Plant ingredients included some essential nutrients such as water, sugars, proteins, fats, as well as the production of their secondary metabolites—polyphenols, flavonoids, phytosterols, etc. Studies have found that some plant ingredients can maintain the intestinal health of dogs by affecting the types and structures of intestinal microbiota, improving intestinal oxidative stress, and reducing proinflammatory cytokines. Therefore, based on the effects of intestinal microbiota on the health of dogs, this study aimed to explore the potential nutritional and health benefits of plant ingredients for dogs, so as to provide reference for improving the intestinal health of dogs and rational canine diet formulation.

Short chain fatty acid (SCFA) plays an important role in regulating the metabolism, endocrine and immune functions of animals and humans. More and more studies have focused on the involvement of SCFA in regulating a variety of neurochemical pathways through the highly correlated gut brain axis, affecting brain physiology and behavior including emotion, cognition and neural response, and playing a key role in body health. At present, there are few studies directly exploring the potential mechanism of SCFA as a key mediator targeted intervention on gut and brain functions and gut brain axis. This review summarized the role of SCFA in gut brain communication and the pathways that SCFA directly or indirectly mediates gut brain interaction, so as to provide theoretical reference for SCFA to further study the mechanism of gut brain axis.

Feeding frequency refers to the number of feeding times per unit time (one day) for feeding animals, which is an important factor affecting the digestion and absorption of nutrients in animals. Moreover, feeding frequency can also play a regulatory role in nitrogen metabolism and nitrogen deposition. Therefore, it is vital in pig production to explore the appropriate feeding frequency in order to improve feed utilization and alleviate feed waste to a certain extent. In this paper, the effects of feeding frequency on feed intake and nitrogen utilization of swine were reviewed to provide a reference for scientific feeding and management in pig production.

Implantation of porcine embryos occurs through extensive cell motility and remodeling. The successful implantation of the embryo depends primarily on the success of the embryo in extending and nourishing the tight connection between the trophectoderm and the endometrial epithelium, which ensures that the gestational body takes up the secretory substances of the uterine gland epithelium necessary for its survival. These processes require uterine and embryo-derived cytokines to complete cell remodeling between endometrium and trophoblast ectoderm, create pro-inflammatory microenvironment during embryo attachment, maintain the balance of immune system during implantation, and coordinate the interaction between uterus and embryo. This paper mainly reviewed the roles and mechanisms of uterine and embryonic-derived cytokines including interleukin-1β (IL-1β), interferon (IFN), fibroblast growth factor (FGF), tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) during the implantation period of porcine embryos, in order to provide reference for the research of embryo attachment and development regulation.

The high incidence of milk fever in dairy cows can be compounded by other diseases and lead to high culling rates. The prevention of milk fever through nutritional means has become one of the animal husbandry top research priorities. Anionic diets regulate calcium metabolism in dairy cows by affecting their acid-base balance, which can effectively prevent the development of milk fever, but also have an impact on cow performance and health. This paper reviewed the mechanisms of calcium homeostasis regulation in dairy cows and related research on anionic diets in recent years, with a view to exploring the potential value of anionic diets and providing references for subsequent applications.

With the large increase in the raised number of pet cats, the incidence of chronic kidney disease (CKD) in cats has significantly increased, and the mortality rate is also significantly increased. Cats with CKD have a chronic disease of unilateral or bilateral renal structural and functional abnormalities for more than 3 months, which can cause permanent and irreversible renal damage. In recent years, the nutritional management of cat CKD has received more and more attention and research. Studies have shown that the nutritional structure management of cat diet plays an important role in the prevention of CKD. Management of the nutritional structure of the diet is essential to improve life quality and reduce mortality in cats with CKD. Different intakes of nutrients and nutritional management patterns have different effects on CKD. In order to provide reference for the prevention and treatment of cat CKD, this article reviewed the relevant research progress on the relationship between cat diet nutrients and CKD from the perspective of nutrition.

The endoplasmic reticulum (ER) was the place where proteins and lipids are biosynthesized and where transmembrane proteins are folded. Both pathological and physiological situations may disturb the function of the ER, resulting in endoplasmic reticulum stress (ERS). However, prolonged and severe ERS can lead to autophagy and/or the induction of cell apoptosis. Several studies implicated ERS as a major factor contributing to many diseases. Therefore, the modulation of ERS pathways has become a potential therapeutic target. Quercetin is a plant-derived secondary metabolite, which belongs to the flavonoids class which presents a range of beneficial effects. The finding of research in recent years, quercetin can decrease the body risk of cancer, liver and pancreas disease, cardiovascular disease, intestinal disease, and reduce organ/tissue damage by regulating ERS signaling, and maintain animal health. The present study mainly reviewed the action mechanism and research progress of quercetin regulating the ERS in animals. The review is aimed to provide a reference for the further development and utilization of quercetin, and also provide a new perspective for animals in treatment of ERS related diseases.

Silent information regulator 2-related enzyme 1 (SIRT1) is a member of the Sirtuins family, which deacetylates chromatin and non-histone proteins, and plays an important role in the regulation of milk fat, milk protein synthesis and mastitis. In this paper, we reviewed the molecular mechanism of SIRT1 regulating milk fat, milk protein synthesis and mastitis through AMP-activated protein kinase (AMPK), Janus kinases-2 (JAK2), mammalian target of rapamycin (mTOR) and nuclear factor-kappaB (NF-κB) signaling pathways, in order to provide theoretical support for milk fat, milk protein synthesis and targeted therapy of mastitis in dairy cows.

The main structure of diet formulas for traditional farming in China is dominated by corn and soybean meal, and the demand for imported soybean meal volume is large. In recent years, with the deterioration of the international environment, the price of protein feed materials has increased significantly. In order to promote the development of animal husbandry, to ensure the supply and quality safety of China's feed, and to implement the Ministry of Agriculture and Rural Affairs on the "efficiency reduction, open-source substitution" task deployment, the soybean meal reduction substitution has become the focus of today's livestock feed development and important direction. Therefore, this paper reviewed the application of alternative technology for soybean meal reduction for feed and the development and the development prospect of new protein feed in recent years, with a view to providing new ideas for the popularization of low protein diet technology and the development of unconventional feed resources in China.

Gastrointestinal tract is the largest and most complex organ in animal body, which is the front line of the body's defense. The structural and function integrity of the gastrointestinal tract is essential for maintaining animal health. Flavonoids are natural, safe and residue-free, which can improve the performance and regulate the gastrointestinal health of animals, so that they are not only expected to become a potential alternative to antibiotics, but also to develop more regulatory products beneficial to animal health. This article reviewed the regulatory effects of flavonoids on gastrointestinal morphology, barrier defense and important physiological defense functions, in aiming to provide a reference for further understanding the regulatory effects of flavonoids on animal gastrointestinal health and their application in animal production.

Proanthocyanidins (PACs) are important natural biologically active substances that are widely existing in various plants. Recent studies have shown that the addition of PACs from different sources in animal diets can regulate the diversity and composition of intestinal microbiota, and interact with the intestinal mucosal immune system through the microbiota and their metabolites to regulate the intestinal immune response. This paper reviewed the role of PACs played in shaping intestinal microbiota and their metabolites, and summarized the regulation of PACs on intestinal immune response and possible mechanisms, providing a reference for the basic research and application of PACs in improving animal intestinal health.

Pogostemon cablin, also known as wrinkled gianthyssop herb, is a traditional medicine homologous for food plant in China. Its stems and leaves have the effects of aromatizing turbidity, appetizing stomach and antiemetic, and releasing heatstroke. It is a commonly used Chinese medicine for digestive diseases and heatstroke. Patchouli oil is the main medicinal part of Pogostemon cablin, and plays an important role in promoting gastrointestinal peristalsis, antibacterial and anti-inflammatory, antioxidant and anti-stress. In recent years, it has been widely studied in animal husbandry. This paper reviewed the biological functions of Pogostemon cablin and its application in livestock production, aiming to provide some theoretical reference for the development and application of Pogostemon cablin as a green feed additive in livestock production.

Biological additives can improve the silage quality of silage, increase the utilization rate of silage, and solve the problem of unbalanced feed supply, thus further promoting the sustainable development of animal husbandry. Biological additives mainly include microbial additives and enzymes. How to give full play to the respective advantages of biological additives and form a synergistic effect has become the key to the efficient utilization of silage. Based on this, this paper analyzes and summarizes the application of biological additives in silage at home and abroad, and summarizes their effects on the fermentation quality, nutritional value, aerobic stability and animal production performance of silage. Additives should focus on the development of compound biological additives (strain combination and bacterial enzyme combination), in order to provide a scientific basis for the development of new compound biological additives with high efficiency, environmental protection, low cost and other advantages.

The purpose of this experiment was to study the effects of low protein diet using fermented canola meal instead of soybean meal on the growth performance, carcass traits and meat quality of finishing pigs. A single factor randomized trial was conducted. A total of 36 Duroc × (Landrace × Large white) crossbred pigs with initial body weight of (60±2) kg were randomly assigned to 3 experimental groups according to sex, with 6 replicates in each group and 2 pigs in each replicate (half male and half female). Pigs in control group and low protein group (LP-SM group) were fed corn-soybean meal diets with crude protein contents of 14.03% and 11.79%, respectively. The pigs in low protein-fermented canola meal group (LP-CM group) was fed diets using fermented rapeseed meal instead of 50% soybean meal, and the dietary crude protein content was 11.81%. Feeding experiment was terminated when pigs reached around 110 kg, all pigs were slaughtered and sampled. The results showed as follows: 1) compared with the control group, no significant difference in growth performance or carcass traits was observed among the three groups (P>0.05). 2) Compared with control group, the activity of serum glutathione peroxidase was significantly higher than that in LP-SM group (P<0.05). Compared with LP-SM group, the total antioxidant capacity of muscle in LP-CM group was significantly decreased (P<0.05). 3) Compared with LP-SM group, the redness value of longissimus dorsi muscle in LP-CM group decreased significantly at 24 and 48 h post slaughter (P<0.05). 4) Longissimus dorsi muscle in the LP-CM group tended to be better flavor (P=0.075) when compared with the control and LP-SM groups (P<0.05). Compared with LP-SM group, the low protein-fermented canola meal diet significantly reduced the turbidity of broth (P<0.05). 5) In the longissimus dorsi muscle, there was no significant difference in content of intramuscular fat among groups (P>0.05), while the content of inosine monphosphate (IMP) was significantly increased in the LP-CM group when compared with the other groups (P<0.01). 6) No significant difference in the content of total fatty acids among groups was observed (P>0.05). When compared with the control group, the contents of C18:1(cis-9) and total monounsaturated fatty acid in LP-CM group were increased (P<0.05), while the contents of C18:2(all-cis-9,12), C20:2(all-cis-11,14) and total polyunsaturated fatty acid were decreased (P<0.05). In conclusion, partial substitution of fermented canola meal for soybean meal on the basis of low protein diet has no negative impact on the growth performance and carcass traits of finishing pigs. Using fermented canola meal in the low protein diet fed to finishing pigs improves IMP content, sensory scores and fatty acid composition of pork.

This experiment aimed to study the whole intestinal number changes of the dominant Lactobacilli in small intestine of piglets before and after weaning, and to study the metabolic differences of some dominant Lactobacilli by comparative metabolomics. The dominant Lactobacilli in small intestine of suckling piglets at 21 days of age were isolated using the gradient dilution and culture-based method. Besides, twenty-four 21-day-old weaned Landrace×Large Yorkshire cross-breed barrows with an average body weight of (7.00±0.50) kg were selected and divided into 4 groups with 6 replicates in each group and 1 pig in each replicate. At 21, 24, 28 and 35 days of age, one piglet from each group was selected and slaughtered, the luminal contents from stomach, jejunum, ileum, caecum and colon were collected and the numbers of different kinds of Lactobacilli in the samples were quantified by real-time PCR. In addition, three dominant Lactobacilli strains were selected for the comparative metabolomics study. The results showed that five dominant Lactobacilli strains were isolated and identified as Lactobacillus amylovorus, Limosilactobacillus reuteri, Lactobacillus johnsonii, Limosilactobacillus mucosae and Ligilactobacillus salivarius. The number of Lactobacilli in the stomach and intestine of piglets was decreased and gradually recovered after weaning, but did not reach the level of suckling period. After weaning, the dominant Lactobacilli in the stomach were Ligilactobacillus salivarius, Limosilactobacillus mucosae and Lactobacillus amylovorus; the dominant Lactobacilli in the small intestine and large intestine were Lactobacillus amylovorus, Limosilactobacillus reuteri and Lactobacillus johnsonii, however, there were difference in the number of three Lactobacilli in different intestinal segments. The comparative metabolomics and liquid chromatographic analysis showed that the major differential metabolic pathways were arginine biosynthesis in amino acid metabolism and citric acid cycle in carbohydrate metabolism of Lactobacillus amylovorus, Limosilactobacillus reuteri and Limosilactobacillus mucosae. This study provides the basis for the dietary regulation of Lactobacilli composition and metabolism in different parts of the intestinal tract of weaned piglets and improve intestinal function and health of weaned piglets.

The objective of this study was to investigate dynamic change of expression of genes related apoptosis and autophagy signal pathways in jejunum of weaned piglets after lipopolysaccharide (LPS) challenge at different time points. A total of 42 weaned piglets with body weight of (7.09±0.90) kg were randomly divided into 7 treatments according to different time points after LPS injection. There were 6 replicates in each treatment and 1 piglet in each replicate. After 14 days of preliminary feeding, the piglets were intraperitoneally injected of 100 μg/kg BW LPS. Piglets were slaughtered before (0 h) and 1, 2, 4, 8, 12 and 24 h after LPS injection, respectively. Jejunal samples were selected to measure the mRNA expression of apoptosis and autophagy signals. The results showed as follows: after LPS challenge, the mRNA relative expression level of Fas ligand (Fasl) significantly increased at 12 and 24 h (P<0.05). The mRNA relative expression levle of B-cell lymphoma XL proyein (Bcl-xl) significantly decreased at 2 h (P<0.05); the mRNA relative expression level of cystein-asparate protease 3 (Caspase 3) significantly increased at 2 h after LPS challenge (P<0.05); the mRNA relative expression level of Bcl-2 associated X protein (Bax) significantly increased at 12 h (P<0.01); the mRNA relative expression level of the mammalian target protein of rapamycin (mTOR) significantly decreased at 1 and 2 h (P<0.05); the mRNA relative expression level of microtubule-associated protein 1A/1B-light chain 3 (LC3) and Unc-51 kinase 1 (ULK1) significantly increased at 1 h (P<0.05); the mRNA relative expression level of autophagy-related gene 16 (Atg16) and autophagy adaptor protein 1 (SQSTM1) significantly increased at 4 h (P<0.01). In conclusion, LPS challenge activates apoptosis and autophagy signal pathways in jejunum of weaned piglets.

In this experiment, the research data of weaned piglets challenged with enterotoxigenic Escherichia coli and lipopolysaccharide as the injury model were collected and Meta analyzed to explore the effects of probiotics on the growth performance of the intestinal injury model in weaned piglets. By searching the databases of CNKI, PubMed, Web of Science and Science Direct, randomized controlled trials related to the effects of probiotics on the growth performance of the weaned piglets' intestinal injury model were screened. And the trials with both injury treatment groups and probiotic intervention injury treatment groups were included in this study. From June 30, 1999 to April 20, 2022, 12 related in vivo study references were screened for inclusion in this trial, with a total sample of 909 cases, and Review Manager 5.4 was used to analyze the included studies. Select the standardized mean difference (SMD) as the effect indicator. The results showed that the addition of probiotic feeding could effectively increase the average daily gain of weaned piglets [SMD=1.35, 95% CI=0.86 to 1.83, P<0.000 01], affect the average daily feed intake [SMD=0.46, 95% CI=-0.16 to 0.76, P<0.000 01], and reduce the feed/gain [SMD=-1.10, 95%CI=-1.61 to -0.59, P<0.000 01]. These results suggest that probiotic preparations can improve the growth performance of the intestinal injury model in the weaned piglets.

This experiment was conducted to study the effects of dietary different levels of Ganoderma lucidum powder on performance, egg quality, immune function and antioxidant ability of local hens. A total of 280 healthy 38-week-old meat and egg dual-purpose type local hens with similar body weight and laying rate were selected and randomly divided into 4 groups with 5 replicates per group and 14 hens per replicate. Hens in the control group were fed a basal diet, while others in experimental groups were fed basal diets supplemented with 2, 4 and 6 g/kg Ganoderma lucidum powder, respectively. The pre-experimental period lasted for 10 days, and the experimental period lasted for 56 days. The results showed as follows: 1) compared with the control group, the laying rate of experimental groups was significantly increased (P<0.01). 2) Compared with the control group, the egg weight of experimental groups was significantly decreased (P<0.05), and the albumen height and Haugh unit of 4 g/kg group and 6 g/kg group were significantly increased (P<0.01). 3) Compared with the control group, the contents of immunoglobulin A (IgA), immunoglobulin M (IgM), interferon-γ (INF-γ) and interleukin-2 (IL-2) in serum of experimental groups were significantly increased (P<0.01), and the serum immunoglobulin G (IgG) content of 4 g/kg group and 6 g/kg group was significantly increased (P<0.01). 4) Compared with the control group, the serum total antioxidant capacity (T-AOC) of 2 g/kg group was significantly increased (P<0.01), and the serum superoxide dismutase (SOD) activity of 4 g/kg group and 6 g/kg group was significantly increased (P<0.01). In conclusion, under the conditions of this experiment, dietary Ganoderma lucidum powder can increase the laying rate of local hens, improve the egg quality and antioxidant ability, enhance the immune function, and the optimal supplemental level is 4 g/kg.

This study was aimed to investigate the effects of Sini powder with Pueraria mixture on liver lipid metabolism and redox status of late-phase laying hens. Two hundred and forty 400-day-old Hy-Line brown laying hens were randomly divided into 4 groups with 6 replicates per group and 10 hens per replicate. Hens in the control group (CON group) were fed a basal diet, and others in experimental group were fed basal diets supplemented with 1 (SP1 group), 2 (SP2 group) and 3 g/kg (SP3 group) Sini powder with Pueraria mixture, respectively. The experiment lasted for 30 days. The results showed as follows: 1) compared with the CON group, the egg laying rate of SP3 group was significantly increased (P<0.01), the average egg weight of SP1 and SP3 groups was significantly decreased (P<0.05), the abdominal fat rate of SP1, SP2 and SP3 groups was significantly decreased (P<0.05), the liver index of SP2 and SP3 groups was significantly decreased (P<0.05 or P<0.01), and the spleen index of SP1 and SP3 groups was significantly increased (P<0.05). 2) Compared with the CON group, the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) in liver of SP1, SP2 and SP3 groups were significantly decreased (P<0.01), and the total antioxidant capacity and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in liver of SP3 group were significantly increased (P<0.01). 3) Compared with the CON group, the contents of triglyceride (TG) and low density lipoprotein-cholesterol (LDL-C) in liver of SP1, SP2 and SP3 groups were significantly decreased (P<0.05 or P<0.01), the liver total cholesterol (TC) content of SP3 group was significantly decreased (P<0.01), the liver high density lipoprotein-cholesterol (HDL-C) of SP1 and SP3 groups was significantly increased (P<0.05 or P<0.01), and the liver free fatty acid (FFA) content of SP1 and SP2 groups was significantly decreased (P<0.05). 4) Compared with the CON group, the mRNA relative expression levels of liver X receptor alpha (LXRα), sterol regulatory element-binding protein 1 (SREBP1) and acetyl CoA carboxylase (ACACA) in liver of SP2 and SP3 groups were significantly decreased (P<0.05 or P<0.01), and the mRNA relative expression levels of peroxisome proliferator activated receptor alpha (PPARα), acyl-CoA oxidase1 (ACOX1) and carnitine palmity1 transferase 1A (CPT1A) in liver of S3 groups were significantly increased (P<0.05 or P<0.01). In conclusion, the Sini powder with Pueraria mixture can decrease the liver fat accumulation and improve lipid metabolism by improving liver redox status, inhibiting liver fat synthesis and promoting liver fat decomposition of late-phase laying hens.

This experiment was conducted to investigate the effects of dietary threonine level on growth performance, carcass quality, fat metabolism and immune function of yellow-feathered broilers from 43 to 63 days, so as to determine the optimal threonine requirement. One thousand and six hundred 43-day-old Lingnan yellow-feathered broilers were selected and randomly divided into 5 groups with 8 replicates in each group and 40 chickens in each replicate. The chickens in the five groups were fed the diets containing 0.50% (basal diet), 0.57%, 0.64%, 0.71% and 0.78% threonine, respectively. The experiment lasted for 21 days. The results showed as follows: 1) dietary threonine level could significantly affect the ratio of feed to gain of yellow-feathered broilers from 43 to 63 days of age (P<0.05), and the ratio of feed to gain in 0.57%, 0.64%, 0.71% and 0.78% threonine groups was significantly lower than that in 0.50% threonine group (P<0.05), but had no significant effects on the average daily gain and average daily feed intake (P>0.05). There was a significant quadratic correlation between dietary threonine level and the ratio of feed to gain (P<0.05). According to the regression equation of the ratio of feed to gain, the optimal dietary threonine level for yellow-feathered broilers was 0.68%, the daily threonine requirement was 0.61 g, and the ratios of threonine to lysine, methionine and tryptophan were 0.76, 1.94 and 4.00, respectively. 2) The eviscerated yield percentage in 0.64%, 0.71% and 0.78% threonine groups was significantly higher than that in 0.50% and 0.57% threonine groups (P<0.05). The meat color brightness (L^*) value of breast muscle in 0.78% threonine group was significantly lower than that in 0.50% and 0.64% threonine groups (P<0.05), and the meat color redness (a^*) value of breast muscle in 0.71% and 0.78% threonine groups was significantly higher than that in 0.50% and 0.64% threonine groups (P<0.05). 3) The serum triglyceride content in 0.78% threonine group was significantly lower than that in 0.50% and 0.64% threonine groups (P<0.05), the serum low density lipoprotein cholesterol content was significantly lower than that in 0.50% threonine group (P<0.05), and the serum insulin content was significantly higher than that in 0.50% threonine group (P<0.05); the serum insulin like growth factor-1 content in 0.64% and 0.71% threonine groups was significantly higher than that in 0.50% threonine group (P<0.05). 4) The T lymphocyte proliferation rate in peripheral blood in 0.64%, 0.71% and 0.78% threonine groups was significantly higher than that in 0.50% and 0.57% threonine groups (P<0.05). According to the regression equation of T lymphocyte proliferation rate, the optimal dietary threonine level for yellow-feathered broilers was 0.75%, the daily threonine requirement was 0.67 g, and the ratios of threonine to lysine, methionine and tryptophan were 0.83, 2.14 and 4.41, respectively. In conclusion, under the conditions of this experiment (the crude protein and lysine levels in the basal diet were 17% and 0.50%, respectively), dietary supplementation with appropriate threonine can improve the growth performance, carcass quality and meat quality of yellow-feathered broilers from 43 to 63 days of age, and significantly affect the fat metabolism. Based on the ratio of feed to gain, the optimal threonine level and daily threonine requirement for yellow-feathered broilers from 43 to 63 days of age are 0.68% and 0.61 g, and the ratios of threonine to lysine, methionine and tryptophan are 0.76, 1.94 and 4.00, respectively.

The aim of this experiment was to study the effects of mixed nano-vitamins A, D and E on performance, intestinal morphology, immune organ indexes, serum immunoglobulin levels and antioxidant indices of broilers. The trial was conducted with 630 1-day-old Arbor Acres (AA) broilers, were randomly allotted to 6 groups consisting of 7 replicates with 15 chickens per replicate. In the control group (CV-100 group), ordinary vitamins A, D and E were added to the basal diet (1 to 21 days of age: vitamin A 9 750 IU/kg, vitamin D₃ 3 750 IU/kg, vitamin E 18 IU/kg; 22 to 42 days of age: vitamin A 7 800 IU/kg, vitamin D₃ 3 000 IU/kg, vitamin E 14 IU/kg), and in the experimental group, mixed nano-vitamins A, D and E were added to the basal diet with the additive amount of 100% (NV-100 group), 90% (NV-90 group), 80% (NV-80 group), 70% (NV-70 group) and 60% (NV-60 group) of the control group. Trial period was 42 days in total. The results showed that the addition of mixed nano-vitamins A, D and E with the additive amount of 60% to 90% of ordinary vitamins A, D and E in the diet had no significant effects on the body weight, average daily gain, average daily feed intake, feed/gain ratio and immune organ indexes of broilers (P>0.05), but significantly increased the total evisceration rate of broilers (P<0.05). The villus height and villus height/crypt depth ratio in jejunum and ileum of 21-day-old broilers in NV-80 group were significantly higher than those in control group (P<0.05). The serum immunoglobulin A (IgA), immunoglobulin M (IgM) and immunoglobulin G (IgG)levels of 21- and 42-day-old broilers in NV-80 group were significantly higher than those in control group (P<0.05). The activities of catalase (CAT) and glutathione peroxidase (GSH-Px) in serum of 21-day-old broilers in NV-80 group were significantly higher than those in control group (P<0.05). In conclusion, dietary supplementation of mixed nano- vitamins A, D and E can improve the total evisceration rate, intestinal development, immune function and antioxidant ability of broilers, and the effect of 80 % nano-vitamins A, D and E replacing ordinary vitamins A, D and E is better.

This experiment aimed to investigate the effects of L-malic acid on growth performance, meat quality and antioxidant capacity of broilers. A total of 288 one-day-old Arbor Acres (AA) broilers were randomly divided into 4 groups with 6 replicates per group and 12 broilers per replicate. The experiment lasted for 42 days. Broilers in the control group were fed a basal diet, and the others in the T1, T2 and T3 groups were fed diets supplemented with 0.40%, 0.80% and 1.20% L-malic acid based on the basal diet, respectively. The results showed as follows: 1) compared with the control group, the average daily gain (ADG) at 1 to 21, 22 to 42 and 1 to 42 days of age of T1 group was significantly increased (P<0.05), and the ratio of feed to gain (F/G) at 22 to 42 and 1 to 42 days of age was significantly decreased (P<0.05); the ADG at 22 to 42 days of age in T2 group was significantly increased (P<0.05), and the F/G at 1 to 42 days of age was significantly decreased (P<0.05). There were no significant differences in average daily feed intake (ADFI) and death rate among all groups (P>0.05). 2) Compared with the control group, at 42 days of age, the half evisceration rate and abdominal fat rate of broilers in all experimental groups were significantly increased (P<0.05), the dripping loss and shear force were significantly decreased (P<0.05), and the total evisceration rate of broilers in T1 group was significantly increased (P<0.05). There were no significant differences in dressing percentage, breast muscle rate, leg muscle rate, and muscle pH_{45 min}, pH_{24 h}, meat color [brightness (L^*), redness (a^*) and yellowness (b^*) values] and cooking loss among all groups (P>0.05). 3) Compared with the control group, serum total antioxidant capacity (T-AOC) in experimental groups was significantly increased at 21 and 42 days of age (P<0.05), and the total superoxide dismutase (T-SOD) activity was significantly increased at 42 days of age (P<0.05); serum glutathione peroxidase (GSH-Px) and catalase (CAT) activities in T2 and T3 groups were significantly increased at 42 days of age (P<0.05); serum malondialdehyde (MDA) content in T1 and T3 groups was significantly decreased at 42 days of age (P<0.05). In conclusion, supplementation of 0.40% L-malic acid can significantly increase the ADG, half evisceration rate, total evisceration rate and abdominal fat rate, and significantly reduce the F/G, muscle dripping loss and shear force of broilers. supplementation of 1.20% L-malic acid can significantly increase the serum T-AOC and T-SOD, GSH-Px, CAT activities, and significantly reduce the serum MDA content of broilers. Based on the indexes of growth performance and meat quality, the quadratic regression analysis model shows that the suitable supplemental level of L-malic acid in diets for broilers is 0.47% to 0.59%.

The experiment aimed to study the effects of dietary crude protein (CP) and lysine (Lys) levels on growth performance and serum biochemical indexes of Beijing You Chickens (BYC) during brooding period. A total of 1 350 one-day-old mixed BYC were randomly divided into 9 groups with 5 replicates, each replicate 30 chickens (half male and half female). A 3×3 factorial design was adopted, dietary CP levels were 17%, 18% and 19%, and dietary Lys levels were 0.85%, 1.00% and 1.15%, respectively. Growth performance was measured at 0 to 3 weeks of age, 4 to 6 weeks of age and 0 to 6 weeks of age, and serum biochemical indexes were measured at 6 weeks of age. The results showed as follows: 1) dietary CP levels had significant effects on weekly average feed intake and weekly body weight gain from 4 to 6 weeks of age (P<0.05), the 19% CP group had the highest weekly average feed intake and the highest weekly body weight gain; Lys levels had effects on feed to gain ratio (F/G) from 4 to 6 weeks of age (P<0.05), among which the 1.00% Lys had the lowest F/G. During 0 to 6 weeks age, dietary CP levels had significant effects on weekly average feed intake (P<0.05), with the increase of CP level, the weekly average feed intake also increased gradually and reached the maximum at 19%; Lys level had effects on the weekly body weight gain and F/G (P<0.05), and the weekly body weight gain in 1.0% and 1.15% Lys groups were higher than in 0.85% Lys group (P<0.05), and F/G was lower than in 0.85% Lys group; the weekly body weight gain was affected by dietary CP and Lys levels in interaction (P<0.05); when dietary CP level was 19% and lysine level was 1.15%, the weekly body weight gain was the highest. 2) Serum uric acid (UC) content was affected by CP levels (P<0.05), and the UC content in the 19% CP group was higher than that in 17% and 18% CP groups (P<0.05); serum albumin content was affected by Lys levels, and the albumen content in 1.15% Lys group was higher than that in 0.85% and 1.00% Lys groups (P<0.05). In conclusion, the present study indicates that dietary CP levels affect the feed intake and dietary Lys levels affect the body weight gain and F/G, and the interaction affect the body weight gain. The suggested CP and Lys levels are 19% and 1.15% for BYC aged from 0 to 6 weeks of age.

This experiment was conducted to study the effects of new compound antioxidants on growth performance, meat quality and antioxidant function of cyan-shank partridge chickens. A total of 2 880 healthy 1-day old cyan-shank partridge chickens with similar weight were randomly divided into 6 groups: control group (basal diet), vitamin E group (basal diet+100 mg/kg vitamin E), ethoxyquin (EQ) group (basal diet+250 mg/kg EQ), X1 group (basal diet+150 mg/kg new compound antioxidant), X2 group (basal diet+300 mg/kg new compound antioxidant), X3 group (basal diet+450 mg/kg new compound antioxidant), there were 8 replicates in each group, 60 replicates in each group. The test period was 54 days. The results showed as follows: 1) compared with the control group, the feed/gain (F/G) of cyan-shank partridge chickens aged 1 to 54 days in X1, X2, X3 groups significantly decreased (P<0.05); compared with EQ group and control group, the average daily gain (ADG) of cyan-shank partridge chickens aged 22 to 54 days and 1 to 54 days in X3 group was significantly increased (P<0.05). 2) Compared with the control group, the muscle brightness in X1, X2 and X3 groups decreased significantly (P<0.05); compared with EQ group and control group, the muscle shear force in X2 group and X3 group decreased significantly (P<0.05), and the muscle cooking loss in X2 group decreased significantly (P<0.05); compared with vitamin E group, EQ group and control group, the redness of muscle in X3 group was significantly increased (P<0.05). 3) Compared with the control group, the catalase (CAT) activity in serum of cyan-shank partridge chickens at 21 and 54 days of age in X1 group significantly increased (P<0.05), the glutathione peroxidase (GSH-Px) activity in serum of cyan-shank partridge chickens at 54 days of age in X2 group significantly increased (P<0.05), and the contents of malondialdehyde (MDA) in kidney, heart and serum of cyan-shank partridge chickens at 21 and 54 days of age significantly decreased (P<0.05); compared with vitamin E group, EQ group and control group, the activity of superoxide dismutase (SOD) in the kidney of cyan-shank partridge chickens at 21 and 54 days of age in X2 and X3 groups significantly increased (P<0.05), the activity of GSH-Px in the kidney and pectoral muscle of cyan-shank partridge chickens at 21 and 54 days of age in X3 group significantly increased (P<0.05), and the content of MDA in the pectoral muscle of cyan-shank partridge chickens at 21 and 54 days of age significantly decreased (P<0.05). It can be seen that the growth performance of cyan-shank partridge chickens can be significantly improved by adding new compound antioxidants to the feed, and 300 or 450 mg/kg of new compound antioxidants can significantly improve the meat quality and antioxidant function of cyan-shank partridge chickens

The purpose of this experiment was to study the effects of dietary copra meal and compound enzyme supplemental levels on antioxidant and lipid metabolism indexes of laying ducks. Five hundred and seventy-six healthy Longyan ducks with similar body weight during egg production peak stage were randomly allotted into 8 groups with 6 replicates per group and 12 ducks per replicate. Ducks were fed experimental diets with copra meal supplemental levels of 0, 6%, 12% and 18% and compound enzyme supplemental levers of 0 and 400 mg/kg according to a two-factor completely randomized trial design. The experiment lasted for 16 weeks. The results showed as follows: 1) dietary compound enzyme supplemental level had significant effects on the plasma glutathione peroxidase (GSH-Px) activity and liver GSH-Px and total superoxide dismutase (T-SOD) activities of laying ducks (P<0.05). 2) Dietary copra meal supplemental level had significant effect on the liver total cholesterol (T-CHO) content of laying ducks (P<0.05), dietary compound enzyme supplemental level had significant effects on the plasma free fatty acid (FFA) content and liver T-CHO and FFA contents of laying ducks (P<0.05), and there was a significant interaction between copra meal and compound enzyme supplemental levels on the plasma FFA content and liver triglyceride (TG) and FFA contents of laying ducks (P<0.05). 3) Dietary compound enzyme supplemental level had significant effects on the egg yolk TG content of laying ducks (P<0.05), and there was a significant interaction between copra meal and compound enzyme supplemental levels on the egg yolk malondialdehyde (MDA) content of laying ducks (P<0.05). 4) Dietary copra meal supplemental level had significant effect on the contents of monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA) and saturated fatty acid (SFA) in egg yolk of laying ducks (P<0.05). In conclusion, dietary compound enzyme can improve the body antioxidant function of laying ducks. The copra meal regulates the fatty acid deposition in egg yolk by affecting dietary fatty acids, and the complex enzyme may affect the lipid metabolism by regulating glucose metabolism.

The purpose of this study was to investigate the effects of different levels of sodium selenite (SS) and yeast selenium (SY) on laying performance, egg quality, egg selenium content and egg selenium conversion rate of laying ducks, and to explore their enrichment and elimination rules in duck eggs. A total of 540 healthy 44-week-old Longyan laying ducks with similar laying performance were randomly divided into 9 groups with 6 replicates in each group and 10 ducks in each replicate. The test period was 16 weeks, which divided into 12 weeks enrichment period and 4 weeks elimination period. In enrichment period, ducks in each group were fed the basal diet (control group, selenium content was 0.15 mg/kg) and basal diets supplemented with 0.3, 0.6, 0.9 and 1.2 mg/kg SS or SY (as selenium), respectively. In elimination period, ducks in each group were fed a basal diet. The results showed as follows: 1) in enrichment period, compared with the control group, dietary SS and SY had no effects on egg laying rate, average egg weight, daily egg mass and feed to egg ratio (P>0.05), but significantly increased the average daily feed intake (weeks 5 to 8, weeks 9 to 12 and weeks 1 to 12, P>0.05). In elimination period, compared with the control group, only dietary SY significantly increased the average daily feed intake (weeks 1 to 12, P<0.05). 2) Compared with the control group, dietary SS and SY had no effects on egg weight, egg shape index, eggshell strength, yolk color, eggshell weight, eggshell ratio and eggshell thickness (P>0.05), however, dietary SS significantly decreased the albumen height and Haugh unit (weeks 2, 4, 12 and mean value), and dietary SY also significantly decreased the protein height and Haugh unit (week 12 and mean value, P<0.05). 3) In enrichment period, compared with the control group, on days 3, 7, 14, 28, 56 and 84, dietary SS and SY significantly increased the egg selenium content (P<0.05), and SY was significantly higher than SS (P<0.05). In elimination period, compared with the control group, on days 3 and 7, dietary SS and SY significantly increased the egg selenium content (P<0.05), and SY was significantly higher than SS (P<0.05). 4) In enrichment period, compared with the control group, on days 3, 7, 28, and 56, dietary SS and SY significantly decreased the egg selenium conversion rate (P<0.05), and SY was significantly higher than SS (P<0.05). In elimination period, compared with the control group, on days 3 and 7, dietary SS and SY significantly increased the egg selenium conversion rate (P<0.05), and SY was significantly higher than SS (P<0.05). 5) The linear regression model was used to fit the egg selenium content, the results showed that the egg selenium content of SY was 4.418, 3.819, 4.381, 4.290,4.276 and 4.38 times of SS on days 3, 7, 14, 28, 56 and 84 days of enrichment period, respectively, and was 4.201, 4.208, 32.10 and 12.17 times of SS on days 3, 7, 14 and 21 in elimination period, respectively. 6) The egg selenium contents were 0.50 (dietary SS) and 0.72 mg/kg (dietary SY) at the supplemental level of 0.3 mg/kg for 3 days. According to the daily recommended amount of selenium-enriched duck eggs in different populations of Chinese residents, it was suggested that the daily intake of duck eggs (65 g) was 0.77 to 2.40 (dietary SS) and 0.53 to 1.67 (dietary SY), respectively. In conclusion, dietary supplementation of 0.3 to 1.2 mg/kg SS and SY increase the average daily feed intake of laying ducks, but decrease the albumen height and Haugh unit, and increase the egg selenium content. Compared with SS, the enrichment rate of SY in duck eggs increase and the elimination rate decrease. The egg selenium content of SY is about four times that of SS, and the egg selenium conversion rate is also higher than that of SS.

The aim of this experiment was to study the effects of dietary supplementation of sea buckthorn flavonoids on the growth performance, meat quality, serum biochemical indexes and immune organ indexes of Guangxi small hemp ducks. One hundred and twenty 4-week-old Guangxi small hemp ducks (female) were randomly divided into 4 groups with 6 replicates per group and 5 ducks per replicate. The ducks in control group were fed a basal diet, and those in the three experimental groups were fed the basal diet supplemented with 0.05%, 0.10% and 0.15% of sea buckthorn flavonoids, respectively. The trial consisted of a pre-test period and a test period, where the pre-test period was 7 days and the test period was 70 days. The results showed as follows: 1) diet supplemented with 0.05% to 0.15% sea buckthorn flavonoids had no significant effects on the final body weight, average daily gain (ADG), average daily feed intake (ADFI) and feed-to-gain ratio (F/G) of Guangxi small hemp ducks (P>0.05). 2) Compared with control group, diet supplemented with 0.05% and 0.10% sea buckthorn flavonoids significantly reduced the drip loss rate of chest muscle (P<0.05), and diet supplemented with 0.10% sea buckthorn flavonoids significantly reduced the pH_{45 min} of leg muscle (P<0.05). 3) On the day 35 of the test, compared with the control group, the serum glutathione peroxidase (GSH-Px) activity was significantly increased in the 0.05% group (P<0.05), the serum malondialdehyde (MDA) content was significantly decreased in the 0.10% group (P<0.05), the serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) contents were significantly decreased in the 0.15% group (P<0.05), and the serum high-density lipoprotein cholesterol (HDL-L) content, total superoxide dismutase (T-SOD) and copper-zinc superoxide dismutase (CuZn-SOD) activities were significantly increased in the 0.05%, 0.01% and 0.15% groups (P<0.05); on the day 70 of the test, compared with the control group, the serum T-SOD activity was significantly increased in the 0.10% and 0.15% groups (P<0.05), the serum triglycerides (TG) and LDL-L contents were significantly decreased in the 0.15% group (P<0.05), the serum CuZn-SOD activity was significantly increased in the 0.05%, 0.01% and 0.15% groups (P<0.05), and the serum MDA content was significantly decreased in the 0.05%, 0.01% and 0.15% groups (P<0.05). 4) Diet supplemented with 0.05% sea buckthorn flavonoids significantly increased the thymus index and spleen index of Guangxi small hemp ducks (P<0.05). On the day 35 of the test, the serum immunoglobulin G (IgG) content in the 0.05% group was significantly increased (P<0.05), and the serum immunoglobulin M (IgM) content in the 0.05%, 0.01% and 0.15% groups was significantly increased (P<0.05), while the serum immunoglobulin A (IgA) content in the 0.10% and 0.15% groups was significantly decreased compared with the control group (P<0.05); on the day 70 of the test, the serum IgA and IgM contents in the 0.05% group were significantly increased (P<0.05), while the serum IgG content in the 0.10% and 0.15% groups was significantly decreased compared with the control group (P<0.05). In conclusion, dietary supplementation of sea buckthorn flavonoids can improve the meat quality, regulate the lipid metabolism, enhance the antioxidant capacity and immunity of Guangxi small hemp ducks. To sum up, the suitable supplemental level of sea buckthorn flavonoids in the diet of Guangxi small hemp ducks aged from 5 to 14 weeks is 0.05%.

This experiment was conducted to investigate the effects of dietary n-6/n-3 polyunsaturated fatty acids (PUFA) ratio on growth performance, slaughter performance, serum lipid indices, intestinal morphology and breast muscle fatty acid composition of meat geese. A total of 120 thirty-two-day-old meat geese (Sanhua geese) with a body weight of (1.0±0.1) kg were randomly divided into 3 groups with 5 replicates per group and 8 geese per replicate. The dietary n-6/n-3 PUFA ratios of groups Ⅰ, Ⅱ and Ⅲ were 1:1, 6:1 and 12:1, respectively. The experiment lasted for 60 days. The results showed as follows: 1) dietary n-6/n-3 PUFA ratio had no significant effects on growth performance of meat geese (P>0.05). 2) The abdominal fat percentage of group Ⅱ was significantly lower than that of other two groups (P<0.05). 3) The serum low density lipoprotein cholesterol (LDL-C) content of group Ⅱ was significantly lower than that of other two groups (P<0.05). 4) The duodenal villus height of group Ⅱ was significantly higher than that of group Ⅰ (P<0.05), the ileal crypt depth of group Ⅱ was significantly lower than that of other two groups (P<0.05), and the ileal villus height/crypt depth of group Ⅱ was significantly higher than that of other two groups (P<0.05). 5) The contents of caprylic acrid γ-linolenic acid, α-linolenic acid, docosahexaenoic acid and n-3 PUFA in breast muscle of group Ⅱ were significantly higher than those of other two groups (P<0.05). In conclusion, when dietary n-6/n-3 PUFA ratio is 6:1, the abdominal fat percentage, serum LDL-C content and ileal crypt depth are the lowest, and the duodenal villus height and breast muscle n-3 PUFA content are the highest.

This experiment was conducted to investigate the effects of dietary bile acid (BA) on performance, nutrient apparent metabolic rates and serum biochemical indices of laying Japanese quails from 16 to 23 weeks of age. Nine hundred and sixty healthy laying Japanese quails of 16-week-old with similar laying rates were randomly divided into 4 groups with 6 replicates per group and 40 quails per replicate. The control group was fed a basal diet, and the experimental groups were fed the basal diets supplemented with 40, 80 and 120 mg/kg BA, respectively. The pre-experimental period lasted for 1 week, and the experimental period lasted for 6 weeks. The results showed as follows, compared with the control group: 1) dietary 80 mg/kg BA significantly increased the laying rate (P<0.05), and significantly decreased the feed to egg ratio (P<0.05); 2) dietary 40 to 120 mg/kg BA extremely significantly increased the crude protein apparent metabolic rate (P<0.01), and dietary 40 mg/kg BA significantly increased the apparent metabolic rates of total energy and dry matter (P<0.05); 3) dietary 40 to 120 mg/kg BA significantly decreased the serum aspartate aminotransferase activity (P<0.05), and dietary 40 and 120 mg/kg BA significantly decreased the ratio of albumin to globulin in serum (P<0.05). In conclusion, dietary BA can improve the performance, the apparent metabolic rates of crude protein, total energy and dry matter, and decrease the serum aspartate aminotransferase activity of and the ratio of albumin to globulin of laying Japanese quails; under the present experimental conditions, the optimal dietary supplemental level of BA is 80 mg/kg.[Chinese Journal of Animal Nutrition, 2023, 35(3):1658-1665]

The purpose of this study was to reveal the effects of selenium yeast supplementation during preperinatal period on metabolic components of milk and to elucidate the biological function of selenium yeast from the perspective of milk metabolites. Twenty healthy Holstein dairy cows in late pregnancy were randomly divided into control group and experimental group, with 10 cows in each group. Cows in the control group were fed a basal diet, and those in the experimental group were fed the basal diet supplemented with 0.15 g/kg DM yeast selenium for 21 days before the expected date of calving, and the supplementation was stopped on the day of calving. The milk of cows in the two groups was collected on the day of calving and day 21 after calving, and the milk metabolites were detected based on ultra-high liquid chromatography-tandem mass spectrometry. Principal component analysis, orthogonal partial least square discriminant analysis and single factor statistical analysis (t-test, fold change) were used to analyze the differences of metabolites in the milk of the control group and the experimental group on the day of calving and day 21 after calving. Differential metabolites were screened with variable importance in projection (VIP)>1 and P<0.05, and cluster analysis and pathway enrichment analysis were performed for the selected differential metabolites. The results show that a total of 20 different metabolites were screened in the milk on the day of calving after selenium yeast supplementation, among which energy-related metabolites, such as L-phenylalanine, α-lactose, galactose-1-phosphate and phosphohydroxypyruvic acid, et al, were significantly up-regulated (P<0.05), and the main metabolic pathway involved in differential metabolites was galactose metabolism [impact value of pathway topology analysis (Impact value)>0.1 and P<0.05]. A total of 20 differential metabolites were screened from the milk on day 21 after calving, among which inflammatory related metabolites, such as leukotriene A4, phytosphingosine, et al, were significantly down-regulated (P<0.05), and the metabolic pathway mainly involved in the biosynthesis of phenylalanine, tyrosine and tryptophan (Impact value>0.1 and P<0.05). In conclusion, the selenium yeast supplementation during preperinatal period can change the nutritional composition of milk on the day of calving and reduce the pro-inflammatory metabolites in milk on day 21 after calving, which indirectly affects the health of calves.

This experiment was conduced to study the effects of capsaicin on growth performance, nutrient apparent digestibility and serum biochemical and antioxidant parameters of Angus crossbred steers, and to explore the potential application of capsaicin of Angus beef cattle in fattening stage. Thirty Angus crossbreed steers with good body condition and similar body weight were selected and randomly divided into control group (CON group) and experimental group (EXP group) with 15 animals per group. The CON group was fed a basal diet, and the EXP group was fed the basal diet supplemented with 1.5 g/d capsaicin per cattle. The pre-experimental period lasted for 14 days, and the experimental period lasted for 90 days. The results showed as follows: 1) there were no significant effect on the body weight, average daily gain, dry matter intake and feed to gain ratio between the two groups (P>0.05). 2) Compared with the CON group, the dry matter apparent digestibility and rumen microbial protein content of the EXP group were significantly increased (P<0.01), and the crude protein apparent digestibility was significantly increased (P<0.05). 3) On day 90, compared with the CON group, the activities of alanine aminotransferase and aspartate aminotransferase in serum of the EXP group were significantly increased (P<0.01), the serum albumin content was significantly increased (P<0.05), and the contents of urea and triglyceride in serum were significantly decreased (P<0.05). In conclusion, dietary supplementation of capsaicin can improve the dry matter and crude protein apparent digestibility of Angus crossbred steers, increase the rumen microbial protein synthesis and serum albumin content, increase the activities of alanine aminotransferase and aspartate aminotransferase in serum, and reduce the contents of urea and triglyceride in serum, but have no significant effects on growth performance and antioxidant capacity.[Chinese Journal of Animal Nutrition, 2023, 35(3):1675-1683]

The purpose of this experiment was to study the effects of dietary niacin on serum biochemical, immune and antioxidant indexes of beef cattle under heat stress. Thirty-six healthy Jinjiang cattle with similar age and weight were selected and randomly divided into 3 groups with 4 replicates in each group and 3 cows in each replicate. The normal temperature group (TN group) and heat stress group (HS group) were fed a basal diet, and the heat stress+niacin group (HN group) was fed the basal diet supplemented with 800 mg/kg niacin. The TN group adopted a cooling system to ensure that the experimental cows were under suitable temperature conditions, while the HS group and the HN group were raised in a high temperature and high humidity environment in summer. The pre-experimental period lasted for 10 days, and the experimental period lasted for 60 days. The results showed as follows: 1) compared with TN group, the serum alkaline phosphatase (ALP) activity of HS group on days 30 and 60 was significantly decreased (P<0.05), the activities of lactate dehydrogenase (LDH), creatine kinase (CK) and alanine aminotransaminase (ALT) in serum on day 30 were significantly increased (P<0.05 or P<0.01), and the serum aspartate aminotransaminase (AST) activity on day 60 was significantly increased (P<0.05); compared with HS group, the activities of AST and ALT in serum on day 30 of HN group were significantly decreased (P<0.05). 2) Compared with TN group, the contents of total protein (TP), albumin (ALB) and glucose (GLU) in serum on days 30 and 60 of HS group were significantly decreased (P<0.05 or P<0.01), and the serum urea nitrogen (UN) content was significantly increased (P<0.05 or P<0.01); compared with HS group, the serum ALB content on day 30 of HN group was significantly increased (P<0.05), and the serum UN content was significantly decreased (P<0.05). 3) Compared with TN group, the serum immunoglobulin A (IgA) content on day 60 of HS group was significantly decreased (P<0.05), the serum immunoglobulin G (IgG) content on days 30 and 60 was significantly decreased (P<0.05), and the serum immunoglobulin M (IgM) content on days 30 and 60 was significantly decreased (P<0.05 or P<0.01); compared with HS group, the contents of IgA and IgG in serum on day 30 of HN group were significantly increased (P<0.05), and the serum IgM content on days 30 and 60 was significantly increased (P<0.05). 4) Compared with TN group, the serum superoxide dismutase (SOD) activity on days 30 and 60 of HS group was significantly decreased (P<0.05), the serum malondialdehyde (MDA) content on days 30 and 60 was significantly increased (P<0.05 or P<0.01), and the serum glutathione peroxidase (GSH-Px) activity and total antioxidant capacity (T-AOC) on day 30 were significantly decreased (P<0.05); compared with HS group, the serum GSH-Px activity on days 30 and 60 of HN group was significantly increased (P<0.05), the serum MDA content on days 30 and 60 was significantly decreased (P<0.05 or P<0.01), and the serum SOD activity and T-AOC on day 60 were significantly increased (P<0.05).5) Compared with TN group, the liver SOD activity of HS group was significantly decreased (P<0.05), and the liver MDA content was significantly increased (P<0.05); compared with HS group, the activities of SOD and GSH-Px in liver of HN group were significantly increased (P<0.05), and the liver MDA content was significantly decreased (P<0.05). In conclusion, heat stress can change the serum biochemical indexes of beef cattle and reduce the body immune function and antioxidant function; the addition of niacin in the diet can improve serum enzyme activities, improve the body immune function and antioxidant function, and effectively relieve beef cattle heat stress.

This experiment was conducted to investigate the effects of Pueraria polysaccharides on serum antioxidant and immune indexes and gut microbiota of calves. Twenty-four healthy (6.20±3.65) days of age Holstein calves with similar age body weight [(47.09±4.50) kg] were randomly divided into control group (group C) and test group (group T), each group contained 12 calves. Calves in group T were fed with 400 mg/kg Pueraria polysaccharides in the milk of each calve every day for 5 days, while others in group C were not added. The serum antioxidant indexes of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), nitric oxide synthase (NOS), catalase (CAT) activities and malondialdehyde (MDA) content, and immune indexes of CD4 molecules (CD4), immunoglobulin A (IgA), secretory immunoglobulin A (sIgA), immunoglobulin G (IgG) contents, the intestinally mucosal permeability index of diamine oxidase (DAO) activity, and the diversity and relative abundance of gut microbiota were detected on day 7. The results showed as follows: 1) compared with group C, the activities of SOD, CAT, NOS and GSH-Px in serum of calves of group T were increased by 10.16%, 1.79%, 7.05% and 3.43% (P>0.05), respectively, and the serum MDA content was decreased by 2.27% (P>0.05). 2) Compared with group C, the serum DAO activity of calves of group T was by 2.38% (P>0.05), and the contents of CD4, sIgA, IgA and IgG in serum were increased by 2.47%, 4.05%, 8.91% and 6.11% (P>0.05), respectively. 3) Compared with group C, the relative abundances of Bacteroidetes, Actinobacteria, Fusobacteria in gut of group T were increased, and the relative abundances of Firmicutes and Proteobacteria in gut were decreased. Compared with group C, the gut Bifidobacterium relative abundance of group T was significantly increased (P<0.05), the [Ruminococcus] gnavus group relative abundance was significantly decreased (P<0.05), and the Clostridium_sensu_stricto_1 relative abundance showed a down tendency (P=0.087). In conclusion, the Pueraria polysaccharides can improve the antioxidant capacity and immune function of calves, regulate the intestinal permeability, promote the growth of probiotics and inhibit proliferation of pathogen, so as to benefit the growth and development of calves.

In order to explore the distribution regularity and nutrient requirement of mineral elements copper, iron and zinc of 70 to 90 kg yak calves, twenty-one male yak calves with healthy physique and similar body weight [(60.44±4.59) kg] were selected and randomly divided into 3 groups, the test calves were slaughtered at an average body weight of 73.61, 81.96 and 96.53 kg, namely the initial slaughter group (BL group), the mid-term slaughter group (M group) and the final slaughter group (F group), respectively. The viscera (including blood), bone (including head and hoof), meat, fat, leather and fleece were weighed and recorded, the contents of mineral elements copper, iron and zinc in tissue were analyzed, the growth performance, slaughter performance and the distribution regularity of mineral elements in each group of calves were analyzed, and the predicted model of net growth requirements of mineral elements copper, iron and zinc of 70 to 90 kg yak calves was established. The results showed as follows: 1) with the body weight of yak calves increased, the slaughter body weight (SBW), empty body weight (EBW), dry matter intake, carcass weight, meat weight, viscera (including blood) weight and fleece weight were significantly increased (P<0.05). The bone weight of F group was significantly higher than that of BL group and M group (P<0.05), and the dressing percentage of M group was significantly higher than that of BL group and F group (P<0.05). 2) The proportion of copper and iron in the viscera (including blood) was the highest, the proportion of zinc in muscle was the highest, and the proportion of copper, iron and zinc in fat was less. 3) The contents of copper, iron and zinc in body of yak calves were highly correlated with EBW, the predicted model of net growth requirements and net growth requirements of copper, iron and zinc of 70 to 90 kg yak calves were: the net growth requirement of copper=4.402 5×EBW^{-0.122 8}, and the net requirement was 2.65 to 2.72 mg/kg EBW; the net growth requirement of iron=94.425 8×EBW^{0.003 9}, and the net requirement was 95.88 to 95.97 mg/kg EBW; the net growth requirement of zinc=5.193 9×EBW^{0.416 1}, and the net requirement was 26.55 to 29.19 mg/kg EBW. In conclusion, in this experiment, the net growth requirement parameters and the distribution regularity of copper, iron and zinc of 70 to 90 kg yak calves can be obtained, which provides a certain reference for the scientific feeding of yak calves.

The purpose of the study was to explore effects of feeding starter during lactation on growth performance and intestinal development of yak calves. Twenty healthy 1-month-old male yak calves with similar body weight of (30.79±3.43) kg were selected and randomly divided into 2 groups (control group and test group), each group contained 10 calves. The pre-feeding period was 30 days, and the experimental period was 165 days. During days 1 to 100, the yak calves in control group were fed with milk replacer and alfalfa hay, the yak calves in test group were fed with milk replacer, alfalfa hay and starter, and the yak calves in two groups were fed with the same amount of milk replacer and the dry matter feeding amount. During days 101 to 165, the yak calves in two groups stopped feeding milk replacer, and changed to feeding the same amount of concentrate and forage combination diet. The results showed as follows: 1) during days 1 to 100, the dry matter intake and body weight of yak calves in test group were significantly higher than those in control group (P<0.05); during days 101 to 165, the body weight and average daily gain of yak calves in test group were significantly higher than those in control group (P<0.05), and the feed to gain ratio was significantly lower than that in control group (P<0.05). 2) The peyer,s patches thickness in ileum of yak calves in test group was significantly higher than that in control group (P<0.05). The activities of trypsin in duodenum and jejunum, chymotrypsin in ileum and α-amylase in cecum of yak calves in test group were significantly higher than those in control group (P<0.05), while the activities of chymotrypsin in duodenum and α-amylase, lipase and cellulase in colon were significantly lower than those in control group (P<0.05). 3) There was no significant difference in the operation classification units (OTUs) and alpha diversity of bacterial flora in jejunum and colon between test group and control group (P>0.05). In jejunum, the relative abundance of Firmicutes at phylum level was the highest, and the relative abundance of Firmicutes in test group was significantly lower than that in control group (P<0.05); at genus level, the relative abundance of Alloprevotella in test group was significantly higher than that in control group (P<0.05). In colon, the relative abundances of Firmicutes and Bacteroidota at phylum level were higher, and there was no significant difference between the two groups (P>0.05); at genus level, the relative abundance of Lactobacillus in test group was significantly higher than that in control group (P<0.05). 4) The metabolic pathways significantly enriched in jejunum were phenylalanine metabolism and valine, leucine and isoleucine degradation, the differential metabolites were 2-phenylethylamine, 2-hydroxyphenylacetic acid and methylmalonate. The metabolic pathways significantly enriched in colon were nicotinate and nicotinamide metabolism, glycolysis/gluconeogenesis and citrate cycle (TCA cycle), et al, the differential metabolites were carboxylated coenzyme, phosphoenolpyruvic acid and oxaloacetate, et al. In conclusion, feeding starter during lactation can promote the growth and development of yak calves, it mainly promotes intestinal digestion, metabolism and immune function by regulating intestinal development and function, changing the richness of intestinal microorganisms and the concentration of metabolites, so as to improve the growth performance of yak calves.

The purpose of this experiment was to study the effects of dietary supplementation of oregano essential oil on meat quality and antioxidant capacity of beef at different postmortem aging time. Eighteen healthy Holstein dairy bulls approximately ten-month-old with similar body weight [(345.19±3.89) kg] were randomly assigned to 2 groups, the control group (CON group) and the oregano essential oil (OEO group), with 3 replicates per group and 3 bulls per replicate. They were fed a basal diet and extra provided 0 (CON group) and 20 g/(d·head) (OEO group) oregano essential oil, respectively. The pre-test period was 30 d, and the formal test period was 270 d. At the end of the feeding trial, six test bulls were selected from each group for slaughter, and 6.0 kg of the longissimus dorsi was taken and divided equally into five portions, stored in an aerobic environment at 4 ℃, and meat quality and antioxidant indexes were measured at 0, 1, 3, 5 and 7 d of postmortem aging, respectively. The results showed as follows: 1) the brightness (L^*) value respectively reached the highest value at the 5 and 7 d of postmortem aging in the CON group and OEO group, and both redness (a^*) value and yellowness (b^*) value reached the highest value at the 7 d of postmortem aging. The L^* value and a^* value in the OEO group were significantly higher than those in the CON group at the 1, 3, 5 and 7 d of postmortem aging (P<0.05), and the b^* value was significantly higher than that in the CON group at the 3 and 5 d of postmortem aging (P<0.05). 2) With the extension of aging time, the drip loss continued to decrease, and the water loss rate and cooking loss increased firstly and then tended to be stable. The drip loss in the OEO group was significantly lower than that in the CON group at 1, 3, 5 and 7 d of postmortem aging (P<0.05), and the water loss rate in the OEO group was significantly lower than that in the CON group at 5 d of postmortem aging (P<0.05). 3) There were no significant differences in marbling score and shear force between the two groups at all stages of postmortem aging (P>0.05). 4) The pH of CON group and OEO group reached the lowest value at the 5 d of postmortem aging, that was the ultimate pH (pHu). The pH of the OEO group was significantly lower than that of the CON group at the 5 and 7 d of postmortem aging (P<0.05). Muscle glycogen content was significantly higher in the OEO group than in the CON group at all stages of postmortem aging (P<0.05). 5) Compared with the CON group, the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) activities, total antioxidant capacity (T-AOC) and reduced glutathione (GSH) content were significantly increased in the OEO group at 0 d of postmortem aging (P<0.05); the GSH-Px and CAT activities were significantly increased in the OEO group at 1 d of postmortem aging (P<0.05); the glutathione S-transferase (GST) activity was significantly increased in the OEO group at the 3 d of postmortem aging (P<0.05); the SOD, GSH-Px activities, T-AOC and GSH content were significantly increased and the malondialdehyde (MDA) content and GST activity were significantly decreased in the OEO group at the 5 d of postmortem aging (P<0.05). In conclusion, dietary supplementation of oregano essential oil can improve the meat color and tenderness of beef at different postmortem aging time to some extent, improve the antioxidant capacity of beef at different postmortem aging time, especially improve the antioxidant capacity of beef at the 5 day of postmortem aging, reduce the pHu of beef, and also can reduce the water loss rate and drip loss of beef at different postmortem aging time to some extent, thus maintaining the water retention capacity of raw meat.

The purpose of this experiment was to study the energy requirement of Yunshang black goat growing and fattening rams. Fifty healthy Yunshang black goat growing and fattening rams with similar body weight (about 30 kg) were selected and randomly divided into 5 groups with 10 goats per group. Goats in 5 groups were fed experimental diets with metabolic energy (ME) levels of 8.01 (group 1), 8.70 (group 2), 9.39 (group 3), 10.07 (group 4) and 10.75 MJ/kg (group 5), respectively. The pre-experimental period lasted for 15 days, and the experimental period lasted for 30 days. The results showed as follows: 1) the average daily gain (ADG) of group 3 was significantly higher than that of other groups (P<0.05), the dry matter intake (DMI) of group 3 was significantly higher than that of groups 1, 2 and 5 (P<0.05), and the feed to gain ratio (F/G) of group 3 was significantly lower than that of other groups (P<0.05). 2) The crude protein apparent digestibility of group 3 was significantly higher than that of other groups (P<0.05), the phosphorus apparent digestibility of group 1 was significantly lower than that of other groups (P<0.05), the crude ash apparent digestibility of groups 2 and 3 was significantly higher than that of group 1 (P<0.05), and the apparent digestibility of neutral detergent fiber and acid detergent fiber of group 5 was significantly higher than that of group 1 (P<0.05). 3) The gross energy intake, methane energy, digestible energy and ME of groups 3, 4 and 5 were significantly higher than those of groups 1 and 2 (P<0.05), and the gross energy apparent digestibility of group 5 was significantly higher than that of group 1 (P<0.05). 4) Regression analysis on ADG, ME and metabolic body weight (W^0.75) of Yunshang black goat growing and fattening rams, the regression model of ME requirement was: ME=0.275 W^0.75+0.048 6 ADG (R²=0.824 5) Based on the above results, the maintenance ME requirement for Yunshang black goat growing and fattening rams is 0.275 MJ/(kg W^0.75·d), and the ME requirement per 100 g weight gain is 8.385 MJ/d.

The purpose of this experiment was to study the crude protein (CP) requirement of Yunshang black goats during growth period. According to a single factor experiment design, fifty healthy rams of Yunshang black goats with similar body weight of (28.16±1.13) kg during growing period were selected and randomly divided into five groups (10 goats in each group), goats were fed diets with CP levels of 8.54% (group 1), 10.59% (group 2), 12.56% (group 3), 14.51% (group 4), and 16.50% (group 5), respectively. Feeding trial was conducted for a pre-test period of 15 days and a formal test period of 30 days. Two 5 d digestion and metabolism tests were conducted using the total fecal and urine collection method on days 11 to 15 and days 26 to 30 of the formal test period, respectively. The results showed as follows: 1) with the dietary CP level increasing, the average daily gain (ADG) showed a trend of firstly increasing and then decreasing, and the ADG of group 3 was significantly higher than that of other groups (P<0.05); the dry matter intake (DMI) showed a trend of firstly increasing and then gradually remaining stable, and the DMI of groups 3, 4 and 5 was significantly higher than that of groups 1 and 2 (P<0.05); the feed to gain ratio (F/G) showed a trend of firstly decreasing and then increasing, and the F/G of group 3 was significantly lower than that of others groups (P<0.05). 2) With the dietary CP level increased, the CP intake, urinary CP content, digestible CP intake and CP deposition were significantly increased (P<0.05); the CP apparent digestibility was gradually increased, and the CP apparent digestibility of group 5 was significantly higher than of other groups (P<0.05). 3) The regression equation between CP deposition and CP intake during the growth period of Yunshang black goats was: CP deposition =0.532 CP intake-1.791 2 (R²=0.998 2), the intercept of this equation was the daily loss of endogenous urinary CP and metabolic fecal CP in Yunshang black goats during the growth period, which were 1.791 2 g/(kg W^0.75·d) for maintenance net protein requirement and 3.369 g/(kg W^0.75·d) for maintenance CP requirement. Combining the CP apparent digestibility mean and maintenance CP requirement data, the maintenance digestible CP requirement is 1.852 g/(kg W^0.75·d).

This experiment was conducted to investigate the effects of lamb milk replacer on growth performance, nutrient apparent digestibility, rumen fermentation parameters, microflora structure and health status of Leizhou goats. Forty-eight healthy male Leizhou goats with similar body weight at 20 days of age were divided into milk replacer group (fed milk replacer+starter) and milk group (fed milk+starter) with 24 replicates per group and 1 lamb per replicate. The pre-trial period lasted for 10 days and the experimental period lasted for 40 days. The results showed as follows: 1) the average body weight at 40 days of age, as well as the average daily gain and apparent digestibilities of dry matter, crude protein, ether extract and ash of lambs from 21 to 40 days of age in milk replacer group were significantly lower than those in milk group (P<0.05). From 21 to 40 days of age, the starter average daily feed intake in milk replacer group was significantly higher than that in milk group (P<0.05), but the average daily total feed intake was significantly lower than that in milk group (P<0.05), and the diarrhea rate was extremely significantly higher than that in milk group (P<0.01). 2) There were no significant differences in the average body weight at 60 days of age, as well as the average daily gain and nutrient apparent digestibility of lambs from 41 to 60 days of age and 21 to 60 days of age in milk replacer group compared with milk group (P>0.05). The starter average daily feed intake in milk replacer group from 41 to 60 days of age and 21 to 60 days of age was extremely significantly higher than that in milk group (P<0.01). The average daily total feed intake in milk replacer group from 41 to 60 days of age was significantly higher than that in milk group (P<0.05), but there was no significant difference between the two groups from 21 to 60 days of age (P>0.05). The diarrhea rate in milk replacer group from 41 to 60 days of age and 21 to 60 days of age was not significantly different from that in milk group (P>0.05). At 60 days of age, there were no significant differences in the contents of ammonia nitrogen and volatile fatty acids, acetic acid to propionate ratio and rumen microbial diversity indices between the two groups (P>0.05). The relative abundances of Firmicutes and Prevotella in rumen in milk replacer group was significantly higher than that in milk group (P<0.05), but there was no significant difference in the relative abundances of other bacteria between the two groups (P>0.05). The weaning survival rate in milk replacer group was 6.67 percentage points higher than that in milk group, and the weak lambing rate was 8.33 percentage points lower than that in milk group. In conclusion, compared with milk feeding, feeding milk replacer to weaned lambs at 20 days of age can reduce the growth performance and nutrient apparent digestibility and increase the diarrhea rate from 21 to 40 days of age. However, it has no significant effects on growth performance, nutrient apparent digestibility, rumen fermentation parameters, microflora structure and health status of lambs from 41 to 60 days of age, but can reduce the weak lambing rate.

The aim of this experiment was to explore the bacteria agent adding methods for improve the grape branch and leaf silage fermentation quality, and then prepare the wrapped package grape branch and leaf silage, clear the grape branch and leaf silage replacing part of corn silage and corn straw on the growth performance, slaughter performance, serum biochemical indexes and economic benefits of Kazakh sheep, provide the basis for the rich straw resources. Four treatments were used in the fermentation experiment, CK treatment (without adding any bacterial agent), EH treatment (supplemented with 5×10⁶ CFU/g FM Enterococcus hirae), M treatment (supplemented with 3% FM molasses), EHM treatment (combined supplemented with 5×10⁶ CFU/g FM Enterococcus hirae and 3% FM molasses), after 60 days of fermentation at room temperature, the bag was opened to detect the nutritional composition, fermentation quality and main microbial number. In the feeding experiment, twenty 3- month-old Kazakh sheep with similar body weight [(30.0±0.7) kg] were randomly divided into 2 groups with 10 sheep per group. Sheep in 2 groups were fed corn silage and corn straw type total mixed ration (CY group) and grape branch and leaf silage type total mixed ration (SP group), respectively. The pre-experimental period lasted for 7 days, and the experimental period lasted for 60 days. The results showed as follows: 1) compared with the grape branch and leaf raw material, the contents of neutral detergent fiber (NDF), acid detergent fiber (ADF) and pH and mold number of EHM treatment were significantly decreased (P<0.05), the lactic acid content and lactic acid bacteria number were significantly increased (P<0.05), and the silage effect of EHM treatment was optimal. 2) There were no significant differences on growth performance, slaughter performance and serum biochemical indexes between CY group and SP group (P>0.05). 3) Compared with CY group, the feed cost of SP group was significantly decreased (P<0.05), and the fattening profit was significantly increased (P<0.05). In conclusion, the combined addition of Enterococcus hirae and molasses can effectively improve the fermentation quality of grape branch and leaf silage, inhibit the growth of Escherichia coli and mold, and promote the propagation of lactic acid bacteria and the content of lactic acid. In addition, the grape branch and leaf silage replacing part of corn silage and corn straw in the diet of fattening Kazakh sheep can save the feed cost and increase economic benefits.

In this study, two non-starch polysaccharide (NSP) enzymes (cellulase and xylanase) were used to treat barley straw and corn straw, respectively. Three sheep with permanent rumen fistulas were used to evaluate the effects of NSP enzymes treatment on nutrient degradation rates, degradation parameters and effective degradation rate of barley straw and corn straw during different fermentation time (12, 24, 36, 48, 60 and 72 h) in sheep rumen by nylon bag method. The results showed that, cellulase and xylanase treatment significantly increased the degradation rates of dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of barley straw in rumen for 12 and 36 h and the degradation rate of crude protein (CP) in rumen for 12 h (P<0.05), but had no significant effects on the nutrient degradation rates of barley straw in rumen after 36 h (P>0.05). Cellulase and xylanase treatment significantly increased the DM degradation rate of corn stover in rumen for 12 h (P<0.05), and cellulase treatment significantly increased the degradation rates of ADF and CP of corn straw in rumen for 12 h (P<0.05). Cellulase and xylanase treatment significantly increased the rapid degradable fraction of DM, NDF, ADF and CP of barley straw (P<0.05), significantly improved the degradation rate of slow degradable fraction of DM, NDF and ADF (P<0.05), and significantly increased the effective degradation rate of barley straw NDF (P<0.05). Cellulase treatment significantly increased the rapid degradation fraction of DM and CP (P<0.05). By comprehensive analysis, the effect of cellulase and xylanase treatment on barley straw is better than that on corn straw, which can effectively improve the rumen degradation rate and utilization efficiency.

The purpose of this experiment was to study the effects of mannan oligosaccharides on feed intake, body weight and serum biochemical indexes of perinatal ewes. Sixty Hu sheep ewes in good condition, weighing (56.72±1.43) kg and 85 d of gestation were selected and divided into 4 groups with 15 ewes in each groups: group Ⅰ was fed a basal diet, and groups Ⅱ, Ⅲ and Ⅳ were fed the basal diet added with 2.5, 5.0 and 10.0 g/(sheep·d) mannan oligosaccharides, respectively. The pretrial period was 5 d, the period of the experiment was from 90 d of pregnancy to 14 d after delivery, and the day of delivery was recorded as the 0 d. During the experiment, the ewe's weight and feed intake were recorded, and serum samples were collected at days -60, -14 and 7, respectively, to determine immune and antioxidant indexes. The results showed as follows: 1) compared with group Ⅰ, the diet supplemented with mannan oligosaccharide significantly increased the prenatal dry matter intake (DMI) in group Ⅳ(P<0.05), but had no significant effect on the ewes'final weight (P>0.05). 2) Compared with group Ⅰ, the addition of mannan oligosaccharide in the diet significantly increased the contents of serum total protein (TP) and glucose (GlU) in groups Ⅲ and Ⅳ on day -14 (P<0.05). 3) Compared with group Ⅰ, the addition of mannan oligosaccharide in the diet significantly increased the contents of serum immunoglobulin A (IgA), interleukin-1β (IL-1β), γ-interferon (IFN-γ) and interleukin-10 (IL-10) in groups Ⅲ and Ⅳ on day -14, and significantly increased the content of serum immunoglobulin G (IgG) in groups Ⅱ, Ⅲ and Ⅳ on day -14 (P<0.05); the contents of serum IgG and IgA in group Ⅳ and the content of IL-10 in groups Ⅱ, Ⅲ and Ⅳ on day 7 were significantly increased (P<0.05). 4) Compared with group Ⅰ, the addition of mannan oligosaccharide in the diet significantly increased the serum total antioxidant capacity (T-AOC) and the activity of superoxide dismutase (SOD) in groups Ⅲ and Ⅳ on day -14 (P<0.05); the activity of serum glutathione peroxidase (GSH-Px) in groups Ⅱ, Ⅲ and Ⅳ on day 7 was significantly increased (P<0.05); but the content of serum malondialdehyde (MDA) had no significant difference among the groups (P>0.05). In conclusion, adding mannan oligosaccharides to the diet can improve the feed intake, nutrient metabolism capacity and immune function of ewes in the perinatal period.

This study was conducted to investigate the effects of sodium butyrate on growth performance, plasma indexes, rumen development of Hu lambs during suckling period. Forty newborn Hu lambs were selected and randomly divided into 2 groups according to the principle of similar body weight, there were 5 replicates in each group and 4 lambs in each replicate. Lambs in the sodium butyrate group (SB group) were orally administered 1.8 mL/kg BW sodium butyrate, and other in the control group (Con group) were orally administered the same volume normal saline. The experiment lasted for 35 days. The results showed as follows: 1) compared with the Con group, the dry matter intake during 29 to 35 days of age of SB group was significantly increased (P<0.05), and the average daily gain during 7 to 35 days of age was significantly increased (P<0.05). 2) Compared with the Con group, the plasma growth hormone content of SB group was significantly increased (P<0.05), and the D-lactate content was significantly decreased (P<0.05); the activities of total superoxide dismutase and catalase in plasma of SB group were significantly increased (P<0.05), and the malondialdehyde content was significantly decreased (P<0.05); the contents of immunoglobulin A and immunoglobulin G in plasma of SB group were significantly increased (P<0.05), and the tumor necrosis factor-α content was significantly decreased (P<0.05). 3) Compared with the Con group, the contents total volatile fatty acid (TVFA), acetic acid and butyric acid in rumen of SB group were significantly increased (P<0.05). 4) Compared with the Con group, the mRNA relative expression levels of insulin-like growth factor Ⅰ (IGF-Ⅰ), insulin-like growth factor Ⅰ receptor (IGF-ⅠR), insulin-like growth factor binding protein-5 (IGFBP-5), zonula occludens-1 (ZO-1), Claudin-1, monocarboxylate transporter isoform 1 (MCT1), sodium/proton exchanger isoform 3 (NHE3) and 3-hydroxy-3-methylglutaryl-CoA lyase (HMGCL) in rumen epithelium of SB group were significantly increased (P<0.05), and the B-cell lymphoma-2-associated X protein (Bax) mRNA relative expression level was significantly decreased (P<0.05). 5) The rumen TVFA content was significantly positively correlated with the mRNA relative expression levels of Claudin-1 and HMGCL in rumen epithelium (P<0.05 or P<0.01), and negatively correlated with the Bax mRNA relative expression level (P<0.01). The rumen butyric acid content was significantly positively correlated with the mRNA relative expression levels of IGF-Ⅰ, IGF-ⅠR, IGFBP-5 and sodium/proton exchanger isoform 1 (NHE1) (P<0.05), and negatively correlated with the Bax mRNA relative expression level (P<0.05). In conclusion, the sodium butyrate supplementation can improve the antioxidant capacity and immune function of lambs, inhibit the rumen epithelial cells apoptosis related genes expression, enhance the expression of genes related to rumen epithelial cells proliferation and development, volatile fatty acid uptake and metabolism, and improve the rumen fermentation function of lambs, so as to improve the growth performance of Hu lambs during suckling period.

This experiment was conducted to study the effects of compound probiotics on diarrhea rate, fecal microorganisms, immunoglobulin and inflammatory factor contents of lambs. Forty-eight healthy Hu sheep lambs aged 36 days of age (half male and half female) with body weight of (12.43±0.27) kg were divided into 4 groups with 3 replicates in each group and 4 lambs in each replicate according to sex and body weight. There were 3 replicates per group and 4 sheep per replicate. The experiment lasted for 31 days, including 10 days of pre-test. Lambs were conventional weaned at 60 days of age, the weaning diary was used for 0 d of the experiment. Control group was not treated, test groups Ⅰ, Ⅱ and Ⅲ were added with 0.5%, 1.0% and 1.5% compound probiotics (Lactobacillus RSG-1:Bacillus subtilis B-1:Bacillus licheniformis Y5-39=1:1:4), respectively. The diarrhea of lambs was recorded during the experiment, and blood and rectal fecal samples were collected on days -14, -7, 0, 3 and 7. Results showed as follows: 1) time significantly affected the diarrhea rate and diarrhea frequency (P<0.05), and the diarrhea rate and diarrhea frequency on days 1 to 7 were significantly higher than those on days -14 to 0. Treatment significantly affected the diarrhea frequency (P<0.05). The diarrhea frequency in test groups Ⅰ, Ⅱ and Ⅲ was lower than that in control group on days 1 to 7 and days -14 to 0. 2) Treatment and time significantly affected the number of Lactobacillus, Bifidobacterium, Escherichia coli and Salmonella (P<0.05). On days -7, 0, 3 and 7, the number of Lactobacillus and Bifidobacterium in test groups Ⅰ and Ⅱ were significantly higher than those in the control group (P<0.05). The number of Salmonella in group Ⅰ, the number of Escherichia coli and Salmonella in group Ⅱ were significantly lower than those in control group (P<0.05). 3) Treatment and time significantly affected the content of serum immune globulin (Ig) A, IgM and IgG (P<0.05). The content of IgG in serum on day 7 in test groups Ⅰ, Ⅱ and Ⅲ was significantly higher than that in the control group (P<0.05), and the contents of IgM and IgG in serum on days 3 and the 7 in test groups Ⅰ and Ⅱ were significantly higher than those in the control group (P<0.05). 4) Treatment and time significantly affected the contents of tumor necrosis factor-α (TNF-α), IL-1β, IL-6 in serum of lambs (P<0.05). Compared with the control group, TNF-α, IL-1β and IL-6 in test group Ⅰ showed a trend of decrease, and the contents of IL-1β on day -7, IL-6 on day 3 and TNF-α on day 7 in the test groups Ⅱ and Ⅲ were significantly lower than those in the control group (P<0.05). The contents of IL-6 and IL-1β in serum on day 3 in test group Ⅱwere significantly lower than those in the control group (P<0.05). In conclusion, adding compound probiotics to diet can improve intestinal flora and immunity of lambs, and reduce the rate of inflammation and diarrhea, and the optimal addition ratio is 1.0% under this experimental condition.

This experiment was conducted to investigate the effects of fucoidan on rumen microflora and metabolomics of weaned lambs. Sixty healthy 60-day-old weaned lambs (Chuanzhong black goat) with similar body weight of (12.5±0.5) kg were randomly divided into 4 groups with 15 lambs in each group. Lambs in control group (CON group) were fed a basal diet, and others in experimental groups were fed the basal diet supplemented with 0.1% (F1 group), 0.3% (F2 group) and 0.5% (F3 group) fucoidan, respectively. The re-experimental period lasted for 7 days, and the experimental period lasted for 30 days. The results showed as follows: 1) compared with the CON group, the final weight, average daily gain and average daily feed intake of F2 and F3 groups were significantly increased (P<0.05), and the feed to gain ratio of F1, F2 and F3 groups was significantly decreased (P<0.05). 2) Compared with the CON group, the rumen pH and of acetic acid, butyric acid and isobutyric acid contents and acetic acid/propionic acid of F1, F2 and F3 groups were significantly increased (P<0.05), and the rumen propionic acid content of F2 and F3 groups was significantly increased (P<0.05). 3) At phyla levels, compared with the CON group, the rumen Verrucomicrobia relative abundance of F1, F2 and F3 groups was significantly increased (P<0.05); the rumen Bacteroidetes relative abundance of F1 and F3 groups was significantly increased (P<0.05), and the Actinobacteria, Euryarchaeota and Spirochaetes relative abundances were significantly decreased (P<0.05). At genera levels, compared with the CON group, the relative abundances of unspecified_BS11, unspecified_RF16 and unspecified_S24_7 in rumen of F1 and F3 groups were significantly increased (P<0.05), and the unspecified_Lachnospiraceaea and unspecified_Veillonellaceae were significantly decreased (P<0.05). 4) The metabolomics results showed that in the positive ion mode, compared with the CON group, the rumen metabolite contents of carbohydrates, peptides, nucleic acids and hormones and transmitters of F1, F2 and F3 groups were significantly decreased (P<0.05), and the metabolite contents of organic acids, vitamins and cofactors, steroids and lipids were significantly increased (P<0.05). In the negative ion mode, compared with the CON group, the rumen metabolite contents of steroids and hormones and transmitters of F1, F2 and F3 groups were significantly decreased (P<0.05), and other metabolite contents were significantly increased (P<0.05). It is concluded that the fucoidan can improve the rumen fermentation and rumen microbial flora diversity and relative abundance of weaned lambs, and affect the rumen metabolites and metabolic pathways.

The objective of this experiment was to study the effects of feeding concentrate supplements containing different proportions of jujube-cotton meal on the growth and development and serum indices of donkey foals. Using single factor experimental design, 24 donkey foals (14 males, 10 females) (one month old) were selected and randomly divided into 3 groups, each group had 8 heads: the control group (feeding 100% corn-soybean meal supplement), test group 1 (feeding 50% jujube-cotton meal and 50% corn-soybean meal supplement), and test group 2 (feeding 100% jujube-cotton meal supplement). Each group had 8 head foals. The adjustment period was 7 days and the formal period was 56 days. The results showed as follows: 1) feeding 50% or 100% jujube-cotton meal concentrate supplements had no significant effects on the body weight, body size and feed intake of foals (P>0.05). Feeding 50% or 100% jujube-cottonseed meal concentrate supplements had no significant effects on the serum lipid and protein contents of foals (P>0.05). 2) Compared with the control group, feeding 50% jujube-cottonseed meal concentrate supplements significantly increased the serum superoxide dismutase activity (P<0.01), significantly increased the content of immunoglobulin M (IgM) (P<0.05), tended to increase the serum growth hormone content (0.05<P<0.10), and significantly decreased the serum malondialdehyde content (P<0.05). 3) Compared with the control group, feeding 100% jujube-cotton meal supplement increased the glucose and immunoglobulin M contents in serum of foals (P<0.05). It can be concluded that jujube-cotton meal concentrate supplement can replace corn-soybean meal supplement to feed suckling foals, which can increase the antioxidant capacity and immune function, and has a potential to promote their growth and development. The proper replacement proportion of jujube-cotton meal supplement is 50%.

The objective of this study was to compare the nutritive value and molecular structure characteristics in different parts (i.e. whole plant, stem, leaf and ear) of Festuca sinensis from Qinghai-Tibet plateau and provide the basic data for the establishment of rapid evaluation technology of nutrient value of plateau forage and the design of livestock diet formula. Conventional nutrient analysis and Cornell net carbohydrate and protein system (CNCPS) were applied to analyze the nutritional value in different parts of Festuca sinensis, at the same time, Fourier transform infrared spectroscopy (FTIR) technology was used to study the molecular structure of different parts and explore the correlation between them. The results showed as follows: 1) there were significant differences in protein components and molecular structure in different parts of Festuca sinensis (P<0.05). Among them, the contents of crude protein (CP), neutral detergent insoluble crude protein (NDICP), insoluble true protein (PB₁), amide Ⅱ peak height, α-helix peak height, β-helix peak height and α-helix peak height to β-helix peak height ratio were highest in ear, while those in stem were lower. Correlations were found between the protein molecular structural parameters and protein components. 2) There were significant differences in carbohydrate components and carbohydrate molecular structure in different parts of Festuca sinensis (P<0.05). Among them, the contents of starch and non-fiber carbohydrate (NFC) in ear were the highest, the contents of neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) and indigestible fiber (CC) in stem were the highest, and the structural carbohydrate peak area, the peak area and peak height of cellulose complex in stem were significantly higher than those in the whole plant and the other parts (P<0.05). The carbohydrate components in different parts of Festuca sinensis had strong correlation with its molecular structure parameters. In conclusion, there are significant differences in the nutritional value and molecular structure characteristics of various parts of Festuca sinensis. When designing the diet formula with Festuca sinensis as the main roughage source, attention should be paid to the combination of supplementary protein feed and the digestibility of the diet. In the next step, the basic data obtained in this study can be used to explore the establishment of rapid evaluation technology of nutritional value of Festuca sinensis.

The purpose of this study was to investigate the effects of different Ganoderma lucidum strains fermenting wheat straw on fiber degradation and nutrient change. Taishan Ganoderma lucidum (G1 group), Ganoderma lucidum HG (G2 group), Ganoderma sinense (G3 group) and Hong Ganoderma (G4 group) were selected to ferment wheat straw, and the control group (CON group) was inoculated with strains on wheat straw, 3 replicates per treatment, and all cultured at 23 °C for 48 d in the dark. After the fermentation, determined nutritional indexes of the substrate to screen the best strains. Results showed as follows: 1) compared with CON group, the pH and the contents of acetic acid, dry matter (DM), acid detergent lignin (ADL), crude fiber (CF), neutral detergent fiber (NDF) and hemicellulose (HC) in wheat straw fermented by Ganoderma lucidum fungi were significantly reduced (P<0.05); the contents of crude protein, crude ash (except G1 group), calcium, phosphorus and amino acids were significantly increased (P<0.05), but there was no significant effect on lactic acid and acid detergent fiber (ADF) contents (P>0.05). 2) Comparison among strains, the pH in G1 group was significantly lower than that in G4 group (P<0.05), the content of acetic acid was significantly higher than that in G3 and G4 groups (P<0.05), the content of arginine was significantly higher than that in G4 group (P<0.05), the content of DM was significantly higher than that in G4 group (P<0.01), the content of ether extract was significantly higher than that in G2, G3 and G4 groups (P<0.01), the content of NDF was significantly lower than that in G3 group (P<0.05), and the content of HC was significantly lower than that in G3 group (P<0.01); the content of ash in G3 group was significantly higher than that in G1 group (P<0.05), and the content of CF was significantly lower than that in G4 group (P<0.01); the content of ADL in G4 group was significantly lower than that in G3 group (P<0.01); mold, propionic acid and butyric acid were not detected in each group. The results indicate that Ganoderma lucidum fungi can effectively degrade the fiber content of wheat straw and improve its nutritional quality. Among them, Taishan Ganoderma lucidum has the best fermentation effect.[Chinese Journal of Animal Nutrition, 2023, 35(3):1863-1869]

This experiment was conducted to investigate the effects of hoarding time on the growth performance and nutritional quality of male Eriocheir sinensis (E. sinensis) in northern Jiangsu. Male healthy E. sinensis with the body weight of (118.10±1.35) g were selected in cages embedded in outdoor ponds. The test period was 90 d, and samples were sampled every 30 days. Detected growth parameters, the contents of conventional nutritional components, free amino acids and fatty acids of E. sinensis. Before hoarding (0 d) was control, 1 to 30 d was the 1^st hoarding stage, 31 to 60 d was the 2^nd hoarding stage, and 61 to 90 d was the 3^rd hoarding stage. The results showed as follows: 1) there were no significant differences in body weight and meat yield (MY) of E. sinensis in different hoarding time (P>0.05). 2) The body weight, hepatosomatic index (HSI), MY, total edible yield (TEY), survival rate (SR) and the contents of conventional nutritional components—crude protein, crude lipid and ash of E. sinensis showed a decreasing trend with the extension of hoarding time. The TEY and SR of E. sinensis in the 3^rd hoarding stage were significantly decreased compared with control and the 1^st and 2^nd hoarding stages (P<0.05). Compared with control, the gonadosomatic index (GSI) of E. sinensis in the 2^nd and 3^rd hoarding stages was significantly increased (P<0.05), while the HSI of E. sinensis in the 3^rd hoarding stage was significantly decreased (P<0.05). 3) Compared with the control, the contents of total non-essential amino acid (ΣNEAA) and total amino acid (ΣTAA) of the three edible tissues (hepatopancreas, gonad and muscle) of E. sinensis in each hoarding stage were decreased. 4) With the extension of hoarding time, the contents of total essential amino acids (ΣEAA), eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA) and total polyunsaturated fatty acids (ΣPUFA) of the three edible tissues increased firstly and then decreased, while the content of total saturated fatty acids (ΣSFA) decreased gradually. 5) In the 2^nd hoarding stage, the ΣPUFA and EPA+DHA content in hepatopancreas and gonad of E. sinensis were significantly higher than those of control (P<0.05). It is concluded that the nutrition of male E. sinensis is lost in the 1^st and 2^nd hoarding stages, however the nutritional quality is improved to a certain extent. While the growth performance and nutritional quality of male E. sinensis are obviously decreased in the 3^rd hoarding stage. It is suggested that the hoarding time cannot exceed 60 days under the conditions of this experiment.

This experiment was conducted to study the effects of dietary fermented silkworm excrement on growth, digestive, immune and inflammation of grass carp (Ctenopharyngodon idella). A total of 240 juvenile grass carp with initial average weight of (44.51±0.42) g were randomly divided into 5 groups with 3 replicates per group and 16 fish per replicate. Fish in 5 groups were fed experimental diets which the fermented silkworm excrement supplemental levels of 0 (control group), 5%, 10%, 15% and 20%, respectively. The experiment lasted for 8 weeks. The results showed as follows: 1) the final body weight, weight gain rate and specific growth rate of 15% and 20% fermented silkworm excrement groups were significantly lower than those of the control group (P<0.05), and the feed conversion rate was significantly higher than that of the control group (P<0.05). 2) The hepatosomatic index and viscerasomatic index of 10%, 15% and 20% fermented silkworm excrement groups were significantly lower than those of the control group (P<0.05), and the intestine weight index of 15% and 20% fermented silkworm excrement group was significantly higher than that of the control group (P<0.05). 3) The body crude protein content of 10%, 15% and 20% fermented silkworm excrement groups was significantly higher than that of the control group (P<0.05), and the body crude ash content of 20% fermented silkworm excrement group was significantly higher than that of the control group (P<0.05). 4) The activities of lipase and trypsin in intestine of the control group were significantly higher than those of other groups (P<0.05). 5) The contents of complement 3 and immunoglobulin M in serum of 15% fermented silkworm excrement group were significantly higher than those of other groups (P<0.05); the serum alanine aminotransferase activity of 20% fermented silkworm excrement group was significantly lower than that of the control group (P<0.05), and the serum lysozyme activity was significantly higher than that of the control group (P<0.05); the serum malondialdehyde (MDA) content of 10%, 15% and 20% fermented silkworm excrement groups was significantly lower than that of the control group (P<0.05). 6) The mRNA relative expression level of tumor necrosis factor-α in intestine of 15% and 20% fermented silkworm excrement groups was significantly higher than that of the control group (P<0.05). To sum up, the addition of fermented silkworm excrement within 10% in the diet dose not affect the growth performance of grass carp; fermented silkworm excrement can improve the non-specific immunity level of grass carp to a certain extent; when the supplemental level of fermented silkworm excrement is more than 15%, the growth performance and digestion of grass carp reduces, and the risk of intestinal inflammation increases. Therefore, the dietary fermented silkworm excrement supplemental level of grass carp should be controlled within 10%, and the regression analysis based on specific growth rate shows that the dietary fermented silkworm excrement suitable supplemental level of grass carp is 8.65%.

This study was conducted to investigate the effects of Isaria cicadae spent mushroom substrate on growth performance, liver antioxidant capacity, serum immunity, intestinal morphology and intestinal microflora of large yellow croaker (Larimichthys crocea), and to provide reference for the development and utilization of green feed additives for large yellow croaker. A total of 180 large yellow croaker with an initial body weight of (273.07±14.90) g were randomly divided into 3 groups with 3 cages in each group and 20 fish in each cage. Fish in the 3 groups were fed a basal diet (IC0 group, as control group) and the basal diet supplemented with 2% (IC2 group) and 6% (IC6 group) of Isaria cicadae spent mushroom substrate, respectively. The experiment lasted for 56 days. The results showed as follows: 1) the weight gain rate (WGR), specific growth rate (SGR) and feed efficiency (FE) in IC6 group were significantly higher than those in IC0 group (P<0.05); the hepatosomatic index (HSI) and viscerosomatic index (VSI) in IC2 group were significantly higher than those in IC0 and IC6 groups (P<0.05); there was no significant difference in survival rate (SR) among all groups (P>0.05). 2) Compared with the control group, the ether extract content of muscle and whole fish in IC2 group was significantly increased (P<0.05), and moisture content of muscle was significantly decreased (P<0.05); the ether extract content of muscle and whole fish in IC6 group was significantly decreased (P<0.05), and the moisture content was significantly increased (P<0.05). 3) Compared with the control group, the activities of liver total superoxide dismutase (T-SOD) and catalase (CAT) in IC6 group were significantly increased (P<0.05); the activity of liver CAT in IC2 group was significantly increased (P<0.05), and the activity of liver glutathione peroxidase (GSH-Px) was significantly decreased (P<0.05); there were no significant differences in the content of malondialdehde (MDA) in liver, the contents of complement 3 (C3), complement 4 (C4), and the activities of lysozyme (LZM), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum among all groups (P>0.05). 4) The number of gobletcells per villus of intestine in IC6 group was significantly higher than that in IC0 and IC2 groups (P<0.05). 5) Compared with IC0 group, the Simpson index and Shannon index of IC6 group were significantly increased (P<0.05), the Shannon index of IC2 group was significantly increased (P<0.05). At the phylum level, compare with IC0 group, the relative abundances of Proteobacteria and Actinobacteriota were significantly improved in IC2 and IC6 groups (P<0.05), while the relative abundances of Bacteroidota, Desulfobacterota, Synergistota and Chloroflexi were significantly decreased in IC2 and IC6 groups (P<0.05). At the genus level, compared with IC0 group, the relative abundance of Bacteroides was significantly improved in IC6 group (P<0.05), the relative abundance of Klebsiella was significantly improved in IC2 group (P<0.05), and the relative abundances of Ruminofilibacter, Desulfomicrobium and Aminobacterium were significantly decreased in IC2 and IC6 groups (P<0.05). In conclusion, the growth performance, antioxidant capacity and intestinal microflora structure of large yellow crook can be improved by adding Isaria cicadae spent mushroom substrate in the diet, and the effect of 6% is better.

This experiment was conducted to study the effects of enzymolytic chicken hemoglobin meal replacing fish meal on growth performance, plasma biochemical and immune parameters, blood cell counts, intestinal morphology, hepatic antioxidant capacity and intestinal flora of juvenile Trachinotus ovatus. A total of 300 robust Trachinotus ovatus with the average body weight of (6.66±0.17) g were randomly divided into 4 groups with 3 replicates per group and 25 fish per replicate. Fish in the control group were fed a basal diet, and others in experimental groups were fed isonitrogenous and isolipid diets with enzymolytic chicken hemoglobin meal replacing 1.5% (P1.5 group), 3.0% (P3.0 group) and 4.5% (P4.5 group) fish meal in the basal diet, respectively. The experiment lasted for 8 weeks. The results showed as follows: 1) the final body weight, weight gain rate, specific growth rate, feed intake and protein efficiency ratio in P3.0 and P4.5 groups were significantly lower than those in P0 and P1.5 groups (P<0.05). 2) There were no significant differences in the contents of moisture, ash, crude protein and ether extract in whole fish among all groups (P>0.05). 3) The plasma glucose (GLU), triglyceride (TG), low density lipoprotein (LDL) contents and glutamic-oxalacetic transaminase (AST) activity in P1.5 group were significantly lower than those in P0, P3.0 and P4.5 groups (P<0.05). 4) The contents of complement 3 (C3) and complement 4 (C4) in plasma in P1.5 and P3.0 groups were significantly higher than those in P0 and P4.5 groups (P<0.05), and the plasma alkaline phosphatase (ALP) activity and numbers of white blood cells and red blood cells in blood in P1.5, P3.0 and P4.5 groups were significantly higher than those in P0 group (P<0.05). 5) The activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in liver in P3.0 and P4.5 groups were significantly lower than those in P0 and P1.5 groups (P<0.05), and the liver malondialdehyde (MDA) content in P4.5 group was significantly higher than that in P0, P1.5 and P3.0 groups (P<0.05). 6) The midgut and hindgut villus height in P3.0 and P4.5 groups was significantly lower than that in P0 and P1.5 groups (P<0.05), and the midgut and hindgut villus width in P4.5 group was significantly lower than that in P0 and P1.5 groups(P<0.05). 7) At the phylum level, the relative abundances of Cyanobacteria and Actinobacteriota in intestine in P1.5 and P4.5 groups were significantly higher than that in P0 group (P<0.05), and the relative abundances of Proteobacteria, Firmicutes and Bacteroidota in intestine were significantly lower than that in P0 group (P<0.05). At the genus level, the relative abundances of Cyanobium_PSC-6307 and Mycobacterium in intestine in P1.5 and P4.5 groups were significantly higher than those in P0 group (P<0.05), and the relative abundances of Lactococcus, Phreatobacter, Alphaproteobacteria_unclassified and Elizabethkingia in intestine were significantly lower than those in P0 group (P<0.05). In conclusion, the replacement of fish meal with 1.5% enzymolytic chicken hemoglobin meal in diet can enhance body immunity, improve the intestinal flora structure, and have similar effects on growth performance, intestinal morphology and antioxidant capacity as fish meal.

This study was conducted to investigate the effects of dietary melatonin on growth, non-specific immunity, antioxidant capacity, intestinal digestive enzyme activities, and mRNA expression of insulin-like growth factor-Ⅰ (IGF-Ⅰ) and heat shock protein 70 (HSP70) in liver of black carp (Mylopharyngodon piceus). A total of 525 juvenile black carp with an initial body weight of (6.44±0.17) g were randomly divided into 5 groups with 3 replicates per group and 35 fish per replicate. The fish in 5 groups were fed basal diets supplemented with 0 (control group), 5, 10, 15 and 20 mg/kg melatonin, respectively. The experiment lasted for 8 weeks. The results showed as follows: 1) compared with the control group, dietary 10 to 20 mg/kg melatonin significantly increased the weight gain rate (WGR) and specific growth rate (SGR) (P<0.05), and significantly decreased the feed conversion ratio (FCR) (P<0.05), but had no significant effects on the survival rate, hepatosomatic index, visceral index and condition factor (P>0.05). Based on the broken line model, it was estimated that when the dietary melatonin level was 9.28 mg/kg, the juvenile black carp got the best WGR. 2) Compared with the control group, dietary 10 and 15 mg/kg melatonin significantly increased the contents of total protein (TP) and complement 3 (C3) and the activities of lysozyme (LSZ) and alkaline phosphatase (ALP) in serum of black carp (P<0.05), and significantly decreased the cumulative mortality after infection with Aeromonas hydrophila (P<0.05). Dietary 15 mg/kg melatonin significantly increased the serum complement 4 (C4) content (P<0.05), and significantly decreased the serum alanine aminotransferase (ALT) activity (P<0.05). Dietary melatonin had no significant effects on serum aspartate aminotransferase (AST) activity (P>0.05). 3) Compared with the control group, dietary 10 and 15 mg/kg melatonin significantly increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), the reduced glutathione (GSH) content and the total antioxidant capacity (T-AOC) in liver of black carp (P<0.05). In addition, dietary 10 mg/kg melatonin significantly increased the catalase (CAT) activity in liver (P<0.05), but dietary melatonin had no significant effects on the glutathione reductase (GR) activity in liver (P>0.05). 4) Compared with the control group, dietary 10 mg/kg melatonin significantly increased the intestinal trypsin activity (P<0.05), but dietary melatonin had no significant effects on the intestinal amylase and lipase activities (P>0.05). 5) The mRNA expression levels of IGF-Ⅰ and HSP70 in liver of black carp were firstly increased and then decreased with the dietary melatonin supplemental level increasing, and the mRNA expression levels of these two genes reached the highest level when the dietary melatonin supplemental level was 10 mg/kg. In conclusion, dietary supplementation with appropriate amount of melatonin can promote the growth of juvenile black carp, improve their non-specific immunity and antioxidant capacity, and enhance the activity of intestinal trypsin. When the dietary melatonin supplemental level is 9.28 mg/kg, the maximum WGR is obtained for juvenile black carp with a body weight of 6.41 to 34.83 g.

The study was performed to investigate the effects of dietary different licorice extract levels on the growth performance, digestion and metabolism of nutrients, serum biochemical indexes, fur quality and organs indexes of raccoon dogs during the fur-growing period. A total of 75 male raccoon dogs of similar weight aged 135 d were randomly assigned to five groups with 15 repetitions each and 1 raccoon dog in each repetition. Raccoon dogs in each group were fed a basal diet adding different levels of licorice extract: 0 (group Ⅰ), 100 (group Ⅱ), 200 (group Ⅲ), 300 (group Ⅳ), 400 mg/kg (group Ⅴ), respectively. The pre-experimental periods lasted for 5 days, and experimental periods were performed for 62 days. The growth performance, digestion and metabolism, nitrogen metabolism, serum biochemical indexes, fur quality and organs indexes of raccoon dogs were determined. The results showed as follows: 1) the final weight and daily gain of raccoon dogs in group Ⅳ were significantly higher than that in group Ⅰ and group Ⅱ (P<0.05); the material-to-weight ratio in group Ⅳ and group Ⅴ was significantly lower than that in group Ⅰ and group Ⅱ (P<0.05). 2) The protein apparent digestibility in group Ⅴ was significantly higher than that in group Ⅰ (P<0.05), and no significant differences existed in the other digestion and metabolism indexes among five groups (P>0.05). 3) The nitrogen intake in group Ⅳ was significantly lower than that in group Ⅰ, group Ⅱ and group Ⅴ (P<0.05), and no significant difference existed between group Ⅲ and group Ⅳ (P>0.05); the nitrogen deposition in group Ⅳ and group Ⅴ were significantly higher than those in group Ⅰ (P<0.05). 4)The contet of serum albumin in group Ⅴ was significantly lower than that in group Ⅰ, group Ⅱ and group Ⅲ (P<0.05), serum aspartate aminotransferase activity in group Ⅴ was significantly lower than that in group Ⅰ (P<0.05), and alanine transaminase activity in group Ⅴ was significantly lower than that in group Ⅰ and group Ⅱ (P<0.05), but no significant differences existed in the other serum biochemical indexes among five groups (P>0.05). 5) The body length in group Ⅳ was significantly longer than that in group Ⅰ (P<0.05), pelt lengths in group Ⅲ and group Ⅳ were significantly longer than that in group Ⅰ (P<0.05), and skin board score was no significant differences among different groups (P>0.05). 6) The liver index in group Ⅳ was significantly lower than that in group Ⅰ (P<0.05), and no significant differences existed in the other organs indexes among five groups (P>0.05). In conclusion, through analyzing the growth performance, nutrient digestibility and metabolism, serum biochemical indexes, fur quality and organ indexes, the diet adding 300 to 400 mg/kg licorice extract has better growth of raccoon dogs during the fur-growing period.

This experiment was conducted to investigate the effects of compound acidifier on digestive enzyme activity, immune function and tight junction protein expression in jejunum of Ila rabbits. A total of 192 healthy (35±2)-day-old weaned male commercial Ira rabbits with similar body weight were randomly divided into 4 groups with 6 replicates per group and 8 rabbits per replicate. The four groups were the blank group (basal diet), the antibiotic group (basal diet+60 mg/kg salinomycin), experimental group Ⅰ (basal diet+0.1% compound acidifier) and experimental group Ⅱ (basal diet+0.2% compound acidifier). The effective components in compound acidifier were formic acid and propionic acid. The experiment lasted for 28 days. The results showed as follows: 1) compared with the blank group, the trypsin activity in jejunum mucosa in experimental group Ⅰ was significantly increased (P<0.05), and there were no significant differences in the activities of lipase and α-amylase in jejunal mucosa among all groups (P>0.05). 2) Compared with the blank group, the contents of interleukin-6 (IL-6) and interleukin-1β (IL-1β) in jejunal mucosa in the antibiotic group, experimental group Ⅰ and experimental group Ⅱ were significantly decreased (P<0.05), and the interleukin-10 (IL-10) content in jejunal mucosa had a tendency to be increased (P=0.086). There were no significant differences in the secreted immunoglobulin A (sIgA) content in jejunal mucosa among all groups (P>0.05). 3) Compared with the blank group, the IL-1β mRNA relative expression level in jejunal mucosa in the antibiotic group, experimental group Ⅰ and experimental group Ⅱ was significantly decreased (P<0.05), and there were no significant differences in the mRNA relative expression levels of IL-6 and IL-10 in jejunal mucosa among all groups (P>0.05). 4) Compared with the blank group, the mRNA relative expression levels of zona occludens-1 (ZO-1) and occludin in jejunal mucosa in the antibiotic group and experimental group Ⅰ were significantly increased (P<0.05), and the claudin-1 mRNA relative expression level in jejunal mucosa in the antibiotic group and experimental group Ⅱ was significantly decreased (P<0.05). There were no significant differences in the claudin-3 mRNA relative expression level in jejunal mucosa among all groups (P>0.05). In conclusion, dietary 0.1% compound acidifier can increase the trypsin activity, enhance the immune ability and promote the expression of tight-junction protein in jejunal mucosa of Ila rabbits. Its effect is similar to that of antibiotics, and it has a good potential for substitution.

This experiment was conducted to study the effects of dietary sodium hyaluronate on feeding performance, blood indices and fur health of cats. Forty adult Linqing-lion cats were randomly divided into 4 groups with 10 replicates per group and 1 cat per replicate. Cats in the control group (group CON) were fed a basal diet, and others in experimental groups were fed basal diets supplemented with 164 (group Ⅰ), 328 mg/kg (group Ⅱ) and 656 mg/kg (group Ⅲ) sodium hyaluronate, respectively. The experiment lasted for 60 days. The results showed as follows: 1) compared with the group CON, the average daily water intake of group Ⅰ was significantly increased (P<0.05). 2) Compared with the group CON, the blood albumin content of group Ⅱ was significantly increased (P<0.05), the blood globulin content of group Ⅲ was significantly increased (P<0.05), and the blood total antioxidant capacity of group Ⅰ was significantly increased (P<0.05). 3) Compared with the group CON, the hair gloss and hair compliance of groups Ⅰ, Ⅱ and Ⅲ were significantly increased (P<0.05), the skin elasticity of groups Ⅱ and Ⅲ was significantly increased (P<0.05), the hair brightness, redness and yellowness values of group Ⅱ was significantly increased (P<0.05), the hair elastic recovery rate of groups Ⅰ, Ⅱ and Ⅲ was significantly increased (P<0.05), the hair fineness of group Ⅲ was significantly decreased (P<0.05), and the skin moisture content of groups Ⅱ and Ⅲ was significantly increased (P<0.05). In conclusion, dietary sodium hyaluronate can improve the average daily water intake, blood albumin content and antioxidant capacity and fur quality of cats. Under the conditions of this experiment, the optimal dietary sodium hyaluronate supplement level for cats is 164 to 328 mg/kg.

The aim of this study was to explore the effects of α-linolenic acid (ALA) on cholesterol synthesis, steroid hormone synthesis and apoptosis of porcine granulosa cells (GCs). Ovarian GCs of 150-day-old healthy sows were collected and the enzyme linked immunosorbent assay (ELISA), real-time fluorescence quantitative PCR (RT-PCR), Western blot and flow cytometry were used to investigate the effects of ALA on cholesterol synthesis, steroid secretion and apoptosis of porcine GCs. The results showed as follows: 1) 50 μmol/L ALA treatment extremely significantly inhibited the synthesis of estradiol (E₂) (P<0.01), but had no significant effect on the synthesis of progesterone (P₄) (P>0.05). 2) 50 μmol/L ALA treatment significantly down-regulated the mRNA relative expression levels of cholesterol side-chain cleavage enzyme (CYP11A1) and 3β-hydroxy steroid dehydrogenase (3β-HSD) (P<0.05), and significantly down-regulated the protein relative expression levels of CYP11A1 and steroidogenic acute regulatory protein (StAR) (P<0.05). 3) 50 μmol/ L ALA treatment significantly down-regulated the mRNA relative expression levels of key cholesterol synthesis genes, including 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), scavenger receptor class B type 1 (SCARB1) and sterol regulatory element-binding protein 2 (SREBP2) (P<0.05). 4) 50 μmol/ L ALA treatment significantly increased the number of live cells (P<0.05), significantly up-regulated the B-cell lymphoma/leukemia-2 (Bcl-2) mRNA relative expression level (P<0.05), and significantly down-regulated the B-cell lymphoma/leukemia-2 associated X protein (Bax) protein relative expression level (P<0.05). It can be seen that ALA inhibits the synthesis of steroids and apoptosis of GCs by inhibiting the synthesis of cholesterol.

The purpose of this study was to explore the regulatory effects of polysaccharide of Atractylodes macrocephala Koidz (PAMK) on cyclophosphamide (CTX) induced liver oxidative stress and abnormal apoptosis in liver of Lingnan yellow chickens. Two hundred and forty healthy 1-day-old Lingnan yellow chickens were randomly divided into 4 groups with 6 replicates per group and 10 chickens per replicate. Chickens in control group and polysaccharide of Atractylodes macrocephala Koidz group (PAMK group) were fed a basal diet, and the others in cyclophosphamide group (CTX group) and polysaccharide of Atractylodes macrocephala Koidz+cyclophosphamide group (PAMK+CTX group) were fed a basal diet supplemented with 400 mg/kg PAMK. At 20, 21 and 22 days of age, the Lingnan yellow chickens in CTX group and PAMK+CTX group were injected with 20 mg/kg CTX into leg muscles, and the Lingnan yellow chickens in control group and PAMK group were injected with 0.5 mL normal saline into leg muscles. The experiment lasted for 27 days. The results showed that compared with CTX group, the apoptosis of liver in PAMK+CTX group was alleviated and the state of liver cells was restored, the degree of inflammatory infiltration was reduced, and the number of punctate necrotic foci was obviously reduced; in addition, the serum malondialdehyde (MDA) content was significantly decreased (P<0.05), the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in serum were significantly increased (P<0.05), and the protein relative expression level of cysteinyl aspartate specific proteinase 3 (Caspase3) and mRNA relative expression level of cysteinyl aspartate specific proteinase 9 (Caspase9) in liver tissue were significantly down-regulated (P<0.05). In conclusion, the PAMK can alleviate the oxidative stress and increase of liver cell apoptosis caused by CTX in Lingnan yellow chickens.

This experiment was conducted to analyze and identify the glycoside hydrolase 9 (GH9) gene family of endogenous cellulase in Procambarus clarkii, and to study its expression characteristics when fed different feeds or under hypoxia-reoxygenation stress, so as to provide theoretical basis for the study of plant feed digestion and utilization in P. clarkii, and to accumulate data for the efficient utilization of endogenous cellulase in animals. The whole genome distribution of the GH9 gene family in P. clarkii was systematically studied by combining bioinformatics and molecular cloning strategies, and the structural characteristics, distribution characteristics of the GH9 gene family in P. clarkia and their expression response patterns when fed different feeds (plant feed, compound feed and animal feed) or under hypoxia-reoxygenation stress were obtained. The results showed as follows: 1) there were seven GH9 gene family members (PcGH9-1, PcGH9-2, PcGH9-3, PcGH9-4, PcGH9-5, PcGH9-6 and PcGH9-7) in the genome of P. clarkii. The cDNA length of GH9 gene family members was 1 843 to 2 354 bp, and the number of encoded amino acids was 490 to 583, which were distributed on the three chromosomes LG23, LG39 and LG54. The GH9 gene family of P. clarkii had one typical Glyco hydro 9 domains with exon number ranging from 7 to 14 and intron number ranging from 6 to 13. The GH9 gene family of P. clarkii could be divided into two subclasses according to whether it has cellulose binding domain (CBD). The first subclass included PcGH9-1, PcGH9-2 and PcGH9-7, and the second subclass included PcGH9-3, PcGH9-4, PcGH9-5 and PcGH9-6. 2) The GH9 gene family of P. clarkii was mainly highly expressed in hepatopancreas. 3) The GH9 gene family expression level and β-1,4-endoglucanase activity of P. clarkii were the highest when fed plant feed and the lowest when fed animal feed. 4) Under hypoxic-reoxygenation stress, the expression levels of PcGH9-1, PcGH9-2, PcGH9-3, PcGH9-4 and PcGH9-5 in hepatopancreas of P. clarkii were decreased with the prolongation of hypoxic-reoxygenation stress, while the expression levels of PcGH9-6 and PcGH9-7 had little change under hypoxic-reoxygenation stress. The of β-1,4-endoglucanase activity under hypoxic-reoxygenation stress was significantly decreased with the prolongation of hypoxic-reoxygenation stress (P<0.05). In conclusion, P. clarkii has endogenous cellulase GH9 gene family, and GH9 gene family members are mainly highly expressed in hepatopancreas. Feeding plant feed can significantly increase the expression of GH9 gene family and the activity of β-1,4-endoglucanasein in hepatopancreas of P. clarkii. Hypoxic-reoxygenation stress can significantly inhibit the expression of GH9 gene family and the activity of β-1, 4-endoglucanase in hepatopancreas of P. clarkii.

The aim of this study was to establish a vascular fistula surgical installation method for investigating the muscle metabolism of pig hind limbs, and to explore the changes of blood flow in the hind limbs of pigs at different time for verifying the feasibility of the proposed method. Seven Duroc×Landrace×Large Yorkshire ternary crossbred pigs with an average body weight of (20.07±2.14) kg were selected, and the carotid, femoral artery and femoral vein vascular fistulas were surgically installed. After a week of recovery of the test pigs, 1% p-amino hippurate (PAH) was perfused through the femoral artery, and samples were continuously collected per hour to measure the blood flow velocity of the femoral vein within 6 h. The results showed that the body condition of the test pigs recovered well and the feed intake was normal, which could be used for the test. The femoral venous blood flow at different time points was significantly different (P<0.05). The porcine carotid-femoral artery-femoral vein vascular fistulas installation technique established in this experiment provides effective means for studying the metabolism of nutrients in the hind limbs of growing pigs.

The aim of this study was to establish an accurate method for the determination of spectinomycin in feed. The sample was extracted with 2% trichloroacetic acid aqueous solution [containing 0.4% ethylenediaminetetraacetic acid disodium salt (EDTA-2Na)]. After its pH was adjusted to (4.7±0.2) and the sample was cleaned-up on the mixed-mode cation-exchange (MCX) solid-phase extraction (SPE). The spectinomycin was separated by a hydrophilic interaction liquid chromatography (HILIC) column with gradient elution using 0.01 mol/L ammonium formate aqueous solution (containing 0.4% formic acid) and 0.01 mol/L ammonium formate acetonitrile-aqueous solution (containing 0.4% formic acid) as mobile phases and finally confirmed and quantified in multiple reaction monitoring (MRM) mode with the electrospray ionization (ESI) positive ion scanning by matrix matching external calibration method. The results show that the limit of detection and limit of quantification of spectinomycin in feed using this solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry method was 1.0 and 2.0 mg/kg, respectively. The regression coefficient (R²) of linear calibration curve for spectinomycin in different feed substrates was over 0.99 within the concentration range from 0.1 to 10.0 μg/mL. At the four spiked levels (2.0, 20.0, 200.0 and 1 000.0 mg/kg), the average recovery rate of spectinomycin was from 91.3% to 104.2% and the relative standard deviation (RSD) was from 1.5% to 9.4%. As a result, the solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry method was sensitive and practical for the determination of spectinomycin in feed.

In order to study the immune regulation and anti-inflammatory effect of Sibiraea angustata polysaccharides (SAPs) on immunosuppressed mice, the immunosuppressed mice model was prepared by subcutaneous injection of cyclophosphamide, and then the gavage test was carried out. One hundred and ten mice were randomly divided into 6 groups, they were normal saline control group (PS group, 20 mice), cyclophosphamide model group (CTX group, 15 mice), levamisole hydrochloride positive group (LH group, 15 mice), and low, medium and high doses of SAPs groups (SAPs-L, SAPs-M, SAPs-H groups, and each group had 20 mice). From day 1 to 10 of the experiment, the dose of 0.01 mL/g BW normal saline was subcutaneously injected in PS group, and the other experimental groups were subcutaneously injected with cyclophosphamide (dissolved by saline solution) at the same dose as PS group, once a day. After the model was induced successfully, mice in the SAPs-L, SAPs-M, SAPs-H groups were given intragastric administration of SAPs (dissolved by saline solution) at the doses of 200, 400 and 800 mg/kg BW, respectively, mice in the LH group were given intragastric administration of levamisole hydrochloride (dissolved by saline solution) at the dose of 30 mg/kg BW, and mice in the CTX and PS groups were given intragastric administration of saline solution at the dose of 0.01 mL/g BW. The gavage test was performed once a day from day 11 for 20 days. The body weight growth rate, immune organs (spleen and thymus) and visceral organs (heart, liver, lung and kidney) indexes, carbon clearance index and phagocytic index, blood routine indexes of mice were measured. Plasma interleukin-2 (IL-2), interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) and immunoglobulin A (IgA) contents were determined by enzyme-linked immunosorbent assay (ELASA) method. The anti-inflammatory effect of SAPs was measured by toe swelling induced by egg white. The results showed that the body weight growth rate and daily feed intake in experimental groups except PS group decreased sharply from days 1 to 10 after cyclophosphamide modeling; after the gavage test from day 11, the body weight growth rate and daily feed intake in SAPs-L, SAPs-M, SAPs-H groups upregulated gradually and tended to PS group. Compared with the PS group, the immune organs and visceral organs indexes, carbon clearance index and phagocytic index, blood routine indexes (white blood cell count, red blood cell count, platelet count, lymphocyte count, neutrophil count, lymphocyte percentage, monocyte percentage and neutrophil percentage) and plasma IL-2, IFN-γ, TNF-α and IgA contents in CTX group were significantly or extremely significantly reduced (P<0.05 or P<0.01), but those indexes in the SAPs-M group were significantly or extremely significantly higher than CTX group (P<0.05 or P<0.01), and the degree of toe swelling caused by egg white was effectively inhibited. Therefore, SAPs at the dose of 400 mg/kg BW can enhance the specific and non-specific immune function of immunosuppressed mice induced by cyclophosphamide, and can alleviate the inflammatory response of mice induced by egg white.

This experiment was to investigate the effects of exposure to dimethyl phthalate (DMP) on growth performance, immune performance and small intestinal tissue morphology of mice during growth and development, as well as the effects of gestational exposure of pregnant mice to DMP on the growth, development and immune performance of offsprings. In experiment 1: thirty 3-week-old female ICR young mice were randomly divided into 3 groups of 10 mice each. Under the condition of feeding the same basal diet, mice in two experimental groups were gavaged with 1 000 and 2 000 mg/(kg·d) DMP (diluted with corn oil as the dose of 1 mL/kg) for 21 d, respectively, and mice in control group were gavaged with the same amount of corn oil. In experiment 2: twenty 2-month-old female ICR mice were selected and randomly divided into 2 groups of 10 mice each, and they were fed the same basal diet. Form the first day after successful mating to delivery, mice in DMP group were gavaged with 1 000 mg/(kg·d) DMP (diluted with corn oil as the dose of 1 mL/kg), and mice in control group were gavaged with the same amount of corn oil. The results of experiment 1 showed as follows: 1) compared with the control group, the final body weight and average daily gain (ADG) of young mice gavaged with 2 000 mg/(kg·d) DMP were significantly decreased (P<0.05), and there was no significant difference in average daily feed intake (ADFI) among the groups (P>0.05). 2) There were no significant differences in liver, spleen and thymus indices among the groups (P>0.05); compared with the control group, young mice gavaged with 1 000 and 2 000 mg/(kg·d) DMP significantly decreased serum immunoglobulin G (IgG) level (P<0.05), and had no significant effect on serum immunoglobulin M (IgM) level (P>0.05). 3) Compared with the control group, young mice gavaged with 1 000 and 2 000 mg/(kg·d) DMP had no significant effects on the villus height and crypt depth of duodenum and ileum, and duodenum villus height/crypt depth (VH/CD) (P>0.05), significantly decreased the villus height of jejunum (P<0.05), significantly increased the crypt depth of jejunum (P<0.05), and significantly decreased the VH/CD of jejunum and ileum (P<0.05). The results of experiment 2 showed as follows: 1) compared with the control group, pregnant mice gavaged with 1 000 mg/(kg·d) DMP during gestation in resulted in reduced but not significant birth weight of filial mice (P>0.05), and the weaning weight and 8-week-old body weight were significantly reduced (P<0.05). 2) Compared with the control group, pregnant mice gavaged with 1 000 mg/(kg·d) DMP during gestation caused a significant reduction in liver and spleen indices and a significant decrease in serum IgG and IgM levels of filial mice (P<0.05). 3) Compared with the control group, the villi height of duodenum, jejunum and ileum of filial mice in the DMP group were significantly reduced (P<0.05), the crypt depth of duodenum, jejunum and ileum had no significant differences (P>0.05), and the VH/CD of jejunum and ileum was significantly decreased (P<0.05). In summary, DMP has a certain impact on the normal growth and development of mice, reduces the immunity of mice, and has certain damage to the small intestinal tissue morphology.