Intestinal microbiota homeostasis plays a central role in maintaining intestinal barrier function, regulating immune responses, and defending against pathogen invasion in weaned piglets. Following the ban on antibiotics in feed, the imbalance of intestinal microbiota homeostasis in weaned piglets has become increasingly prominent, posing a critical bottleneck for the healthy and sustainable development of swine industry in China. This paper systematically reviewed the novel nutritional regulation targets proposed over the past decade for establishing intestinal microbiota homeostasis in weaned piglets, with a focus on the core metabolic pathways of gut microbiota, including short-chain fatty acids, bile acids and tryptophan. It also explored the mechanisms of the microbiota-gut-brain axis and the microbiota-gut-liver axis in regulating growth performance and stress responses in weaned piglets. Furthermore, it summarized recent research progress on nutritional interventions—such as dietary fiber, protein, amino acids and plant-derived bioactive compounds—that improved intestinal health by reshaping the composition and metabolic functions of the intestinal microbiota. This review aimed to provide a reference for establishing a nutritional regulation technique system targeting intestinal microbiota homeostasis to improve intestinal health in weaned piglets, thereby promoting the high-quality development of the swine industry under the antibiotic-free farming condition.

Meat quality is a complex, multidimensional trait closely related to genetic background, nutritional regulation, and other factors. This article reviewed the main evaluation indicators of meat quality in yellow-feathered broilers and summarized the regulatory mechanisms of genetic factors on meat quality from the perspectives of intramuscular fat (IMF) content and muscle fiber type. On this basis, it analyzed the genetic interactions between nutrients and meat quality at the nutrigenomics level, identified the key links through which nutrients influence meat quality formation by regulating specific genetic elements, and aimed to integrate existing research findings to provide a reference for the practice of “precision nutritional regulation of meat quality” in yellow-feathered broilers.

Resistin (RETN), a cysteine-rich adipokine widely expressed in both central and peripheral tissues, serves as a key signaling molecule that links feeding regulation with energy homeostasis. It plays important biological functions in the regulation of feeding and energy balance. This article reviewed the discovery, molecular structure and tissue distribution of RETN, as well as its role and mechanisms in regulating feeding and metabolism. The purpose of this review was to provide a systematic reference for further understanding of the physiological functions of RETN, and to offer a theoretical basis for the regulation of animal feeding and growth performance through interventions targeting the RETN signaling pathway.

As an essential fat-soluble vitamin and natural antioxidant, vitamin E exerts multiple physiological functions in the health of dogs and cats. By scavenging free radicals and inhibiting lipid peroxidation, it protects cells and tissues from oxidative injury, thereby mitigating the adverse effects of oxidative stress on various tissues and organs in dogs and cats. Because animals cannot synthesize vitamin E de novo and must obtain it from the diet, appropriate vitamin E supplementation in canine and feline diets is of critical importance. This review systematically summarized the physiological functions and research advances of vitamin E on exercise performance, cardiac function, reproductive performance, skin health, and other aspects in dogs and cats, with the aim of guiding its rational application in diets for dogs and cats.

Fermented feed is an emerging feed type that has developed rapidly in recent years and is characterized by high digestibility, reduced anti-nutritional factors, improved palatability, and enhanced feed conversion efficiency. With the rapid expansion of the livestock industry, fluctuating feed prices coupled with a sluggish market for animal products have made cost reduction and efficiency improvement critical challenges in animal production. Consequently, fermented feed has attracted increasing research attention. Previous studies have primarily focused on the effects of fermented feed on animal performance, whereas relatively limited attention has been paid to the underlying mechanisms by which fermented feed improves animal performance and microbial fermentation enhances feed quality. Meanwhile, as a novel feed category, fermented feed lacks unified standards for production and quality evaluation, which restricts its large-scale application and market pricing. Based on a comprehensive review of domestic and international literature published in recent years, this article summarized the development of fermented feed, its advantages, key aspects of fermentation technology, and the current status and future trends of its application, with the aim of providing references for future research in this field.

Haematococcus pluvialis (H. pluvialis) is rich in natural astaxanthin, proteins, lipids, carbohydrates and other nutrients, possessing biological activities such as antioxidant and anti-inflammatory effects, which can improve the growth performance, meat quality and immune function of swine without toxic or side effects. Therefore, H. pluvialis as a feed additive shows great potential in pig production to enhance the health of swine. This paper summarizes the nutritional characteristics and biological activities of H. pluvialis and reviews its application in pig production, aiming to deepen the understanding of its biological activities and provide a strong reference for its efficient application in pig production.

Faced with the challenges of intensification and large-scale expansion in global livestock industry, precision livestock farming (PLF) has become a critical pathway for enhancing production efficiency. As the core technical support of PLF, artificial intelligence (AI) leverages machine learning to mine massive breeding data for predicting disease risks and achieves non-contact monitoring through computer vision technology. While minimizing flock stress caused by manual intervention, it significantly improves monitoring efficiency and accuracy. This paper systematically reviews the cutting-edge applications of AI in modern broiler farming, focusing on four dimensions: broiler health monitoring, welfare assessment, behavioral decoding, and production management. It further delves into the principles and practices of technologies such as computer vision, bioacoustics analysis, and multi-source sensors. In addition, this paper outlines the future directions of precision broiler farming, pointing out that multi-modal data fusion, the development of explainable AI, and the application of AI-driven robots will drive the transformation of the broiler industry toward a high-level, sustainable, and intelligent direction.

Equol is a non-steroidal estrogenic active compound produced via microbial metabolism of plant isoflavones, exhibiting pronounced significant antioxidant and anti-inflammatory activities as well as estrogen-like effects. Equol in bovine milk is mainly derived from isoflavones in diet of dairy cows. Dietary isoflavones are converted to equol in the rumen through microbial deglycosylation, demethylation and reduction reactions; equol is then transferred to the mammary gland via the blood circulation and secreted into milk. This review systematically summarized the bioactivities of equol, the origin, formation and transfer processes of equol in bovine milk, and dietary regulation strategies and their influencing factors. Particular emphasis was placed on the role of isoflavone-rich feed ingredients such as red clover in elevating milk equol contents, as well as differences in milk equol contents across countries, and feeding and management systems. In addition, feasible approaches for equol enrichment through dietary optimization were discussed, aiming to provide a theoretical basis and technical support for the development of functional dairy products.

Monocarboxylates are key participants in the life metabolic processes of animal organisms, and their absorption efficiency directly affects the production performance and health status of animals. The effective exertion of the physiological functions of monocarboxylates relies on transmembrane transport mediated by monocarboxylate transporters (MCTs), whose normal expression and functional implementation depend on the synergistic effect of accessory proteins. This review systematically summarized the accessory proteins for MCTs in rumen epithelium of ruminants, with a particular focus on two types of accessory proteins: cluster of differentiation 147 (CD147, also known as Basigin) and glycoprotein 70 (gp70, also known as Embigin). It elaborated on their structural characteristics and function, and their molecular regulatory mechanisms, and deeply analyzed their roles in critical physiological processes of ruminants, such as monocarboxylate transport and energy metabolism in rumen epithelial of ruminants. Furthermore, combined with the application prospects of accessory proteins for MCTs in precision nutrition regulation, disease prevention, genetic breeding and fields, this review provided new insights and practical directions for improving the production performance, health management and molecular breeding of ruminants.

As global demand for dairy products continues to rise, unlocking the lactation potential of dairy cows has become central to animal nutrition research. The interaction between rumen microorganisms and host metabolites, along with the “rumen-blood-mammary gland” axis they mediate, represents a key mechanism regulating milk production efficiency. This review summarizes core differences between high-yielding and low-yielding dairy cows: in high-yielding cows, microbial enrichment of Prevotella and other species in the rumen enhances carbohydrate degradation, increases propionic acid production, decreases the acetic acid/propionic acid, and promotes vitamin B₁₂ synthesis, thereby optimizes energy metabolism and milk precursor supply. Rumen-derived metabolites transported via blood to the mammary gland then activate lactose and milk fat synthesis-related gene expression through signaling pathways such as G-protein-coupled receptor 41 (GPR41)-protein kinase A (PKA) and mechanistic target of rapamycin (mTOR). The article further summarizes precision nutrition strategies based on multi-omics technologies, including intervention pathways targeting propionic acid production and methane suppression, optimizing nitrogen metabolism cycles, and stabilizing peripartum rumen microbiota, provides theoretical foundations and practical references for nutritionally regulating the “rumen-blood-mammary gland” axis to enhance dairy cow milk production performance.

Extracellular vesicles (EVs) are natural nanoscale structural particles composed of lipid bilayer encapsulating biological molecules such as proteins and nucleic acids, and play a significant role in the communication process of biological cells. EVs derived from intestinal microbiota serve as an important medium for information exchange between microorganisms and between microorganisms and the host. They act as both signal molecule delivery tools and immune response regulatory factors, participating in host immune regulation through multiple mechanisms such as direct interaction with immune cells, specific activation of immune responses, and induction of local immune tolerance. Maintain the homeostasis of the host's intestinal tract and ensure intestinal health. In addition, microbial EVs can directly or indirectly participate in the host's carbohydrate metabolism, lipid metabolism, amino acid metabolism and other nutrient metabolism processes, and are potential novel intervention targets for metabolic diseases. This article provides new ideas for disease prevention and control strategies based on EVs by deeply exploring the mechanism of gut microbiota-host interaction, and offers a reference for the development and application of microbial EVs in the fields of animal nutrition and intestinal health. Subsequent research should focus on the safety and controllability assessment of microbial EVs and promote their application in green livestock and poultry breeding.

With the widespread application of plant protein sources such as soybean meal in livestock and poultry diets, allergic enteritis triggered by their antigenic components (e.g., glycinin and β-conglycinin) has become a key issue constraining the healthy development of the animal industry. This paper systematically reviews the sensitization characteristics, pathogenic mechanisms and intervention strategies of major dietary antigenic proteins. It focuses on elucidating the multi-dimensional damaging pathways through which these antigens impair the intestinal barrier and immune homeostasis, involving the synergistic roles of oxidative stress-inflammatory network interactions, disruption of intestinal barrier integrity, programmed cell death and gut dysbiosis in disease pathogenesis. Furthermore, it comprehensively assesses the research progress and application potential of green nutritional strategies, including natural plant extracts, probiotics and prebiotics, specific nutrients and dietary structure optimization. The prospects for efficient prevention and control of this condition through future directions such as multi-omics integration analysis, precision nutrition and the development of green additives are also discussed. This review aims to provide a reference for mechanistic research and comprehensive prevention strategies against diet-induced allergic enteritis, and to offer a theoretical basis for innovating animal intestinal health regulation systems.

The animal husbandry industry has long been at the forefront of complaints from various industries due to the malodor and peculiar smell of livestock farm. The livestock farm odor originates from undigested feed components and endogenous host metabolites, which are volatile substances produced by the synergistic action of hindgut microbiota. This paper systematically reviews the intestinal production pathways of ammonia (NH₃), hydrogen sulfide (H₂S), 3-methylindole (skatol) and other major odor substances, summarizes the core microbiota and rate-limiting enzymes involved in the process, and briefly describes the main methods to reduce the source of aquaculture odor, so as to provide support for the development of precise microecological intervention technology and the development of green animal husbandry.

China has relatively abundant stored grains (such as rice, wheat and corn), which are highly nutritious and serve as an important source for reducing the use of corn and soybean meal to address the shortage of feed grains. However, long-term storage can lead to a decrease in the nutritional value of stored grains, an increase in fatty acid value, and a decline in antioxidant enzyme activity. Direct feeding may cause problems such as reduced performance, impaired digestive enzyme activity, and weakened antioxidant function in animals, which restricts their high-value utilization. This review systematically expounds the deterioration patterns of the quality of grains with long storage period and their impact on livestock and poultry production, as well as the improvement effects of physical treatment (such as expansion, pulsed electric field, etc.), addition of antioxidants (such as tea polyphenols, vitamin E, etc.), microbial fermentation, and enzyme preparation treatment on their physical and chemical properties, nutrient digestibility, anti-nutritional factors, and antioxidant capacity, in order to provide a reference for enhancing their feed value and safe utilization in livestock and poultry diets.

This experiment aimed to investigate the effects of different selenium sources—selenohomolanthionine (SeHLan), selenium yeast (SeY) and sodium selenite (SS)—on growth performance, meat quality, tissue selenium deposition, and systemic antioxidant capacity of finishing pigs. A total of 336 healthy “Duroc×Landrace×Yorkshire” finishing pigs with an initial body weight of approximately 60 kg were randomly allocated into four groups, each consisting of four replicates with 21 pigs per replicate. The four groups were fed experimental diets supplemented with different selenium sources (all based on selenium content): SS group (control group) received 0.4 mg/kg SS; SS-SeHLan group received 0.2 mg/kg SeHLan+0.2 mg/kg SS; SeHLan group received 0.4 mg/kg SeHLan; and SeY group received 0.4 mg/kg SeY. The experimental period lasted for 45 days. The results showed as follows: 1) no significant differences were observed in the growth performance of finishing pigs among the different selenium sources (P>0.05). 2) Compared with the SS group, redness (a^*) value, glutathione peroxidase (GSH-Px) activity and total antioxidant capacity (T-AOC) in the longissimus dorsi of the SS-SeHLan, SeHLan and SeY groups were significantly increased (P<0.05), while malondialdehyde (MDA) content in the longissimus dorsi of the SeHLan and SeY groups was significantly reduced (P<0.05). Notably, longissimus dorsi GSH-Px activity and a^* value of the SeHLan group were significantly higher than those of the SeY group (P<0.05). 3) Compared with the SS group, serum GSH-Px activity of the SS-SeHLan, SeHLan and SeY groups was significantly increased (P<0.05), with the highest level observed in the SeHLan group. Furthermore, serum superoxide dismutase (SOD) activity and T-AOC of the SeHLan and SeY groups were significantly improved (P<0.05), while serum total cholesterol and MDA contents were significantly decreased compared with the SS group (P<0.05). 4) Compared with the SS group, selenium content in the longissimus dorsi, liver and serum of the SS-SeHLan, SeHLan and SeY groups was significantly elevated (P<0.05), and selenium content in the kidney of the SeHLan and SeY groups was also significantly increased (P<0.05). In conclusion, organic selenium sources SeHLan or SeY are superior to inorganic selenium source SS in improving meat quality, enhancing systemic antioxidant capacity, and promoting tissue selenium deposition. Importantly, the novel organic selenium source SeHLan demonstrates the potential to outperform traditional organic selenium source SeY in upregulating key antioxidant enzyme activities and improving meat color, indicating its promise as a highly effective selenium additive.

This experiment was conducted to explore the effects of dietary supplementation with porcine-derived Lactobacillus johnsonii and xylooligosaccharides on growth performance and intestinal health of growing pigs. A total of 120 Duroc×Landrace×Yorkshire growing pigs with an initial body weight of (25.04±0.19) kg were selected and randomly divided into 4 groups, with 3 replicates in each group and 10 pigs in each replicate. The control group (CON group) was fed a basal diet, while the experimental groups were fed the basal diets supplemented with 5×10⁶ CFU/g porcine-derived Lactobacillus johnsonii (PLJ group), 0.02% xylooligosaccharides (XOS group), and 5×10⁶ CFU/g porcine-derived Lactobacillus johnsonii+0.02% xylooligosaccharides (PLJ+XOS group), respectively. The experiment lasted for 35 days after 7-day adaption. The results showed as follows: 1) compared with CON group, the average daily gain (ADG) of growing pigs in each experimental group was significantly increased (P<0.05), and the feed to gain ratio in PLJ+XOS group was significantly decreased (P<0.05); meanwhile, the ADG in PLJ+XOS group was significantly higher than that in PLJ group and XOS group (P<0.05). 2) Compared with CON group, the ileal villus height and villus height to crypt depth ratio (V/C) in each experimental group were significantly increased (P<0.05); meanwhile, the ileal villus height in PLJ+XOS group was significantly higher than that in PLJ group and XOS group (P<0.05), and the ileal V/C was significantly higher than that in PLJ group (P<0.05). 3) Compared with CON group, the transepithelial electrical resistance in ileum in PLJ group and PLJ+XOS group was significantly increased (P<0.05), while the FITC-dextran 4kDa content in ileum as well as the diamine oxidase activity and the D-lactic acid content in serum were significantly decreased (P<0.05). 4) Compared with CON group, the secretory immunoglobulin A (sIgA) content in ileum in each experimental group was significantly increased (P<0.05), while the contents of interleukin-6, interleukin-1β and tumor necrosis factor-α in ileum were significantly decreased (P<0.05). There was a significant interaction between porcine-derived Lactobacillus johnsonii and xylooligosaccharides on the sIgA content in ileum (P<0.05). 5) Compared with CON group, the Shannon index and Chao1 index of ileal microbiota in each experimental group were significantly increased (P<0.05), the Escherichia coli number in ileum was significantly decreased (P<0.05), and the Bifidobacterium number in ileum was significantly increased (P<0.05). There was a significant interaction between porcine-derived Lactobacillus johnsonii and xylooligosaccharides on the numbers of Lawsonia intracellularis and Lactobacillus in ileum (P<0.05). In conclusion, dietary supplementation with porcine-derived Lactobacillus johnsonii and xylooligosaccharides alone or in combination can enhance the growth performance and intestinal health of growing pigs, and the combination has a better effect.

This experiment was conducted to study the differences in dietary nutrient digestion in different intestinal segments of Ningxiang and Baning pigs. In experiment 1, each 6 healthy castrated Ningxiang and Baning boars with initial body weights of (45.50±1.20) kg and (43.35±0.30) kg, respectively, were selected and fed the same corn-soybean meal type basal diet with 0.3% titanium dioxide supplementation. The pre-test period was 7 days and the formal test period was 3 days. The digestive energy (DE), metabolic energy (ME) and apparent total tract digestibility (ATTD) of nutrients in diet were determined by the total fecal and urine collection method. In experiment 2, each 6 healthy castrated Ningxiang and Baning boars with initial body weights of (48.87±0.22) kg and (50.75±1.19) kg, respectively, were equipped with T-shaped fistulas at the end of ileum and the posterior end of cecum and fed the same corn-soybean meal type basal diet in experiment 1. The pre-test period was 5 days and the formal test period was 4 days. The ileal digesta and cecal digesta were collected each for 2 days to determine the apparent ileal digestibility (AID) and apparent cecal digestibility (ACD), respectively. The results showed as follows: 1) the DE and ME of diet in Ningxiang pigs were 15.71 and 15.16 MJ/kg, and those in Baning pigs were 15.64 and 15.19 MJ/kg, respectively. There was no significant difference between the two pig breeds (P>0.05). 2) The AID of dietary gross energy (GE), crude protein (CP) and ether extract (EE) in Ningxiang pigs was extremely significantly higher than that of Baning pigs (P<0.01), and the AID of dietary neutral detergent fiber (NDF) was significantly higher than that of Baning pigs (P<0.05). 3) The ACD of dietary GE in Ningxiang pigs was extremely significantly higher than that of Baning pigs (P<0.01), and the ACD of dietary acid detergent fiber (ADF) was significantly higher than that of Baning pigs (P<0.05). The ACD of dietary EE and crude fiber (CF) in Baning pigs were extremely significantly higher than that of Ningxiang pigs (P<0.01). 4) The ATTD of dietary GE, dry matter, organic matter, CF, NDF and ADF in Ningxiang pigs was significantly or extremely significantly higher than that of Baning pigs (P<0.05 or P<0.01). In conclusion, compared to Baning pigs, Ningxiang pigs demonstrate superior efficiency in the small intestine digestion of dietary GE, CP and EE, as well as in the total tract digestion of dietary fiber.

This experiment was conducted to investigate the effects of Brevibacillus laterosporus on growth performance, serum indexes and intestinal health of growing pigs. Fifty four 7-week-old “Duroc×Landrace×Large White” three hybrid growing pigs were selected and randomly divided into 3 groups with 6 replicates per group and 3 pigs per replicate. The control group (CON group) was fed a basal diet, the viable bacteria group (BL group) fed the basal diet supplemented with Brevibacillus laterosporus viable bacteria (5×10¹⁰ CFU/kg), and the heat-inactivated bacteria group (HBL group) was fed the basal diet supplemented with Brevibacillus laterosporus heat-inactivated bacteria (5×10¹⁰ CFU/kg). The pre-experimental period lasted for 7 days, and the experimental period lasted for 40 days. The results showed as follows: 1) compared with the CON group, the average daily gain and final body weight of the BL group were significantly decreased (P<0.05). 2) Compared with the CON group, the contents of total cholesterol (T-CHO), low density lipoprotein cholesterol (LDL-C) and malondialdehyde (MDA) in serum of BL group and HBL group were significantly decreased (P<0.05), the serum catalase (CAT) activity of the BL group was significantly increased (P<0.05), and the serum total antioxidant capacity (T-AOC) of the HBL group was significantly increased (P<0.05). 3) Compared with the CON group, the mRNA relative expression levels of mucin 2 (MUC2) and Occludin in colon mucosa of the BL group were significantly increased (P<0.05), and the mRNA relative expression levels of mucin 1 (MUC1) and MUC2 in colon mucosa of the HBL group were significantly increased (P<0.05). 4) Compared with the CON group, the contents of acetate and isovalerate in colon of BL group and HBL group were significantly decreased (P<0.05), and the colon isobutyrate content of HBL group was significantly decreased (P<0.05). 5) Compared with the CON group, the colon Lactobacillus relative abundance of BL group and HBL group was significantly increased (P<0.05), the colon Streptococcus relative abundance of BL group and HBL group was significantly decreased (P<0.05), and the colon Terrisporobacter relative abundance of HBL group was significantly decreased (P<0.05). In conclusion, dietary Brevibacillus laterosporus viable bacteria and heat-inactivated bacteria can enhance intestinal barrier of growing pigs, optimize the structure of intestinal microbiota, thereby improve the intestinal health. Under the conditions of this experiment, the Brevibacillus laterosporus heat-inactivated bacteria shows comprehensive benefits with more application prospects than live bacteria.

This experiment was conducted to explore the effects of dietary fiber from different sources during mid-to-late gestation of Rongchang sows on intestinal morphology, antioxidant capacity and immune function of newborn piglets. Sixty pregnant Rongchang sows with 2 to 5 parities and similar backfat thickness at 60 days of gestation were selected for the experiment and randomly divided into 4 groups, with 15 replicates in each group and 1 sow in each replicate. The dietary fiber sources of the four groups were wheat bran (WB group), beet pulp (BP group), soybean hull (SH group), and combined fiber (beet pulp∶wheat bran=2∶5, MF group), respectively. On the day of sows giving birth, six litters of piglets were randomly selected from each group, and one piglet with a body weight close to the average was chosen from each litter for slaughter and sampling. The results showed as follows: 1) the dietary fiber source during mid-to-late gestation of Rongchang sows had no significant effects on the organ indices and serum inflammatory factor contents of newborn piglets (P>0.05). 2) The villus height to crypt depth ratio in duodenum of newborn piglets in BP group was significantly higher than that in SH group and MF group (P<0.05). 3) The serum catalase activity and total antioxidant capacity of newborn piglets in BP group were significantly higher than those in the other three groups (P<0.05). 4) Compared with the other three groups, the interleukin-10 (IL-10) relative expression level in thymus of newborn piglets in BP group was significantly increased (P<0.05), while the nuclear factor-κB (NF-κB) relative expression level in thymus was significantly decreased (P<0.05); the relative expression levels of interleukin-6 (IL-6) and IL-10 in spleen in WB group were significantly decreased (P<0.05), and the relative expression levels of IL-10 and tumor necrosis factor-α (TNF-α) in ileum were significantly decreased (P<0.05). In conclusion, dietary fiber from different sources during mid-to-late gestation of Rongchang sows can specifically regulate the antioxidant status and innate immunity of their offspring. Among them, beet pulp can improve the intestinal morphology of newborn piglets, enhance their antioxidant capacity and increase their anti-inflammatory ability, while wheat bran shows certain potential for anti-inflammatory regulation. Therefore, in the diet of Rongchang pregnant sows, beet pulp or wheat bran should be given priority as the source of fiber.

This experiment aimed to investigate the effects of different dietary calcium-to-phosphorus ratios on growth performance, nutrient apparent digestibility, serum markers and bone parameters of finishing Landrace×Bamei crossbred pigs. Thirty-six healthy 10-month-old finishing Landrace × Bamei crossbred pigs with similar body weight [(49.57±0.92) kg] were randomly divided into three groups with 3 replicates per group and 4 pigs per replicate. The groups were fed experimental diets with calcium-to-phosphorus ratios of 1.1∶1 (low ratio group, LPG), 1.3∶1 ( medium ratio group, MPG) and 1.5∶1( high ratio group, HPG), respectively. The pre-trial period lasted 7 days, and the experimental period lasted 90 days. The results showed as follows: 1) compared with the LPG and MPG groups, feed-to-gain ratio in the HPG group was significant decreased (P<0.05). 2) Compared with the LPG group, the apparent digestibility of crude protein and calcium in the HPG group was significantly increased (P<0.05). 3) Compared with the LPG group, the serum calcium content in the HPG group was significantly increased (P<0.05); compared with the LPG and MPG groups, the contents of serum 1,25-dihydroxyvitamin D₃, calcitonin, osteoprotegerin, osteocalcin and osteopontin, and the activities of serum alkaline phosphatase and bone-specific alkaline phosphatase in the HPG group were significantly or extremely significantly increased (P<0.05 or P<0.01), whereas the contents of serum parathyroid hormone, fibroblast growth factor 23 and carboxy-terminal telopeptide of type Ⅰ collagen, and the activity of serum tartrate-resistant acid phosphatase 5b were extremely significantly decreased (P<0.01). 4) Compared with the LPG groups, the femoral bone mineral content (BMC) in the HPG group was significantly increased (P<0.05); compared with the LPG and MPG groups, the femoral bone mineral density (BMD) in the HPG group was extremely significantly increased (P<0.01). In conclusion, under the conditions of this experiment, a dietary calcium-to-phosphorus ratio of 1.5∶1 reduces the feed-to-gain ratio, increases the apparent digestibility of calcium and crude protein, and promotes bone formation and bone mineralization in finishing pigs.

This study aimed to investigate the protective effect and underlying mechanism of sodium selenite (Na₂SeO₃) against deoxynivalenol (DON)-induced intestinal injury in chicken embryos. Intestinal epithelial cells (IECs) were isolated from the intestinal tissue of 15-day-old chicken embryos. The cell density was adjusted to 1.5×10⁵ cells/mL, and the cells were plated into 96-well plates at 100 μL per well. After cell adhesion, 10 μL of complete medium (control group), 5 μmol/L Na₂SeO₃ (Na₂SeO₃ group), 2 μg/mL DON (DON group), or 2 μg/mL DON+5 μmol/L Na₂SeO₃ (DON+ Na₂SeO₃ group) was added, and the cells were further incubated for 24 hours. Separately, 9-day-old chicken embryos were randomly divided into four groups, each group consisted of 5 replicates with 20 eggs per replicate. According to a dose of 100 μL per 50 g of egg weight, each chicken embryo received an injection of sterile ultrapure water (control group), 0.43 μg Na₂SeO₃ (Na₂SeO₃ group), 10 μg DON (DON group) or 10 μg DON+0.43 μg Na₂SeO₃ (DON+ Na₂SeO₃ group). DON and Na₂SeO₃ were dissolved in 100 μL of sterile ultrapure water and injected aseptically into the allantoic cavity. The chicken embryos were then further incubated until hatching at 21 days of age. The results showed as follows: 1) DON exposure significantly decreased the intestinal weight and intestinal index of chicks (P<0.05), significantly increased plasma malondialdehyde (MDA) content (P<0.05), extremely significantly increased plasma hydrogen peroxide (H₂O₂) content (P<0.01), significantly decreased plasma total antioxidant capacity (T-AOC) (P<0.05), and induced ultrastructural damage such as mitochondrial cristae swelling and rupture. Na₂SeO₃ intervention partially reversed the decrease in intestinal index, enhanced antioxidant capacity, and alleviated mitochondrial structural damage. 2) At the cellular level, DON exposure caused an extremely significant decrease in the proliferation viability of chicken embryo IECs (P<0.01), significantly increased intracellular MDA content (P<0.05), extremely significantly increased intracellular H₂O₂ content (P<0.01), extremely significantly decreased intracellular T-AOC (P<0.01), and significantly increased intracellular reactive oxygen species (ROS) level (P<0.05). Na₂SeO₃ intervention reversed these changes. 3) In terms of molecular mechanisms, DON extremely significantly upregulated the mRNA relative expression levels of mammalian target of rapamycin (mTOR) and ubiquitin-binding protein p62 (SQSTM1) in chicken embryo IECs (P<0.01), while extremely significantly downregulated the mRNA relative expression level of microtubule-associated protein light chain 3 (LC3) (P<0.01). Na₂SeO₃ intervention restored these DON-induced abnormalities in autophagy-related gene expression. In conclusion, Na₂SeO₃, via its antioxidant properties, can scavenge excessive ROS, ameliorate oxidative stress, and regulate the autophagy signaling pathway. These actions collectively alleviate DON-induced mitochondrial damage, oxidative stress, and autophagic flux disruption in the intestine, thereby exerting a protective effect. This study provides an experimental basis for understanding the intestinal toxicity mechanism of DON and developing selenium-based nutritional intervention strategies.

This experiment was conducted to investigate the effects of dietary Clostridium autoethanogenum protein (CAP) replacing soybean meal on performance, egg quality, serum indices and intestinal health of laying hens. A total of 240 Hy-Line brown laying hens with similar laying rate of 47-week-old were selected and randomly divided into 2 groups, with 10 replicates in each group and 12 hens in each replicate. The control group was fed a corn-soybean meal type basal diet, while the experimental group was fed a diet in which 3% CAP was supplemented and the proportion of soybean meal was reduced. The pre-test period was 7 days and the formal test period was 63 days. The results showed as follows: 1) compared with the control group, the laying rate in the experimental group was significantly increased (P<0.05), and the feed to egg ratio was significantly decreased (P<0.05). 2) Compared with the control group, the albumen height in the experimental group was significantly increased (P<0.05), and the Haugh unit was significantly decreased (P<0.05). 3) Compared with the control group, the serum albumin content in the experimental group was extremely significantly decreased (P<0.01), the serum contents of triglyceride and total cholesterol were extremely significantly increased (P<0.01), and there was no significant difference in the serum total protein content (P>0.05); the serum malondialdehyde content, the activities of catalase, glutathione peroxidase and superoxide dismutase as well as the total antioxidant capacity were all extremely significantly increased (P<0.01); the serum contents of tumor necrosis factor-α, interleukin-1β and interleukin-6 were extremely significantly increased (P<0.01), while the serum interleukin-10 content was extremely significantly decreased (P<0.01). 4) Compared with the control group, the jejunal contents of immunoglobulin A, immunoglobulin G, immunoglobulin M and secretory immunoglobulin A in the experimental group were all extremely significantly increased (P<0.01); the duodenal crypt depth was significantly decreased (P<0.05), while the jejunal villus height and the ratio of villus height to crypt depth was significantly increased (P<0.05). 5) Compared with the control group, the Chao1 index and Shannon index of cecal microbiota in the experimental group were significantly decreased (P<0.05), and the microbiota structure was changed, but there was no significant difference in stability and functional prediction. In conclusion, dietary CAP replacing soybean meal can increase the performance and albumen height of laying hens, improve the antioxidant capacity and immune function, and promote intestinal health by improving intestinal tissue morphology and cecal microbiota structure.

This study aimed to investigate the effects of adding thymol-carvacrol cocrystal in drinking water on lipid metabolism of laying hens in late laying period. Firstly, a total of 96 sixty-week-old Hy-Line brown laying hens were randomly assigned into 2 groups with 6 replicates per group and 8 hens per replicate. Hens in control group were given normal drinking water, while those in experimental group received drinking water added with 30 mg/L thymol-carvacrol cocrystal. The experiment lasted for 4 weeks following a 1-week pre-feeding period. Serum and hepatic lipid metabolism indicators in were measured at the end of the trial. Secondly, network pharmacology was employed to screen key targets of thymol-carvacrol cocrystal in regulating lipid metabolism in laying hens, their binding characteristics were validated by molecular docking technology, and the core pathways were identified through pathway enrichment analysis. The results showed as follows: 1) at end of week 4, compared with the control group, the experimental group had significantly lower serum triglyceride and total cholesterol contents (P<0.05), as well as significantly lower liver steatosis score and hepatic triglyceride content (P<0.05). 2) Prostaglandin-endoperoxide synthase 2 (PTGS2) and albumin (ALB) were identified as the core targets through which the thymol-carvacrol cocrystal regulated lipid metabolism in laying hens. 3) Molecular docking revealed that the binding energies of the main active components of the thymol-carvacrol cocrystal with PTGS2 and ALB were all below -20.92 kJ/mol. 4) Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis identified 8 related signaling pathways, among which the calcium signaling pathway was the most significantly enriched. In conclusion, thymol-carvacrol cocrystal may improve lipid metabolism of laying hens in late laying period by acting on core targets such as PTGS2 and ALB, and by regulating the calcium signaling pathway.

This experiment aimed to investigate the regulatory effects of dietary added with lemairamin (WGX-50) on performance, serum biochemical indicators and follicle development of laying hens in late laying period. A single-factor randomized experimental design was adopted. A total of four hundred and eighty 60-week-old healthy Hy-Line Brown laying hens with similar initial body weight [(2.01±0.07) kg] and no significant differences in laying performance (P>0.05) were randomly divided into four groups, with 8 replicates per group and 15 hens per replicate. Each group was fed the basal diet supplemented with 0 (control), 0.5, 1.0 and 2.0 mg/kg WGX-50, respectively. The pre-test period lasted for 2 weeks, and the formal test period lasted for 8 weeks. The results showed as follows: 1) compared with the control group, the laying rate and average egg weight in the 0.5, 1.0 and 2.0 mg/kg WGX-50 supplemented groups exhibited an increasing tendency, while the average daily feed intake showed a decreasing tendency, but no significant differences were observed (P>0.05). The feed-to-egg ratio in the 1.0 and 2.0 mg/kg WGX-50 supplemented groups was significantly decreased compared with the control group (P<0.05). 2) Compared with the control group, the serum total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities in the 1.0 and 2.0 mg/kg WGX-50 supplemented groups were significantly increased (P<0.05), while the malondialdehyde (MDA) content was significantly decreased (P<0.05). 3) Compared with the control group, the serum interleukin-1β (IL-1β) content in the 0.5, 1.0 and 2.0 mg/kg WGX-50 supplemented groups was significantly decreased (P<0.05), and the serum tumor necrosis factor-α (TNF-α) content in the 1.0 and 2.0 mg/kg WGX-50 supplemented groups was significantly decreased (P<0.05). 4) Compared with the control group, the serum follicle-stimulating hormone (FSH) and estradiol (E₂) contents in the 1.0 and 2.0 mg/kg WGX-50 supplemented groups were significantly increased (P<0.05). 5) Compared with the control group, the total number of follicles in the ovary in the 0.5, 1.0, and 2.0 mg/kg WGX-50 supplemented groups was significantly increased (P<0.05); the numbers of small yellow follicles (SYF) and large white follicles (LWF) in the 1.0 mg/kg WGX-50 supplemented group were significantly increased (P<0.05); the diameter of F1 hierarchical follicles in the 1.0 and 2.0 mg/kg WGX-50 supplemented groups was significantly increased (P<0.05); and the diameter of F3 hierarchical follicles in the 1.0 mg/kg WGX-50 supplemented group was significantly increased (P<0.05). In conclusion, dietary supplemented with WGX-50 exerts positive effects on improving the performance, antioxidant capacity, anti-inflammatory capacity and follicle development of laying hens in late laying period. Under the conditions of this experiment, the appropriate dietary WGX-50 supplemented amount is 1.0 to 2.0 mg/kg.

This experiment was conducted to explore the effects of dietary black soldier fly larva meal on the performance, egg quality, antioxidant capacity, and serum biochemical and immune indices of laying hens. A total of 640 Hy-Line brown laying hens aged 38 weeks with a similar body weight of (1.78±0.10) kg, a laying rate of (80.51±1.04)%, and good health were selected and randomly divided into 4 groups, with 8 replicates in each group and 20 hens in each replicate. The control group was fed a basal diet (without adding black soldier fly larva meal), while the experimental groups were fed diets in which 2%, 4%, and 6% black soldier fly larva meal was added, respectively, and the proportion of soybean meal was reduced. The pre-experiment lasted for 1 week and the formal experiment lasted for 8 weeks. The results showed as follows: 1) compared with the control group, the average egg weight in the 4% black soldier fly larva meal addition group was significantly increased (P<0.05); 2) compared with the control group, the eggshell thickness in each experimental group was significantly increased (P<0.05), and the yolk color in the 4% and 6% black soldier fly larva meal addition groups was significantly improved (P<0.05); 3) compared with the control group, the activities of serum glutathione peroxidase and liver catalase in the 4% and 6% black soldier fly larva meal addition groups were significantly increased (P<0.05); 4) compared with the control group, the total protein and globulin contents in serum in the 4% black soldier fly meal addition group were significantly increased (P<0.05), and the contents of low-density lipoprotein and very low-density lipoprotein in serum in each experimental group were significantly decreased (P<0.05); 5) compared with the control group, the contents of serum immunoglobulin A and complement 4 in the 4% black soldier fly larva meal addition group were significantly increased (P<0.05). In conclusion, dietary 4% black soldier fly larva meal can increase the average egg weight, yolk color and eggshell thickness of laying hens, and enhance the antioxidant capacity and immune function of the body, which is conducive to reducing the use of soybean meal in laying hen production.

This experiment was conducted to investigate effects of supplementing different compound enzyme preparations in low-protein diets on performance, serum indices, intestinal digestive enzyme activities and nutrient apparent digestibility of laying hens. A total of 1 080 Hy-Line brown laying hens aged of 58 weeks were randomly divided into six groups with six replicates per group and 30 hens per replicate. The control group was fed a corn-soybean meal basal diet with a crude protein (CP) level of 14.73%. The experimental groups were fed a low-protein diet in which the CP level was reduced by 1 percentage point relative to the basal diet by replacing part of soybean meal with wheat bran, and were supplemented without or with different compound enzyme preparations. Group M0 received the low-protein diet without extra enzyme supplementation, whereas groups M1, M2, M3 and M4 received the low-protein diet supplemented with 0.1% compound enzyme preparations M1 (xylanase 8 000 U/kg + mannanase 150 U/kg + glucanase 600 U/kg), M2 (xylanase 8 000 U/kg + mannanase 150 U/kg + glucanase 600 U/kg + amylase 1 050 U/kg), M3 (xylanase 8 000 U/kg + mannanase 150 U/kg + glucanase 600 U/kg + protease 120 U/kg) and M4 (xylanase 8 000 U/kg + mannanase 150 U/kg + glucanase 600 U/kg + amylase 1 050 U/kg + protease 120 U/kg), respectively. The pre-experimental period lasted for 7 days and the formal experimental period lasted for 84 days. The results showed as follows: 1) the laying rate in groups M1, M2, M3 and M4 was significantly higher than that in group M0 (P<0.05), with no significant difference compared with the control group (P>0.05); the average egg weight in the control group and groups M2, M3 and M4 was significantly higher than that in groups M0 and M1 (P<0.05). 2) Compared with group M0, the serum total protein content in groups M3 and M4 was significantly increased (P<0.05), with no significant difference compared with the control group (P>0.05); the serum uric acid content in groups M1, M2, M3 and M4 was significantly lower than that in the control group and group M0 (P<0.05). 3) Compared with the control group and group M0, the intestinal trypsin activity in groups M3 and M4 was significantly increased (P<0.05), and the amylase activity in groups M2 and M4 was significantly increased (P<0.05); the intestinal lipase activity in group M0 was significantly decreased compared with the control group (P<0.05), whereas that in groups M3 and M4 was significantly increased compared with the control group (P<0.05). 4) Compared with the control group and group M0, the dry matter apparent digestibility in groups M2, M3 and M4 was significantly increased (P<0.05); the crude protein apparent digestibility in groups M3 and M4 was significantly increased (P<0.05); the apparent digestibility of crude fat, ash and calcium in groups M1, M2, M3 and M4 was significantly increased (P<0.05). 5) Compared with group M0, the apparent digestibility of essential amino acids lysine, methionine and threonine in group M4 was significantly increased by 2.35, 1.95 and 3.64 percentage points, respectively (P<0.05), and did not differ significantly from that in the control group (P>0.05). In conclusion, supplementation of compound enzyme preparations can improve the performance of laying hens fed low-protein diets, enhance intestinal digestive enzyme activities, and promote the apparent digestibility of conventional nutrients and amino acids, thereby alleviating the negative effects of low-protein diets. Under the conditions of this experiment, supplementation of 0.1% compound enzyme preparation M4 (containing xylanase, mannanase, glucanase, amylase and protease) shows the optimal effects.

This experiment was conducted to explore the effects of adding a compound crude extract of Codonopsis pilosula, Astragalus membranaceus and Magnolia officinalis to drinking water on performance, egg quality, intestinal morphology and ovarian index of laying hens during late laying period. A total of 2 430 Hy-Line grey laying hens of 76-week-old with similar body weight were selected and randomly divided into 3 groups, with 6 replicates in each group and 135 hens in each replicate. The groups were fed the same basal diet, and 0 (control group, CON group), 0.3% (G1 group) and 0.5% (G2 group) (based on dietary mass) of compound crude extract of Codonopsis pilosula, Astragalus membranaceus and Magnolia officinalis was added to the drinking water, respectively. The pre-test period was 3 days and the formal test period was 42 days. The results showed as follows: 1) compared with CON group, the average weight of normal eggs in G1 and G2 groups was significantly increased (P<0.05). 2) Compared with CON group, the albumen pH and yolk weight in G1 and G2 groups was extremely significantly increased on day 14 (P<0.01), while the albumen pH and egg shape index were significantly decreased on day 28 (P<0.05); the eggshell thickness in G1 group was extremely significantly decreased on day 14 (P<0.01); the albumen weight in G2 group was significantly decreased on day 42 (P<0.05). 3) Compared with CON group, the number of white blood cells in G2 group was significantly increased (P<0.05). 4) Compared with CON group, the crypt depth in ileum in G1 and G2 groups was extremely significantly increased (P<0.01), and the villus height to crypt depth ratio in ileum was extremely significantly decreased (P<0.01). 5) Compared with CON group, the ovarian index in G1 group showed an increasing trend (P>0.05), while that in G2 group showed a decreasing trend (P>0.05). In conclusion, adding an appropriate concentration of compound crude extract of Codonopsis pilosula, Astragalus membranaceus and Magnolia officinalis to drinking water can increase the average weight of normal eggs of laying hens during late laying period, and regulate the egg quality indices such as yolk weight and albumen pH at specific stages. At the same time, it can regulate the immune status of the body, improve intestinal health and affect reproductive function. Under the conditions of this experiment, it is recommended that the appropriate addition concentration of the compound crude extract of Codonopsis pilosula, Astragalus membranaceus and Magnolia officinalis in the drinking water of laying hens during late laying period be 0.3%.

This study aimed to investigate the effects of fermented wheat bran on the growth performance, serum biochemical indices and expression of signaling regulation genes in the hypothalamic and cecal tissues of broilers. A total of 180 one-day-old Arbor Acres (AA) broiler chicks (male) were selected and randomly allocated into 3 groups. They were fed the following diets for a 42-day feeding trial: a basal diet (without wheat bran or fermented wheat bran, CON group), a diet containing 7% wheat bran (WB group), and a diet containing 7% fermented wheat bran (FWB group). Each group consisted of 6 replicates with 10 birds per replicate. The results showed that: 1) during each trial phases (1 to 7 days of age, 8 to 21 days of age and 22 to 42 days of age) and the entire period (1 to 42 days of age), there were no significant differences in average daily gain (ADG), average daily feed intake (ADFI), and feed-to-gain ratio (F/G) among the groups (P≥0.05). 2) At 21 days of age, the serum total protein (TP), globulin (GLB) and urea nitrogen (UN) contents in the FWB group were significantly higher than those in the CON and WB groups (P<0.05), and the serum aspartate aminotransferase (AST) activity was significantly higher than that in the CON group (P<0.05). 3) At 21 days of age, the acetic acid and propionic acid contents in the cecal content of broilers in the FWB group were significantly higher than those in the WB group (P<0.05). At 42 days of age, the propionic acid content in the cecal content of broilers in the FWB group was significantly higher than that in the CON and WB groups (P<0.05). 4) At 42 days of age, the mRNA relative expression level of G protein-coupled receptor 41 (GPR41) in the cecal tissue of broilers in the FWB group was significantly higher than that in the CON and WB groups (P<0.05), and the mRNA relative expression level of G protein-coupled receptor 109A (GPR109A) was significantly higher than that in the WB group (P<0.05). At 21 days of age, the mRNA relative expression level of interleukin-10 (IL-10) in the hypothalamic tissue of broilers in the FWB group was significantly higher than that in the CON and WB groups (P<0.05). At 42 days of age, the mRNA relative expression level of interleukin-1β (IL-1β) in the hypothalamic tissue of broilers in the FWB group was significantly lower than that in the CON group (P<0.05). These results indicate that dietary supplementation with 7% fermented wheat bran can optimize the expression of genes related to signaling pathways, such as short-chain fatty acid metabolism and central inflammation, thereby improving the physiological status of broilers.

This study was conducted to determine the standard ileal digestibility (SID) of 18 amino acids of cottonseed meals (CSM) from different sources in starter broilers, and to establish amino acid SID prediction equations based on chemical components of cottonseed meals. A total of 780 healthy 10-day-old male Cobb white broilers with similar body weight were randomly assigned to 13 groups with 6 replicates per group and 10 broilers per replicate. The experimental groups included a nitrogen-free diet group, a soybean meal diet group and 11 CSM diet groups. Titanium dioxide (TiO₂) was supplemented at 0.50% in all diets as an exogenous marker. The experimental period lasted for 3 days. Ileal digesta were collected at the end of the trial, and the SID of amino acids was calculated based on the contents of amino acids and TiO₂ in diets and digesta. The results showed as follows: 1) the average crude protein content of 11 CSM from different sources was 62.12% (53.91% to 67.12%). Among essential amino acids, arginine had the highest average content of 6.91% (6.19% to 8.18%), while methionine showed the lowest average content of 0.56% (0.47% to 0.70%). Among non-essential amino acids, glutamic acid had the highest average content of 11.93% (10.71% to 13.50%), and cysteine had the lowest average content of 0.69% (0.58% to 0.82%). The average SID of crude protein of CSM in starter broilers was 85.61% (76.02% to 92.44%), and the average SID values of 18 amino acids ranged from 67.53% to 91.78%. Among all amino acids, arginine had the highest SID, whereas lysine had the lowest. Except for methionine, CSM from different sources exerted a significant effect on the SID of 17 amino acids (P<0.05). The coefficient of determination (R²) of the established SID prediction equations for amino acids ranged from 0.417 to 0.900. High fitting quality with R²>0.8 was achieved for the prediction equations of lysine, arginine, phenylalanine, glycine, serine, glutamic acid, tyrosine and proline. The prediction equation for arginine SID exhibited the highest goodness of fit: arginine SID=61.382-1.599×crude protein-0.369×neutral detergent fiber+2.405×total amino acids (R²=0.900, P<0.001). In conclusion, the amino acid SID of CSM varies among different sources. Crude protein, neutral detergent fiber and total amino acid contents can serve as key predictors for amino acid SID of CSM in starter broilers, and the prediction equation for arginine SID has the optimal fitting performance.

The aim of this study was to investigate the effects of chitosan oligosaccharide (COS) on hepatic function, endoplasmic reticulum stress, mitochondrial mass and NOD-like receptor protein 3 (NLRP3) inflammasome activation in heat-stressed broilers. A total of one hundred of forty-four 28-day-old male Arbor Acres (AA) broilers with similar body weight [(1 469.07±117.26) g] were randomly divided into 3 groups, with 6 replicates per group and 8 broilers per replicate. Broilers in control (CON) group were housed in a room maintained at (24±1) ℃. Broilers in the heat stress (HS) group and COS group were housed in a room maintained at (34±1) ℃ from 08:00 to 18:00, while the temperature during the remaining time was maintained at (24±1) ℃. Broilers in the CON and HS groups were fed the basal diet, and those in the COS group were fed the basal diet supplemented with 200 mg/kg COS. The experiment lasted for 14 d. The results showed as follows: 1) compared with the CON and COS groups, hepatic alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutaminase (GLS) and glutamine synthase (GS) activities of the HS group were significantly increased (P<0.05). 2) Compared with the CON and COS groups, mRNA relative expression levels of hepatic progesterone X receptor (PXR), cytochrome P450 family 1 subfamily A member 2 (CYP1A2), cytochrome P450 family 2 subfamily D member 6 (CYP2D6) and cytochrome P450 family 3 subfamily A member 4 (CYP3A4) of the HS group were significantly up-regulated (P<0.05). 3) Compared with the CON and COS groups, mRNA relative expression levels of hepatic glucose regulated protein 78 (GRP78), protein kinase RNA-like ER kinase (PERK), X-box binding protein 1 (XBP1) and transcriptional factor C/EBP homologous protein (CHOP) of the HS group were significantly up-regulated (P<0.05). 4) Compared with the CON and COS groups, mRNA relative expression levels of hepatic peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) and mitochondrial transcription factor A (TFAM) of the HS group were significantly down-regulated (P<0.05), while mRNA relative expression levels of mitochondrial dynamin-related protein 1 (DRP1), PTEN-induced kinase1 (PINK1) and E3 ubiquitin protein ligase (Parkin) of the HS group were significantly up-regulated (P<0.05). Compared with the CON group, mRNA relative expression level of hepatic selective autophagy adaptor protein p62 (p62) of the HS and COS group was significantly up-regulated (P<0.05). 5) Compared with the CON and COS groups, mRNA relative expression levels of hepatic NLRP3, cysteinyl aspartate specific proteinase 1 (Caspase 1) and interleukin-18 (IL-18) of the HS group were significantly up-regulated (P<0.05). In conclusion, dietary supplementation with 200 mg/kg COS can promote hepatic mitochondrial biogenesis in heat-stressed broilers, followed by inhibiting mitochondrial division, alleviating mitophagy, endoplasmic reticulum stress and inflammatory response, and finally alleviating hepatic damage and improving ammonia detoxification capacity in heat-stressed broilers.

This experiment was conducted to explore the effects of corn stover fermented by lactic acid bacteria on growth performance, nutrient apparent digestibility, and rumen fermentation parameters and microbiota of beef cattle. Forty healthy Simmental cattle aged 16 months were selected and randomly divided into the control group (CON group) and the lactic acid bacteria group (LAB group), with 20 replicates in each group and 1 cattle in each replicate. The CON group was fed a basal diet mainly composed of corn stover as roughage, while the LAB group replaced the corn stover in the basal diet with the lactic acid bacteria-fermented corn stover in equal amounts. The pre-experiment was 15 days and the formal experiment was 75 days. The results showed as follows: 1) compared with the CON group, the final body weight, average daily gain and dry matter intake in the LAB group were significantly increased (P<0.05). 2) Compared with the CON group, the apparent digestibility of dry matter and crude protein in the LAB group was significantly increased (P<0.05). 3) Compared with the CON group, the contents of rumen ammonia nitrogen, microbial protein, propionic acid, butyric acid and total volatile fatty acids in the LAB group were significantly increased (P<0.05), while the rumen acetic acid content was significantly decreased (P<0.05). 4) Compared with the CON group, the Shannon index of the rumen microbiota in the LAB group was significantly decreased (P<0.05), and the Simpson index was significantly increased (P<0.05). The relative abundances of Streptococcus, Succiniclasticum, Prevotellaceae_UCG-003 and Acetobacter in the LAB group were significantly increased (P<0.05). In conclusion, the corn stover fermented by lactic acid bacteria can enhance the growth performance of beef cattle by optimizing the rumen microbiota structure, improving the rumen fermentation, and increasing the nutrient apparent digestibility.

This study aimed to investigate the effects of feeding high-moisture corn (HMC) on the performance, serum parameters and intestinal metabolism of Simmental crossbred bulls. A total of 32 healthy Simmental crossbred bulls aged 20 months with similar body weight [(415.10±15.37) kg] were randomly assigned to 2 groups with 16 bulls in each group. The control group (CK group) was fed a basal diet, while the HMC group fed the diet which used HMC replacing 45% common corn in the basal diet (dry matter basis). The trial included a 10-day adaptation period followed by a 160-day formal feeding period. The results showed as follows: 1) compared with the CK group, feeding HMC significantly increased the final body weight, average daily gain, average daily feed intake, net meat weight and net meat percentage of Simmental crossbred bulls (P<0.05 or P<0.01), and significantly decreased the feed to gain ratio (P<0.05). 2) Compared with the CK group, feeding HMC significantly increased the serum triglycerides (day 80), immunoglobulin M (day 80), immunoglobulin G (day 40, day 80 and day 160), immunoglobulin A (on days 80 and 160) contents, as well as the superoxide dismutase (day 40 and day 80) and glutathione peroxidase (day 40, day 80 and day 160) activities of Simmental crossbred bulls (P<0.05 or P<0.01), and significantly decreased the serum urea nitrogen (day 40, day 80 and day 160), tumor necrosis factor-α (day 40, day 80 and day 160) and malondialdehyde (day 80 and day 160) contents (P<0.05 or P<0.01). 3) The metabolomics analysis identified a total of 1 253 fecal differential metabolites (1 040 up-regulated and 213 down-regulated). KEGG enrichment analysis indicated that the differential metabolites were main enrichment in bile secretion, tyrosine metabolism and cholesterol metabolism pathways, which promoted the enrichment of metabolites related to protein and lipid metabolism. In conclusion, feeding HMC can improve the performance of Simmental crossbred bulls, enhance the body immune function and antioxidant capacity, and enhance the body protein and lipid metabolism.

This experiment was conducted to investigate the effects of dietary supplementation with different doses of Ganoderma lucidum polysaccharides (GLP) on the growth performance, serum indices and fecal microbiota of lactating calves. Thirty-two healthy Simmental beef calves with similar ages of (9.0±2.0) days and weights of (51.67±4.05) kg were selected and randomly divided into 4 groups, with 8 replicates in each group and 1 calf in each replicate. The control group was fed a basal diet, while the experimental groups were fed the basal diets supplemented with 5 (GLP5 group), 10 (GLP10 group) and 20 g/(head·d) (GLP20 group) GLP, respectively. The pre-test period was 7 days and the formal test period was 50 days. The results showed as follows: 1) compared with the control group, the final body weight and average daily gain in GLP10 group were significantly increased (P<0.05), while the fecal score and diarrhea rate were significantly decreased (P<0.05). 2) Compared with the control group, the serum alanine aminotransferase activity in GLP10 group was significantly decreased (P<0.05); the serum total antioxidant capacity and activities of superoxide dismutase, glutathione peroxidase and catalase were significantly increased (P<0.05), while the serum malondialdehyde content was significantly decreased (P<0.05); the serum diamine oxidase activity and tumor necrosis factor-α content were significantly decreased (P<0.05), while the serum contents of immunoglobulin A, immunoglobulin M, immunoglobulin G, interleukin-2 and interleukin-4 were significantly increased (P<0.05). 3) Compared with the control group, the Chao1 index, Shannon index and Simpson index of fecal microbiota in GLP10 group were significantly increased (P<0.05); the relative abundances of Actinobacteriota and Proteobacteria in feces were significantly increased (P<0.05); the relative abundances of Cryptobacteroides, Lactobacillus and Blautia in feces were significantly increased (P<0.05), while the relative abundances of Faecousia and Phocaeicola in feces were significantly decreased (P<0.05). In conclusion, dietary supplementation with 10 g/(head·d) GLP can enhance the growth performance of lactating beef calves, reduce the occurrence of diarrhea, strengthen the immune function and antioxidant capacity, improve the structure of fecal microbiota, and promote body health.

This study aimed to investigate the effects of rumen-protected amino acids supplementation in low protein starter on growth performance and thymus and spleen development of yak calves. Twenty-seven Datong yak calves (female) with similar genetic backgrounds, days of age (42 to 45 days of age) and body weight [(36.86±2.53) kg] were randomly assigned to 3 groups with 9 calves per group. The high protein group (HP group) was fed a starter containing 19% protein level, the low protein group (LP group) was fed a starter containing 17% protein level, and the low protein+rumen-protected amino acids group (LP+RPAA group) was fed a starter containing 17% crude protein level and supplemented with rumen-protected amino acids (lysine and methionine). The pre-experimental period lasted for 21 days, and the experimental period lasted for 100 days. The results showed as follows: 1) the rumen-protected amino acids supplementation in low protein starter had no significant effect on growth performance of yak calves (P>0.05). 2) The thymus cortical area of HP and LP+RPAA groups was significantly higher than that of LP group (P<0.05). The thymus immunoglobulin G content of LP+RPAA group was significantly higher than that of HP and LP groups (P<0.05). The thymus interleukin-2 content of HP and LP+RPAA groups was significantly higher than that of LP group (P<0.05). 3) The spleen white medulla area of HP and LP+RPAA groups was significantly higher than that of LP group (P<0.05). The spleen immunoglobulin G and interleukin-1β contents of LP and LP+RPAA groups was significantly higher than that of HP group (P<0.05). The spleen interleukin-4 content of HP and LP+RPAA groups was significantly higher than that of LP group (P<0.05). In conclusion, reducing the protein level in starter from 19% to 17% and supplementing with rumen-protected lysine and methionine can maintained growth performance of yak calves, and improving the thymus and spleen histomorphology and immune function.

This study aimed to investigate the effects of combined supplementation of Clostridium butyricum culture (CBC) and Aspergillus oryzae culture (AOC) in late gestation diet on growth performance and serum biochemical indicators of ewes, as well as on the growth and development of their offspring lambs. Forty-five healthy Altay ewes with singleton pregnancies at day 121 of gestation, weighing (71.64±2.83) kg, were randomly divided into 3 groups with 3 replicates per group and 5 ewes per replicate. Ewes in the three groups were fed a basal diet (CK group), or experimental diets supplemented with 0.21% CBC (CBC group) and 0.21% CBC+0.50% AOC (CBC+AOC group), respectively, for 30 days (from day 121 to 150 of gestation). The results showed as follows: 1) compared with the CK group, the body weight of ewes in the CBC+AOC group on day 150 of gestation and day 30 postpartum was significantly increased (P<0.05). From day 121 to 150 of gestation, the average daily gain (ADG) in the CBC+AOC group and CBC groups was extremely significantly increased (P<0.01). 2) Compared with the CK group, the serum contents of total protein (TP), β-hydroxybutyric acid (β-HB), glucose (GLU) and triglyceride (TG) in the CBC+AOC group on day 150 of gestation were extremely significantly increased (P<0.01), while the serum urea content was significantly decreased (P<0.05); moreover, the serum β-HB and GLU contents in the CBC+AOC group on day 30 postpartum were extremely significantly increased (P<0.01). The serum GLU content in the CBC group on day 150 of gestation and day 30 postpartum was extremely significantly increased (P<0.01). 3) Compared with the CK group, the total antioxidant capacity (T-AOC), and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) in serum of ewes in the CBC+AOC group on day 150 of gestation were significantly increased (P<0.05), the serum malondialdehyde (MDA) content was extremely significantly decreased (P<0.01), and the serum diamine oxidase (DAO) activity and D-lactic acid (D-LA) content were significantly decreased (P<0.05); on day 30 postpartum, serum CAT and SOD activities of ewes in the CBC+AOC group were significantly increased (P<0.05), serum GSH-Px activity was extremely significantly increased (P<0.01), and serum D-LA content was significantly decreased (P<0.05); in the CBC group, serum SOD activity on day 150 of gestation was significantly increased (P<0.05), serum MDA content was extremely significantly decreased (P<0.01), and serum GSH-Px activity on day 30 postpartum was extremely significantly increased (P<0.01). 4) The body oblique length and withers height of lambs in the CBC+AOC group on days 1 and 30 after birth were extremely significantly higher than those in the CK group and CBC group (P<0.01), and the withers height on day 60 after birth was significantly higher than that in the CK group and CBC group (P<0.05). The chest girth of lambs in the CBC+AOC group on days 1, 30 and 60 after birth was significantly increased (P<0.05). 5) Compared with the CK group, the serum TP content of lambs in the CBC+AOC group on day 30 after birth was extremely significantly increased (P<0.01), while the serum contents of urea and total cholesterol (TC) were significantly decreased (P<0.05), and the serum GLU content was significantly increased (P<0.05); on day 60 after birth, the serum urea content of lambs in the CBC+AOC group was extremely significantly decreased (P<0.01), and the serum TP and albumin (ALB) contents were significantly increased (P<0.05); the serum T-AOC and the activities of GSH-Px and CAT of lambs in the CBC+AOC group on day 30 after birth were significantly increased (P<0.05), and the serum T-AOC and the activities of GSH-Px, SOD and CAT of lambs on day 60 after birth were extremely significantly increased (P<0.01); the serum MDA content of lambs in the CBC+AOC group and CBC group on day 30 after birth was extremely significantly decreased (P<0.01). In conclusion, combined supplementation of CBC and AOC in late gestation diet can effectively increase the ADG of ewes, enhance their antioxidant capacity, immune function and intestinal barrier function, promote protein metabolism, improve energy metabolism, and benefit the early growth and development of offspring lambs. Moreover, the combined supplementation of CBC and AOC shows better effects than supplementation with CBC alone.

This experiment aimed to investigate the effects of dietary crude protein levels on growth performance, serum biochemical and antioxidant indices and plasma metabolome of ewes in later stage of pregnancy. Thirty Donghanhu hybrid ewes with similar body weight [(70.17±2.17) kg] and good health condition in later stage of pregnancy (75±5 days of gestation), confirmed by B-ultrasound to be carrying twins or triplets, were selected and randomly divided into 3 groups, with 10 ewes per group. The three groups were fed experimental diets with high (group A, crude protein level of 16.11%, metabolizable energy level of 8.07 MJ/kg), low (group B, crude protein level of 12.10%, metabolizable energy level of 8.07 MJ/kg) and medium (group C, crude protein level of 14.31%, metabolizable energy level of 8.10 MJ/kg) crude protein levels, respectively. The experiment lasted for 70 days, including a 10-day pre-trial period and a 60-day formal trial period. The results showed as follows: 1) there were no significant differences in performance of ewes among all groups (P>0.05). 2) Activities of aspartate aminotransferase and alkaline phosphatase in serum of ewes in group A were extremely significantly higher than those in groups B and C (P<0.01). The serum total protein content in group A was extremely significantly higher than that in group B (P<0.01) and significantly higher than that in group C (P<0.05). The serum urea nitrogen content in groups A and B was extremely significantly lower than that in group C (P<0.01). The serum albumin content in groups A and C was extremely significantly higher than that in group B (P<0.01). The serum creatinine content in group A was significantly higher than that in group B (P<0.05). The serum triglyceride content in group A was significantly higher than that in group C (P<0.05). 3) There were no significant differences in serum antioxidant indices among all groups (P>0.05). 4) Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that differential plasma metabolites between groups A and B were significantly enriched in the glycine, serine and threonine metabolism pathway; differential plasma metabolites between groups B and C were significantly enriched in the unsaturated fatty acid biosynthesis pathway; and differential plasma metabolites between groups A and C were significantly enriched in the amino acid biosynthesis pathway. In conclusion, under the conditions of this experiment, diet with crude protein level of 16.11% and metabolizable energy level of 8.07 MJ/kg (high crude protein level) is recommended for ewes in later stage of pregnancy.

This experiment aimed to investigate the corn processing methods on intestinal starch digestion dynamics and serum volatile fatty acid concentrations of sheep. Three healthy adult sheep with permanent duodenal fistulas were used in a 3×3 Latin square design. Three experimental groups were established: dry whole corn group (DWC group), dry rolled corn group (DRC group) and dry ground corn group (DGC group). The experiment consisted of three periods with 21 days per period. Diet formulations and raw material sources were identical across all groups, with only the corn processing method differing. The results showed as follows: 1) the foregut starch apparent digestibility in the DWC group was significantly lower than that in the DGC group before morning feeding (P<0.05), while the foregut starch apparent digestibility of DWC group was significantly higher than DRC and DGC groups at 2, 4, 8 and 10 hours after morning feeding (P<0.05). 2) Compared with the DRC group, the DWC group exhibited significantly higher total tract starch apparent digestibility and significantly lower hindgut starch apparent digestibility (P<0.05), as well as significantly reduced starch content in rectal digesta and total volatile fatty acid (TVFA) concentration in rectal digesta at 4 and 6 hours after morning feeding (P<0.05). Compared with the DGC group, the DWC group had significantly higher total tract starch apparent digestibility (P<0.05), significantly reduced concentrations of TVFA, acetate and valerate in rectal digesta before morning feeding (P<0.05), and significantly reduced the mean values TVFA, acetate, butyrate, valerate, isobutyrate and isovalerate concentrations in rectal digesta (P<0.05). 3) The serum butyrate concentration in the DWC group was significantly higher than that in DRC and DGC groups before morning feeding (P<0.05). At 2 hours after morning feeding, the serum isobutyrate concentration in the DWC group was significantly lower than that in the DGC group (P<0.05), whereas the serum valerate concentration at 4 and 6 hours after morning feeding in the DWC group was significantly higher than that in DRC and DGC groups (P<0.05). There were no significant differences in serum biochemical indices among the groups (P>0.05). In conclusion, compared with dry rolled and dry ground corn, dry whole corn improves the overall starch utilization efficiency of sheep by enhancing foregut starch digestibility and reducing hindgut starch fermentation.

This experiment was conducted to investigate the effects of dietary supplementation with Chinese chive seed flavonoids on the fermentation characteristics of compound stomach of Hu sheep, while elucidating the spatial succession patterns of microbiota from the perspective of gastrointestinal tract. Twenty 3-month-old male Hu sheep with a similar body weight of (19.56±1.59) kg were selected and randomly divided into 2 groups, with 10 replicates in each group and 1 lamb in each replicate. The control group was fed a basal diet, while the experimental group was fed the basal diet supplemented with 0.24% Chinese chive seed flavonoids. The pre-test period lasted for 7 days, followed by a main experimental period of 90 days. The results showed as follows: 1) dietary supplementation with Chinese chive seed flavonoids significantly increased the dry matter intake of Hu sheep (P<0.05), while no significant differences were observed in final body weight, average daily gain and feed to gain ratio (P>0.05). 2) Regarding the rumen fermentation parameters, the contents of total volatile fatty acids, propionic acid, butyric acid, isovaleric acid and valeric acid in rumen in the experimental group were significantly higher than those in the control group (P<0.05). 3) Analysis of the gastrointestinal microbiota revealed that, at the phylum level, compared with the control group, the Spirochaetota relative abundance in all compartments of compound stomach in the experimental group was significantly increased (P<0.05). Notably, Deinococcota and Bdellovibrionota were specifically detected in the omasum and abomasum in the experimental group. Furthermore, the relative abundances of Myxococcota in duodenum, Acidobacteriota in jejunum, and Nitrospirota in rectum in the experimental group were significantly increased (P<0.05). At the genus level, compared with the control group, the cellulolytic bacteria such as Ruminococcus and Fibrobacter in compound stomach in the experimental group were significantly enriched (P<0.05). Linear discriminant analysis (LDA) effect size (LEfSe) analysis (LDA>4) revealed that the differentially enriched genera in the compound stomach primarily included Sphingobacterium, Treponema and Prevotella, while Bacteroides, Bacillus and Bifidobacterium were the predominant enriched genera in the intestinal segments. In conclusion, dietary supplementation with Chinese chive seed flavonoids can optimize the gastrointestinal microbiota structure, improve the rumen fermentation pattern, and thereby enhance the nutrient intake and metabolic homeostasis of Hu sheep.

This study aimed to investigate the effects of water-soluble extract of onion on growth performance, slaughter performance and muscle physical and chemical indicators of mutton sheep. Thirty-six healthy 3-month-old Dorper×thin-tailed Han crossbred weaned male lambs with similarly condition and body weight [(26.26±2.94) kg] were randomly divided into 4 groups with 3 replicates per group and 3 lambs per replicate. The control group (CON group) was fed a basal diet, and the experimental groups were fed the basal diet supplemented with 2 (OE2 group), 4 (OE4 group) and 8 g/(d·lamb) (OE8 group) water-soluble extract of onion, respectively. The pre-experimental period lasted for 15 days, and the experimental period lasted for 60 days. The results showed as follows: 1) compared with the CON group, the feed to gain ratio of OE2, OE4 and OE8 groups showed a significantly decreased trend (P=0.064). 2) Compared with the CON group, the GR value of OE4 and OE8 groups was significantly increased (P<0.05), and the loin eye area of OE2, OE4 and OE8 groups showed a significantly increased trend (P=0.070). 3) Compared with the CON group, the longissimus dorsi cooking loss rate of the OE4 group was significantly decreased (P<0.05), and the longissimus dorsi redness (a^*) value of OE2, OE4 and OE8 groups showed a significantly increased trend (P=0.051). 4) Compared with the CON group, the longissimus dorsi phenylalanine (Phe) content in hydrolyzed amino acids of OE4 and OE8 groups was significantly increased (P<0.05). 5) Compared with the CON group, the longissimus dorsi leucine (Leu) content in free amino acids of OE2 and OE8 groups showed a significantly increased trend (P=0.062). 5) Compared with the CON group, the longissimus dorsi heneicosanoic acid (C21∶0) content of the OE2 group was significantly increased (P<0.05), and the longissimus dorsi heptadecenoic acid (C17∶1) content of the OE4 group showed a significantly increased trend (P=0.055). In summary, dietary supplemented with 4 and 8 g/(d·lamb) water-soluble extract of onion can effectively enhances the slaughter performance of mutton sheep, and holds potential for improving the amino acids and fatty acids composition of mutton.

This experiment was conducted to investigate the effects of glutamine (Gln) on growth performance, nutrient apparent digestibility, rumen digestive enzyme activities and microbial counts of weaned lambs. A total of 219 healthy Hu ewe lambs with similar body weight at (45±2) days of age were randomly divided into 4 groups, which were fed pellet feed with 0 (control group), 0.5%, 1.0% and 2.0% Gln added, respectively, along with the same total mixed ration (TMR). The control group was set with 3 replicates (9 lambs in one replicate and 15 lambs in each of the other two replicates), and each experimental group was set with 4 replicates (15 lambs per replicate). Additionally, two Gln addition duration treatments were arranged in each experimental group: 2 replicates with 14-day addition (S group) and the other 2 replicates with long-term addition (60-day addition, L group). Lambs were weaned at about 45 days of age, and the experiment started on the day of weaning with a trial period of 60 days. The results showed as follows: 1) under both 14-day and long-term Gln addition conditions, the average daily gain (ADG) of lambs in the 0.5%, 1.0% and 2.0% Gln groups during days 1 to 60 was significantly higher than that in the control group (P<0.05), with the 2.0% Gln group being the highest; the feed to gain ratio (F/G) during days 1 to 60 was significantly lower than that in the control group (P<0.05), with the 2.0% Gln group being the lowest. The apparent digestibility of dry matter, neutral detergent fiber and acid detergent fiber in the 1.0% and 2.0% Gln groups was significantly higher than that in the control group (P<0.05). The activities of rumen β-glucosidase, α-amylase, pectinase and protease in the 2.0% Gln group were significantly higher than those in the other three groups (P<0.05), and the activity of rumen carboxymethyl cellulase was significantly higher than that in the 0.5% Gln group and control group (P<0.05); the activities of rumen pectinase and protease in the 1.0% Gln group were significantly higher than those in the 0.5% Gln group and control group (P<0.05). The counts of total protozoa and total methanogens in rumen of the 0.5%, 1.0% and 2.0% Gln groups were significantly lower than those in the control group (P<0.05), and the counts of Ruminobacter amylophilus, Ruminococcus albus and Ruminococcus flavefaciens in rumen of the 2.0% Gln group were significantly higher than those in the 0.5% Gln group and control group (P<0.05). 2) When the Gln addition level was 2.0%, compared with the L group, the F/G in the S group during days 1 to 60 was significantly decreased (P<0.05), the crude protein apparent digestibility was significantly increased (P<0.05), the rumen protease activity was significantly increased (P<0.05), and the counts of total protozoa and total methanogens in rumen were both significantly decreased (P<0.05). Additionally, the counts of Ruminococcus albus and Prevotella ruminicola were significantly increased (P<0.05). In conclusion, dietary addition of an appropriate amount of Gln can increase the counts of beneficial rumen microbial populations, digestive enzyme activities and nutrient apparent digestibility of weaned lambs, thereby increasing ADG, decreasing F/G and improving growth performance. Under the conditions of this experiment, the optimal scheme is the combination of 2.0% Gln addition level and 14-day addition duration.

This study aimed to investigate the protein requirements of growing (9 to 12 months of age) Dezhou donkeys through feeding experiment and nitrogen-free diet experiment, thereby providing theoretical and empirical support for the establishment of feeding standards for Dezhou donkeys. 1) Feeding experiment: forty 9-month-old Dezhou donkeys were randomly allocated to 5 groups with 8 donkeys in each group (half male and half female). Donkeys in 5 groups were fed diets with different protein levels. The pre-experimental period lasted for 15 days, and the experimental period lasted for 100 days, and the experimental period was divided into three phases: early phase (days 1 to 30), middle phase (days 31 to 60) and late phase (days 61 to 100). At the end of each phase of feeding experiment, four donkeys in each group were selected for digestion and metabolism experiment. 2) Nitrogen-free diet experiment: four Dezhou donkeys (half male and half female) aged 9 months with body weight of (140.0±2.5) kg were selected in group A, and four Dezhou donkeys (half male and half female) aged 12 months with body weight of (185.0±1.0) kg were selected in group A, the digestion and metabolism experiment was performed, and 1.8 and 2.3 kg of nitrogen-free diet were fed daily, respectively. The pre-experimental period lasted for 7 days, and the experimental period lasted for 4 days. The results showed as follows: 1) during early phase, middle phase and late phase of the feeding experiment, with dietary protein level increased, the nitrogen intake, digestible nitrogen and urinary nitrogen were significantly increased (P<0.05), the retained nitrogen showed an increasing trend, while the net protein utilization and biological value of protein show a decreasing trend. 2) In the nitrogen-free diet experiment, the retained nitrogen of group A was -10.89 g/d, and the retained nitrogen of group B was -15.90 g/d. 3) The regression equations for protein requirement and digestible protein requirement of growing Dezhou donkeys were established as follows: protein requirement (g/d)=4.320 1W^0.75+0.478 4ADG (r=0.935 9, R²=0.875 9, n=80, P<0.01), and digestible protein requirement (g/d)=3.181 1W^0.75+0.377 5ADG (r=0.897 7,R²=0.805 9,n=80,P<0.01). In the formula: W^0.75 represented metabolic body weight; ADG represented average daily gain. In conclusion, this experiment has established protein requirement models for growing Dezhou donkeys. Under this experimental conditions, the maintenance protein intake and maintenance digestible protein of growing Dezhou donkeys were 4.320 1 and 3.181 1 g/kg W^0.75, respectively; the protein intake and digestible protein required per 1 g of gain were 0.478 4 and 0.377 5 g, respectively.

This experiment was conducted to study the effects of solid-state fermented black soldier fly dried larva meal on growth performance, body composition, serum antioxidant indices and intestinal tissue structure of channel catfish (Ictalurus punctatus). A total of 420 channel catfish with an initial average weight of (34.08±0.01) g were selected and randomly divided into 4 groups with 3 replicates in each group and 35 fish in each replicate. Each group was fed isonitrogenous and isolipidic experimental diets supplemented with 0 (H0 group), 1.04% (H1 group), 2.08% (H2 group) and 3.12% (H3 group) solid-state fermented black soldier fly dried larva meal, respectively. The experimental period was 60 days. The results showed that compared with the H0 group, the final body weight, weight gain rate and specific growth rate of H1 group were significantly increased (P<0.05), and the feed coefficient rate was significantly decreased (P<0.05); the whole fish ether extract content of H2 and H3 groups was significantly increased (P<0.05), and the whole fish moisture content of H3 group was significantly decreased (P<0.05); the activities of superoxide dismutase, catalase and glutathione peroxidase in serum of H1 to H3 groups were significantly increased (P<0.05), and the serum total antioxidant capacity of H1 group was significantly increased (P<0.05). There were no significant differences in intestinal villus height and muscular thickness among all groups (P>0.05). In conclusion, adding 1.04% to 3.12% solid-state fermented black soldier fly dried larva meal to the diet can improve the growth performance of channel catfish, enhance the body antioxidant capacity, and increase the body fat deposition, while has no negative impact on the intestinal tissue structure. Under the conditions of this experiment, it is recommended that the appropriate supplemental level of solid-state fermented black soldier fly dried larva meal in diet for channel catfish is 1.04%.

This experiment was conducted to investigate the effects of replacing fish meal with Yarrowia lipolytica on growth, nitrogen and phosphorus excretion and intestinal health of Macrobrachium rosenbergii. A total of 750 healthy M. rosenbergii with an initial body weight of (0.25±0.03) g were randomly divided into 5 groups with 3 replicates per group and 50 shrimps per replicate. Shrimps in the 5 groups were fed experimental diets in which fish meal in the basal diet was replaced with Y. lipolytica at the levels of 0 (YL0 group), 5% (YL5 group), 10% (YL10 group), 20% (YL20 group) and 40% (YL40 group), respectively. The feeding trial lasted for 8 weeks. The results showed as follows: 1) compared with YL0 and YL40 groups, the weight gain rate (WGR) of YL10 group was significantly increased (P<0.05), and the feed conversion ratio (FCR) was significantly decreased (P<0.05). 2) The protein deposition rate (PDR) and phosphorus deposition rate (PPDR) in YL10 group were significantly higher than those in YL0 and YL40 groups (P<0.05), the apparent digestibility of crude protein (ADCP) was significantly higher than that in YL40 group (P<0.05), and the nitrogen excretion (NE) and phosphorus excretion (PE) were significantly lower than those in YL0 and YL40 groups (P<0.05). 3) Compared with YL0 and YL40 groups, the serum triglyceride (TG) content in YL20 group was significantly decreased (P<0.05); the serum total cholesterol (T-CHO) content and the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in YL10 group were significantly decreased (P<0.05); the serum glucose (GLU) content in YL5 and YL10 groups was significantly increased (P<0.05). 4) Compared with YL0 and YL40 groups, the activities of intestinal trypsin, lipase and amylase and the intestinal villus height in YL10 group were significantly increased (P<0.05). Compared with YL0 group, the relative abundances of Firmicutes and Bacillus in intestinal microflora of YL10 group were significantly increased (P<0.05), while the relative abundances of Bacteroidota and Cloacibacterium were significantly decreased (P<0.05). In conclusion, replacing fish meal with an appropriate proportion of Y. lipolytica in the diet could significantly improve the nitrogen and phosphorus deposition efficiency of M. rosenbergii, reduce the excretions of nitrogen and phosphorus metabolic wastes, enhance the antioxidant capacity, improve intestinal health, and promote the growth performance. Based on the regression analysis of WGR, PDR and NE, the appropriate replacement proportion of fish meal with Y. lipolytica in the diet of M. rosenbergii is 15.43% to 16.93%.

This experiment aimed to determine the optimal supplemental level of threonine in a low-protein diet for Ussuri raccoon dogs during the winter fur-growing period. A total of 75 male Ussuri raccoon dogs were randomly divided into 5 groups with 15 raccoon dogs per group. Raccoon dogs in the control group (group C) were fed a conventional protein diet (24% crude protein), while those in the four experimental groups were fed low-protein diets (22% crude protein, a 2-percentage-point reduction in protein level) supplemented with 0 (group L0), 0.3% (group L1), 0.6% (group L2) and 0.9% (group L3) threonine, respectively. The adaptation period lasted for 7 days, followed by a formal experimental period of 62 days. The results showed as follows: 1) the average daily gain (ADG) in groups L1 and L2 was extremely significantly higher than that in groups L0, L3 and C (P<0.01), while the feed-to-gain ratio (F/G) in groups L1 and L2 was extremely significantly lower than that in groups L0 and L3 (P<0.01). 2) The apparent digestibility of dry matter, crude protein and ether extract in groups L1 and L2 was extremely significantly higher than that in groups L0 and C (P<0.01). 3) Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in group L1 were significantly lower than those in groups L0 and C (P<0.05). Serum glucose and triglyceride contents in groups L1 and L2 were extremely significantly lower than those in groups L0 and C (P<0.01), while high-density lipoprotein cholesterol (HDL-C) content in groups L1 and L2 was extremely significantly higher than that in groups L0 and C (P<0.01). 4) Body length in groups L1 and L2 was extremely significantly higher than that in groups L0 and C (P<0.01). 5) The liver index in group L3 was extremely significantly higher than that in groups L0, L2 and C (P<0.01). In conclusion, under the conditions of this experiment, reducing the dietary protein level from 24% to 22% and supplementing with 0.3% threonine does not negatively affect the growth performance of Ussuri raccoon dogs during the winter fur-growing period. Moreover, some serum biochemical indices and nutrient apparent digestibility are even superior to those of animals fed the conventional protein diet.

This study aimed to investigate the improvement effect of N-carbamylglutamate (NCG) on the intestinal mucosal barrier function of weaned rabbit kits. A total of 90 three-week-old New Zealand white rabbit kits were randomly divided into a dam-reared group (NC group), a weaning stress group (WS group), and an NCG intervention group (NCG group), with 10 replicates per group and 3 rabbit kits per replicate. The kits in the NC group were naturally suckled by their dams throughout the experimental period, whereas those in the WS and NCG groups were reared independently after weaning at three weeks of age. The WS group was fed a basal diet, while the NCG group was fed the basal diet supplemented with 600 mg/kg NCG. The experimental period lasted 14 days. The results showed as follows: 1) compared with the WS group, dietary NCG supplementation significantly improved the growth performance of weaned rabbit kits (P<0.05), significantly reduced the diarrhea rate (P<0.05), and significantly improved the jejunal morphology (P<0.05), as evidenced by increased villus height, decreased crypt depth, increased villus height-to-crypt depth ratio, and increased number of goblet cells. 2) Compared with the WS group, dietary NCG supplementation significantly reduced the serum diamine oxidase (DAO) activity and the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) (P<0.05), and significantly upregulated the expression of tight junction protein genes and proteins in the jejunal mucosa (P<0.05). 3) Compared with the WS group, dietary NCG supplementation significantly decreased the malondialdehyde (MDA) content in the serum and jejunal tissue (P<0.05), and significantly increased the total antioxidant capacity (T-AOC) and total superoxide dismutase (T-SOD) activity (P<0.05). 4) Compared with the WS group, dietary NCG supplementation significantly upregulated the phosphorylation level of adenosine monophosphate-activated protein kinase (AMPK) α in the jejunal tissue (P<0.05), significantly upregulated the expression of AMPK-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway-related factors [genes: Nrf2, superoxide dismutase 2 (SOD2), heme oxygenase-1 (HO-1); protein: NAD(P)H:quinone oxidoreductase 1 (NQO1)] (P<0.05), and significantly inhibited the expression of Kelch-like ECH-associated protein 1 (Keap1) (P<0.05). In conclusion, dietary supplementation with 600 mg/kg NCG may alleviate weaning stress-induced intestinal mucosal barrier injury by activating the intestinal AMPK-Nrf2 signaling pathway and enhancing antioxidant capacity, thereby promoting intestinal development and improving the growth performance of weaned rabbit kits.

This experiment aimed to investigate the effects of yam polysaccharides on performance, nutrient apparent digestibility, intestinal morphology and intestinal microbiota of meat rabbits. A total of 200 healthy 28-day-old New Zealand meat rabbits with similar body weights were randomly divided into 4 groups, with 5 replicates per group and 10 rabbits per replicate. The control group (YP0 group) was fed a basal diet, while the experimental groups were fed the basal diets supplemented with 150 (YP1 group), 300 (YP2 group) and 450 mg/kg (YP3 group) yam polysaccharides, respectively. The experiment lasted for 42 days, including a 7-day pre-test period and a 35-day formal test period. The results showed that compared with the YP0 group: 1) the final body weight, average daily gain and full eviscerated rate of meat rabbits in the YP2 and YP3 groups were significantly increased (P<0.05), and the feed conversion ratio in all experimental groups was significantly decreased (P<0.05); 2) the apparent digestibility of ether extract and neutral detergent fiber in the YP2 and YP3 groups was significantly increased (P<0.05); 3) the jejunal villus height and villus height/crypt depth ratio in all experimental groups were significantly increased (P<0.05), and the ileal villus height/crypt depth ratio in the YP2 and YP3 groups was significantly increased (P<0.05); 4) the relative abundances of Firmicutes, Clostridia, Lachnospirales, Lachnospiraceae and Blautia in cecum in the YP2 and YP3 groups were significantly increased (P<0.05), and the relative abundance of Oscillibacter in cecum in the YP2 group was significantly increased (P<0.05). Additionally, linear discriminant analysis effect size (LEfSe) analysis revealed that the cecal microbiota in the YP2 group was enriched with taxa such as Lachnospirales, Lachnospiraceae, Natranaerovirga and Butyrivibrio; the cecal microbiota in the YP3 group was enriched with taxa such as Firmicutes, Clostridia, Blautia, Marvinbryantia and Lachnotalea, and the functional abundance of reductive_acetogenesis in this group was significantly higher than that in the YP0 group (P<0.05). In conclusion, dietary supplementation with 300 or 450 mg/kg yam polysaccharides can promote the growth and development of meat rabbits, improve nutrient apparent digestibility, and optimize intestinal morphology and microbial composition.

This study aimed to investigate the effects of dietary supplementation with mink-derived Lactobacillus brevis (LB) and its postbiotics on the performance, nutrient digestion and absorption and intestinal immune of growing female minks. A 2×2 two-factor design was employed, with two factors being LB (isolated from the intestinal contents of healthy minks) and LB postbiotics (LBP, prepared by autoclaving the aforementioned mink-derived LB), and the addition for both them was set at 0 or 0.10%. A total of 88 healthy 12-week-old red-eyed white female minks were randomly assigned to 4 groups, each with 11 replicates of 2 minks per replicate. The four groups were: CON group (basal diet), LB group (basal diet+0.10% LB), LBP group (basal diet+0.10% LBP) and LB-LBP group (basal diet+0.10% LB+0.10% LBP). The adaptation period lasted for 1 week, followed by an 8-week experimental period. The results showed that: 1) dietary supplementation with 0.10% LB significantly decreased guard hair length on the back (P<0.05), significantly increased under hair length on the head and under hair thickness on the tail (P<0.05), and significantly decreased the guard hair to under hair ratio on the head and tail (P<0.05); it also significantly increased the apparent digestibility of ether extract (P<0.05) and significantly increased the secretory immunoglobulin A (sIgA) content in the jejunal mucosa (P<0.05). 2) Dietary supplementation with 0.10% LBP significantly increased body weight at 16 weeks of age (P<0.05) and average daily gain from 12 to 16 weeks of age (P<0.05), and significantly decreased the feed-to-gain ratio from 12 to 16 weeks of age (P<0.05); it also significantly increased the apparent digestibility of ether extract (P<0.05), significantly increased the activities of trypsin and lipase in the duodenum (P<0.05), and significantly decreased the contents of interleukin-6 (IL-6) and interferon-γ (IFN-γ) in the jejunal mucosa (P<0.05). 3) Significant interactions between LB and LBP were observed for body weight at 20 weeks of age, average daily gain from 12 to 20 weeks of age, under hair length on the head, under hair thickness on the back, guard hair to under hair ratio on the tail, and sIgA content in the jejunal mucosa (P<0.05), but these interactions were not synergistic. In conclusion, dietary supplementation with 0.10% LB can improve fur quality, while dietary supplementation with 0.10% LBP can enhance nutrient digestion and absorption and improve growth performance of growing female minks. No synergistic effect is observed between LB and its postbiotics.

This experiment was conducted to explore the effects of dietary supplementation with quercetin on growth performance and plasma biochemical and antioxidant indices of German shepherds with exercise-induced fatigue. Thirty adult German shepherds aged 2 to 3 years, with similar body weight of (32.50±0.10) kg and good health condition, were selected and randomly divided into 3 groups, with 10 dogs in each group (half male and half female). The control group was fed a basal diet, while the experimental groups were fed the basal diets supplemented with 50 (low-dose quercetin group) and 100 mg/kg quercetin (high-dose quercetin group), respectively. The experiment lasted for 4 weeks, during which the exercise-induced fatigue training was conducted. The results showed as follows: 1) dietary supplementation with quercetin could significantly alleviate the body weight loss caused by exercise-induced fatigue (P<0.05), and significantly increase the average daily feed intake (P<0.05); 2) the exercise-induced fatigue led to a significant increase in plasma contents of glucose and urea nitrogen, as well as activities of alanine aminotransferase, aspartate aminotransferase and creatine kinase (P<0.05), and a significant decrease in plasma calcium content (P<0.05); 3) the exercise-induced fatigue led to a significant decrease in plasma activities of superoxide dismutase and glutathione peroxidase (P<0.05), and a significant increase in malondialdehyde content and lactate dehydrogenase activity (P<0.05); 4) dietary supplementation with 100 mg/kg quercetin could significantly alleviate the changes in the above plasma biochemical and antioxidant indices (P<0.05), and restore them to the levels before exercise-induced fatigue (P>0.05). In conclusion, dietary supplementation with 100 mg/kg quercetin can alleviate the negative effects of exercise-induced fatigue on the growth and plasma biochemical and antioxidant indicators of German shepherds.

This experiment aimed to investigate the regulation mechanism of tea tree essential oil (TTO) on meat quality of broilers based on metabolomics and network pharmacology. A total of 180 one-day-old Cobb broilers with similar body weight were randomly divided into 2 groups with 6 replicates per group and 15 chickens per replicate. The control group was fed a basal diet, and the experimental group was fed the basal diet supplemented with 300 mg/kg TTO. The experimental period lasted for 42 days. At the end of the experiment, the breast muscle, thigh muscle and plasma samples were collected to measure the meat quality, and performed the non-targeted metabolomic analysis. Using the network pharmacology method, the TTO component-target interaction map of tea tree essential oil was constructed, the obesity related intersection targets were screened, the GO function and KEGG pathway enrichment analysis were performed, and the molecular docking method was used to verify the interaction between the active components and core targets. The results showed that the redness (a^*) value in breast muscle and thigh muscle of the experimental group was significantly lower than that of the control group (P<0.05). A total of 2 395 plasma differential metabolites were identified in two groups, of which 257 were significantly different (P<0.05). In the experimental group, the levels of metabolites such as 1-stearoyl-2-arachidoyl and 1-palmitoyl-2-arachidoyl-sn-glycerol-3-phosphate were increased, and L-arginine metabolites were up-regulated. The network pharmacology analysis showed that TTO mainly acted on targets such as epidermal growth factor receptor (EGFR), estrogen receptor 1 (ESR1) and hypoxia-inducible factor 1A (HIF1A), it was closely related to the functional pathways such as adipocytokine signaling pathway and peroxisome proliferator activated receptor (PPAR) signaling pathway. The molecular docking binding energy was less than -5 kcal/mol, and indicated the stable binding. In conclusion, the addition of TTO in the diet can regulate the obesity-related target genes by regulating the pathways such as glycerophospholipid metabolism, linoleic acid metabolism and α-linolenic acid metabolism, and then has a certain effect on the meat quality of broilers.

This experiment aimed to investigate the effects and mechanisms of dietary fenugreek leaf powder (FLP) supplementation on liver lipid metabolism in yellow-feathered chickens using liquid chromatograph mass spectrometer (LC-MS)-based untargeted liver metabolomics. A total of 240 twenty-one-day-old yellow-feathered chickens were randomly allocated into 4 groups with 6 replicates per group ad 10 birds per replicate. The control group (CON group) was fed a basal diet, and the experimental groups were fed the basal diets supplemented with 0.5% (0.5%FLP group), 1.0% (1.0%FLP group) and 2.0% (2.0%FLP group) FLP, respectively. The experiment lasted for 42 days. The results showed as follows: 1) compared with the CON group, the final body weight and average daily gain of 0.5%FLP group and 1.0%FLP group were significantly increased (P<0.05), and the average daily feed intake of 0.5%FLP group, 1.0%FLP group and 2.0%FLP group were significantly increased (P<0.05). 2) Compared with the CON group, the liver weight, liver index and abdominal fat percentage of 0.5%FLP group, 1.0%FLP group and 2.0%FLP group were significantly decreased (P<0.05). 3) The liver histopathological results revealed that dietary FLP reduced the liver lipid deposition. 4) Compared with the CON group, the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and contents of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) in serum of 0.5%FLP group, 1.0%FLP group and 2.0%FLP group were significantly decreased (P<0.05), and the serum high-density lipoprotein cholesterol (HDL-C) content was significantly increased (P<0.05). 5) The metabolomics pathway enrichment analysis revealed that dietary FLP down-regulated the fatty acid biosynthesis and unsaturated fatty acid biosynthesis pathways. 6) Compared with the CON group, the mRNA relative expression levels of fatty acid synthase (FASN), acetyl-CoA carboxylase (ACC), sterol regulatory element-binding protein 1 (SREBP1), stearoyl-CoA desaturase (SCD) and 3-hy-droxy-3-methyl glutaryl coenzyme A reductase (HMGCR) in liver of 0.5%FLP group, 1.0%FLP group and 2.0%FLP group were significantly decreased (P<0.05), and the mRNA relative expression levels of peroxisome proliferation-activated receptor alpha (PPARα), microsomal triglyceride transfer protein (MTTP) and carnitine palmitoyltransferase 1A (CPT1A) in liver were significantly increased (P<0.05). In conclusion, the FLP has improving effects on the growth performance and liver lipid metabolism of yellow-feathered chickens. By down-regulating the expression of lipogenic genes (FASN, SREBP1) and up-regulating fatty acid oxidation genes (PPARα, CPT1A), FLP modulates fatty acid and unsaturated fatty acid biosynthesis in liver, ultimately improving blood lipid content and reducing liver lipid deposition of yellow-feathered broilers.

This study aimed to explore the sulfated modification of pumpkin peel polysaccharides (PPPs) and their anti-fatigue mechanism, and clarify the functional mechanism by which they alleviate exercise-induced fatigue via energy metabolism and antioxidant pathways. Using pumpkin peel powder as the raw material, PPPs were extracted by hot water extraction, and sulfated pumpkin peel polysaccharide 1 (SPP1) and sulfated pumpkin peel polysaccharide 2 (SPP2) with degrees of substitution of 0.36±0.01 and 0.67±0.02, respectively, were synthesized using the chlorosulfonic acid-pyridine method. A completely randomized single-factor experimental design was adopted. Sixty 6-week-old male Kunming mice were randomly divided into five groups with 12 mice per group. The five groups were: normal control group (NC group), fatigue control group (FC group) and three intervention groups. The three intervention groups were intragastrically administered 0.2 mL of 125 mg/kg BW of PPPs (P group), SPP1 (S1 group) and SPP2 (S2 group) daily, while the NC and FC groups received an equal volume of saline. After 4 weeks of continuous intragastric administration, exercise-induced fatigue models were established in all groups except the NC group, and samples were collected immediately after model establishment. The results showed as follows: 1) compared with PPPs, the total sugar content of SPP1 and SPP2 decreased significantly (P<0.05), while the uronic acid content increased significantly (P<0.05); the degree of substitution of SPP2 was significantly higher than that of SPP1 (P<0.05); sulfated modification effectively altered the chemical composition and spatial conformation of PPPs, and the higher the degree of substitution, the more obvious the structural changes. 2) Compared with the FC group, the skeletal muscle fibers of mice in the P, S1 and S2 groups were more regularly arranged and the interstitium was significantly narrowed, with the S2 group showing more intact muscle fibers. Compared with the FC group, the exhaustive time of swimming in mice in the P, S1 and S2 groups was significantly increased by 5.47%, 5.43% and 8.31%, respectively (P<0.05); the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in serum, as well as the contents of hepatic glycogen and muscle glycogen, were significantly increased (P<0.05); the contents of malondialdehyde (MDA), triglyceride, lactic acid (LA) and urea nitrogen (UN) in serum, as well as lactate dehydrogenase (LDH) activity, were significantly decreased (P<0.05). The activities of SOD, GSH-Px and CAT in serum of the S2 group were significantly higher than those in the P and S1 groups (P<0.05), but not significantly different from those in the NC group (P>0.05); the contents of MDA, triglyceride, LA and UN, as well as LDH activity in serum of the S2 group, were significantly lower than those in the P and S1 groups (P<0.05), but not significantly different from those in the NC group (P>0.05). In conclusion, under the conditions of this experiment, sulfated modification enhances the anti-fatigue activity of PPPs, and the high-substitution-degree SPP2 exhibits the optimal effect. Its mechanism is closely related to enhancing the body’s antioxidant capacity, optimizing energy metabolism and promoting the clearance of fatigue metabolites.

In this experiment, 8-week-old male MC4R^Flox/Flox mice were selected to conditionally knock out the melanocortin-4 receptor (MC4R) gene in the tibialis anterior muscle (TA) region using AAV2/9-CAG-Cre-EGFP virus, thereby establishing a Cre-LoxP conditional knockout model (CKO model) to investigate the effect of the MC4R gene on intramuscular fat deposition. A total of four groups were set up in the experiment and treated as follows: 1) normal control group (NC group), 4 wild-type mice fed a conventional basal diet; 2) control group (CON group), 4 MC4R^Flox/Flox mice injected with 6 mL of normal saline into the left TA and fed a high-fat diet; 3) conventional MC4R knockout group (KO group), 4 MC4R^-/- mice fed a high-fat diet; 4) conditional MC4R knockout group (CKO group), 4 MC4R^Flox/Flox mice injected with 6 mL of AAV2/9-CAG-Cre-EGFP virus at a titer of 1×10¹² vg/mL into the left TA and fed a high-fat diet. At 9 weeks after AAV2/9-CAG-Cre-EGFP virus injection, the mice in each group were anesthetized and then euthanized by cervical dislocation. The TA tissues were quickly isolated for subsequent measurements. The results showed that, compared with the CON group, the protein relative expression level of MC4R in the TA of the CKO group was significantly downregulated (P<0.05). Hematoxylin-eosin (HE) and oil red O staining revealed obvious fat deposition in the TA, a notable increase in TA volume, and a significant increase in TG content in the TA (P<0.05), indicating that conditional knockout of the MC4R gene leaded to intramuscular fat deposition. Compared with the CON group, the mRNA relative expression levels of the adipogenesis-related genes acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) in the TA of the CKO group were significantly increased (P<0.05). Furthermore, compared with the CON group, the protein relative expression levels of phosphorylated extracellular signal-regulated kinase (pERK), uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor γ (PPARγ), adipocyte protein 2 (aP2) and phosphorylated serine/threonine protein kinase (pS6K1) in the TA of the CKO group were significantly increased (P<0.05), while the protein relative expression levels of phosphorylated AMP-activated protein kinase (pAMPK) and phosphorylated hormone-sensitive lipase (pHSL) were significantly decreased (P<0.05). These results suggest that conditional knockout of the MC4R gene induces intramuscular fat deposition in mice by enhancing adipocyte transcriptional differentiation and regulating fatty acid oxidative metabolism. This may provide a theoretical reference for exploring the mechanisms underlying the formation of marbled beef.

This experiment investigated the effects of long-term storage on the characteristics, nutritional value and in vitro degradation characteristics of ensiled alfalfa-based fermented total mixed ration (FTMR). A total of six ensiled alfalfa-based FTMR formulas were designed in this experiment: early-finishing (formula 1), mid-finishing (formula 2) and late-finishing (formula 3) for beef cattle, and early-finishing (formula 4), mid-finishing (formula 5) and late-finishing (formula 6) for mutton sheep. Each formula was prepared with six replicates and stored for 6 and 12 months, respectively. After stored for 6 and 12 months, the samples were collected upon opening to determine fermentation indicators, nutrient contents and in vitro degradation characteristics. The results showed as follows: 1) except for formula 4, the pH of formula 1, 2, 3, 5 and 6 stored for 12 months were significantly or extremely significantly lower than each of those stored for 6 months (P<0.05 or P<0.01). The lactic acid (LA), acetic acid (AA) and ammonia nitrogen (NH₃-N) contents of all formulas stored for 12 months were significantly or extremely significantly higher than each of those stored for 6 months (P<0.05 or P<0.01). The propionic acid (PA) content and Fleig’s score of formulas 2, 3, 5 and 6 stored for 12 months were significantly or extremely significantly higher than each of those stored for 6 months (P<0.05 or P<0.01). 2) There was no significant difference in the dry matter (DM) and crude protein (CP) contents among all formulas stored for different time (0, 6 and 12 months) (P>0.05). The neutral detergent fiber (NDF) content of formula 3 stored for 6 and 12 months was significantly lower than that stored for 0 month (P<0.05). The NDF and acid detergent fiber (ADF) contents of formula 6 stored for 0 and 6 months were significantly higher than those stored for 12 months (P<0.05), and the total digestible nutrients (TDN) and relative feeding value (RFV) were significantly lower than those stored for 12 months (P<0.05). 3) The in vitro dry matter digestibility (IVDMD) and in vitro crude protein digestibility (IVCPD) of formula 3 stored for 6 months were significantly higher than those stored for 0 months (P<0.05), and the IVDMD and in vitro NDF digestibility (IVNDFD) of formula 6 stored for 6 months were significantly higher than those stored for 0 month (P<0.05). The cumulative gas production after 12 h of in vitro digestion of formula 1 stored for 6 months was extremely significantly lower than that stored for 0 month (P<0.01), while the cumulative gas production after 12 h in vitro digestion of formulas 2 and 3 stored for 6 months was significantly higher than that stored for 0 month (P<0.05). The cumulative gas production after 24 h of in vitro digestion of formula 5 stored for 6 months was significantly lower than that stored for 0 month (P<0.05). The cumulative gas production after 48 h of in vitro digestion of formulas 4 and 5 stored for 6 months was significantly lower than that stored 0 month (P<0.05). The pH of the digestive solution after 48 h of in vitro digestion of formulas 3, 4, 5 and 6 stored for 6 months were significantly higher than those stored for 0 month (P<0.05). In conclusion, storage for 12 months can reduce the pH of each ensiled alfalfa-based FTMR, increase LA, AA and PA contents, but also increase NH₃-N content, exacerbate protein degradation; storage for 6 months can reduce the NDF content of the ensiled alfalfa-based FTMR for the late-finishing of beef cattle (formula 3) and increase its IVDMD and IVCPD; storage for 12 months can reduce the NDF and ADF contents of the ensiled alfalfa-based FTMR for the late-finishing of mutton sheep (formula 6) and increase its TDN content, RFV, IVDMD and IVNDFD.

This experiment was conducted to evaluate the fermentation quality, nutritional components and in vitro rumen fermentation characteristics of mixed silage of rice straw with different proportions of Pleurotus eryngii spent mushroom substrate, and to explore the optimal addition ratio of PESMS. Five groups were set up in this experiment: CK (100% rice straw), P10 (90% rice straw+10% PESMS), P20 (80% rice straw+20% PESMS), P30 (70% rice straw+30% PESMS) and P40 groups (60% rice straw+40% PESMS), and all groups added 1% compound microbial inoculant, each group contained 6 replicates. Samples were collected and analyzed after 45 days of sealed fermentation. The results showed as follows: 1) in the mixed silage, the dry matter, crude protein, calcium and phosphorus contents of P20, P30 and P40 groups were significantly higher than those of the CK group (P<0.05), while the neutral detergent fiber and acid detergent fiber contents were significantly lower than those of the CK group (P<0.05); the pH and ammoniacal nitrogen content of P40 group were significantly higher than those of other groups (P<0.05); the propionic acid and butyric acid contents of P10, P20, P30 and P40 groups were significantly higher than those of the CK group (P<0.05). 2) In the in vitro fermentation experiment, the ammoniacal nitrogen and microbial protein contents of P20 group were significantly higher than those of other groups (P<0.05), the acetic acid, propionic acid, butyric acid, isobutyric acid, isovaleric acid, valeric acid and total volatile fatty acids (TVFA) contents of P10, P20 and P30 groups were significantly higher than those of CK and P40 groups (P<0.05), and the in vitro degradation rate of dry matter (IVDMD) and in vitro degradation rate of crude protein (IVCPD) of P30 and P40 groups were significantly higher than those of other groups (P<0.05). In conclusion, under the conditions of this experiment, the addition of 20% to 30% PESMS can effectively enhance the nutritional value, fermentation quality and in vitro fermentation nutrient degradation rates of rice straw silage.

To improve the fermentation quality and nutrient utilization efficiency of Caragana korshinskii Kom., a two-stage 3×2 factorial design was conducted to investigate the effects of aerobic fermentation with Trichoderma reesei (TR) or cellulase combined with ensiling with Lactobacillus plantarum (LP) on silage quality and in vitro rumen fermentation characteristics of Caragana korshinskii Kom. The first stage was an aerobic fermentation period (7 d), with three treatments set: no additive (CK treatment), 70 mL/kg fresh weight (FW) TR (TR treatment) and 70 mg/kg FW cellulase (CE treatment). The second stage was a silage period (60 d), using the products of the first stage as raw materials, with two treatments set: inoculation with 70 mg/kg FW LP (LP treatment) and no inoculation with LP (NLP treatment). The results showed as follows: 1) after 7 d of aerobic fermentation, compared with the CK treatment, the contents of neutral detergent fiber (NDF), hemicellulose and tannin in the TR and CE treatments were significantly decreased (P<0.05); the contents of acid detergent fiber (ADF) and cellulose in the TR treatment were significantly decreased (P<0.05). 2) After 60 d of ensiling, compared with the CK treatment, TR and CE treatments could significantly reduce the contents of fiber components (NDF, ADF, hemicellulose, cellulose) in Caragana korshinskii Kom. silage (P<0.05), and the TR+LP treatment exhibited a strong synergistic effect, which could further significantly decrease the fiber component contents (P<0.05). The TR+LP treatment had the lowest pH and ammonia nitrogen (NH₃-N) content, the highest lactic acid and acetic acid contents, and the optimal fermentation quality of Caragana korshinskii Kom. silage. 3) Scanning electron microscopy results showed that both TR and CE treatments could destroy the cell wall structure of Caragana korshinskii Kom. silage, resulting in cracks and holes; the degradation effect on lignocellulose was further enhanced after inoculation with LP, and the structural damage was the most obvious in the TR+LP treatment. 4) In vitro rumen fermentation results indicated that the TR+LP treatment had the best improvement effects on in vitro dry matter digestibility (IVDMD), in vitro neutral detergent fiber digestibility (IVNDFD), in vitro acid detergent fiber digestibility (IVADFD) and in vitro gas production of Caragana korshinskii Kom. silage. In conclusion, the combined treatment of TR and LP can optimize the silage quality of Caragana korshinskii Kom., degrade lignocellulose and improve in vitro digestibility through synergistic effects.

This experiment aimed to study the quality of mixed silage of tail vegetables and straw and its in vitro fermentation characteristics through orthogonal experimental design, and to screen out the best process combination. The experiment adopted a L₉ (3⁴) four-factor and three-level orthogonal experimental design. The proportions of tail vegetables (cabbage and Chinese cabbage was 1∶1) to straw (oat straw) were set at 2∶8, 3∶7 and 4∶6, the addition amounts of lactic acid bacteria were 0.5×10⁵, 1.0×10⁵ and 2.0×10⁵ CFU/g, the addition amounts of corn meal were 3%, 6% and 9%, and the silage time was 60, 75 and 90 days, respectively. The optimal fermentation combination was comprehensively evaluated and selected by measuring indicators such as fermentation quality, aerobic stability, nutrient contents, and rumen fermentation parameters in vitro. The results showed that: 1) taking the fermentation quality as the evaluation basis, the suitable fermentation combination was as follows: the addition amount of lactic acid bacteria was 2.0×10⁵ CFU/g, the proportion of tail vegetables to straw was 2∶8, the addition amount of corn meal was 3%, and the silage time was 75 days. 2) Taking the aerobic stability as the evaluation basis, the suitable fermentation combination was as follows: the addition amount of lactic acid bacteria was 0.5×10⁵ CFU/g, the proportion of tail vegetables to straw was 4∶6, the addition amount of corn meal was 9%, and the silage time was 75 days. 3) Taking the nutrient contents as the evaluation basis, the suitable fermentation combination was as follows: the addition amount of lactic acid bacteria was 0.5×10⁵ CFU/g, the proportion of tail vegetables to straw was 3∶7, the addition amount of corn meal was 3%, and the silage time was 75 days. 4) Taking the gas production in vitro fermentation as the evaluation basis, the suitable fermentation combination was as follows: the addition amount of lactic acid bacteria was 1.0×10⁵ CFU/g, the proportion of tail vegetables to straw was 4∶6, the addition amount of corn meal was 6%, and the silage time was 90 days. Taking the in vitro fermentation parameters as the evaluation basis, the suitable fermentation combination was as follows: the addition amount of lactic acid bacteria was 1.0×10⁵ CFU/g, the proportion of tail vegetables to straw was 4∶6, the addition amount of corn meal was 6%, and the silage time was 75 days. In conclusion, the recommended optimal process combination for mixed silage of tail vegetables and straw is as follows: the addition amount of lactic acid bacteria is 0.5×10⁵ CFU/g, the proportion of tail vegetables to straw is 4∶6, the addition amount of corn meal is 6%, and the silage time is 75 days.

This experiment was conducted to investigate the effects of different cellulase addition levels on in vitro rumen fermentation characteristics of pepper straw. Leizhou goats were selected as the rumen fluid donors, and pepper straw was used as the fermentation substrate. Cellulase was added to the substrate at the levels of 0 (control group), 10 000, 20 000 and 30 000 U/kg for a 48 h in vitro fermentation trial. The experiment was set up with 2 independent batches, 4 groups in each batch, and 4 replicates at each sampling time point. The results showed as follows: 1) compared with the control group, the in vitro gas production of the 30 000 U/kg group was significantly increased at 6, 9, 24 and 48 h of fermentation (P<0.05). 2) Compared with the control group, the dry matter digestibility (DMD), neutral detergent fiber digestibility (NDFD) and acid detergent fiber digestibility (ADFD) in all experimental groups were significantly increased at 24 h of fermentation (P<0.05); at 48 h of fermentation, the DMD in the 30 000 U/kg group was significantly increased (P<0.05), and the NDFD and ADFD in all experimental groups were significantly increased (P<0.05). 3) Compared with the control group, the pH and ammonia nitrogen (NH₃-N) concentration in all experimental groups were significantly increased at 48 h of fermentation (P<0.05), the microbial protein (MCP) concentration in the 20 000 and 30 000 U/kg groups was significantly increased (P<0.05), and the concentrations of total volatile fatty acids (TVFA), acetic acid and propionic acid in the 30 000 U/kg group were significantly increased (P<0.05). 4) The determination results of microbial flora at 48 h of fermentation showed that the Simpson index of the 30 000 U/kg group was significantly higher than that of the control group (P<0.05). At the phylum level, the dominant flora were Bacteroidota and Firmicutes; at the genus level, the dominant flora included Succiniclasticum, Prevotella, Succinivibrio and so on. In conclusion, the addition of 30 000 U/kg cellulase to pepper straw can increase its in vitro gas production, nutrient digestibility, as well as NH₃-N and TVFA concentrations, and improve the rumen fermentation effect.

This study aimed to compare and analyze the feeding value of different parts (stems and leaves) from waste of two Luffa cylindrica varieties (Rousigua and Xianggua 1), so as to provide data support for the development of unconventional roughage resources and the design of diet formulations. The experiment employed conventional chemical analysis methods and the Cornell net carbohydrate and protein system (CNCPS) to evaluate the nutrient contents of stems and leaves from waste of two Luffa cylindrica varieties, the Fourier transform infrared spectroscopy (FTIR) technology was used to analyze their molecular structure parameters, finally, the in vitro rumen degradation trial was conducted to systematically assess their utilization value in ruminants. The results showed as follows: 1) the neutral detergent fiber, acidic detergent fiber, hemicellulose, cellulose, carbohydrates and crude protein contents in Luffa cylindrica stems were significantly higher than those in Luffa cylindrica leaves (P<0.05). The indigestible fiber (CC) content was the highest in the leaves of Rousigua (P<0.05), the crude protein and fiber-bound protein (PB) contents were the highest in the leaves of Xianggua 1, and the undegradable protein (PC) content was the highest in the leaves of Rousigua. 2) The total carbohydrate region total peak area in Luffa cylindrica stems was significantly higher than that in Luffa cylindrica leaves (P<0.05), and the structural carbohydrate sub-peak Ⅱ and Ⅲ peak heights were significantly higher than those in Luffa cylindrica leaves (P<0.05). The amide Ⅰ region peak height/ amide Ⅱ region peak height in Luffa cylindrica stems was significantly higher than that in Luffa cylindrica leaves (P<0.05), and the amide Ⅰ region peak area/amide Ⅱ region peak area and α-helix peak height/β-sheet peak height were significantly lower than those in Luffa cylindrica leaves (P<0.05). 3) The in vitro rumen fermentation dry matter digestibility and ammonia nitrogen, acetic acid and total volatile fatty acid contents in Luffa cylindrica stems were significantly higher than those in Luffa cylindrica leaves (P<0.05), and the pH was significantly lower than that in Luffa cylindrica leaves (P<0.05). 4) Correlations were found between the partial molecular structural parameters of carbohydrates and proteins and their corresponding nutrients as well as the in vitro fermentation parameters (P<0.05). In conclusion, Luffa cylindrica waste can be exploited as a roughage resource for ruminants, with the leaves of Xianggua 1 exhibiting relatively high nutritional value. The FTIR technology has the potential to rapidly determine the nutritional value of Luffa cylindrica waste.

This experiment was conducted to study the effects of different mixed silage ratios and additives on the fermentation quality of alfalfa and sunflower mixed silage. Using a two-factor experimental design, three mass ratios of alfalfa and sunflower were set at 3∶7, 5∶5 and 7∶3, respectively, and four treatments were set for each ratio, namely the Lactobacillus plantarum treatment (LP treatment), the Lactobacillus buchneri treatment (LB treatment), the sucrose treatment (SUG treatment) and the treatment without additives (CK treatment, control), with 3 replicates in each treatment. Silage was carried out at room temperature for 60 days to determine the nutrient contents, fermentation quality and microbiota. The results showed as follows: 1) under each mixed silage ratio, the contents of dry matter and water-soluble carbohydrates in SUG treatment were higher, and the ether extract content in LP treatment was higher. Compared with the other mixed silage ratios, when the mixed silage ratio was 3∶7, the crude protein content was lower and the neutral detergent fiber content was higher. 2) Under each mixed silage ratio, LP treatment had a lower pH, a higher lactic acid content, and a lower ammonia nitrogen (NH₃-N) content. When the mixed silage ratio was 7∶3, the pH in each treatment was higher than that of the other mixed silage ratios. Meanwhile, when the mixed silage ratio was 5∶5, the lactic acid content was higher and the NH₃-N content was lower. In addition, when the mixed silage ratio was 5∶5, the acetic acid content in LP treatment was significantly higher than that in the other treatments (P<0.05), and also significantly higher than that in the other mixed silage ratios (P<0.05); the propionic acid content in SUG treatment was significantly higher than that in other treatments (P<0.05). 3) The results of microbiota analysis indicated that at a 5∶5 mixed silage ratio, Lactiplantibacillus was enriched in LP and SUG treatments, Lentilactobacillus was enriched in LB treatment, and Lactococcus, Weissella and Enterobacter were enriched in CK treatment. In conclusion, when the mixed silage ratio of alfalfa and sunflower is 5∶5, the fermentation effect is better. Adding Lactobacillus plantarum can improve the fermentation quality, while adding sucrose is beneficial for nutrient preservation.

This experiment was conducted to explore the effects of adding lactic acid bacteria on the fermentation quality and microbiota of whole plant corn and sunflower mixed silage. The whole plant corn and whole plant sunflower were selected for mixed ensiling in a ratio of 5∶5 in this experiment. A single-factor design was adopted to set up three groups, namely the control group (CK group, no additives were added), the Lactobacillus buchneri group (LB group, Lactobacillus buchneri was added), and the Pediococcus pentosaceus group (PP group, Pediococcus pentosaceus was added), with 3 replicates in each group. After 60 days of room-temperature sealed fermentation, the nutrient contents, fermentation quality and microbiota were determined. The results showed as follows: 1) the contents of crude protein and water-soluble carbohydrate in LB group were significantly lower than those in CK group and PP group (P<0.05), and the acid detergent fiber content in PP group was significantly lower than that in CK group and LB group (P<0.05). 2) The pH and acetic acid content in LB group and PP group were significantly lower than those in CK group (P<0.05), while the lactic acid content was significantly higher than that in CK group (P<0.05). Meanwhile, the lactic acid content in PP group was significantly higher than that in LB group (P<0.05). 3) The V-Score score was the highest in PP group, followed by LB group, and the lowest in CK group. 4) Compared with CK group, the ACE index and Chao1 index of microbiota in LB group and PP group were significantly decreased (P<0.05), and the Shannon index was significantly increased (P<0.05). At the phylum level, compared with CK group, the Firmicutes relative abundance in PP group was increased, while the Proteobacteria relative abundance was decreased; at the genus level, compared with CK group, the Lentilactobacillus relative abundance in LB group and PP group was increased. In conclusion, the addition of Lactobacillus buchneri and Pediococcus pentosaceus can both improve the fermentation quality of whole plant corn and sunflower mixed silage by optimizing the microbiota structure. Under the conditions of this experiment, the silage effect of adding Pediococcus pentosaceus is better.

This experiment was conducted to explore the effects of Pediococcus pentosaceus on fermentation quality and microbiota of alfalfa and Silphium perfoliatum mixed silage. Alfalfa and Silphium perfoliatum were selected as silage raw materials and mixed in ratio of 1∶1. A control group (CK group) and a Pediococcus pentosaceus group (PP group) were set up (with 3 replicates in each group), no additives were added to CK group, while Pediococcus pentosaceus was added to PP group. Sealed fermentation was carried out at room temperature for 60 days, and the nutrient contents, fermentation quality and microbiota were determined. The results showed as follows: 1) compared with CK group, the dry matter content in PP group was significantly decreased (P<0.05), and the contents of crude protein, ether extract and water-soluble carbohydrates were significantly increased (P<0.05). 2) Compared with CK group, the pH in PP group was significantly decreased (P<0.05), the lactic acid content was significantly increased (P<0.05), and the contents of propionic acid and ammonia nitrogen were significantly decreased (P<0.05). 3) Compared with CK group, the ACE index, Chao index and Sobs index of microbiota in PP group were significantly decreased (P<0.05). At the phylum level, compared with CK group, the Bacillota relative abundance in PP group was increased, while the Pseudomonadota relative abundance was decreased; at the genus level, compared with CK group, the relative abundances of Lactiplantibacillus, Pediococcus and Lentilactobacillus in PP group were increased, while the Enterococcus relative abundance was decreased. Meanwhile, compared with the raw materials, the addition of Pediococcus pentosaceus could reduce the relative abundances of Sphingomonas and Clostridium. In conclusion, the addition of Pediococcus pentosaceus can regulate the microbiota of alfalfa and Silphium perfoliatum mixed silage, thereby improving the fermentation quality.

This study aimed to determine the optimal microbial agent and substrate moisture content for mixed solid-state fermentation of whole-plant forage rapeseed and rapeseed meal, in order to optimize fermentation process conditions, thereby effectively degrading anti-nutritional factors in the fermentation substrate and improving its nutritional quality. A full factorial experiment with two factors was conducted. Four levels of microbial agents (agent A, agent B, agent C and blank control) and three levels of substrate moisture content (55%, 60% and 65%). A total of 12 groups were designed, including 9 experimental groups and 3 control groups. Experimental group 1: agent A + 55% moisture; group 2: agent A + 60% moisture; group 3: agent A + 65% moisture; group 4: agent B + 55% moisture; group 5: agent B + 60% moisture; group 6: agent B + 65% moisture; group 7: agent C + 55% moisture; group 8: agent C + 60% moisture; group 9: agent C + 65% moisture. The three control groups had no microbial agent, with substrate moisture contents of 55% (CK1), 60% (CK2) and 65% (CK3), respectively. Each group had three replicates, and the weight of fermentation substrate per replicate was set as 1 kg. Fermentation was carried out at room temperature for 30 days. The results showed as follows: except for experimental group 5, crude protein content after fermentation in the other experimental groups was significantly or extremely significantly higher than that before fermentation (P<0.05 or P<0.01); the increase rate of crude protein in experimental group 9 was extremely significantly higher than that in all other groups (P<0.01). The phytic acid content after fermentation in experimental groups 8 and 9 was extremely significantly lower than that before fermentation (P<0.01), while that in the other experimental groups was extremely significantly higher than that before fermentation (P<0.01); among them, experimental group 9 had the highest phytic acid degradation rate (93.94%). After fermentation, the tannin content in all experimental groups was extremely significantly lower than that before fermentation (P<0.01); under different substrate moisture contents, the average tannin degradation rates of adding microbial agents A, B and C were 71.12%, 74.04% and 67.66%, respectively, which were extremely significantly higher than that of no addition (P<0.01). Except for experimental group 9, the glucosinolate content after fermentation in the other experimental groups was significantly or extremely significantly lower than that before fermentation (P<0.05 or P<0.01); under different substrate moisture contents, the average glucosinolate degradation rates of adding microbial agents A, B and C were 32.65%, 33.10% and 26.18%, respectively, which were extremely significantly higher than that of no addition (P<0.01). The microbial agent factor alone could explain 90.40%, 98.20%, 97.50% and 93.20% of the variation in crude protein, phytic acid, tannin and glucosinolate contents, respectively, with the largest proportion of variation explained and the strongest statistical evidence. The interaction between microbial agent and substrate moisture content contributed the most to the variation in crude fiber content, explaining 52.30% of the variation. In conclusion, under the conditions of this experiment, the fermentation process using microbial agent C with a substrate moisture content of 65% is optimal, showing the best improvement effect on the nutritional quality of the mixed solid-state fermentation substrate of whole-plant forage rapeseed and rapeseed meal.

This experiment was conducted to investigate the effects of different soil selenium application concentrations on conventional nutrients, biomass, selenium contents, selenium accumulation characteristics and in vitro fermentation gas production, gas production parameters, fermentation parameters of alfalfa under simulated potting conditions. A completely randomized design was employed, divided into 3 groups with 10 replicates in each group, 30 pots. The soil selenium application concentrations in 3 groups were 0 control (control group), 0.4 (low selenium application group) and 4.0 mg/kg (high selenium application group), respectively. The results showed as follows: 1) the fresh weight and dry weight in alfalfa of low selenium application group and high selenium application group were significantly higher than those of the control group (P<0.05). 2) With the soil selenium concentration increased, the alfalfa crude ash content was significantly increased (P<0.05), and the acid detergent fiber (ADF) content showed a decreasing trend (P=0.063); no significant differences were observed in contents of dry matter (DM), ether extract (EE), neutral detergent fiber (NDF), crude protein (CP), calcium (Ca) and phosphorus (P) in alfalfa among all groups (P>0.05). 3) With the soil selenium concentration increased, the contents of total selenium, inorganic selenium and organic selenium in alfalfa was significantly increased (P<0.05); the selenium transport coefficient of low selenium application group and high selenium application group was significantly higher than that of the control group (P<0.05). 4) The slow gas production, gas production rate and theoretical gas production of high selenium application group were significantly higher than those of the control group (P<0.05), and the slow gas production and theoretical gas production of low selenium application group were significantly higher than those of the control group (P<0.05). 5) No significant differences were observed in alfalfa in vitro fermentation parameters among all groups (P>0.05). In summary, the soil selenium application can enhance the biomass and selenium accumulation of alfalfa, improve the quality and in vitro rumen gas production parameters of alfalfa, and the optimal soil selenium concentration is 4.0 mg/kg.

This study aimed to investigate the effects of calving season on diversity and composition of the colostrum microbial community of dairy cows, and to screen functional lactic acid bacteria with potential application value. A total of 38 healthy Holstein cows were divided into two groups according to calving season: late spring calving group (LS group, calving from April to June) and post-summer calving group (PS group, calving from September to November), with 19 cows in each group. Colostrum samples were collected within 6 h after calving. Milk composition analysis showed that there were no significant differences in the contents of fat, protein, lactose, total solids, and somatic cell count between the two groups (P>0.05). However, the milk urea nitrogen content in the LS group was significantly higher than that in the PS group (P<0.05). The results of 16S rRNA sequencing indicated that the dominant phyla in dairy cow colostrum were Proteobacteria, Firmicutes and Bacteroidota; their relative abundances in the LS group were 81.79%, 13.70% and 3.48%, respectively, and in the PS group were 74.15%, 4.77% and 18.75%, respectively. Alpha diversity analysis showed no significant differences in the richness and diversity of the colostrum microbial community between the two groups (P>0.05), but principal coordinate analysis (PCoA) revealed a significant differentiation in community structure between the two groups (P<0.05). Linear discriminant analysis effect size (LEfSe) analysis further identified 26 differential bacterial families. Among them, 11 families, including Enterobacteriaceae, Moraxellaceae, Aeromonadaceae and Lactobacillaceae, were significantly enriched in the LS group (P<0.05), while 15 families, including Pseudomonadaceae, Chitinophagaceae and Xanthobacteraceae, were significantly enriched in the PS group (P<0.05). A total of 24 lactic acid bacteria were isolated and identified from the colostrum. Further screening showed that Latilactobacillus sakei L17, Lactococcus lactis L20 and Lactococcus formosensis L21 exhibited excellent stress resistance and antibacterial activity, with no hemolytic activity and sensitivity to most antibiotics, indicating good potential for probiotic development. In conclusion, calving season mainly affects the milk urea nitrogen content and microbial community structure of dairy cow colostrum, and colostrum from cows calving in late spring has a higher potential for functional lactic acid bacteria mining. The three lactic acid bacteria strains screened in this study can provide strain support for calf health promotion and probiotic resource development.

This experiment aimed to screen out strains that can effectively degrade zearalenone (ZEN) and study their degradation effects. Using the ZEN degradation rate as the criterion, strains with ZEN-degrading ability were screened from various samples such as moldy feed, corn and soil; their species were identified by morphological observation, physiological and biochemical identification and 16S rDNA sequencing. The optimal growth and degradation conditions of the screened zearalenone-degrading strain were investigated, and the degradation-active substances were preliminarily analyzed. Crude enzyme solution was extracted from the fermentation supernatant of the screened ZEN-degrading strain using the ammonium sulfate precipitation method, and the molecular masses of the active proteins in the crude enzyme solution were determined. ZEN was added to corn flour, soybean meal powder and wheat bran, followed by inoculation with the screened ZEN-degrading strain. After 72 hours of cultivation, the detoxification effects of the screened ZEN-degrading strain on ZEN in different feeds were investigated. The results showed that, the strain HD-R1, screened from cornfield soil, exhibited a degradation rate of 84.61% against 1 μg/mL ZEN. This strain was identified as Bacillus subtilis. Its optimal growth medium was LB medium, with a logarithmic growth phase of 2 to 18 h. The optimal temperature and initial pH for both growth and degradation for strain HD-R1 were 37 ℃ and pH 7.0, respectively. The degradation-active substances of strain HD-R1 were primarily extracellular enzymes present in the fermentation supernatant, and the molecular masses of these extracellular enzymes were preliminarily estimated to be 38, 60 or 70 kDa. The ZEN degradation rate of strain HD-R1 in artificially contaminated corn flour, soybean meal powder and wheat bran was 44.10%, 62.08% and 76.32%, respectively. In summary, Bacillus subtilis HD-R1 screened in this study can effectively degrade ZEN in LB medium and artificially contaminated feeds, demonstrating good application potential for ZEN detoxification in feeds.