain ratio of the EPP group, LEPP-Ca group and HEPP-Ca group was significantly decreased (P<0.05). 2) On the 28th day of the experiment, the total protein (TP) content in serum of LEPP-Ca group was significantly higher than that of EPP group and HEPP-Ca group (P<0.05); on the 70th day of the experiment, compared with the control group, the serum alanine transaminase (ALT) activity of the HEPP-Ca group was significantly increased (P<0.05). 3) The breast muscle rate of LEPP-Ca group was significantly higher than that of EPP group and HEPP-Ca group (P<0.05), and the abdominal fat rate was significantly lower than that of control group and EPP group (P<0.05). 4) Compared with the control group, the heart index of EPP group, LEPP-Ca group and HEPP-Ca group increased significantly (P<0.05), and the liver index of HEPP-Ca group decreased significantly (P<0.05). The spleen index of LEPP-Ca group was significantly higher than that of control group, EPP group and HEPP-Ca group (P<0.05). In summary, the addition of 200 mg/kg EPP-Ca to the diet can improve the growth performance of yellow-feathered broilers, increase the chest muscle rate, promote the body’s metabolism of protein and the growth and development of immune organs, and thus improve the body’s immunity.

This study was conducted to analyze the contents of chemical components in wheat from different sources, and evaluate the apparent ileal digestibilities (AID) and standardized ileal digestibilities (SID) of amino acids in wheat for medium-growing yellow-feathered broilers, as well as establish their predicting equations based on their contents of chemical components. Two hundred and seventy-six healthy 63-day-old medium-growing yellow-feathered broilers were used in a one-way completely randomized design, included 1 nitrogen-free diet group and 10 wheat diet groups, with six replicates per group. There were 6 chickens per replicate in the nitrogen-free diet group, and there were 4 chickens per replicate in the wheat diet groups. The experimental period was 5 days. At 67 days of age, the ileal digesta was collected. The amino acid contents in ingredients, diets and ileal digesta, as well as the titanium dioxide (TiO2) content in diets and ileal digesta were determined, and then both AID and SID of amino acids were calculated. The results showed as follows: 1) the means of gross energy (GE), dry matter (DM), crude protein (CP), ether extract (EE), crude ash (Ash), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), phytic acid (PA) and nitrogen-free extract (NFE) of 10 wheats were 14.32 MJ/kg, 88.42%, 12.66%, 1.49%, 1.46%, 2.03%, 11.16%, 2.78%, 0.58% and 70.78%, respectively. Additionally, the mean contents of 18 amino acids in wheat ranged from 0.12% to 4.20%. 2) The means of AID and SID of 18 amino acids of wheat from different sources in medium-growing yellow-feathered broilers ranged from 58.6% to 89.7% and 75.8% to 94.1%, respectively, glutamic acid exhibited the highest AID and SID. wheat from different sources significantly affected the AID of 18 amino acids and the SID of 17 amino acids (P<0.05), but not affected the SID of serine (P>0.05). 3) In this study, 18 predicting equations of amino acids SID of wheat for medium-growing yellow-feathered broilers were established. Excepted the predicted values of leucine, isoleucine and histidine SID, the predicted values of SID of other 15 amino acids in the checked wheat sample fell within the ranges of the measured value±standard deviation of corresponding amino acids SID, and most equations had coefficients of determination (R²) greater than 0.8, indicating their good predicting responses. It is concluded that the contents of chemical components and amino acids AID and SID of wheat from different sources exist difference, and the established predicting equations can serve as a valuable reference for quickly predicting the SID of amino acids of wheat for medium-growing yellow-feathered broilers in the future.

This experiment aimed to investigate the effects of hydroxytyrosol (HT) and paeoniflorin (PF) on growth performance, intestinal morphology and antioxidant capacity of broilers. A total of 240 one-day-old Arbor Acres Plus (AA⁺) broilers were randomly divided into 4 groups (6 replicates per group, and 10 birds per replicate): broilers in control group (CON group) were fed a basal diet, broilers in HT group were fed a test diet supplemented with 500 mg/kg HT based on the basal diet, broilers in PF group were a test diet supplemented with 500 mg/kg PF based on the basal diet, and broilers in HT+PF group were fed a test diet supplemented with 500 mg/kg HT and 500 mg/kg PF based on the basal diet. The trial lasted for 35 days. The results showed as follows: 1) compared with the CON group, the average body weight at 21 and 35 days of age and average daily gain from 1 to 21 days of age and 1 to 35 days s of age in the HT group were significantly increased (P<0.05). 2) Dietary supplementation with HT significantly increased the thymus index of broilers (P<0.05). 3) Dietary supplementation with PF significantly reduced plasma creatinine content (P<0.05); the activity of alkaline phosphatase in plasma was significantly decreased in the HT, PF and HT+PF groups compared with the CON group (P<0.05). 4) Dietary supplementation with HT significantly decreased the crypt depth of the duodenum, jejunum and ileum (P<0.05), and significantly increased the villus height to crypt depth ratio (P<0.05); dietary supplementation with PF significantly increased the villus height of the duodenum and ileum (P<0.05), significantly decreased the crypt depth in the duodenum, jejunum and ileum (P<0.05), and significantly increased the villus height to crypt depth ratio (P<0.05); compared with the CON group, the HT+PF group showed significantly lower crypt depth of the duodenum, jejunum and ileum (P<0.05), and showed significantly higher villus height to crypt depth ratio of the jejunum and ileum (P<0.05). 5) Dietary supplementation with HT significantly increased the hydrogen peroxide (H₂O₂) content in the jejunum (P<0.05), significantly decreased the serum catalase (CAT) activity and liver glutathione peroxidase (GSH-Px) activity, as well as breast muscle H₂O₂ and malondialdehyde (MDA) contents (P<0.05); dietary supplementation with PF significantly increased the CAT activity in the breast muscle (P<0.05), significantly decreased the CAT and GSH-Px activities in the serum, the MDA content in the liver and jejunum, and the H₂O₂ content in the jejunum and breast muscle (P<0.05); compared with the CON group, the CAT activity in the breast muscle in the HT+PF group were significantly increased (P<0.05), while the CAT activity in the serum and the MDA content in the liver and breast muscle were significantly decreased (P<0.05). In conclusion, dietary supplementation with HT alone can improve the growth performance of broilers, while the combined addition of HT and PF can synergistically enhance the intestinal morphology and antioxidant capacity of broilers.

This study aimed to evaluate the effects of thymol on growth performance of broilers and its mechanism. A total of 200 one-day-old 817 broilers were randomly assigned into 4 groups with 5 replicates per group and 10 broilers per replicate. Broilers in the control group (group C) were fed a basal diet, and the others in experimental groups were fed the basal diet supplemented with 100 (group T1), 200 (group T2) and 300 mg/kg (group T3) thymol, respectively. The experiment lasted for 42 days, which was divided into two phases: 1 to 21 days of age and 22 to 42 days of age. The results showed as follows: 1) during 1 to 42 days of age, the feed to gain ratio of group T2 was significantly lower than that of group C and group T1 (P<0.05). 2) At 21 days of age, the serum aspartate aminotransferase (AST) activity of group T1, group T2 and group T3 was significantly lower than that of group C (P<0.05). At 42 days of age, the serum alkaline phosphatase (ALP) activity of group T1 was significantly lower than that of group C and group T3 (P<0.05). 3) At 21 days of age, the serum malondialdehyde (MDA) content of group T2 and group T3 was significantly lower than that of group C (P<0.05), and the serum immunoglobulin M (IgM) content of group T2 and group T3 was significantly higher than that of group C (P<0.05). At 42 days of age, the serum the serum MDA content of group T2 and group T3 was significantly lower than that of group C (P<0.05), and the serum glutathione peroxidase (GSH-Px) activity and IgM content of group T2 were significantly higher than those of group C (P<0.05). 4) At 21 days of age, the serum Newcastle disease virus (NDV) antibody titer of group T1, group T2 and group T3 was significantly higher than that of group C (P<0.05). 5) At 42 days of age, the jejunal villus height of group T2 and group T3 was significantly higher than that of group C (P<0.05). 6) At 21 days of age, the mRNA relative expression level of nuclear factor erythroid 2-related factor 2 (Nrf2) in jejunum of group T1 and group T2 was significantly higher than that of group C (P<0.05). At 42 days of age, the mRNA relative expression level of Kelch-like ECH-associated protein 1 (Keap1) in jejunum of group T1 was significantly lower than that of group C (P<0.05). In conclusion, dietary thymol can improve the antioxidant capacity and immune function of broilers, promote intestinal morphology, maintain flock health, and thus improve their growth performance. In addition, thymol may improve the antioxidant capacity of broilers by activating p62-Nrf2-Keap1 signaling pathway. Under the experimental conditions, when dietary thymol supplemental level is 200 mg/kg, the feeding effect is the best.

This experiment was conducted to explore the effects of dietary water extract of vine tea (Ampelopsis grossedentata) on performance, egg quality, serum biochemical indices and intestinal morphology of laying hens during later laying period. A total of 288 healthy Jingfen laying hens of 55-week-old with similar laying rate were selected and randomly divided into 4 groups with 8 replicates in each group and 9 hens in each replicate. Hens in the control group were fed a basal diet, while those in the experimental groups were fed the basal diet supplemented with 25, 50 and 75 mg/kg water extract of vine tea, respectively. The pre-test period was 5 days and the formal test period was 56 days. The results showed as follows: 1) compared with the control group, dietary 25, 50 and 75 mg/kg water extract of vine tea could significantly reduce the average daily feed intake of laying hens (P<0.05), dietary 50 mg/kg water extract of vine tea tended to reduce the feed-to-egg ratio (P=0.079), and dietary 75 mg/kg water extract of vine tea tended to reduce the defective egg rate (P=0.087); 2) compared with the control group, dietary 75 mg/kg water extract of vine tea significantly reduced the egg yolk color (P<0.05), and dietary 50 and 75 mg/kg water extract of vine tea significantly reduced the egg yolk ratio (P<0.05); 3) compared with the control group, dietary water extract of vine tea had no significant effect on serum biochemical indices of laying hens (P>0.05); 4) compared with the control group, dietary 50 mg/kg water extract of vine tea significantly reduced the serum tumor necrosis factor-α content of laying hens (P<0.05); 5) compared with the control group, dietary 75 mg/kg water extract of vine tea significantly increased the villus height in duodenum of laying hens (P<0.05), and significantly reduced the crypt depth in jejunum (P<0.05). In conclusion, adding an appropriate amount of water extract of vine tea to the diet of Jingfen laying hens can improve their performance, reduce the occurrence of inflammation and improve intestinal morphology. The suitable addition amounts of water extract of vine tea are 50 and 75 mg/kg.

This experiment was conducted to evaluate the nutritional values of Zanthoxylum bungeanum leaves in diet for laying hens and to explore the effects of different dietary Zanthoxylum bungeanum leaf supplemental levels on performance, egg quality, serum biochemical indices, antioxidant function and cecal microbiota of laying hens. In experiment 1, the apparent metabolizable energy of Zanthoxylum bungeanum leaves was determined by the indicator method. A total of 96 healthy 38-week-old Lohmann pink laying hens with similar body weight were selected and randomly divided into 2 groups with 8 replicates in each group and 6 hens in each replicate. Hens in the control group were fed a corn-soybean meal type basal diet, while those in the experimental group were fed an experimental diet supplemented with 5% Zanthoxylum bungeanum leaves in the basal diet. The pre-test period was 7 days and the formal test period was 3 days. In experiment 2, a total of 288 healthy 58-week-old Lohmann pink laying hens were selected and randomly divided into 4 groups with 8 replicates in each group and 9 hens in each replicate. Hens in each group were fed diets supplemented with 0 (control), 1%, 2% and 3% Zanthoxylum bungeanum leaves in the basal diet, respectively. The pre-test period was 2 weeks and the formal test period was 8 weeks. The results showed as follows: 1) the apparent metabolizable energy of Zanthoxylum bungeanum leaves in diet for laying hens was 5.32 MJ/kg, and the nitrogen-corrected apparent metabolizable energy was 5.21 MJ/kg. 2) Compared with the control group, the dietary supplementation of 2% and 3% Zanthoxylum bungeanum leaves significantly decreased the soft-shell egg rate from weeks 5 to 8 and weeks 1 to 8 (P<0.05), and the dietary supplementation of 2% Zanthoxylum bungeanum leaves significantly increased the average egg weight from weeks 1 to 4, weeks 5 to 8, and weeks 1 to 8 (P<0.05). 3) Compared with the control group, the dietary supplementation of 3% Zanthoxylum bungeanum leaves significantly increased the egg yolk color at weeks 4 and 8 (P<0.05), and the egg yolk color was increased linearly with the increase of Zanthoxylum bungeanum leaf supplemental level (P<0.05). 4) Compared with the control group, the different dietary Zanthoxylum bungeanum leaf supplemental levels significantly increased the villus height in duodenum of laying hens (P<0.05), and the villus height in duodenum showed linear and quadratic changes with the increase of Zanthoxylum bungeanum leaf supplemental level (P<0.05). 5) With the increase of Zanthoxylum bungeanum leaf supplemental level, the total antioxidant capacity (T-AOC), malondialdehyde (MDA) content and total superoxide dismutase (T-SOD) activity in serum of laying hens were changed linearly (P<0.05), and the T-AOC and catalase (CAT) activity in liver was increased linearly (P<0.05). Compared with the control group, the dietary supplementation of 3% Zanthoxylum bungeanum leaves significantly increased the T-AOC in egg yolk (P<0.05), and the T-AOC in egg yolk was increased linearly with the increase of Zanthoxylum bungeanum leaf supplemental level (P<0.05); the dietary supplementation of Zanthoxylum bungeanum leaves had no significant effects on serum biochemical and immune indices (P>0.05). 6) At the genus level, compared with the control group, the Christensenellaceae_R-7_group relative abundance in cecum of laying hens in 3% Zanthoxylum bungeanum leaf supplemental group was significantly decreased (P<0.05), and the GCA-900066575 relative abundance in cecum was significantly increased (P<0.05). In conclusion, the dietary supplementation of 3% Zanthoxylum bungeanum leaves can reduce the soft-shell egg rate, enhance the egg yolk color and antioxidant function, and improve the intestinal morphology.

This experiment aimed to investigate the bone-protective effect and mechanism of Epimedium extract in laying hens during late laying period. A total of 180 healthy 60-week-old Hy-Line Brown laying hens with similar egg production rates were selected and randomly divided into 2 groups, each containing 6 replicates of 15 hens. The pre-feeding period lasted one week, while the trial period lasted 15 weeks. The control group was fed a basal diet, whereas the Epimedium extract group was fed the basal diet supplemented with 200 mg/kg Epimedium extract. The results showed that: compared with the control group, 1) the hens in the Epimedium extract group significantly increased the laying rate at 62 to 65 weeks of age (P<0.05) and significantly decreased the feed-to-egg ratio at 66 to 69 weeks of age and 70 to 76 weeks of age (P<0.05); 2) at 76 weeks of age, the eggs in the Epimedium extract group exhibited a tendency to increase eggshell thickness (P=0.097) and significantly increased albumen height and Haugh unit at 69 and 76 weeks of age (P<0.05); 3) at 76 weeks of age, the hens in the Epimedium extract group significantly decreased the serum osteocalcin (BGP) content and tartrate-resistant acid phosphatase(TRAP) activity (P<0.05); 4) at 69 weeks of age, the hens in the Epimedium extract group significantly increased the femur index (P<0.05); 5) at 76 weeks of age, the hens in the Epimedium extract group tended to increase tibia strength (P=0.085); 6) at 76 weeks of age, the hens in the Epimedium extract group significantly increased femur bone mineral density and bone mineral content (P<0.05); 7) at 76 weeks of age, the addition of 200 mg/kg Epimedium extract to the diet improved the microstructure of bone tissue; 8) the addition of 200 mg/kg Epimedium extract to the diet up-regulated the relative mRNA expression of osteoprotegerin (OPG), runt-related transcription factor 2 (RUNX2), bone morphogenetic protein 2 (BMP2) and SMAD family member 4 (Smad4) in the bone tissue (P<0.05). Overall, these results indicate that the dietary supplementation with 200 mg/kg Epimedium extract increases the laying rate during the late laying period, reduces the feed-to-egg ratio, enhances egg quality by increasing albumen height and Haugh unit, decreases bone turnover, promotes osteoblast differentiation, improves bone density and bone microstructure, and exerts a protective effect on bones.

This experiment was conducted to study the effects of dietary non-phytate phosphorus (NPP) levels on performance, egg quality, serum biochemical indices, tibia indices and phosphorus apparent digestibility of laying hens aged from 20 to 62 weeks. A total of 420 healthy 20-week-old Hy-Line Brown laying hens with similar body weight were randomly divided into 5 groups with 6 replicates per group and 14 hens per replicate. Dietary NPP levels in 5 groups were 0.10%, 0.12%, 0.14%, 0.16% and 0.18%, respectively, and 1 000 FTU/kg high-efficiency phytase was supplemented in all diets. The pre-experimental period lasted for 1 week, and the experimental period lasted for 42 weeks. The results showed as follows: 1) there were no significant differences in performance among all groups (P>0.05). 2) At 44, 52 and 60 weeks of age, the eggshell thickness of 0.10% NPP group was significantly lower than that of 0.18% NPP group (P<0.05); there were no significant differences in albumen height, Haugh unit, eggshell strength and eggshell color among all groups (P>0.05). 3) There were no significant differences in the contents of calcium, phosphorus, calcitonin, parathyroid hormone and 1,25-dihydroxyvitamin D₃ and the activity of alkaline phosphatase (ALP) in serum of laying hens among all groups (P>0.05). 4) The tibia ash content of 0.10% NPP group was significantly lower than that of other groups (P<0.05), the tibia calcium content was significantly lower than that of 0.12%, 0.14% and 0.18% NPP groups (P<0.05), and tibia phosphorus content was significantly lower than that of 0.12% and 0.14% NPP groups (P<0.05); there were no significant differences in tibia defatted dry weight and tibia strength among all groups (P>0.05). 5) The phosphorus intake and excretion of 0.14%, 0.16% and 0.18% NPP groups were significantly higher than that of 0.10% group (P<0.05); there were no significant differences in apparent digestibility of calcium and phosphorus among all groups (P>0.05). In conclusion, under the condition of adding 1 000 FTU/kg high-efficiency phytase, reducing dietary NPP level has no significant effect on performance and serum biochemical indices of laying hens aged from 20 to 62 weeks, however, it has significant effects on eggshell thickness, tibia quality and phosphorus excretion. Considering performance, egg quality, tibia quality and phosphorus excretion of laying hens, when diet adding 1 000 FTU/kg high-efficiency phytase, it is recommended that the NPP supplemental level is 0.02% in corn-soybean meal-based diet for laying hens aged from 20 to 62 weeks (dietary NPP level is 0.12%).

This experiment aimed to study the dietary metabolic energy and crude protein requirements of Qingyuan partridge chickens aged from 31 to 60 days, providing a basis for precise breeding of Qingyuan partridge chickens. The experiment adopted a 3×3 experimental design, with three metabolic energy levels of high (12.98 MJ/kg), medium (12.56 MJ/kg) and low (12.14 MJ/kg), and three crude protein levels of high (18.5%), medium (17.5%) and low (16.5%). A total of 9 kinds of experimental diets were prepared. A total of 2 160 healthy 31-day-old Qingyuan partridge hens were selected and randomly divided into 9 groups according to the principle of consistent body weight, with 6 replicates in each group and 40 hens in each replicate. The test period was 30 days. The results showed as follows: 1) dietary metabolic energy level had significant effects on the final body weight, average daily gain and feed/gain ratio (P<0.05). The average daily gain in the high metabolic energy group was significantly higher than that in the medium and low metabolic energy groups (P<0.05), while the feed/gain ratio was significantly lower than that in the medium and low metabolic energy groups (P<0.05). Dietary crude protein level had no significant effects on the final body weight, average daily feed intake, average daily gain and feed/gain ratio (P>0.05). Dietary metabolic energy level had a significant effect on the content of high-density lipoprotein cholesterol in serum (P<0.05), which was manifested as the high metabolic energy group being significantly higher than the medium and low metabolic energy groups (P<0.05). Dietary crude protein level had a significant effect on the albumin content in serum (P<0.05), which was manifested as the low crude protein group being significantly higher than the medium crude protein group (P<0.05). Dietary metabolic energy and crude protein levels had significant interactions on the contents of high-density lipoprotein cholesterol and urea nitrogen in serum (P<0.05). 3) Dietary metabolic energy and crude protein levels had no significant effects on the contents of crude protein and crude fat in the chest muscle, as well as the gross energy, crude protein and crude fat contents in the empty body (P>0.05). 4) Dietary metabolic energy and crude protein levels had significant effects on both energy and protein deposition rates, and there was a significant interaction between the two (P<0.05). Among them, the energy and protein deposition rates of the high metabolic energy and high crude protein group were significantly higher than those of the other groups (P<0.05). Under the conditions of this experiment, the models of daily metabolic energy and crude protein requirements of Qingyuan partridge chickens aged from 31 to 60 days established on the basis of experimental data are ME_i=3.693 7×BW^0.75+12.165 6×ADG and CP_i=0.021 8×BW^0.75+0.347 4×ADG (ME_i represented daily metabolic energy requirement; CP_i represented daily crude protein requirement; BW^0.75 represented metabolic body weight; ADG represented average daily weight gain). According to the above models and dry matter intake, the dietary metabolic energy and crude protein requirements of Qingyuan partridge chickens aged from 31 to 60 days are 12.49 MJ/kg and 16.65%, respectively.

This experiment was conducted to investigate the effects of different dietary metabolic energy (ME) and crude protein (CP) levels on growth performance, slaughter performance and serum biochemical indices of Qingyuan partridge chickens during 91 to 120 days of age, and to determine the dietary appropriate ME and CP levels for Qingyuan partridge chickens aged 91 to 120 days. A 3×3 two-factor completely randomized trial design was used in this experiment, and three ME levels [high (13.21 MJ/kg), medium (12.70 MJ/kg) and low (12.19 MJ/kg)] and three CP levels [high (15.50%), medium (14.50%) and low (13.50%)] were set up to prepare nine experimental diets. A total of 2 160 healthy 91-day-old Qingyuan partridge chickens were randomly divided into 9 groups with 6 replicates per group and 40 chickens per replicate. The experiment lasted for 30 days. The results showed as follows: 1) the final body weight of high energy group was significantly higher than that of medium energy group (P<0.05), and the ratio of feed to gain of high energy group was significantly lower than that of medium energy group and low energy group (P<0.05). The average daily feed intake of low energy group was significantly higher than that of medium energy group and high energy group (P<0.05). The average daily feed intake of low protein group was significantly higher than that of medium protein group and high protein group (P<0.05), and the ratio of feed to gain of high protein group was significantly lower than that of medium protein group and low protein group (P<0.05). 2) Dietary ME level significantly affected the abdominal fat percentage (P<0.05). The abdominal fat percentage was increased with dietary ME level increasing, and the high energy group was significantly higher than the low energy group and medium energy group (P<0.05). 3) The interaction effect between dietary ME and CP levels had significant effects on the contents of total protein and albumin in serum (P<0.05), and the dietary ME level also significantly affected the serum total protein content (P<0.05). The serum total protein content of medium energy group was significantly lower than that of high energy group and low energy group (P<0.05). Under this experimental condition, the ME and CP requirement models for Qingyuan partridge chickens aged 91 to 120 days are established based on experimental data as ME_i=3.435 2×BW^0.75+18.027×ADG and CP_i=0.042 6×BW^0.75+0.120 7×ADG (ME_i represents ME requirement; CP_i represents CP requirement; BW^0.75 represents metabolic body weight; ADG represents average daily gain). Using these models, the appropriate levels of dietary ME and CP for Qingyuan partridge chickens aged 91 to 120 days are determined to be 12.75 MJ/kg and 14.25%, respectively.

This experiment was conducted to explore the effects of dietary compound plant extract on growth performance, serum biochemical indices and intestinal health of Xiaoshan chickens. A total of 384 healthy 100-day-old Xiaoshan chickens (female) with similar body weight were selected and randomly divided into 4 groups, with 8 replicates in each group and 12 chickens in each replicate. Chickens in the control group (BC group) were fed a basal diet, while those in the experimental groups were fed the basal diets supplemented with 200 (CPE200 group), 400 (CPE400 group) and 600 mg/kg (CPE600 group) compound plant extract (the active ingredients were cinnamaldehyde and thymol), respectively. The pre-test period was 5 days and the formal test period was 60 days. The results showed as follows: 1) compared with BC group, the body weight at 120 and 135 days of age in CPE400 group was significantly increased (P<0.05), the average daily gain from 105 to 120 days of age and the average daily feed intake from 105 to 150 days of age were significantly increased (P<0.05), and the feed to gain ratio from 105 to 120 days of age was significantly decreased (P<0.05). 2) Compared with BC group, the contents of serum interleukin-1β (IL-1β), interleukin-2 (IL-2), interleukin-6 (IL-6), interferon-γ and tumor necrosis factor-α (TNF-α) in the experimental groups were significantly increased (P<0.05), and the contents of serum interleukin-10 (IL-10) and globulin were significantly decreased (P<0.05). 3) Compared with BC group, the villus height in jejunum in CPE400 group was significantly increased (P<0.05), and the crypt depth in jejunum in CPE600 group was significantly increased (P<0.05). 4) Compared with BC group, the contents of IL-1β, IL-2, IL-6 and TNF-α in ileum in the experimental groups were significantly increased (P<0.05), and the IL-10 content in ileum was significantly decreased (P<0.05). 5) Compared with BC group, the activities of superoxide dismutase and catalase in ileum in the experimental groups were significantly decreased (P<0.05), and the malondialdehyde content in ileum was significantly increased (P<0.05); the total antioxidant capacity in ileum in CPE400 group and CPE600 group was significantly decreased (P<0.05); the glutathione peroxidase activity in ileum in CPE200 group and CPE600 group was significantly decreased (P<0.05). 6) There was no significant difference in the relative abundance of cecal microbiota at phylum and genus levels between BC group and CPE400 group (P>0.05). At the species level, the relative abundances of Faecousia intestinavium and Blautia merdipullorum in ileum in CPE400 group was significantly higher than those in BC group (P<0.05). In conclusion, dietary 400 mg/kg compound plant extract can enhance the growth performance of Xiaoshan chickens, improve the intestinal morphological structure, and adjust the cecal microbiota. However, there are also certain potential risks.

This experiment aimed to investigate the effects of dietary crude protein level on the reproduction performance and nutrient apparent availability of breeder pigeons, and the growth performance, slaughtering performance, serum biochemical indexes of squabs under the “2+3” production mode. One hundred and twenty pairs of 4-year-old healthy silver king pigeons with similar egg laying time and interval were selected and randomly divided into 5 groups, with 8 replicates in each group and 3 pairs of breeder pigeons in each replicate. The experimental diets were prepared using the mode of “granular+grain+health sand”, and crude protein levels in the diets for groups Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ and Ⅵ were 14.50%, 15.00%, 15.50%, 16.00%, and 16.50%, respectively. The pretrial period lasted 14 days. Two reproductive cycles were stated in trial period. The first cycle included empty nest period, 18-day incubation period and 28-day feeding period, and the second cycle included 18-day incubation period and 28-day feeding period. The results showed as follows: 1) the broken rate in the first cycle of groups Ⅳ and Ⅴ was significantly lower then that of groups Ⅱ and Ⅲ (P<0.05), the fertility rate of breeding egg in the first cycle of groups Ⅲ and Ⅳ was significantly higher than that of groups Ⅱ (P<0.05), the hatchability of setting eggs in the first cycle of group Ⅲ was significantly higher than that of group Ⅴ (P<0.05), and the hatchability of setting eggs in the second cycle of groups Ⅱ, Ⅳ and Ⅴ was significantly higher than that of group Ⅰ (P<0.05). 2) The crude protein apparent availability of breeder pigeons of group Ⅲ was significantly higher than that of groups Ⅰ, Ⅳ andⅤ (P<0.05). 3) The 28-day-old weight and average daily gain (ADG) of squabs in the first cycle of groups Ⅲ and Ⅴ were significantly higher than those of group Ⅱ (P<0.05), the 28-day-old weight and average daily gain (ADG) of squabs in the second cycle of groups Ⅲ, Ⅳand Ⅴ were significantly higher than those of group Ⅰ (P<0.05), and the net feed conversion ratio (NFCR) in the first cycle, the second cycle and the full cycle of group Ⅲ was significantly lower than that of group Ⅰ (P<0.05). 4) The semi-eviscerated percentage and eviscerated percentage of group Ⅳ were significantly higher than those of groups Ⅰ and Ⅱ (P<0.05), and the breast muscle percentage of group Ⅴ was significantly higher than that of the group Ⅰ and Ⅱ (P<0.05). 5) The serum total protein (TP) content of group Ⅳ and Ⅴ was extremely significantly higher than that of groups Ⅰ and Ⅱ (P<0.01), the serum globulin (GLB) content of group Ⅴ was significantly higher than that of groups Ⅰ and Ⅱ (P<0.05), the serum uric acid (UA) content of groups Ⅲ, Ⅳ and Ⅴ was significantly higher than that of group Ⅰ (P<0.05), the serum glucose (GLU) content of groups Ⅲ and Ⅳ were significantly higher than that of group Ⅰ (P<0.05), and the serum total cholesterol (T-CHO) content of groups Ⅳ and Ⅴ was significantly higher than that of group Ⅰ (P<0.05). 5) There was a quadratic relationship between the fertility of breeder eggs, hatchability of setting eggs, crude protein apparent availability of breeder pigeons, and NFCR and eviscerated percentage of squabs in the first cycle and dietary crude protein level of breeder pigeons (P<0.05), the suitable dietary crude protein levels of breeder pigeons estimated by fitting equations to achieve maximum fertility rate of breeding eggs in the first cycle, maximum hatchability of setting eggs in the first cycle, maximum crude protein apparent availability, minimum NFCR of feeding period in the first cycle, minimum NFCR of feeding period in the second cycle, minimum NFCR in the full cycle and maximum eviscerated percentage were 15.64%, 15.51%, 15.41%, 15.63%, 15.81%, 15.95%, and 15.65%, respectively. In summary, the dietary crude protein level for breeding pigeons significantly affects the fertility rate of breeding eggs, hatchability of setting eggs, apparent availability of crude protein of breeding pigeons, as well as the NFCR, semi-eviscerated percentage, eviscerated percentage, breast muscle percentage, and certain serum biochemical indexes of squabs. Combined with the results of quadratic curve regression analysis, it is recommended that the dietary crude protein level of breeding pigeons under the “2+3” production mode range from 15.50% to 16.00%.

The study evaluated the effects of coated folic acid (CFA) and palm fat powder (PFP) on lactation performance, blood indices and liver lipid metabolism of perinatal dairy cows. Thirty-two Holstein cows with similar parity, body weight, milk yield during the previous lactation and expected delivery date were assigned in a randomized block design to 4 groups with 8 cows in each group. Cows in the control group (CON group) were fed a basal diet, and those in CFA group, PFP group and CFA+PFP group were fed the basal diet supplemented with 6.75 g/d CFA, 500 g/d PFP and 6.75 g/d CFA+500 g/d PFP, respectively. The experiment period was from 42 days of prepartum to 21 days of postpartum. The results showed as follows: 1) compared with CON group, the body weight change (BWC, increased) of cows in prepartum, yields of actual milk, 4% fat-corrected milk (FCM), milk fat and milk protein, as well as milk total 4 to 15 carbon fatty acid content and feed efficiency (FE) were significantly greater after CFA supplementation (P<0.05); the serum contents of non-esterified fatty acid (NEFA) and β-hydroxybutyric acid (BHBA) in both prepartum and postpartum and the liver contents of total lipid and triglyceride (TG) in postpartum were significantly lower (P<0.05). 2) Compared with CON group, the BWC (increased) of cows in prepartum, yields of actual milk, 4% FCM and milk fat, as well as total 16 carbon fatty acid content and FE were significantly greater after PFP supplementation (P<0.05). 3) The interaction between CFA and PFP was not significant on BWC, lactation performance, blood indices and liver lipid content (P>0.05). 4) The results of transcriptome sequencing of liver tissues on day 21 of postpartum showed that the expressions of fatty acid synthase (FASN), stearoyl-CoA desaturase 1 (SCD1) and sterol regulatory element-binding protein-1c (SREBP-1c) of cows in CFA group were significantly greater compared with CON control (P<0.05), and the expressions of retinoid X receptor gamma (RXRγ), fatty acid translocase (CD36), apolipoprotein A1 (APOA1), 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) and adiponectin receptor 2 (ADIPOR2) were significantly lower (P<0.05); the FASN expression in PFP group was significantly greater compared with CON control (P<0.05), and the expressions of RXRγ, long-chain acyl-CoA synthetase 4 (ACSL4) and CD36 were significantly lower (P<0.05); the expressions of FASN, CD36 and SCD1 in CFA+PFP group were significantly greater compared with CON control (P<0.05), and the expressions RXRγ, APOA1 and glycerol kinase (GK) were significantly lower (P<0.05). In conclusion, the supplementation of CFA or PFP can improve the lactation performance of perinatal dairy cows, and the supplementation of CFA can decrease the liver lipid content; the regulation of CFA on liver lipid metabolism is via AMPK signaling pathway and CD36, and PFP is via PPAR signaling pathway and ACSL1 and CD36; however, the supplementation of CFA and PFP together is not recommended.

The purpose of this study was to investigate the maintenance protein requirement of Yunshang black goats during pregnancy. Fifty female Yunshang black goats with 2 litters and 45 days of pregnancy were randomly divided into 5 groups with 10 replicates in each group and 1 goat per replicate. The experimental period consisted of the pre- (60 to 90 days), mid- (91 to 120 days) and late-pregnancy (121 to 150 days) 3 periods for a total of 90 days. The dietary crude protein (CP) levels in 5 groups during different periods were: pre-pregnancy, 6.35%, 8.35%, 10.35%, 12.35% and 14.35%; mid-pregnancy, 7.85%, 9.85%, 11.85%, 13.85% and 15.85%; late-pregnancy, 9.35%, 11.35%, 13.35%, 15.35% and 17.35%. The digestive and metabolic tests were carried out on the 73 to 77 days, 113 to 117 days and 133 to 137 days of pregnancy. The results showed as follows: 1) with the dietary CP level increased, the dry matter intake (DMI) and average daily gain (ADG) of Yunshang black goats during pre-, mid-, late- and whole pregnancy were linearly significantly increased (P<0.05), and the feed to gain ratio (F/G) was linearly significantly decreased (P<0.05). 2) With the dietary CP level increased, the nitrogen intake (NI), fecal nitrogen, urinary nitrogen, digestible nitrogen, apparent digestibility of nitrogen, nitrogen nitrogen retention (NR) and biological value of nitrogen were linearly significantly increased (P<0.05). 3) The regression relationship between NI and NR of metabolic body weight of Yunshang black goats during pre-, mid- and late-pregnancy were NR=0.600 9×NI-0.286 3 (R²=0.992 2), NR=0.648 7×NI-0.334 3 (R²=0.998 9), NR=0.735 2×NI-0.414 5 (R²=0.996 7), respectively. In conclusion, with the dietary CP level increased, the protein digestion and metabolism ability of Yunshang black goats during pregnancy is improved; the maintenance net nitrogen requirements during pre-, mid- and late-pregnancy are 0.29, 0.33 and 0.41 g/(kg W^0.75·d), respectively, and the maintenance crude protein requirements are 1.79, 2.09 and 2.59 g/(kg W^0.75·d), respectively.

The purpose of this study was to investigate the energy requirement of Yunshang black goats during pregnancy. Fifty Yunshang black goats with similar body weight [(61.75±0.57) kg] and double pregnant lambs were randomly divided into 5 groups with 10 replicates in each group and 1 goat per replicate. The dietary metabolizable energy (ME) in 5 groups (groups 1 to 5) during pre-pregnancy (pregnancy 61 to 90 days) were 7.73, 8.13, 8.53, 8.93, 9.35 MJ/kg, the dietary ME during mid-pregnancy (pregnancy 91 to 120 days) were 7.62, 8.10, 8.61, 9.10, 9.60 MJ/kg, and the dietary ME during late-pregnancy (pregnancy 121 to 150 days) were 7.70, 8.20, 8.70, 9.20, 9.70 MJ/kg. The pre-experimental period lasted for 10 days, and the experimental period lasted for 90 days. The digestive and metabolic tests were carried out on the 76 to 80 days, 106 to 110 days and 136 to 140 days of pregnancy. The results showed as follows: 1) during mid-pregnancy and late-pregnancy, the final body weight (FBW) and average daily gain (ADG) of groups 3, 4 and 5 were significantly higher than those of groups 1 and 2 (P<0.05). 2) During pre-pregnancy, mid-pregnancy and late-pregnancy, the digestible energy (DE), ME, gross energy digestibility (DE/GE) and gross energy metabolic rate (ME/GE) of group 1 were significantly lower than those of groups 3, 4 and 5 (P<0.05). 3) The regression model of ME requirements of Yunshang black goats during pre-pregnancy, mid-pregnancy and late-pregnancy were as follows: ME=0.404W^0.75+0.040ADG (R²=0.981), ME=0.422W^0.75+0.024ADG (R²=0.917), ME=0.469W^0.75+0.026ADG (R²=0.918). In conclusion, with the dietary energy leve increase, the DE/GE and ME/GE of Yunshang black goats during pregnancy show an increasing trend. The maintenance ME of Yunshang black goats during pre-pregnancy, mid-pregnancy and late-pregnancy are 0.404, 0.422 and 0.469 MJ/kg W^0.75, respectively.

This study was conducted to examine the effects of low-, medium- and high-nutrient level diets on the growth performance, serum biochemical indices, slaughter performance and meat quality of Hu sheep. Thirty-six healthy male Hu lambs with similar body weight [(20.89±0.54) kg] were selected and randomly divided into 3 groups with 3 replicates in each group, and 4 sheep in each replicate. The lambs in the 3 groups were fed with a basal diet (MN group), a low-nutrient level diet with 90% energy and protein levels of the basal diet (LN group), and a high-nutrient level diet with 110% energy and protein levels of the basal diet (HN group). The experiment included a 7-day adaptation period followed by a 120-day formal trial period. The results showed as follows: 1) the final body weight (FBW) and average daily gain (ADG) of Hu sheep in the HN group were significantly higher than those in the LN and MN groups (P<0.05). The average daily dry matter intake (ADDMI) in the HN group was extremely significantly higher than that in the LN and MN groups (P<0.01), while the feed-to-gain ratio (F/G) was extremely significantly lower than that in the LN and MN groups (P<0.01). 2) On day 1 of the trial, no significant differences were observed among the 3 groups in the contents of serum albumin (ALB), total protein (TP), glucose (GLU), triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), as well as the activities of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (P>0.05). On day 60 of the trial, the HN group exhibited significantly higher serum TG and TP contents than the LN group (P<0.05). On day 120 of the trial, serum ALB and TC contents in the HN group were significantly elevated compared with the LN group (P<0.05). 3) There were no significant differences in slaughter rate, backfat thickness and GR value among the 3 groups (P>0.05), but the loin eye area in the HN group was significantly larger than that in the LN and MN groups (P<0.05). 4) There were no significant differences in pH_{45 min}, meat color, cooking loss, drip loss and water loss rate among the 3 groups (P>0.05), nevertheless, compared with the LN group, the shear force in the HN group was significantly decreased (P<0.05). Therefore, an appropriately high nutrient level (1.1 times the energy and protein levels of the control group) can improve the growth performance, enhance body metabolic function, increase loin eye area, and reduce shear force, thereby improving meat quality.

The purpose of this experiment was to study the effects of dietary compound Chinese herbal medicine on growth performance and serum biochemical, immune, antioxidant indexes and metabolites of Hu sheep. Forty-eight healthy male Hu sheep lambs with similar body weigh [(20.90±0.53) kg ] were randomly divided into 4 groups with 3 replicates in each group and 4 sheep in each replicate. The control group (CON group) was fed a basal diet, and the experimental groups were fed basal diets supplemented with 0.25% (0.25% CHM group), 0.50% (0.50% CHM group) and 1.00% (1.00% CHM group) compound Chinese herbal medicine, respectively. The pre-experimental period lasted for 7 days, and the experimental period lasted for 120 days. The results showed as follows: 1) dietary supplemented with compound Chinese herbal medicine did not significantly affect the growth performance of Hu sheep (P>0.05). 2) The serum glucose (GLU) content of 0.25% CHM group, 0.50% CHM group and 1.00% CHM group was significantly higher than that of CON group (P<0.05), and the serum albumin (ALB) content was significantly higher than that of CON group (P<0.01). 3) The serum superoxide dismutase (SOD) activity of 0.25% CHM group, 0.50% CHM group and 1.00% CHM group was significantly higher than that of CON group (P<0.01), the serum malondialdehyde (MDA) content of CON group was significantly lower than that of 0.25% CHM group (P<0.05), and the serum catalase (CAT) activity of 1.00% CHM group was significantly higher than that of CON group and 0.25% CHM group (P<0.01). The contents of immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM) and interferon-γ (IFN-γ) in serum of 0.25% CHM group, 0.50% CHM group and 1.00% CHM group were significantly higher than those of CON group (P<0.01), and those of the 0.25% CHM group were significantly higher than those of other groups (P<0.01). 4) The serum metabolomics analysis showed that the compound Chinese herbal medicine may regulated the body immune and antioxidant capability through the glycerophospholipid metabolism and retrograde endocannabinoid signaling metabolic pathways. In conclusion, dietary appropriate amount of compound Chinese herbal medicine can improve the immune, antioxidant capacity and metabolic level of Hu sheep, and it is recommended to add 0.25%.

This experiment was conducted to investigate the effects of Caragana korshinskii tannins (CKT) on growth performance, nutrient apparent digestibility, small intestinal morphology and antioxidant function of fattening lambs fed high-concentrate diets. Twenty-four 3-month-old Dorper×Mongolian crossbred male lambs were randomly divided into 3 groups with 8 replicates per group and 1 lamb per replicate. Lambs in control group (CON group) were fed a diet with a concentrate to forage ratio of 3∶7, those in high-concentrate group (HC group) were fed a high-concentrate diet with a concentrate to forage ratio of 7∶3, and those in CKT group were fed a diet supplemented with 2 g/kg CKT in the high-concentrate diet. The pre-trial period lasted for 15 days, and the formal trial period lasted for 60 days. The results showed as follows: 1) compared with CON group, the average daily gain (ADG) of lambs in HC group was significantly increased (P<0.05), while the feed-to-gain ratio (F/G) was significantly decreased (P<0.05). 2) Compared with CON group, the apparent digestibility of crude protein (CP) and ether extract (EE) of lambs in HC group was significantly increased (P<0.05). 3) Compared with CON group, the villus height (VH) and villus height/crypt depth (V/C) in ileum of lambs in HC group were significantly decreased (P<0.05). Compared with HC group, the VH in ileum of lambs in CKT group was significantly increased (P<0.05), the crypt depth (CD) in jejunum and ileum was significantly decreased (P<0.05), and the V/C in duodenum and ileum was significantly increased (P<0.05). 4) Compared with CON group, the total antioxidant capacity (T-AOC) in jejunum of lambs in HC group was significantly decreased (P<0.05), while the malondialdehyde (MDA) content in ileum was significantly increased (P<0.05); moreover, the mRNA relative expression levels of NAD(P)H: quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) in duodenum, NQO1 in jejunum and superoxide dismutase 1 (SOD1) in ileum were significantly decreased (P<0.05). Compared with HC group, the MDA content in ileum of lambs in CKT group was significantly decreased (P<0.05), and the mRNA relative expression levels of catalase (CAT) in duodenum, glutathione peroxidase 1 (GPx1) in jejunum and SOD1 in ileum were significantly increased (P<0.05). In conclusion, high-concentrate diet supplemented with 2 g/kg CKT can improve the antioxidant function of fattening lambs by enhancing the morphological structure of small intestine, regulating MDA content in small intestine, and increasing the expression of genes related to antioxidant, while not affecting their growth performance, thereby alleviating the oxidative damage to small intestine caused by high-concentrate diet and promoting overall health.

The purpose of this study was to investigate the effects of compound additives on growth performance, nutrient apparent digestibility and intestinal health of weaned lambs. A total of 115 healthly six-month-old weaned male lambs of small tail Han sheep with similar body weight were radomly divided into 5 groups with 23 lambs in each group. Group 1 (control group) was fed a basal diet, group 2 was fed the basal diet+6.0 g/kg medical stone+0.2 g/kg complex plant essential oil+5.0 mg/kg cobalt glycinate, group 3 was fed the basal diet+6.0 g/kg medical stone+0.2 g/kg of complex plant essential oil+5.0 mg/kg cobalt glycine+0.2 g/kg coated L-carnitine, group 4 was fed the basal diet+6.0 g/kg medical stone+0.2 g/kg complex plant essential oil+5.0 mg/kg cobalt glycine+0.2 g/kg Bacillus coagulans, and group 5 was fed the basal diet+6.0 g/kg medical stone+0.2 g/kg complex plant essential oil+0.2 g/kg coated L-carnitine+5.0 mg/kg cobalt glycine+0.2 g/kg Bacillus coagulans. The pre-feeding period was 15 days, and the formal test period was 60 days. The results were as follows: 1) the average daily gain and apparent digestibility of crude protein (CP), neutral detergent fiber (ADF), acid detergent fiber (NDF) of groups 2, 4 and 5 were significantly higher than those of group 1 (P<0.05). 2) The villus height/crypt depth in jejunum and ileum of groups 2, 3, 4 and 5 was significantly higher than that of group 1 (P<0.05). 3) The mRNA relative expression levels of zonula occludens protein-1 (ZO-1) and Claudin-1 in ileum and jejunum of groups 4 and 5 were significantly higher than those of group 1 (P<0.05). 4) The relative abundances of Bacteroidota and Rikenellaceae_RC9_gut_group in rumen, ileum and jejunum of group 5 were significantly higher than those of group 1 (P<0.05). The relative abundances of Firmicutes and Clostridium in jejunum and Turicibacter in ileum of group 2 were significantly higher than those of groups 3, 4 and 5 (P<0.05). In conclusion, dietary supplemented with compound additives based on medical stone can increase average daily gain and nutrient apparent digestibility of weaned lambs, improve intestinal morphology and flora structure. Under the conditions of this experiment, the effects of groups 2 (complex plant essential oil+cobalt glycinate) and 5 (complex plant essential oil+cobalt glycinate+coated L-carnitine+Bacillus coagulans) are better.

The purpose of this study was to evaluate the effects of intracellular antibacterial peptide on the intestinal barrier function of lambs. Thirty 72-day-old Hu sheep with duodenal fistula and similar body condition [body weight: (18.29±0.49) kg] were selected and randomly divided into five groups, including control group, positive control group, 0.5 g/kg intracellular antimicrobial peptide group, 1.0 g/kg intracellular antimicrobial peptide group and 2.0 g/kg intracellular antimicrobial peptide group, each group had six replicates and 20 lambs in each replicate. The pre-trial lasted for 7 d and the formal trial lasted for 35 d. The three groups of adding intracellular antimicrobial peptide were administered at 07:00 and 17:00 daily with 0.5, 1.0 and 2.0 g/kg of intracellular antimicrobial peptide CPP-C3M4 (the peptide powder was dissolved in 5 mL of sterile saline, with antimicrobial peptide content of 22.5 mg/g). The challenge test was conducted in the last 3 days of the formal trial period. Each lamb in the positive control group and the three adding intracellular antimicrobial peptide groups received 5 mL of freshly cultured Salmonella typhimurium (with a bacterial concentration of 1×10¹³ CFU/mL) through the duodenal fistula at 08:00 daily from the 33rd day of the formal trial, and the perfusion continued for 3 days. The results showed as follows: 1) intracellular antimicrobial peptide could penetrate the jejunal epithelial cells of lambs to play a role. 2) Compared with the positive control group, adding 1.0 and 2.0 g/kg intracellular antimicrobial peptide could improve the morphological structure of the jejunum of lambs, significantly increase the jejunal villus height and villus height to crypt depth ratio, and reduce the crypt depth (P<0.05), and significantly decrease the jejunal crypt depth (P<0.05). 3) Compared with the positive control group, the number of goblet cells and the mRNA relative expression level of mucin 2 (MUC2) in the jejunum of lambs were significantly increased by adding 0.5, 1.0 and 2.0 g/kg intracellular antimicrobial peptide (P<0.05). 4) Adding 0.5, 1.0 and 2.0 g/kg intracellular antimicrobial peptide all cloud significantly inhibit the increase of endotoxin (ET), D-lactic acid (D-LA) contents and diamine oxidase (DAO) activity in serum of lambs stimulated by Salmonella (P<0.05); compared with the 0.5 g/kg intracellular antimicrobial peptide group, the contents of ET, D-LA and DAO activity in the 1.0 and 2.0 g/kg intracellular antimicrobial peptide groups were significantly decreased (P<0.05). 5) Compared with the positive control group, adding 1.0 and 2.0 g/kg intracellular antimicrobial peptide significantly increased the mRNA relative expression levels of tight junction protein genes in jejunum of lambs, such as Occludin, Claudin-1 and zonula occluden-1 (ZO-1) (P<0.05). In conclusion, intracellular antimicrobial peptide can target and act on the intestinal epithelial cells of lambs, improve the intestinal barrier function and maintain the integrity of intestinal barrier. From the point of view of reducing feed cost, 1.0 g/kg intracellular antimicrobial peptide is recommended as feed additive to protect lamb intestinal health.

The objective of this experiment was to study the effects of vitamin E (VE) on growth performance, antioxidant capacity and skin performance of Dezhou donkeys. Twenty-one 10-month-old Dezhou donkeys were randomly divided into 3 groups, with 7 replicates in each group and 1 donkey in each replicate. The 3 groups of Dezhou donkeys were fed a concentrate supplement with 60 (control), 200 and 400 mg/kg VE, roughage was soybean straw. The pre-trial period lasted for 7 days, and the formal trial period lasted for 135 days. The results showed as follows: 1) compared with the control group, the addition of 200 and 400 mg/kg VE had no significant effects on growth performance, dressed weight, dressed percentage and fresh skin rate of Dezhou donkeys (P>0.05), and addition of 400 mg/kg VE tended to enhance fresh skin weight significantly (P=0.076). 2) Compared with the control group, the addition of 200 and 400 mg/kg VE significantly increased glutathione peroxidase and superoxide dismutase activities and total antioxidant capacity in serum (P<0.05), and significantly reduced malondialdehyde content in serum of Dezhou donkeys (P<0.05). 3) Compared with the control group, the addition of 400 mg/kg VE significantly increased back skin thickness, and the addition of 200 and 400 mg/kg VE significantly increased back dermal skin thickness, hydroxyproline content, and collagen percentage in back skin of Dezhou donkeys (P<0.05), while the hydroxyproline content in the addition of 400 mg/kg VE group was significantly higher than that in the addition of 200 mg/kg VE group (P<0.05). 4)Compared with the control group, the addition of 200 and 400 mg/kg VE significantly enriched the signal pathways of extracellular matrix organization, collagen fibril organization, collagen biosynthetic process, and skin development in the back skin. It is concluded that the addition of 200 and 400 mg/kg VE to the concentrate supplement can improve the antioxidant capacity, promote the deposition of extracellular matrix in the skin (especially collagen), and increase the thickness of the dermis skin, thus increasing the skin production of Dezhou donkeys, however, the effect is better with the addition of 400 mg/kg.

This study aimed to evaluate the effects of dietary supplementation with Clostridium butyricum or Chinese herbal preparation on the hepatic antioxidant capacity, immune function and gut microbiota of bullfrog (Aquarana catesbeiana) tadpoles and froglets. The control group was fed a basal diet, while the experimental groups were supplemented with 5×10⁹ CFU/kg of Clostridium butyricum or 5 g/kg of Chinese herbal preparation in the basal diet, respectively. The feeding trial lasted for 30 days during both the tadpole and froglet stages. During the tadpole stage, each group was replicated in three tanks, with 100 tadpoles per tank. During the froglet stage, each group was replicated in three tanks, with 30 froglets per tank. The results showed that compared with the control group, dietary supplementation with Clostridium butyricum or Chinese herbal preparation significantly increased the weight gain rate of both tadpoles and froglets (P<0.05). During the tadpole stage, compared with the control group, dietary supplementation with Clostridium butyricum significantly enhanced the total antioxidant capacity (T-AOC) in the liver, as well as the activities of acid phosphatase (ACP), alkaline phosphatase (AKP), and lysozyme (LZM) (P<0.05); dietary supplementation with Chinese herbal preparation significantly increased the T-AOC and immunoglobulin M (IgM) content in the liver (P<0.05). During the froglet stage, compared with the control group, dietary supplementation with Clostridium butyricum significantly increased the T-AOC, reduced glutathione (GSH) and IgM contents in the liver, as well as the activities of ACP and LZM (P<0.05); dietary supplementation with Chinese herbal preparation significantly enhanced the T-AOC, catalase (CAT) and LZM activities, as well as the IgM content in the liver (P<0.05). Compared with the control group, dietary supplementation with Clostridium butyricum significantly increased the mRNA relative expression levels of tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), and interleukin-10 (IL-10) in the liver of tadpoles (P<0.05). Compared with the control group, dietary supplementation with Clostridium butyricum significantly increased the mRNA relative expression levels of TNF-α and IL-10 in the liver of froglets (P<0.05), while dietary supplementation with Chinese herbal preparation significantly increased the mRNA relative expression levels of TNF-α, TGF-β and IL-10 in the liver of froglets (P<0.05). Gut microbiota analysis indicated that Clostridium butyricum or Chinese herbal preparation could positively modulate the gut microbiota structure by increasing the relative abundance of Firmicutes and decreasing the relative abundance of Bacteroidetes. In conclusion, dietary supplementation with 5×10⁹ CFU/kg of Clostridium butyricum or 5 g/kg of Chinese herbal preparation can enhance the hepatic antioxidant capacity and immune function of tadpoles and froglets, optimize the gut microbiota structure, thereby improving disease resistance and reducing the risk of disease occurrence.

This study was conducted to explore the effects of faba bean powder on the growth, body wall nutritional composition and gut microbiota structure of sea cucumber (Apostichopus japonicus). Faba bean powder was used to replace 0 (control group), 10% and 20% (experimental groups) of the compound feed for sea cucumbers to prepare experimental diets. Each type of experimental diet was corresponding to 3 tanks, and 20 sea cucumbers with body weight of (20.0±0.5) g were put into each tank. The experiment lasted for 60 days. The results showed as follows: 1) when the replacement ratio of faba bean powder was 20%, the specific growth rate (SGR) and weight gain rate (WGR) of sea cucumbers were significantly higher than those of the control group (P<0.05), and also significantly higher than those of the 10% replacement group (P<0.05). 2) The crude protein content of the body wall in the 20% replacement group was the highest, which was 4.08%, followed by the 10% replacement group, which was 4.06%, both significantly higher than the control group (3.67%) (P<0.05); the ether extract content of the body wall was the highest in the 10% replacement group, which was 0.80%, significantly higher than the other two groups (P<0.05). 3) The dominant bacterial phyla in the gut microbiota of all three groups were Verrucomicrobiota, Proteobacteria and Bacteroidota. When the replacement ratio of faba bean powder reached 20%, the relative abundance of Verrucomicrobiota in the gut microbiota of sea cucumbers was the highest, while the relative abundance of Proteobacteria was the lowest. These results suggest that using faba bean powder as a feed source to replace 20% of the compound feed can effectively improve the gut microbiota structure and promote the growth of sea cucumbers.

This experiment was conducted to investigate the effects of low fish meal diet supplemented with stickwater hydrolysate meal on growth performance, serum indexes and intestinal health of Chinese soft-shelled turtles (Pelodiscus sinensis). Four isonitrogenous and isolipidic experimental diets were formulated: the FM50 diet containing 50% fish meal (positive control group), the FM40 diet containing 40% fish meal (negative control group), and the SHM3 and SHM6 diets, which were prepared by adding 3% and 6% stickwater hydrolysate meal respectively, to the FM40 diet. Three hundred and sixty healthy Chinese soft-shelled turtles with uniform body size and an initial body weight of (9.84±0.27) g were selected and randomly divided into 4 groups, with 3 replicates per group and 30 turtles per replicate. The turtles in each group were fed the four experimental diets described above and a 56-day feeding trial was conducted. The results showed as follows: 1) compared with the FM50 group, the feed conversion ratio in the FM40 group was significantly increased (P<0.05), the activities of serum glutamic-oxaloacetic transaminase (GOT), alkaline phosphatase (AKP), acid phosphatase (ACP), lysozyme (LZM), serum superoxide dismutase (SOD) and catalase (CAT), as well as the contents of complement 3 (C3), complement 4 (C4) and immunoglobulin M (IgM) were significantly decreased (P<0.05), intestinal villus height and the activities of trypsin (TPS) and α-amylase (α-AMS) were significantly decreased (P<0.05), and the mRNA relative expression levels of intestinal Toll-like receptor 4 (TLR4), Toll-like receptor 5 (TLR5) and Toll-like receptor 8 (TLR8) were significantly increased (P<0.05). 2) Compared with the FM40 group, the FCR in the SHM3 and SHM6 groups was significantly decreased (P<0.05), while specific growth rate and weight gain rate were significantly increased (P<0.05), the activities of serum GOT, AKP, ACP, LZM, SOD and CAT, as well as the contents of C3, C4 and IgM were significantly increased (P<0.05), intestinal villus height and the activities of TPS and α-AMS were significantly increased (P<0.05), and the mRNA relative expression levels of intestinal TLR4 and TLR8 were significantly decreased (P<0.05). In conclusion, feeding low fish meal diets results in reduced growth performance, decreased immune function and intestinal digestion-absorption capacity, as well as impaired intestinal health in Chinese soft-shelled turtles; however, appropriate supplementation of stickwater hydrolysate meal can alleviate the above negative effects caused by low fish meal diets.

This study aimed to investigate the effects of feeding diets with different energy and protein levels during the lactation period on reproductive performance and gene expression related to follicle development in female rabbits, while maintaining the same energy and protein levels during the non-lactating period. One hundred Ira meat rabbits at 1 week before delivery were selected and randomly divided into 5 groups, with 5 replicates per group and 4 rabbits per replicate. The body weight [(5.21±0.58) kg] between replicates was similar. A 2-factor, 2-level and 1 control experimental design was adopted, and five diets with different energy and protein levels (Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ) were formulated. The trial was divided into three phases: phase 1 [from the start of the trial to the first delivery of the female rabbits (7 days)], all groups were fed diet Ⅴ; phase 2 [lactation period (35 days)], groups Ⅰ, Ⅱ, Ⅲ, Ⅳ and Ⅴ were fed diets Ⅰ, Ⅱ, Ⅲ, Ⅳ and Ⅴ, respectively; phase 3 [from the end of the lactation period to the second delivery of the female rabbits (7 days)], all groups were fed diet Ⅴ again. The group Ⅴ with unchanged nutritional levels in the three phases was used as the control group. The trial period was 49 days. The results showed as follows: 1) there were significant interactions between dietary energy and protein levels on the average daily feed intake (ADFI) during the 2nd, 3rd and 4th weeks of lactation and the body weight on day 35 of female rabbits (P<0.05). Dietary energy levels significantly affected the ADFI of female rabbits during the 1st and 5th weeks of lactation (P<0.05). Compared with group Ⅴ, the ADFI of female rabbits in groups Ⅰ, Ⅱ and Ⅲ decreased significantly during the 1st week of lactation (P<0.05); the ADFI in groups Ⅰ and Ⅳ decreased significantly during the 3rd and 4th weeks of lactation (P<0.05); the ADFI in groups Ⅰ and Ⅱ decreased significantly during the 5th week of lactation (P<0.05). The body weight of female rabbits in group Ⅳ before the first delivery was significantly lower than that in group Ⅴ (P<0.05). 2) There was a significant interaction between dietary energy and protein levels on the average milk yield of female rabbits during the 5th week of lactation (P<0.05). Dietary energy levels significantly affected colostrum yield, average milk yield of female rabbits during the 4th and 5th weeks of lactation (P<0.05), as well as the individual body weight of offspring during the 2nd and 5th weeks of lactation and the average daily gain (ADG) of offspring from 1 to 35 days of age (P<0.05). Dietary protein levels significantly affected the average milk yield during the 1st, 3rd and 5th weeks of lactation (P<0.05). Compared with group Ⅴ, the average milk yield of female rabbits in group Ⅱ decreased significantly during the 4th week of lactation (P<0.05); the individual body weight of offspring in group Ⅰ during the 5th week of lactation and the ADG from 1 to 35 days of age decreased significantly (P<0.05). 3) The proportion of tertiary follicles of female rabbits in groups Ⅲ and Ⅳ decreased significantly compared with group Ⅴ (P<0.05). 4) The mRNA relative expression levels of follicle-stimulating hormone receptor (FSHR) and anti-Müllerian hormone (AMH) in ovary of female rabbits in groups Ⅱ and Ⅳ increased significantly compared with group Ⅴ (P<0.05); the mRNA relative expression level of growth differentiation factor 9 (GDF9) in ovary of female rabbits in group Ⅰ increased significantly (P<0.05); the mRNA relative expression levels of forkhead box protein L2 (FOXL2), inhibin α (INHA) and estrogen receptor 1 (ESR1) in ovary of female rabbits in group Ⅱ increased significantly (P<0.05). In conclusion, under the conditions of this experiment, when female rabbits were fed a diet with a digestible energy level of 10.00 MJ/kg and a crude protein level of 16.93% during the non-lactating period, feeding a diet with a digestible energy level of 9.50 to 10.00 MJ/kg and a crude protein level of 16.93% to 18.00% during the lactation period was more beneficial for increasing feed intake and improving reproductive performance such as milk production and offspring growth. Conversely, feeding a diet with a digestible energy level of 10.50 MJ/kg and a crude protein level of 16.43% during the lactation period had a more significant effect on regulating genes related to follicle development in ovary of female rabbits, such as FSHR, AMH, FOXL2, INHA and ESR1.

The aim of this experiment was to investigate the effects of extracellular polysaccharides from lactic acid bacteria (LAB-EPS) on the morphology of gastrointestinal tissues and the expression of tight junction related genes and proteins in intestinal tissues of lambs. Twenty-four Sunite lambs with similar body weight [(7.07±1.73) kg] and healthy physical condition at the age of 15 days were randomly divided into four groups: blank control group, challenge control group, challenge+Astragalus polysaccharide (ASP) group and challenge+extracellular polysaccharides (EPS) group. There were 6 lambs in each group, with 3 males and 3 females. Daily oral gavage of equal volumes of different solutions were administered to lambs in each experimental group. The blank control group and the challenge control group were given physiological saline, while the challenge+ASP group received a dose of 1 mg/(lamb·d) of ASP. The challenge+EPS group received a dose of 1 mg/(lamb·d) of EPS. Daily continuous administration until the end of the experiment for a total of 49 days. On the 43rd and 44th day of the experiment, the lambs in the challenge control group, challenge+ASP group, and challenge+EPS group were selected for Escherichia coli challenge treatment, with a challenge dose of 10⁹ CFU per lamb. Finally, on the 49th day of gavage treatment, three lambs were randomly selected from each group for slaughter. Gastrointestinal tissue samples were collected from the lambs for morphological analysis and expression detection of tight junction related genes and proteins. The results showed as follows: 1) compared with the blank control group, the challenge control group suffered some degree of damage to the intestinal mucosal tissue of lambs under Escherichia coli challenge treatment, manifested as pathogenic Escherichia coli causing loose arrangement of intestinal mucosal cells, increased intercellular space, and villous erosion. In contrast, the challenge+EPS group had normal gastrointestinal mucosal tissue, with only a tendency towards villous flattening. 2)The height of rumen papillae in the challenge+EPS group was significantly higher than that in the challenge control group and the blank control group (P<0.05), while the width of rumen papillae in the challenge+EPS group was significantly lower than that in the challenge control group and the blank control group (P<0.05). The villus height of the duodenum, jejunum and ileum in the challenge+EPS group was significantly higher than that in the challenge control group (P<0.05), and the crypt depth of the duodenum in the challenge+EPS group was significantly lower than that in the challenge control group (P<0.05). 3) The mRNA relative expression levels of Claudin-1 and Occludin in the duodenal tissue, the Claudin-1, Claudin-4 and Occludin in the jejunal tissue, and the Claudin-1, Claudin-4 in the ileal tissue were significantly increased in the challnege+EPS group compared with the challenge control group (P<0.05). 4) The protein relative expression levels of Claudin-1, Claudin-4 and Occludin in the duodenal and ileal tissues and the Claudin-1 and Occludin in the jejunal tissue were significantly increased in the challnege+EPS group compared with the challenge control group (P<0.05). In summary, LAB-EPS can greatly alleviate gastrointestinal mucosal damage in lambs induced by Escherichia coli, promote the development of ruminal papillae and intestinal villi, and protect the mucosal integrity of the duodenum, jejunum and ileum by upregulating tight junction related genes and proteins. These findings indicate LAB-EPS as a promising probiotic agent for mitigating Escherichia coli-induced diarrhea in lambs.

This study aimed to investigate the potential mechanisms of dietary calcium/phosphorus (Ca/P) ratio on egg quality by analyzing its effects on the production performance, egg quality, tibia quality, serum biochemical indices and the expression of genes related to vitamin D α-hydroxylation, calcium and phosphorus absorption in laying hens. One hundred and eight 48-week-old Hy-Line brown laying hens at the peak laying period were selected and randomly divided into 3 groups with 6 replicates per group and 6 hens in each replicate. Hens in each group were fed diets with normal (3.6% Ca, 0.5% P, Ca/P=7.2∶1), low (3.0% Ca, 0.5% P, Ca/P=6.0∶1) and high (4.2% Ca, 0.5% P, Ca/P=8.4∶1) Ca/P ratios, respectively. The pre-experimental period lasted for 1 week, and the experimental period lasted for 4 weeks. The results showed as follows: 1) compared with the normal Ca/P ratio group and the high Ca/P ratio group, the laying rate of laying hens in the low Ca/P ratio group was extremely significantly decreased (P<0.01), the eggshell thickness was significantly decreased (P<0.05), and the contents of serum 1,25-dihydroxyvitamin D₃ [1,25-(OH)₂D₃] and parathyroid hormone (PTH) were significantly increased (P<0.05). The mRNA relative expression levels of membrane vitamin D receptor (mVDR), nuclear vitamin D receptor (nVDR), calcium-binding protein-D28K (CABP-D28K), plasma membrane calcium ATPase 1b (PMCA1b), sodium-dependent type Ⅱb phosphorus transporter (Na/Pi-Ⅱb) in duodenum, and cytochrome P450 family member 24A1 (CYP24A1) in liver in the low Ca/P ratio group were extremely significantly higher than those in the normal Ca/P ratio group and the high Ca/P ratio group (P<0.01), while the mRNA relative expression levels of fibroblast growth factor 23 (FGF23) and Klotho in liver were extremely significantly lower than those in the normal Ca/P ratio group and the high Ca/P ratio group (P<0.01). 2) With the increased in dietary Ca/P ratio, eggshell strength, average egg weight, tibia calcium and phosphorus contents, and serum FGF23 and Klotho contents showed upward trends, though the differences were not significant (P>0.05). 3) Compared with the normal Ca/P ratio group, the high Ca/P ratio group showed no significant changes in eggshell thickness, eggshell strength, average egg weight, laying rate (P>0.05), as well as the mRNA relative expression levels of mVDR, nVDR, CABP-D28K, PMCA1b, Na/Pi-Ⅱb in duodenum, and CYP24A1, FGF23 and Klotho in liver of laying hens (P>0.05). In conclusion, a low Ca/P ratio diet reduces eggshell strength and thickness, negatively affecting egg quality. The responses of indicators in laying hens are as follows: through a compensatory metabolic mechanism, the expression of FGF23 and Klotho in liver is downregulated, reducing the inhibitory effect on CYP24A1, thereby indirectly promoting the production of 1,25-(OH)₂D₃. Meanwhile, the expression of nVDR, mVDR, CABP-D28K, PMCA1b, Na/Pi-Ⅱb in duodenum related to calcium and phosphorus absorption is upregulated to enhance calcium and phosphorus absorption. However, these indicators show no response when the dietary Ca/P ratio exceeds normal nutritional requirements.

This study was conducted to investigate the correlation between dietary vitamin D₃ deficiency or excess and vitamin D metabolism, as well as its effects on egg quality of laying hens, from the perspective of the fibroblast growth factor 23/Klotho (FGF23/Klotho) axis. A single-factor completely randomized design was adopted. Ninety-six 42-week-old Roman pink laying hens were selected and randomly divided into 4 groups with 8 replicates per group and 3 hens per replicate. Hens in each group were fed basal diets supplemented with 0 (deficiency), 2 000 (low level), 4 000 (normal level) and 8 000 IU/kg (excess) vitamin D₃, respectively. The experimental period lasted for 4 weeks. The results showed as follows: 1) in the 0 IU/kg group, eggshell strength and eggshell proportion of laying hens were lower than those in the 2 000 and 4 000 IU/kg groups, though the difference was not significant (P>0.05); tibia defatted weight was significantly lower than that in the 2 000 and 4 000 IU/kg groups (P<0.05); serum alkaline phosphatase activity was significantly higher than that in the other three groups (P<0.05), while serum 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃] and FGF23 levels were significantly lower than those in the other three groups (P<0.05), serum Klotho content was also lower than that in the other three groups, but the difference was not significant (P>0.05). The mRNA relative expression levels of nuclear vitamin D receptor (nVDR) in duodenum of laying hens in the 0 and 2 000 IU/kg groups were significantly lower than those in the 4 000 and 8 000 IU/kg groups (P<0.05), and the mRNA relative expression level of sodium-dependent type Ⅱb phosphate transporter (Na/Pi-Ⅱb) in duodenum was significantly lower than that in the 8 000 IU/kg group (P<0.05); the mRNA relative expression levels of FGF23 and cytochrome P450 family 27 subfamily B member 1 (CYP27B1) in kidney in the 0 IU/kg group were significantly higher than those in the other three groups (P<0.05), and the mRNA relative expression level of Klotho in kidney was significantly higher than that in the 2 000 and 8 000 IU/kg groups (P<0.05). 2) In the 8 000 IU/kg group, eggshell strength, eggshell proportion, and tibia ash weight of laying hens were lower than those in the 2 000 and 4 000 IU/kg groups, but the differences were not significant (P>0.05); tibia defatted weight was significantly lower than that in the 2 000 and 4 000 IU/kg groups (P<0.05); serum 1,25(OH)₂D₃ content was significantly lower than that in the 4 000 IU/kg group (P<0.05), and serum FGF23 and Klotho contents were also lower than those in the 4 000 IU/kg group, but the differences were not significant (P>0.05). The mRNA relative expression levels of membrane vitamin D receptor (mVDR), nVDR, and Na/Pi-Ⅱb in duodenum of laying hens in the 8 000 IU/kg group were significantly higher than those in the other three groups (P<0.05); there were no significant differences in the relative mRNA expression levels of FGF23, Klotho, and CYP27B1 in kidney between the 8 000 IU/kg group and the 2 000 and 4 000 IU/kg groups (P>0.05). In conclusion, both dietary vitamin D₃ deficiency and excess can lead to decline in egg quality, which is related to the FGF23/Klotho axis and vitamin D metabolism. However, the response indices and regulatory mechanisms in laying hens differ between these two conditions. Under dietary vitamin D₃ deficiency, FGF23,Klotho and CYP27B1 in kdiney of laying hens act as internal response indices to participate in the regulation of egg quality and calcium-phosphorus metabolism. In contrast, under dietary vitamin D₃ excess, nVDR, mVDR and Na/Pi-Ⅱb in duodenum of laying hens serve as the internal response indices involved in regulating egg quality and calcium-phosphorus metabolism.

This experiment was conducted to explore the meat quality characteristics and metabolic differences in breast muscle between the local breed Hetian chickens and the fast-growing Cobb broilers, providing a basis for the development and utilization of local breed chicken products. Each thirty Hetian chickens and Cobb broilers were selected for the experiment under the same feeding management and nutritional level. The Cobb broilers were fed until 42 days of age and the Hetian chickens were fed until 120 days of age for slaughter. The slaughter performance and meat quality were determined. Breast muscle tissues were collected, and the composition of metabolites was analyzed based on metabolomics. Orthogonal partial least squares-discriminant analysis (OPLS-DA) was used to screen for differential metabolites, and the metabolic differences affecting the meat quality of different chicken varieties were determined through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The results showed as follows: 1) compared with Cobb broilers, the leg muscle rate of Hetian chickens was significantly decreased (P<0.05), the values of brightness (L^*) and redness (a^*) in breast muscle were significantly increased (P<0.05), and the shear force in breast muscle was extremely significantly increased (P<0.01). A total of 2 765 metabolites were identified in breast muscle of Hetian chickens and Cobb broilers using non-targeted metabolomics method, and 615 differential metabolites were screened out [variable projection importance (VIP)>1, P<0.05]. Among them, 210 metabolites were up-regulated and 405 metabolites were down-regulated in breast muscle of Hetian chickens. Moreover, among these metabolites, amino acid and its metabolites have the highest content and proportion, followed by benzene and substituted derivatives, glycerophospholipids, organic acid and its derivatives, as well as aldehydes, ketones, esters, etc. The histidine content in breast muscle of Hetian chickens was higher than that of Cobb broilers, while the contents of glutamic acid and its derivatives in breast muscle of Cobb broilers were higher than those of Hetian chickens. The contents of phosphatidylcholine and phosphocholine in breast muscle of Hetian chickens were higher than those of Cobb broilers, and the lysophosphatidylcholine content in breast muscle of Cobb broilers was higher than that of Hetian chickens. KEGG pathway enrichment analysis showed that glycerophospholipid metabolism, arachidonic acid metabolism, linoleic acid metabolism, alpha-linolenic acid metabolism, histidine metabolism and porphyrin metabolism were the main pathways to distinguish Hetian chickens from Cobb broilers. To sum up, there are differences in meat quality, muscle metabolites and metabolic pathways between Hetian chickens and Cobb broilers. The muscle of Hetian chickens shows higher levels in metabolic pathways such as amino acids and phospholipids, with brighter, redder meat color and richer flavor. The muscle of Cobb broilers has a higher glutamic acid content and is more tender than that of Hetian chickens.

This experiment aimed to explore the effects of diets with different roughage sources (oat hay, alfalfa hay and their mixed hay) on intestinal immune function of yak calves during lactation based on transcriptomics analysis. Twenty-one healthy male yak calves at 45 days of age with body weight of (36.47±0.99) kg were randomly divided into 3 groups (7 calves in each group) using a single-factor experimental design: the alfalfa hay group (AH group), the oat hay group (OH group) and the mixed hay group (AO group, alfalfa hay∶oat hay= 1∶1). The calves in each group were fed the same amount of milk replacer, concentrate and hay, with a concentrate-to-forage ratio of 3∶7. When the solid dry matter intake reached 1 kg/d, five calves from each group were slaughtered, and the jejunum and colon tissues were collected for transcriptomic sequencing and analysis. The pre-feeding period was 21 days, and the formal experimental period was 120 days. The results showed as follows: 1) the transcriptome analysis of jejunum showed that there were 100 3 differentially expressed genes (DEGs) between the AO and AH groups, 1 553 DEGs between the OH and AH groups, and 919 DEGs between the AO and OH groups. The GO enrichment analysis indicated that 680 GO terms were annotated by the DEGs between the AH and OH groups, 646 GO terms by the DEGs between the AH and AO groups, and 606 GO terms by the DEGs between the AO and OH groups. The KEGG enrichment analysis showed that the AO group mainly enhanced the immune function of jejunum by activating the complement and coagulation cascades and antigen processing and presentation. 2) The transcriptome analysis of colon showed that there were 3 362 DEGs between the AO and AH groups, 1 299 DEGs between the OH and AH groups, and 1 297 DEGs between the AO and OH groups. The GO enrichment analysis indicated that 665 GO terms were annotated by the DEGs between the AH and OH groups, 869 GO terms by the DEGs between the AH and AO groups, and 695 GO terms by the DEGs between the AO and OH groups. The KEGG enrichment analysis showed that the AO group mainly enhanced the immune function of colon by activating the chemokine signaling pathway and tight junctions. In conclusion, feeding the mixed hay increase promote the expression of immune related genes in jejunum and colon, regulate the intestinal immune response ability and health level, which is conducive to the healthy and high-quality cultivation of yak calves during the lactation period.

This study was conducted to develop a method for determination of zearalenone and its masked forms (zearalanone, zearalenone-14-glucoside and zearalenone-14-sulfate) in animal feed, blood and muscle using liquid chromatography-tandem quadrupole linear ion trap mass spectrometry. Animal feed, blood and muscle samples were extracted using acetonitrile+0.2 mol/L phosphate buffer solution (pH 3.0, 9∶1), followed by multi-impurity adsorption purification, and quantified by matrix-matching calibration using liquid chromatography. The results showed that zearalenone and its masked forms exhibited good linearity in 1 to 100 μg/L, with determination coefficients greater than 0.99. The detection limits ranged from 0.62 to 1.72 μg/kg, and the quantification limits ranged from 2 μg/kg to 5 μg/kg. The addition recovery rates ranged from 81.7% to 104.7%, with relative standard deviations of less than 20%. This method was applied to detect zearalenone and its masked forms in feed, blood and muscle samples from chickens, with all target compounds were detected in the feed, zearalenone, zearalenone-14-glucoside and zearalanone were detected in the blood, while zearalenone and zearalanone were detected in the muscle. The established method is suitable for monitoring the zearalenone and its masked forms in feed, blood and muscle.

This experiment was conducted to study the effects of exogenous protease on in vitro nutrient digestibility of soybean meal under different bionic parameter conditions. Through the bionic digestive system of monogastric animals, the orthogonal experimental design was adopted, the effects of add exogenous protease or not add exogenous protease on nutrient digestibility of soybean meal at different addition amount (1 and 2 g) in stomach and intestinal digestion simulated digestion stages were explored, and the effects of exogenous protease under different conditions of simulated gastric fluid digestion time, pH, volume and endogenous protease activity were studied. The results showed as follows: 1) in stomach and intestinal digestion simulated digestion stages, the dry matter digestibility (DMD), gross energy digestibility (GED) and enzymatic hydrolyzate gross energy (EHGE) of soybean meal add exogenous protease were significantly higher than those of not add exogenous protease (P<0.01), and the GED and EHGE of soybean meal of 1 g sample amount than were significantly higher than those of 2 g sample amount (P<0.01). 2) The DMD, GED and EHGE of soybean meal were significantly increased with gastric fluid digestion time increased (P<0.01). 3) The DMD, GED and EHGE of soybean meal were significantly decreased with gastric fluid pH increased (P<0.01). 4) The DMD, GED and EHGE of soybean meal were significantly increased with gastric fluid volume decreased (P<0.01). 5) The DMD, GED and EHGE of soybean meal were significantly increased with gastric fluid endogenous protease activity increased (P<0.01). 6) Under the conditions of simulated gastric fluid digestion time, pH and endogenous protease activity, the DMD, GED and EHGE of soybean meal add exogenous protease were significantly higher than those of not add exogenous protease (P<0.01). In conclusion, add exogenous protease can improve the in vitro nutrient digestibility of soybean meal.

This experiment utilized the “three-step in vitro method” (pepsin-pancreatin-cecal fluid method) to simulate the gastrointestinal environment of donkeys in vitro, aiming to investigate the effects of amino acid (AA) supplementation in low crude protein (CP) diets on nutrient degradation rates and cecal fermentation characteristics. Adult female Dezhou donkeys were selected as donors for cecal fluid. A 2×4 factorial completely randomized design was adopted, with factor 1 being AA supplementation: non-AA-supplementation (no lysine or methionine added) and AA-supplementation (lysine and methionine added); with the AA-supplemented treatments adding different levels of lysine (0.07%, 0.13%, 0.20% and 0.25%) and methionine (0.01%, 0.02%, 0.04% and 0.05%); factor 2 included four CP levels: 13.5%, 12.5% (the normal CP level), 11.5%, and 10.5%, resulting in eight dietary treatments with six replicates each. Feed residues degraded through gastric (1 h) and small intestinal (24 h) phases were further incubated in vitro with cecal fluid for 48 h. The results demonstrated that compared to the no AA supplementation, AA supplementation improved the degradation rates of dry matter (DM), ether extract (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF) in the gastric-small intestinal-cecal phases extremely significantly by 2.55%, 4.72%, 3.31% and 3.62%, respectively (P<0.01), and significantly increased crude protein (CP) degradation rate by 0.66% (P<0.05), supplementation with AA improved the in vitro feed utilization rate in donkeys, thereby promoting nutrient degradation and enhancing digestion and absorption. Compared to the normal CP level treatment (12.5% CP), the 10.5% CP treatment exhibited an extremely significant reduction in CP degradation rate by 1.49% (P<0.01), with no significant effects on other nutrient degradation rates (P>0.05). Compared to the no AA supplementation, AA supplementation extremely significantly increased ammonia nitrogen (NH₃-N) content by 1.89% (P<0.01), which remained within the optimal range for microbial growth, and extremely significantly elevated bacterial crude protein (BCP) content by 2.14% (P<0.01). The 13.5% CP treatment showed extremely significantly higher BCP content than other groups (P<0.01), while no significant difference was observed between the 10.5% CP and 11.5% CP treatments (P>0.05). Dietary CP levels and AA supplementation had no significant effects on gas production at different time points (P>0.05). Compared to the no AA supplementation treatment, AA supplementation extremely significantly increased total volatile fatty acid (TVFA) content (P<0.01), improving cecal fermentation. Comprehensive analysis indicates that the 10.5% CP diet supplemented with AA achieved optimal in vitro nutrient degradation rates and cecal fermentation characteristics in donkeys.

This experiment was conducted to investigate the effects of adding different macroalgae on rumen methane (CH₄) emissions in dairy cows through in vitro fermentation experiments. In experiment 1, five species of macroalgae were collected from the southern coastal waters of China, including Asparagopsis taxiformis, Colpomenia sinuosa, Sargassum 1, Sargassum 2 and Eucheuma. Each macroalga was added at four different doses [0 (control), 2%, 6% and 10%, organic matter basis), with three replicates per dose. In experiment 2, the bromoform was added to the diet at four different doses [0 (control), 0.01%, 0.03% and 0.05%, organic matter basis), with three replicates per dose. After 24 h in vitro fermentation, the gas and fermentation broth were collected for the determination of gas production parameters and rumen fermentation parameters. The results showed as follows: 1) compared with the control treatment, the addition of different doses of Asparagopsis taxiformis significantly reduced the total gas production (TGP), as well as the production of CH₄ and carbon dioxide (CO₂) (P<0.05), and the reduction was decreased linearly with the increase of the addition dose (P<0.05); among them, the inhibition rate of CH₄ by adding 2% Asparagopsis taxiformis was 96%, and the hydrogen (H₂) production was significantly increased at the same time (P<0.05). Compared with the control treatment, the addition of 10% Asparagopsis taxiformis significantly reduced the total volatile fatty acid (TVFA) content (P<0.05); the addition of different doses of Asparagopsis taxiformis significantly reduced the acetic acid proportion and the ratio of acetic acid to propionic acid (P<0.05), and significantly increased the proportions of propionic acid, butyric acid and valeric acid (P<0.05); the addition of 6% and 10% Asparagopsis taxiformis significantly reduced the contents of ammonia nitrogen (NH₃-N) and microbial protein (MCP) (P<0.05). 2) Compared with the control treatment, the addition of different doses of Colpomenia sinuosa significantly reduced the TGP and CO₂ production (P<0.05), and the reduction was decreased linearly with the increase of the addition dose (P<0.05); the addition of 10% Colpomenia sinuosa significantly reduced the CH₄ production (P<0.05), while the addition of 6% and 10% Colpomenia sinuosa significantly increased the H₂ production (P<0.05); the addition of different doses of Colpomenia sinuosa had no significant effect on the contents of TVFA and MCP (P>0.05), but significantly increased the acetic acid proportion and the ratio of acetic acid to propionic acid (P<0.05). 3) Compared with the control treatment, the addition of two species of Sargassum had no significant effect on the gas production parameters and the contents of TVFA, NH₃-N and MCP (P>0.05). 4) Compared with the control treatment, the addition of 6% and 10% Eucheuma significantly reduced the contents of TGP and MCP (P<0.05). 5) Compared with the control treatment, the addition of different doses of bromoform significantly reduced the TGP and production of CH₄ and CO₂ (P<0.05), significantly increased the H₂ production (P<0.05), and significantly reduced the NH₃-N content (P<0.05). In conclusion, under in vitro fermentation conditions, the addition of Asparagopsis taxiformis, Colpomenia sinuosa and bromoform can inhibit the ruminal CH₄ production and modify the rumen fermentation pattens, whereas Sargassum and Eucheuma do not exhibit anti-methanogenic effects.

This experiment was conducted to study the mechanism of red clover enhancing anti-immune stress in rabbits based on network pharmacology method and molecular docking technology. All the components of red clover were obtained through the HERB database, the active ingredients and corresponding related targets of red clover were obtained according to the information calculated by the SwissADME database and SwissTarget Preliminary platform, and the potential targets of anti-immune stress in rabbits were mined by combining the disease information platforms GeneCard and OMIM, and the protein-protein interaction (PPI) network was constructed by using the target data, and the gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were carried out, finally, the Autodock software and PyMOL software were used to molecularly dock and visualize the core targets with the corresponding components to verify the docking activity. The results showed that there were 29 active ingredients corresponding to 344 potential targets for anti-immune stress in rabbits, including 49 key targets, and the top 10 degree value were caspase 3 (CASP3), epidermal receptor growth factor (EGFR), estrogen receptor 1 (ESR1), proto-oncotyrosine protein kinase (SRC), matrix metalloproteinase 9 (MMP9), prostaglandin G/H synthase 2 (PTGS2), peroxisome proliferator-activated receptor γ (PPARG), Toll-like receptor 4 (TLR4), phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit α isoform (PIK3CA), tyrosine protein kinase Nyn (FYN). GO analysis showed that the target functions included 92 biological processes, 21 cellular components and 32 molecular functions, and 123 pathways were enriched by KEGG pathway (P<0.05), and the core targets were mainly involved in cancer pathway, prostate cancer, endocrine therapy resistance, estrogen signaling pathway, phosphatidylinositol 3-kinase-protein kinase pathway, breast cancer, lipid and atherosclerosis, glioma, chemocarcinogenic-receptor activation, interleukin-17 signaling pathway and other pathways. Finally, through molecular docking verification, the calculated binding chemical energy was less than 0 kJ/mol, indicating that the active ingredient of red clover and the corresponding core target could be spontaneously and stably combined. In conclusion, this study reveal that the red clover has multi-component, multi-target and multi-channel anti immune stress effects in rabbits through network pharmacological methods and molecular docking technology, which provide a theoretical basis for the development and application of red clover.

This experiment was conducted to investigate the effects of diets supplemented with different levels of Camellia oleifera protein powder on the growth performance, slaughter performance, serum biochemical indexes and muscle flavor substances contents of yellow feathered broilers. A total of 384 male fast-onset yellow-feathered broilers aged 28 days with similar body weight and healthy condition were randomly divided into 4 groups (8 replicates per group and 12 chickens per replicate): the broilers in the control group were fed a basal diet, and the others in the three experimental groups were fed the basal diet supplemented with 1%, 2% and 4% Camellia oleifera protein powder to replace some corn and soybean meal, respectively. The experiment lasted for 28 days. The results showed as follows: Compared with the control group, there were no significant differences in slaughter weight at 56 days of age, average daily gain, average daily feed intake and feed to gain ratio of broilers in 1% and 2% Camellia oleifera protein powder groups (P>0.05); with the dietary Camellia oleifera protein powder supplemental level increasing, the slaughter weight at 56 days of age and average daily gain of broilers were linearly decreased (P<0.05), and the average daily feed intake was linearly and quadratic changed (P<0.05). 2) With the dietary Camellia oleifera protein powder supplemental level increasing, the abdominal fat percentage of broilers was linearly decreased (P<0.05); there were no significant differences in dressing percentage, eviscerated yield percentage, half-eviscerated yield percentage, breast muscle percentage and leg muscle percentage of broilers among groups (P>0.05). 3) With the dietary Camellia oleifera protein powder supplemental level increasing, the contents of serum total cholesterol and high-density lipoprotein cholesterol were linearly decreased (P<0.05). 4) Compared with the control group, the contents of lysine, threonine, arginine, glutamic acid, tyrosine, alanine, proline and total amino acid, total sweet amino acid, total flavor amino acid and total umami amino acid in breast muscle of broilers in 2% Camellia oleifera protein powder group were significantly increased (P<0.05), while the content of myristate was significantly decreased (P<0.05). In conclusion, dietary supplementation of 1% to 2% Camellia oleifera protein powder has no effect on growth performance, slaughter performance and serum biochemical indexes of yellow feather broilers; dietary supplementation of 2% Camellia oleifera protein powder can decrease the percentage of abdominal fat and increase the content of flavor amino acids in muscle of broilers.

This experiment was conducted to study the effects of lactic acid bacteria preparation on fermentation quality, nutritional value and nutrient in vitro degradation rates of mixed silage of corn straw and Suaeda salsa with different ratios. The fresh corn straw and Suaeda salsa were selected with 30 kg each, and mixed based on 5 mixing ratios (100% corn straw, 75% corn straw and 25% Suaeda salsa, 50% corn straw and 50% Suaeda salsa, 25% corn straw and 75% Suaeda salsa, 100% Suaeda salsa), named 100∶0, 75∶25, 50∶50, 25∶75 and 0∶100 groups, with 2 treatments in each ratio, included control (CON, sprayed sterile normal saline) and Lactobacillus plantarum group (LP, sprayed 1×10⁶ CFU/g Lactobacillus plantarum). Each treatment contained 4 replicates with 1 kg per replicate, and anaerobic fermentation for 60 days. The results showed as follows: 1) the yeast number of 25∶75 and 0∶100 groups was significantly lower than that of other groups (P<0.05), and the lactic acid bacteria number of 50∶50, 25∶75 and 0∶100 groups was significantly higher than that of other groups (P<0.05). The lactic acid bacteria preparation had no significant effects on yeast and lactic acid bacteria numbers (P>0.05). 2) The pH of 0∶100 group was significantly higher than that of other groups (P<0.05), the lactic acid content of 50∶50 and 25∶75 groups was significantly higher than that of other groups (P<0.05), and the acetic acid, propionic acid and butyric acid contents of 0∶100 group was significantly higher than that of other groups (P<0.05). The lactic acid bacteria preparation had no significant effects on pH and organic acid contents (P>0.05). 3) With the Suaeda salsa ratio increased, the organic matter, neutral detergent fiber and acid detergent fiber contents were significantly decreased (P<0.05), and the crude protein and ether extract contents were significantly increased (P<0.05). The ammonia nitrogen content of 0∶100 group was significantly higher than that of other groups (P<0.05), and the water-soluble carbohydrate content was significantly lower than that of other groups (P<0.05). The lactic acid bacteria preparation had no significant effects on nutrient components (P>0.05). 4) At 24, 48 and 72 hours after in vitro digestion, the in vitro degradation rate of crude protein of 50∶50 and 25∶75 groups was significantly higher than that of other groups (P<0.05), and the in vitro degradation rate of organic matter of 0∶100 group was significantly higher than that of other groups (P<0.05). The lactic acid bacteria had no significant effects on in vitro degradation rates of nutrients at each time point (P>0.05). In conclusion, comprehensive all indices, the recommended mixing ratios of mixed silage of corn straw and Suaeda salsa are 75∶25 and 50∶50.

This experiment was conducted to study the effects of partial replacement of corn with over-aged paddy rice at different husking levels on growth performance, slaughter performance and intestinal health of broilers. Nine hundred 12-day-old white-feather broilers were randomly divided into 3 groups, with 10 replicates per group and 30 chickens (half male and half female) per replicate. Chickens in the control group (CON group) were fed a basal diet. The partially husked rice group (CCM group) used 20% and 30% partially husked rice (incompletely husked over-aged paddy rice) to replace corn during the 12 to 24 days of age and 25 to 38 days of age stages, respectively. The brown rice group (CM group) used 20% and 30% brown rice (completely husked over-aged paddy rice) to replace corn during the 12 to 24 days of age and 25 to 38 days of age stages, respectively. The experimental period lasted for 27 days. The results showed as follows: 1) there were no significant differences in growth performance and slaughter performance indexes of broilers among all groups (P>0.05). 2) Duodenum relative weight of broilers in CCM group was significantly higher than that in CON and CM groups (P<0.05), and jejunum unit length weight of broilers in CM group was significantly higher than that in CON group (P<0.05); compared with CON group, intestinal gas production in CCM and CM groups showed a decreasing trend (P=0.077). 3) Partial replacement of corn with partially husked rice or brown rice had no significant effect on cecal microbiota α-diversity of broilers (P>0.05), but significantly affected microbiota β-diversity (P<0.05); the relative abundances of Bacteroidetes and Bacteroides of cecal microbiota in CON group were significantly higher than those in CCM and CM groups (P<0.05), while the relative abundances of Firmicutes and Oscillospira were significantly lower than those in CCM and CM groups (P<0.05). 4) Partial replacement of corn with partially husked rice could reduce the feed cost by 0.22 CNY per chicken and the feed cost for weight gain by 0.05 CNY per kilogram. In conclusion, partial replacement of corn with partially husked rice or brown rice processed from over-aged paddy rice in the diets at 12 to 38 days of age has no adverse effects on growth performance and slaughter performance of broilers, and improves intestinal development and the structure and function of intestinal microflora. Combining economic benefits, it is recommended to partially replace corn with partially husked rice in broiler diets, with a replacement ratio of 20% in the middle chicken stage (12 to 24 days of age) and 30% in the big chicken stage (25 to 38 days of age).

The purpose of this experiment was to explore the influencing factors of isoflavone content in red clover and the best extraction conditions by thermal reflux. By selecting four different varieties of red clover, the isoflavone contents in their leaves and stems were analyzed respectively to determine the effects of varieties and plant parts on the isoflavone contents. Box-Behnken design was used to design a response surface experiment with three factors and three levels. The solid to liquid ratio, extraction temperature and extraction time were the factors affecting the extraction efficiency, the yield of isoflavones in red clover was taken as the investigation basis, and 80% ethanol was used as the extraction solvent to determine the best extraction conditions. The results showed as follows: 1) the Xuanli variety of red clover had the highest total isoflavone content, which was 5.92 g/kg DM, and significantly higher than that in the other three varieties (P<0.05); the total isoflavone content and mass percentage in leaves of red clover were significantly higher than those in stems (P<0.05). 2) The optimum extraction conditions were as follows: the solid to liquid ratio was 1∶18 (g∶mL), the extraction temperature was 90 ℃, and the extraction time was 1 h. Under these conditions, the isoflavone yield was 93.71%. It can be seen that the variety of red clover significantly affects the isoflavone content, and the isoflavone enrichment degree in leaves is higher than that in stems. This experiment successfully screened out the best extraction conditions of red clover isoflavones, which provided effective data support for industrial production of red clover isoflavones.

This experiment was conducted to explore the effects of Lactiplantibacillus plantarum and Enterococcus faecium on fermentation quality and bacterial community of hybrid Broussonetia papyrifera silage, and to provide technical references for the development and utilization of hybrid Broussonetia papyrifera. There were 4 treatments as follows: the CK treatment was supplemented 10 mg/kg deionized water, the LP treatment was inoculated 5×10⁶ CFU/g FM Lactiplantibacillus plantarum, the EF treatment was inoculated 5×10⁶ CFU/g FM Enterococcus faecium, and the LPEF treatment was inoculated 5×10⁶ CFU/g FM Lactiplantibacillus plantarum and Enterococcus faecium (number ration 1∶1), each treatment contained 5 replicates, fermentation for 60 days. The results showed as follows: 1) at ensiled 7, 14, 30 and 60 days, the water soluble carbohydrate (WSC) content of LP treatment was significantly lower than that of CK treatment (P<0.05); at ensiled 14, 30 and 60 days, the WSC content of EF treatment was significantly lower than that of CK treatment (P<0.05). 2) At ensiled 3, 7, 14 and 30 days, the pH of LP and EF treatments was significantly lower than that of CK treatment (P<0.05); at ensiled 14 and 60 days, the ammoniacal nitrogen content of LP, EF and LPEF treatments was significantly lower than that of CK treatment (P<0.05); at ensiled 14 days, the lactic acid content of LP, EF and LPEF treatments was significantly higher than that of CK treatment (P<0.05); at ensiled 3, 7 and 14 days, the lactic acid bacteria number of LP, EF and LPEF treatments was significantly higher than that of CK treatment (P<0.05); at ensiled 3, 7, 30 and 60 days, the aerobic stability number of LP treatment was significantly lower than that of CK treatment (P<0.05); at ensiled 7, 14, 30 and 60 days, the mold number of LP, EF and LPEF treatments was significantly lower than that of CK treatment (P<0.05). 3) At ensiled 3, 30 and 60 days, the main phyla in hybrid Broussonetia papyrifera silage was Firmicutes (60.37% to 83.37%), followed by Proteobacteria (15.70% to 31.72%). 4) At ensiled 3 days, the relative abundance of Aerococcus of CK treatment was significantly increased (P<0.05), and the relative abundance of Enterobacter of LPEF was significantly increased (P<0.05); at ensiled 60 days, the relative abundance of Lactobacillus of LP was significantly increased (P<0.05), and the relative abundance of Enterococcus of LPEF was significantly increased (P<0.05). In conclusion, the addition of Lactiplantibacillus plantarum and Enterococcus faecium in hybrid Broussonetia papyrifera silage affect the bacterial community composition, improve the relative abundance of the Lactobacillus, reduce the pH, increase the lactic acid content, improve the fermentation quality, and it has the potential to improve the quality of hybrid Broussonetia papyrifera silage.

This study aimed to investigate the effects of compound fermentation of Bacillus licheniformis and Lactobacillus plantarum on the nutritional components and in vitro rumen fermentation characteristics of steam-exploded corn straw. Corn straw was randomly divided into 4 groups: control group (CON group, untreated), steam explosion group (Q group, steam explosion treatment), microbial fermentation group (J group, microbial fermentation treatment), steam explosion+microbial fermentation group (JQ group, steam explosion+microbial fermentation treatment). The strains added to the microbial fermentation groups were Bacillus licheniformis (5×10⁶ CFU/g) and Lactobacillus plantarum (1.2×10⁶ CFU/g). Each group had 5 replicates. After 45 days of fermentation, the bags were opened and sampled to detect relevant indicators. The results showed as follows: 1) compared with the CON group, the contents of dry matter (DM), acid detergent fiber (ADF), neutral detergent soluble (NDS) and soluble carbohydrate (WSC) in the Q and JQ groups were significantly increased (P<0.05), and the contents of neutral detergent fiber (NDF) and hemicellulose (ADS) were significantly decreased (P<0.05). 2) Compared with the CON group, the 72 h cumulative gas production (GP_{72 h}) in the Q and JQ groups decreased significantly (P<0.05), and the JQ group was lower than the Q group (P<0.05). 3) Compared with the CON group, the in vitro crude protein degradability (IVCPD) in the J, Q and JQ groups was significantly increased (P<0.05). The in vitro neutral detergent fiber degradability (IVNDFD) and in vitro acid detergent fiber neutral detergent fiber (IVADFD) in the Q and JQ groups were significantly decreased (P<0.05). Moreover, the IVCPD in the JQ group was significantly lower than that in the Q group (P<0.05). 4) Compared with CON group, the pH of Q and JQ groups increased significantly (P<0.05), and the concentrations of ammonia nitrogen (NH₃-N) and microbial protein (MCP) decreased significantly (P<0.05). The concentrations of acetic acid, butyric acid and total volatile fatty acid (TVFA) in the Q group decreased significantly compared with CON group (P<0.05), and the concentration of MCP in the JQ group was significantly higher than that of Q group (P<0.05). 5) Correlation analysis showed that IVDMD was significantly negatively correlated with IVOMD, FOM and RENB (P<0.05). IVNDFD and IVADFD were significantly negatively correlated with ADF, WSC, NDS contents and NH₃-N concentration (P<0.05), and significantly positively correlated with GP_{72 h} and MCP concentration (P<0.05). There was a significant positive correlation between IVCPD and RDP (P<0.05). In summary, the compound fermentation of Bacillus licheniformis and Lactobacillus plantarum is helpful to increase the MCP concentration of corn straw treated by steam explosion.

The purpose of this experiment was to screen bacterial strains exhibiting good tolerance, antibacterial activity, and high cellulase production, in order to provide high-quality candidates for the development of feed microecological preparations. Initially, the treated cattle manure sample stock solution was selectively cultured on sodium carboxymethylcellulose (CMC-Na) medium. Strains with desirable traits were primarily screened using Congo red staining and secondarily screened using the DNS method. Subsequently, the target strain was characterized through morphological, physiological, and biochemical analysis, as well as 16S rDNA sequencing. Fermentation conditions were optimized using a single-factor approach. Concurrently, antibiotic susceptibility, stress resistance, in vitro antibacterial activity, and hemolytic activity assays were conducted to evaluate its probiotic properties and safety. The results showed that the successful isolation of one Bacillus amyloliquefaciens strain with high cellulase production. The maximum cellulase activity reached 126.37 U/mL. The strain exhibited good tolerance to simulated gastric and intestinal fluids, along with antibacterial activity against Escherichia coli, Mycobacterium tuberculosis, and Staphylococcus aureus. It was sensitivity to most common antibiotics and was non-hemolytic. Crucially, no detectable mobile drug resistance genes, virulence genes, or pathogenic genes were identified. In conclusion, the Bacillus amyloliquefaciens isolated from cattle manure in this study has good probiotic potential and safety, and can be used as a candidate strain for feeding probiotics.

This experiment aimed to isolate strains with low antibiotic resistance, higher safety, and probiotic potential from the feces of wild Milvus migrans. Fresh fecal samples of wild Milvus migrans were collected. After isolating the strains, morphological observation, Gram staining microscopy and biochemical identification were carried out. PCR amplification and 16S rRNA sequencing were used to identify the species and genus of the isolated strains, and in vitro probiotic potential determination and in vivo safety evaluation were conducted on them. The results showed as follows: 1) one strain of Priestia megaterium was isolated from the feces of wild Milvus migrans in this experiment and named Priestia megaterium YF9. 2) The survival rates of this strain were 9.16%, 65.98% and 83.77% under the conditions of pH 2, 4, and 6, respectively, and 74.91%, 59.95% and 9.44% under the conditions of bile salt concentrations of 0.1%, 0.2% and 0.3%, respectively. 3) The auto-aggregation rate of this strain was 55.43% after 4 hours and as high as 91.76% after 24 hours. 4) The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging rate of this strain was 60.85%. 5) This strain was only intermediate to erythromycin and clindamycin, showed sensitivity to the remaining 12 antibiotics, and had no hemolytic activity. 6) This strain had a good inhibitory effect on Staphylococcus aureus. 7) After intragastric administration of this strain, no mice died. There were no abnormalities in their morphology, hair, secretions, and excreta. No bleeding was observed in the organs during the autopsy, and no abnormalities were found macroscopically. There were no significant changes in body weight and hematological parameters (P>0.05). In conclusion, the Priestia megaterium YF9 isolated from the feces of wild Milvus migrans in this experiment has low antibiotic resistance, good in vitro probiotic potential, and in vivo safety, and can be used as a candidate strain for animal probiotic preparations.

This experiment was conducted to screen and identify probiotics with high cellulase activity from the rumen of yaks, providing a reference for their subsequent application as feed additives in animal husbandry. In the experiment, LB-carboxymethyl cellulose solid medium and Congo red staining were used to isolate and preliminarily screen the cellulase-producing bacteria. Then, the dinitrosalicylic acid (DNS) method was used for re-screening to obtain bacteria with high cellulase activity. Finally, the morphological, physiological and biochemical, molecular biological and probiotic identification were conducted on them, and the enzyme production conditions were optimized. The results showed as follows: 1) a total of 10 strains with the ability to degrade cellulose were screened and obtained in the experiment. Among them, 5 strains were Bacillus amyloliquefaciens, 3 strains were Bacillus licheniformis, and 2 strains belonged to Bacillus. 2) The activities of exoglucanase and endoglucanase of strain YR3.2 (as Bacillus amyloliquefaciens) were significantly higher than those of the other strains (P<0.05), which were 78.09 and 54.69 U/mL, respectively. 3) Except for a few strains that were resistant to tetracycline and erythromycin, most strains were susceptible to eight antibiotics and had good inhibitory effects on Escherichia coli and Staphylococcus aureus. None of the 10 strains contained the virulence factor genes of ace, gelE and cylA. The surface hydrophobicity rate and self-agglutination rate of strain YR3.2 were the highest, which were 97.55% and 80.84%, respectively. 4) The optimal combination of enzyme production conditions for strain YR3.2 was initial pH of 7.0, time of 36 h, and temperature of 35 ℃. Under these conditions, the carboxymethyl cellulase activity was 72.78 U/mL. After 7 days of liquid fermentation, the loss rates of rapeseed straw and oat straw were 18.52% and 23.34%, respectively. In conclusion, strain YR3.2 has high cellulase activity and probiotic properties, and can be used as a candidate strain in forage processing and animal husbandry.