As an indispensable “multifunctional organ” and “second largest genome” of animal hosts, the gut microbiota forms a “community of life with close interactions” together with the host. The establishment of the gut microbiota is dominated by host genetic regulation, while also being influenced by environmental factors, and it exhibits distinct heritable characteristics and microbiability (i.e., the core ability to regulate the host’s phenotypic traits). To systematically clarify the functional characteristics of gut microbiota in aquatic animals, this paper elaborated on the intrinsic correlations between the gut microbiota and host genetics, nutritional metabolism, phenotypic traits, as well as social behaviors, summarized the remodeling effect of targeted genetic breeding on the structure and function of the gut microbiota, and outlined the prospects of its potential application value in the aquaculture field. This review aimed to provide scientific support for the nutritional regulation, genetic research, and industrial application of the gut microbiota.

With increasing consumer demand for high-quality meat, pork quality has become a central focus in the development of the swine industry. Producing premium pork has become an inevitable requirement for promoting the high-quality growth of the pig production sector. Therefore, an in-depth understanding of the formation process and molecular mechanisms underlying pork quality, together with the application of nutritional strategies to regulate and improve pork quality, is of great significance for advancing high-quality development in pig farming. Probiotics, as active microorganisms with immunomodulatory, gut microecology-balancing, and antioxidant functions, have demonstrated substantial application potential in livestock production. Combining domestic and international animal models and swine production studies, this review systematically summarized the molecular mechanisms by which probiotics regulated skeletal muscle satellite cell proliferation and differentiation and reshaped muscle fiber-type composition and metabolic phenotypes, and integrated the research progress on probiotics in improving pork quality. This review aimed to elucidate the potential biological mechanisms through which probiotics improve meat quality, thereby providing a theoretical basis and technical support for the use of probiotics in producing high-quality pork.

Intramuscular fat (IMF) content is a critical factor determining beef quality, playing a pivotal role in flavor and texture of beef, and it also represents a bottleneck in enhancing the efficiency and quality of China’s beef cattle industry. This review summarizes key genes influencing intramuscular fat deposition in beef cattle and explores advances in nutritional interventions aimed at improving IMF. The findings aim to provide a theoretical foundation and novel insights for future precision nutrition strategies to enhance intramuscular fat deposition in beef cattle.

Illite is a layered aluminosilicate clay mineral, mainly composed of alumina, silica and other mineral elements. The unique layered structure and pore channels of illite endow it with important functions such as antibacterial, methane adsorption and heavy metal adsorption. Adding illite in diets can improve the growth performance, intestinal health and meat quality of livestock and poultry, as well as enhance immune function and reduce methane production in rumen. This article provides a review of the structure and composition, industry status, purification process, safety and biological functions of illite, and further explores the application prospects of illite in livestock and poultry production.

Plant polyphenols, as active compounds extracted from natural plants, are characterized by their environmental friendliness, safety and absence of pollution. They possess diverse biological activities, including antioxidant, anti-inflammatory, antimicrobial and growth-promoting functions, which can effectively enhance animal health, production performance and meat quality in livestock. Therefore, this review summarizes the sources, functions, mechanisms of action and applications of plant polyphenols in swine production, aiming to provide references for pig practical farming practices.

Soybean is one of the most important oil-seed crops worldwide. As a natural by-product generated during soybean oil refining, soybean phospholipids (SPL) possess multiple functional properties, including emulsification, wetting, dispersion, and antioxidant activity. In the field of animal nutrition, particularly in poultry production, SPL serves several physiological roles: providing nutrients, building cell membranes, regulating lipid metabolism, and enhancing antioxidant capacity and immune function. Under appropriate conditions, SPL can effectively improve poultry performance and health status. This article systematically reviewed the structure, composition, metabolic pathways and nutritional functions of SPL, while specifically highlighting its latest research progress in regulating poultry physiological functions. The aim is to provide theoretical foundations and practical references for promoting its scientific application in poultry health farming.

Bile acids are important signaling molecules for communication between intestinal microbiota and the host. As key bioactive substances, bile acids promote the digestion and absorption of nutrients in poultry; improve lipid metabolism and enhance the antioxidant and detoxification capabilities in liver; regulate the intestinal microbiota structure and be beneficial to intestinal health. This article reviews the metabolic cycle of bile acids and their effects and possible mechanisms on the performance, liver metabolism and intestinal health of poultry, with the aim of providing a reference for the scientific application of bile acids in poultry production.

Dietary fiber is a core natural source of short-chain fatty acids (SCFAs) in monogastric animal production that can be precisely regulated through diet formulation. SCFAs produced via intestinal microbial fermentation of dietary fiber serve as key metabolites regulating animal gut health and play an irreplaceable role in maintaining gut health of monogastric animals. As important energy substrates for intestinal epithelial cells, SCFAs also exert critical functions in sustaining intestinal barrier integrity, modulating intestinal immunity, and stabilizing intestinal microecological balance. This paper reviewed the classification and fermentation characteristics of dietary fiber, as well as the regulatory effects of its fermentation products on gut health of monogastric animals, with emphasis on the physiological functions of SCFAs and their mechanisms of action in intestinal mechanical barrier, immune response, and microbial homeostasis. It aims to provide references for nutritional regulation research and healthy breeding practices in monogastric animals.

Rumen bacteria play a key role in the digestion of cellulose in ruminants. This review focuses on the major cellulose degrading bacteria in the rumen and the types of cellulases produced by these bacteria, and elaborates on the characteristics and mechanisms of cellulose degradation by rumen bacteria, as well as the synergistic effects of their cellulases. Endoglucanases, exoglucanases and β-glucosidases secreted by rumen bacteria act synergistically, they cleave long cellulose chains sequentially, produce oligosaccharides, hydrolyze oligosaccharides and relieve feedback inhibition, thereby driving cellulose degradation. Cellulosomes can enhance the efficiency of enzymatic hydrolysis, and microbial substrate adhesion, interspecies cross-feeding and interspecific hydrogen transfer further optimize the degradation process. In practical applications, cellulase preparations can improve the digestibility of ruminant diets, but they face challenges such as reduced enzyme activity caused by the rumen environment, large variations in adaptability to different feeds and relatively high costs. This review provides a reference for understanding the process of ruminal cellulose degradation and promoting research and application in the field of ruminant nutrition.

D-amino acids are natural stereoisomers of L-amino acids, sharing identical molecular formulas and backbone structures but differing in optical rotation and biological activity due to their chiral difference at the α-carbon. In the genome of organisms, L-amino acids, encoded by codons, are utilized for protein synthesis, the genetic mechanism that caused a long-held belief that proteins are composed solely of 20 canonical L-amino acids. However, advancements in chiral difference identification techniques have been discovering diverse D-amino acids and isolating them in living organisms. For instance, D-serine (D-Ser), acts as a critical neurotransmitter regulating the N-methy-D-aspartate receptor, influencing neural transmission, learning and memory, its dysregulation may implicate in neurodegenerative diseases. D-alanine (D-Ala) and D-glutamate (D-Glu) modulate bacterial survival by altering cell wall structures and affect animal immune responses. Additionally, gut microbiota-derived D-amino acids profoundly impact host metabolism and health, particularly in energy balance and metabolic regulation. These findings highlight the growing hot research of D-amino acid diversity and their biological significance. This review systematically organizes current knowledge on the functions and mechanisms of D-amino acids and explores their potential applications and strategic utilization in livestock production, providing a theoretical foundation for their development in the feed industry.

Against the background of the ban on antibiotics in feed, plant extracts as a new type of green feed additive have attracted unprecedented attention. Rosemary (Rosmarinus officinalis L.) is rich in a variety of active components, including phenolic acids, flavonoids, terpenoids and lipids. Its main active components-such as rosmarinic acid, carnosic acid, oleanolic acid and ursolic acid-have been extensively reported to exert biological effects including antioxidant, anti-inflammatory, antibacterial activities and improvement of intestinal health. Based on recent research reports on the main active components of rosemary, this paper reviews their primary biological functions, and discusses in detail the effects and underlying mechanisms of rosemary in improving growth performance, immune function, antioxidant capacity and meat quality in livestock and poultry, with a view to providing a reference for the rational application of rosemary in animal production.

Cellulase is a type of complex enzyme system that can efficiently degrade cellulose, consisting of multiple components such as endoglucanase, cellobiohydrolase and β-glucosidase. When applied in feed, cellulase can specifically hydrolyze cellulose and hemicellulose into small carbohydrate molecules absorbable by animals, thereby improving feed digestibility and utilization efficiency. Therefore, it has attracted extensive attention in the field of efficient and healthy livestock and poultry breeding. This paper reviews the microbial sources of cellulase, modification methods of high-yield cellulase strains and their applications in animal nutrition, aiming to provide references for improving the cellulase production efficiency of microbial strains and promoting the efficient application of cellulase in animal production.

As natural and green immunomodulators, Chinese herbal medicine feed additives demonstrate significant application value in alleviating immune stress in animals. Immune stress can trigger excessive inflammatory responses or immunosuppression in the body, severely damaging the health of livestock and poultry, and thereby restricting the full expression of their productive performance. Chinese herbal medicines are rich in various active components such as polysaccharides, flavonoids and alkaloids. They exert a bidirectional immunomodulatory effect, manifesting as both anti-inflammatory and immune-enhancing actions, through mechanisms including inhibiting the release of pro-inflammatory cytokines, regulating macrophage polarization, promoting the development of immune organs, and enhancing antibody levels. These effects are primarily mediated by key signaling pathways such as the Toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-κB) pathway. This article systematically reviewed the effects and molecular mechanisms of active components in Chinese herbal medicines on anti-inflammation and immune enhancement, aiming to provide a theoretical basis for the development of efficient and safe Chinese herbal medicine feed additives.

Selenium is a key trace element for maintaining normal physiological functions in humans and animals, and plays an important role in antioxidation, biological membrane protection, immune regulation and metabolic regulation. In livestock and poultry production, selenium also plays a key role in improving the meat quality of livestock and poultry. Appropriate supplementation of selenium can enhance the tenderness of livestock and poultry muscle and have a positive impact on meat color and water-holding capacity. With the growth of consumers’ demand for high-quality livestock and poultry meat, selenium-enriched meat has become a market hotspot due to its unique nutritional value. Feeding selenium-enriched diets to increase the selenium content in livestock and poultry products has become an effective way to produce selenium-enriched meat products. Therefore, in production practice, the reasonable supplementation of selenium in diets is of great significance for the high-quality development of livestock industry. This article mainly expounds the effects of selenium on the meat quality of livestock and poultry and its mechanism, introduces the production and advantages of selenium-enriched meat, and analyzes the current problems and future development directions of the selenium-enriched industry.

Ruminant production is a major source of agricultural methane emissions. Systematic differences in digestive physiology, inherent rumen fermentation characteristics and dominant production systems between cattle and sheep may lead to species-specific patterns of methane production characteristics and responses to mitigation strategies. However, comparative studies on cattle and sheep under the same conditions are still very scarce. Most existing studies are carried out based on a single species, and confounding factors such as feeding system, nutritional level and experimental methods among different studies make it difficult to directly define the species-specific contribution to the heterogeneity of mitigation effects. Focusing on the core pathways of methanogenesis in ruminants, this review systematically examined the key physiological and production characteristics of cattle and sheep. It summarized the mechanisms of action, mitigation efficacy, and safe dosage ranges of five mainstream mitigation additives: 3-nitrooxypropanol, lipids, tannins, red macroalgae and nitrates. The review clarified the potential sources of variability in mitigation outcomes reported in existing studies. By synthesizing current evidence, it reviewed the research progress in ruminant methane mitigation from the perspectives of animal physiology, production system compatibility, and dose safety control. The purpose of this review is to provide a reference for future standardized research on cattle and sheep methane mitigation that is tailored to species and production scenarios, and to support the development of precision mitigation technology systems.

This experiment aimed to investigate the effects of plantain herb and probiotic fermented plantain herb on growth performance and serum biochemical indicators of Liaoning black pigs. The experiment adopted a single-factor randomized block design, a total of 160 healthy (50±5) days of age Liaoning black pigs with similar initial weight [(23.10±1.65) kg] were randomly divided into 5 groups with 4 replicates in each group and 8 pigs in each replicate. The control group was fed a basal diet, and the experimental groups were fed the basal diets supplemented with 0.2% plantain herb (0.2% PL group), 0.4% plantain herb (0.4% PL group), 0.2% probiotic fermented plantain herb (0.2% PFPL group) and 0.4% probiotic fermented plantain herb (0.4% PFPL group), respectively. The pre-experimental period lasted for 3 days, and the experimental period lasted for 28 days. The results showed as follows: 1) compared with the control group, the final body weight of 0.2%, 0.4% PFPL groups was extremely significantly increased (P<0.01); the average daily gain and average daily feed intake of 0.4% PFPL group were extremely significantly increased (P<0.01), and the feed to gain ratio was extremely significantly decreased (P<0.01). 2) Compared with the control group, the serum aspartate aminotransferase and alanine aminotransferase activities of 0.4% PL group and 0.2%, 0.4% PFPL groups were extremely significantly decreased (P<0.01). 3) Compared with the control group, the serum triglycerides and total cholesterol contents of 0.2%, 0.4% PL groups and 0.2%, 0.4% PFPL groups were significantly or extremely significantly decreased (P<0.05 or P<0.01), and the serum high-density lipoprotein cholesterol content of 0.4% PL group and 0.2%, 0.4% PFPL groups was significantly or extremely significantly increased (P<0.05 or P<0.01). 4) Compared with the control group, the serum immunoglobulin A, immunoglobulin M, immunoglobulin G, complement 3 and complement 4 contents of 0.2%, 0.4% PFPL groups were significantly or extremely significantly increased (P<0.05 or P<0.01), and the serum interleukin-1β, interleukin-6 and tumor necrosis factor-α contents were significantly or extremely significantly decreased (P<0.05 or P<0.01). 5) Compared with the control group, the serum total antioxidant capacity and superoxide dismutase, glutathione peroxidase activities of 0.4% PL group and 0.2%, 0.4% PFPL groups were significantly or extremely significantly increased (P<0.05 or P<0.01), and the serum myeloperoxidase activity and malondialdehyde content were extremely significantly decreased (P<0.01). 6) Compared with the control group, the serum creatine kinase and lactate dehydrogenase activities of 0.4% PL group and 0.2%, 0.4% PFPL groups were extremely significantly decreased (P<0.01). 7) Compared with the control group, the serum creatinine and urea nitrogen contents of 0.4% PL group and 0.2%, 0.4% PFPL groups were extremely significantly decreased (P<0.01). In conclusion, adding plantain herb and probiotic fermented plantain herb to the basal diet can improve the growth performance, protein and fat metabolism status and enhance the immune function and antioxidant ability of Liaoning black pigs, and alleviate the stress damage. Under the experimental conditions, it is advisable to add 0.4% probiotic fermented plantain herb in the basal diet for Liaoning black pigs.

This study aimed to investigate the effects of replacing different proportions of corn with prickly ash seed (PAS) on reproductive performance, nutrient apparent digestibility, urinary metabolites, and fecal microbiota of Yimeng black sows during late pregnancy. A total of 36 healthy Yimeng black sows with similar parity and body condition were randomly divided into 6 groups with 6 replicates per group and 1 sow per replicate. Sows in the control group (CON group) were fed a basal diet, while those in the experimental groups were fed diets in which 0.5% (0.5% PAS group), 1.0% (1.0% PAS group), 2.0% (2.0% PAS group), 4.0% (4.0% PAS group) or 6.0% (6.0% PAS group) of corn in the basal diet was replaced by an equal amount of PAS, respectively. The experiment lasted from day 80 of gestation until 10 days after delivery. The results showed as follows: 1) compared with the CON group, no significant differences were observed in number of total litter size, number of live piglets per litter, live piglet rate, as well as birth weight, body weight of piglet at 10 day of age and weaning weight of piglets in any experimental group (P>0.05). 2) The apparent digestibility of organic matter (OM) in 6% PAS group was significantly lower than that in the other groups (P<0.05); however, no significant differences were detected among groups in apparent digestibility of crude protein (CP), ether extract (EE), calcium (Ca) or phosphorus (P) (P>0.05). 3) Compared with the CON group, 2% PAS and 4% PAS groups showed significant upregulation of L-dopa, quercetin-3-galactoside and 2,3-dihydroxyoctanoic acid in urine (P<0.05), and significant downregulation of N-piperidine-3-carboxamide, aspartic acid, phenylalanine, lysine, serine and methionine in urine (P<0.05); urinary differential metabolites in 2% PAS and 4% PAS groups were significantly enriched in pathways such as steroid hormone biosynthesis, nucleotide metabolism and tryptophan metabolism (P<0.05). 4) Compared with the CON group, Shannon index of fecal microbiota was significantly increased in 4% PAS group (P<0.05), while Simpson index was significantly decreased in 2% PAS and 4% PAS groups (P<0.05). At the genus level, compared with the CON group, relative abundances of Clostridium and Lactobacillus of fecal microbiota were significantly increased in 2% PAS and 4% PAS groups (P<0.05), while that of Streptococcus was significantly decreased in 2% PAS and 4% PAS groups (P<0.05). Furthermore, the relative abundance of Acinetobacter in 2% PAS group was significantly higher than that in the other groups (P<0.05), while relative abundances of Lachnospiraceae_XPB1014_group and norank_f_Muribaculaceae were significantly lower than those in the other groups (P<0.05). In conclusion, replacing 0.5% to 6.0% of corn with PAS in the diet has no obvious negative effects on reproductive performance of late-gestation sows or the growth performance of their offspring. Meanwhile, moderate inclusion of PAS reduces the levels of amino acids in sow urine and increases the richness and diversity of fecal microbiota, indicating that PAS supplementation alters metabolic pathways and microbial composition.

This experiment was conducted to explore the effects of Broussonetia papyrifera leaf polysaccharide (BPP) supplementation in formula milk on growth performance and ileal barrier function in piglets challenged by rotavirus. Twenty-four 7-day-old healthy Duroc×Landrace×Yorkshire piglets were selected and randomly divided into 2 groups with 12 piglets in each group using a 2×2 factor design. They were fed formula milk supplemented with 0 and 110 mg/kg BPP, respectively. The experiment lasted for 24 days. On day 21, six piglets were randomly selected from each of the two groups for RV challenge, while the remaining piglets were not challenged. The results showed as follows: 1) RV challenge significantly decreased the average daily gain (ADG) of piglets (P<0.05), and induced moderate-to-severe diarrhea in piglets (incidence was 83.33%); BPP supplementation in formula milk significantly alleviated the decline of ADG caused by RV challenge (P<0.05), and significantly decreased the incidence of moderate-to-severe diarrhea (P<0.05). 2) RV challenge significantly decreased the villus height and the villus height to crypt depth ratio in ileum (P<0.05), significantly increased the crypt depth in ileum (P<0.05), simultaneously significantly increased the contents of RV-specific immunoglobulin M (RV-IgM), protein carbonyl, and malondialdehyde (MDA) in ileal mucosa (P<0.05), and significantly decreased the total antioxidant capacity (T-AOC) in ileal mucosa (P<0.05); BPP supplementation in formula milk significantly alleviated the negative effects of RV challenge on ileal morphology and antioxidant indices in ileal mucosa (P<0.05). 3) RV challenge significantly increased the mRNA relative expression levels of Caspase-3 and B-cell lymphoma-2 associated X protein (Bax) in ileal mucosa and the ratio of Bax to B-cell lymphoma-2 (Bcl-2) (P<0.05); BPP supplementation in formula milk significantly increased the mRNA relative expression levels of mucin 1 (MUC1), Occludin and Bcl-2 in ileal mucosa (P<0.05), significantly decreased the Bax mRNA relative expression level and the ratio of Bax to Bcl-2 in ileal mucosa (P<0.05), and significantly alleviated the negative effects of RV challenge on the mucosal barrier function and apoptosis in ileum (P<0.05). In conclusion, BPP supplementation in formula milk can effectively alleviate the decline in growth performance and the incidence of diarrhea in piglets induced by RV infection by enhancing the antioxidant capacity of ileal mucosa, inhibiting excessive apoptosis, and improving intestinal morphology and barrier function.

This experiment was conducted to explore the effects of dietary supplementation with biological protein API (an artificially designed recombinant biological protein containing the functional fragment of catfish antimicrobial peptide parasin I) on the growth performance, nutrient apparent digestibility and fecal microbiota of weaned piglets. Fifty-four 28-day-old Duroc×Landrace×Yorkshire weaned and castrated piglets with a body weight of (8.45±0.41) kg were selected and randomly divided into 3 groups, with 6 replicates in each group and 3 piglets in each replicate. The control group (CON group) was fed a basal diet, the KBX group was fed the basal diet+2 000 mg/kg KBX (commercial compound antibiotic alternative product), and the API group was fed the basal diet+1 000 mg/kg API product. The experimental period was 42 days, divided into three stages: days 1 to 14, days 15 to 28, and days 29 to 42. The results showed as follows: 1) compared with the CON group, the body weight of weaned piglets in the API group was significantly increased on days 28 and 42 of the experiment (P<0.05), and the average daily gain from days 29 to 42 of the experiment and throughout the entire period (days 1 to 42 of the experiment) was significantly increased (P<0.05). 2) Compared with the CON group, the crude protein apparent digestibility in the API group was significantly increased (P<0.05); compared with the CON group and the KBX group, the gross energy apparent digestibility in the API group was significantly increased (P<0.05). 3) Compared with the CON group, the contents of fecal acetic acid, isobutyric acid and total short-chain fatty acids in the API group were significantly increased (P<0.05). 4) Compared with the CON group, the relative abundances of Proteobacteria and Streptococcus in feces in the API group were significantly decreased (P<0.05), while the Prevotellaceae_NK3B31_group relative abundance in feces was significantly increased (P<0.05). In conclusion, dietary supplementation with biological protein API can enhance the growth performance and apparent nutrient digestibility of weaned piglets, improve the structure of fecal microbiota, and increase the contents of short-chain fatty acids in feces. Moreover, the effect is superior to that of the compound antibiotic alternative product KBX.

This experiment was conducted to investigate the effects of fermented honeysuckle on growth performance, immune function, antioxidant capacity and fecal microbiota of weaned piglets. A total of 80 healthy weaned Zaozhuang Heigai piglets with similar body weight of (7.30±0.50) kg were randomly divided into 4 groups with 5 replicates per group and 4 piglets per replicate. The control group (CON group) was fed a basal diet, while the experimental groups were supplemented with 0.8% honeysuckle (HO group), 0.8% honeysuckle plus 0.01% Lactobacillus plantarum (HL group) and 0.8% fermented honeysuckle (FH group) in the basal diet, respectively. The whole trial lasted for 35 days, including a 5-day preliminary trial and a 30-day formal trial. The results showed as follows: 1) compared with the CON group, the final body weight and average daily gain in the HO, HL and FH groups were significantly increased (P<0.05), while the feed-to-gain ratio was significantly decreased (P<0.05). The crude protein digestibility in the FH group was significantly increased (P<0.05). 2) On day 15 of the trial, compared with the CON group, the serum immunoglobulin M (IgM) content in the FH group was significantly increased (P<0.05); the serum interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) contents in the HL and FH groups were extremely significantly decreased (P<0.01), the serum interferon-γ (IFN-γ) content was significantly decreased (P<0.05), the serum swine foot-and-mouth disease type O antibody titer was extremely significantly increased (P<0.01), and the serum classical swine fever antibody blocking rate was significantly increased (P<0.05). On day 30 of the trial, compared with the CON group, the serum immunoglobulin G (IgG), IgM and interleukin-10 (IL-10) contents in the FH group were significantly increased (P<0.05); the serum IL-1β content in the HO, HL and FH groups was significantly decreased (P<0.05), the serum swine foot-and-mouth disease type O antibody titer was extremely significantly increased (P<0.01), and the serum classical swine fever antibody blocking rate was significantly or extremely significantly increased (P<0.05 or P<0.01). 3) Compared with the CON group, on day 15 of the trial, the serum malondialdehyde (MDA) content in the HO, HL and FH groups was significantly decreased (P<0.05), and the serum catalase (CAT) content was significantly increased (P<0.05); on day 30 of the trial, the serum CAT content in the HO, HL and FH groups was extremely significantly increased (P<0.01). 4) Compared with the CON group, the FH group showed increased relative abundance of Selenomonas, Mitsuokella and Eubacterium_ruminantium_group in feces, and decreased relative abundance of Clostridium_sensu_stricto_1. 5) Pearson correlation analysis showed that the relative abundance of UCG-005 in fecal was significantly or extremely significantly positively correlated with serum IgG, IgM, IL-10, glutathione peroxidase (GSH-Px), CAT contents, and apparent crude protein digestibility (P<0.05 or P<0.01); the relative abundance of Clostridium_sensu_stricto_1 was significantly or extremely significantly negatively correlated with serum IgG, IgM, IL-10 and CAT contents (P<0.05 or P<0.01), and was significantly or extremely significantly positively correlated with serum interleukin-6 (IL-6), IL-1β and IFN-γ contents (P<0.05 or P<0.01). In conclusion, dietary supplementation with fermented honeysuckle can promote the growth of weaned piglets, enhance immune function and antioxidant capacity, and optimize the composition of intestinal microbiota.

This experiment aimed to investigate spatial distribution characteristics of mucin glycosylation modifications in different intestinal segments (duodenum, jejunum, ileum, cecum and colon) of 50-day-old piglets and their association with intestinal barrier function, as well as to explore effects of pine polyphenols (PP) on sialylation glycosylation modification in piglet ileum. In experiment 1, eight healthy weaned piglets (Duroc × Landrace × Yorkshire) at 22 days of age were selected, raised to 50 days of age, and then slaughtered for sampling. In experiment 2, forty-eight healthy weaned piglets (Duroc × Landrace × Yorkshire) at 24 days of age were randomly divided into three groups, with eight replicates per group and two piglets per replicate. CON group was fed a basal diet and intraperitoneal injection of normal saline; lipopolysaccharide (LPS) group was fed a basal diet and intraperitoneal injection of 100 μg/kg BW LPS; PP group was fed a basal diet supplemented with 500 mg/kg PP and intraperitoneal injection of 100 μg/kg BW LPS. On day 28 of the experiment, intraperitoneal injections of LPS or normal saline were administered, and the piglets were slaughtered 4 h later for sampling. The results showed as follows: 1) jejunal villus height was significantly higher than that in the duodenum and ileum (P<0.05), and ileal villus height was the lowest; the crypt depth in the cecum and colon was significantly greater than that in the small intestinal segments (P<0.05); the jejunal villus height/crypt depth ratio was the highest, significantly higher than that in the duodenum and ileum (P<0.05), and the lowest value was observed in the ileum; goblet cell number in the jejunum was significantly higher than that in the duodenum and ileum (P<0.05). 2) Among mucin-related genes, the mRNA relative expression level of resistin like beta (RETNLB) gene in the jejunum was significantly higher than that in other intestinal segments (P<0.05); the mRNA relative expression level of anterior gradient protein 2 (AGR2) gene in the colon was significantly higher than that in the ileum and cecum (P<0.05); the mRNA relative expression level of trefoil factor 3 (TFF3) gene in the ileum was significantly lower than that in the duodenum and jejunum (P<0.05); the mRNA relative expression level of mucin 4 (MUC4) gene in the jejunum and ileum was significantly lower than that in other intestinal segments (P<0.05). 3) Among Tn antigen-related genes, the mRNA relative expression level of N-acetylgalactosaminyltransferase 12 (GALNT12) gene in the colon and cecum was significantly higher than that in other segments (P<0.05); among core structure modification-related genes, the mRNA relative expression level of N-acetylglucosaminyltransferase 2 (GCNT2) gene in the jejunum was significantly higher than that in other segments (P<0.05), the mRNA relative expression level of N-acetylglucosaminyltransferase 1 (GCNT1) gene in the colon was significantly higher than that in the duodenum, jejunum and ileum (P<0.05), and the mRNA relative expression level of core 1 synthase (C1GALT1) gene in the colon was significantly higher than that in the jejunum, ileum and cecum (P<0.05); among terminal structure modification-related genes, the mRNA relative expression level of β-galactoside α-2,6-sialyltransferase 1 (ST6GAL1) gene in the ileum was significantly higher than that in other segments (P<0.05), and the mRNA relative expression level of β-1,4-galactosyltransferase 4 (B4GALT4) gene in the colon was significantly higher than that in other segments (P<0.05). 4) Compared with LPS group, dietary supplementation with PP significantly increased the mRNA relative expression levels of β-galactoside α-2,3-sialyltransferase 1 (ST3GAL1), β-galactoside α-2,3-sialyltransferase 3 (ST3GAL3) and ST6GAL1 genes in the ileum of piglets (P<0.05). In conclusion, there are significant segment-specific characteristics of intestinal mucin glycosylation modifications in piglets: the jejunum is characterized by a high number of goblet cells and core structure modifications, which are beneficial for mucus barrier formation; the ileum predominantly exhibits sialylation modifications; and the colon is enriched in core extension and terminal structure modifications. Dietary supplementation with PP can regulate sialylation glycosylation modification in the ileum of piglets.

This study aimed to investigate the effects of dietary supplementation of cassia leaf extract (CLE) during late gestation and lactation on the reproductive performance of sows and the health of their offspring. A total of 48 healthy Landrace×Large White crossbred sows at 2 to 3 parities were randomly assigned to four groups with 12 sows per group. Sows in the control group (CON) were fed a basal diet, while those in the experimental groups received the basal diet supplemented with 50 (group A), 100 (group B) or 150 mg/kg (group C) CLE. The feeding trial lasted from day 100 of gestation until weaning on day 21 postpartum. The results showed that: 1) compared with the CON group, dietary CLE supplementation during late gestation and lactation significantly reduced the average litter number of weak piglets (P<0.05). 2) Compared with the CON group, the milk protein rate, the contents of non-fat solids and total solids in colostrum were significantly increased in group A (P<0.05). 3) Compared with the CON group, serum malondialdehyde (MDA) content were significantly decreased of sows in groups B and C and of piglets in group A (P<0.05), while serum superoxide dismutase (SOD) activity was significantly increased of piglets in groups A and C (P<0.05). 4) Compared with the CON group, serum alkaline phosphatase (ALP) activity was significantly increased of sows in group A and of piglets in groups A and B (P<0.05). 5) Fecal 16S rDNA sequencing revealed that, compared with the CON group, the relative abundance of Methanobrevibacter in sow feces was significantly increased in group A (P<0.05); in piglet feces, the relative abundance of Bacteroidota was significantly decreased (P<0.05), while the Firmicutes/Bacteroidota ratio was significantly increased in group A (P<0.05); the relative abundance of Desulfobacterota was significantly increased in group B (P<0.05); the relative abundance of Phascolarctobacterium was significantly increased in group C (P<0.05). 6) Non-targeted metabolomics analysis of piglet serum showed that, compared with the CON group, differential metabolites in group A were significantly enriched in the glutathione metabolism pathway, alanine, aspartate and glutamate metabolism pathway, glyoxylate and dicarboxylate metabolism pathway, and nitrogen metabolism pathway; differential metabolites in group C were significantly enriched in the taurine and hypotaurine metabolism pathway, glutathione metabolism pathway, butanoate metabolism pathway, and bile acid metabolism pathway. In conclusion, dietary supplementation of CLE during late gestation and lactation can improve sows’ reproductive performance and antioxidant capacity. Moreover, by improving colostrum quality, it enhances piglets’ antioxidant capacity and modulates gut microbiota homeostasis through a “sow-to-offspring transmission” pathway, thereby promoting healthy growth of piglets.

This study aimed to compare the carcass traits and meat quality of Jinhua pigs at different months of age. Six male Jinhua pigs at 6, 7, 8, 9, 10, 11 and 12 months of age were randomly selected for slaughter in the experiment, to determine the carcass traits, meat quality characteristics and longissimus dorsi amino acid and fatty acid composition. The results showed as follows: 1) compared with 6 months of age, the pre-slaughter weight, carcass total weight, slaughter rate and backfat thickness at shoulder, thoracolumbar junction and lumbosacral junction at 12 months of age were significantly increased (P<0.05), the skin weight, bone weight, fat weight and meat weight in shoulder, loin and ham were significantly increased (P<0.05), and the lean meat percentage was significantly decreased (P<0.05). 2) Compared with 6 months of age, the muscle intramuscular fat content at 12 months of age was significantly increased (P<0.05). 3) The longissimus dorsi total amino acid (TAA) content at 6 to 7 months of age was significantly lower than that at 8 to 12 months of age (P<0.05), the longissimus dorsi essential amino acids (EAA) content at 7 months of age was significantly lower than that at 8 to 12 months of age (P<0.05), and the longissimus dorsi non-essential amino acid (NEAA) content at 6 to 7 months of age was significantly lower than that at 8 to 12 months of age (P<0.05). 4) The longissimus dorsi stearic acid (C18∶0) content at 12 months of age was significantly higher than that at 6 months of age (P<0.05), the longissimus dorsi oleic acid (C18∶1) content at 12 months of age was significantly lower than that at 7 months of age (P<0.05), and the longissimus dorsi arachidonic acid (C20∶4) content at 12 months of age was significantly higher than that at 6 to 11 months of age (P<0.05). In summary, the Jinhua pigs continue to develop from 6 to 12 months of age, and the carcass traits, meat quality characteristics and longissimus dorsi amino acid and fatty acid composition show significant changes.

This experiment was conducted to investigate the effects of dietary oil sources and addition levels on β-carotene deposition and antioxidant capacity of broilers. A total of 960 one-day-old Arbor Acres white-feathered broilers were selected and randomly divided into 6 groups with 4 replicates per group and 40 broilers per replicate. Each replicate was divided into 2 cages with 20 males and 20 females, respectively. A 2×3 factorial design was adopted, with two dietary oil sources (soybean oil and lard) and three addition levels (low, medium and high). During the starting period (1 to 21 days of age), the low, medium and high oil addition levels were 1.50%, 3.00% and 4.50%, respectively; during the growing period (22 to 35 days of age), the corresponding levels were 3.27%, 4.75% and 6.22%, respectively; and during the finishing period (36 to 42 days of age), the levels were 5.14%, 6.59% and 8.03%, respectively. All diets were supplemented with 20 mg/kg β-carotene throughout the experiment. The trial lasted for 42 days. The results showed as follows: 1) dietary oil sources, addition levels and their interaction had no significant effects on slaughter performance, meat quality and serum lipid indices of broilers (P>0.05). 2) The serum total antioxidant capacity (T-AOC) of soybean oil group was significantly higher than that of lard group (P<0.05), while the lard group exhibited significantly higher serum glutathione peroxidase (GSH-Px) activity and total hepatic β-carotene deposition than the soybean oil group (P<0.05). 3) The serum superoxide dismutase (SOD) activity in the medium oil addition level group was significantly higher than that in the low and high oil addition level groups (P<0.05); the hepatic vitamin A content and total deposition in the medium and high oil addition level groups were significantly higher than those in the low oil addition level group (P<0.05). With the increase of dietary oil addition level, the final body weight (P=0.059) and European performance index of broilers showed an increasing tendency (P=0.059), while the feed to gain ratio presented a decreasing tendency (P=0.099), and hepatic β-carotene content tended to rise (P=0.065). In conclusion, dietary oil sources (soybean oil vs. lard) have no significant influence on the growth performance of broilers. Nevertheless, lard facilitates hepatic β-carotene deposition, while soybean oil exerts superior effects on enhancing serum T-AOC. Increasing dietary oil addition level can effectively promote hepatic deposition of β-carotene and vitamin A, and exert a moderate improvement on broiler growth performance.

This experiment was conducted to investigate the effects of dietary supplementation with different forms of selenium sources on growth performance, selenium content in blood and tissues, antioxidant capacity and meat quality of broilers. A total of 360 one-day-old Ross 308 male broilers were randomly divided into 4 groups, with 9 replicates per group and 10 broilers per replicate. Broilers in the four groups were fed basal diets supplemented with sodium selenite (CON group), hydroxy-selenomethionine (HMSeBA group), selenium nanoparticles (SeNPs group) and coated sodium selenite (CSe group), respectively, with each selenium source added at 0.3 mg/kg (on a selenium basis). The pre-trial period lasted for 7 days (1 to 7 days of age), and the formal trial period lasted for 42 days (8 to 49 days of age). The results showed as follows: 1) different forms of selenium sources had no significant effects on average daily feed intake, average daily gain, feed-to-gain ratio at any stage and mortality rate of broilers (P>0.05). 2) In serum, the selenium content of the CSe group was significantly higher than that of the CON, HMSeBA and SeNPs groups (P<0.05); in the liver, the selenium content of the CSe and HMSeBA groups was significantly higher than that of the CON group (P<0.05); in the breast muscle, the selenium content of the HMSeBA and CSe groups was significantly or extremely significantly higher than that of the CON group (P<0.05 or P<0.01). 3) Compared with the CON group, the serum glutathione peroxidase (GSH-Px) activity of the CSe, HMSeBA and SeNPs groups was significantly increased (P<0.05), and the malondialdehyde (MDA) content was extremely significantly decreased (P<0.01); the serum total superoxide dismutase (T-SOD) activity of the CSe group was extremely significantly higher than that of the CON group (P<0.01), and significantly higher than that of the SeNPs and HMSeBA groups (P<0.05); the serum total antioxidant capacity (T-AOC) of the CSe group was extremely significantly higher than that of the CON and SeNPs groups (P<0.01), and significantly higher than that of the HMSeBA group (P<0.05). Compared with the CON group, the liver GSH-Px activity of the CSe, HMSeBA and SeNPs groups was significantly increased (P<0.05), and the T-AOC was extremely significantly increased (P<0.01), with the T-AOC of the CSe group being extremely significantly higher than that of the HMSeBA group (P<0.01). 4) The 45 min lightness ( ${\mathrm{L}}_{45\mathrm{ }\mathrm{m}\mathrm{i}\mathrm{n}}^{\mathrm{*}}$) value of breast muscle in the CSe group was significantly lower than that in the CON and HMSeBA groups (P<0.05); the 45 min redness ( ${\mathrm{a}}_{45\mathrm{ }\mathrm{m}\mathrm{i}\mathrm{n}}^{\mathrm{*}}$) value of breast muscle in the HMSeBA, SeNPs and CSe groups was significantly higher than that in the CON group (P<0.05); the 48 and 72 h cooking loss of breast muscle in the CSe group was significantly or extremely significantly lower than that in the CON group (P<0.05 or P<0.01). The 48 h cooking loss of leg muscle in the HMSeBA, SeNPs and CSe groups was extremely significantly lower than that in the CON group (P<0.01), and that in the CSe group was significantly lower than that in the HMSeBA group (P<0.05); the 72 h cooking loss of leg muscle in the CSe and SeNPs groups was significantly lower than that in the CON group (P<0.05). In conclusion, under the condition of equal supplementation (0.3 mg/kg selenium), different forms of selenium sources have no significant effects on the growth performance of broilers; however, hydroxy-selenomethionine, selenium nanoparticles and coated sodium selenite are superior to sodium selenite in increasing selenium content in blood and tissues, enhancing antioxidant capacity, and improving meat quality, with coated sodium selenite showing the best overall performance.

This study aimed to investigate the effects of earthworm antimicrobial peptides (EAMPs) on the growth performance, nutrient apparent metabolic rates, blood biochemical indicators and intestinal function of yellow-feathered broiler chicks, and to evaluate their potential as an alternative to antibiotics. A total of 240 healthy 1-day-old male Tiejiao-Ma Huang broiler chicks with an average body weight of (29.66±0.27) g were randomly allocated into 4 groups, each with 6 replicates of 10 chicks per replicate. The control group (CON group) was fed a basal diet, the antibiotic group (AGP group) was fed the basal diet supplemented with 30 mg/kg flavomycin, the EAMP1 group was fed the basal diet supplemented with 75 mg/kg EAMPs, and the EAMP2 group was fed the basal diet supplemented with 150 mg/kg EAMPs. The experiment lasted for 21 days. The results showed as follows: 1) compared with the CON and AGP groups, dietary supplementation with 75 or 150 mg/kg EAMPs significantly increased the body weight at 21 days of age and average daily gain from 1 to 21 days of age of yellow-feathered broiler chicks (P<0.05); meanwhile, compared with the CON group, dietary supplementation with 75 or 150 mg/kg EAMPs also significantly decreased the feed-to-gain ratio from 1 to 21 days of age (P<0.05). 2) Compared with the CON group, dietary supplementation with 75 or 150 mg/kg EAMPs significantly increased the apparent metabolic rates of dry matter, gross energy, crude protein, calcium and total phosphorus of yellow-feathered broiler chicks (P<0.05); in addition, compared with the AGP group, dietary supplementation with 75 or 150 mg/kg EAMPs significantly increased the apparent metabolic rates of dry matter and crude protein (P<0.05). 3) Compared with the CON and AGP groups, dietary supplementation with 75 or 150 mg/kg EAMPs significantly decreased the plasma uric acid (UA) content (P<0.05), significantly increased the serum immunoglobulin Y (IgY) content (P<0.05), significantly enhanced the serum catalase (CAT) activity (P<0.05), and significantly decreased the serum interleukin-1β (IL-1β) and interleukin-6 (IL-6) contents (P<0.05); furthermore, the serum tumor necrosis factor-α (TNF-α) content in the AGP, EAMP1 and EAMP2 groups was significantly lower than that in the CON group (P<0.05). 4) Compared with the CON and AGP groups, dietary supplementation with 75 or 150 mg/kg EAMPs significantly increased the jejunal villus height and villus height/crypt depth ratio (P<0.05); compared with the CON group, the serum diamine oxidase (DAO) activity and D-lactic acid (D-LA) content in the AGP, EAMP1 and EAMP2 groups were significantly decreased (P<0.05). In conclusion, dietary supplementation with 75 or 150 mg/kg EAMPs can improve the growth performance and nutrient utilization, enhance immune function and antioxidant capacity, alleviate inflammatory response, and improve intestinal function of yellow-feathered broiler chicks, demonstrating the potential to replace antibiotics.

This experiment aimed to investigate the effects of silybin on performance, egg quality and immune function of laying hens in late laying period. A total of 192 five hundred and eighty-day-old Hy-Line grey laying hens were randomly divided into two groups with 8 replicates per group and 12 hens per replicate. The control group was fed a basal diet, and the experimental group was fed the basal diet supplemented with 500 mg/kg silybin. The pre-experimental period lasted for 7 days, and the experimental period lasted for 56 days. The results showed that compared with the control group: 1) the feed to egg ratio on 1 to 56 days of the experimental group was significantly decreased (P<0.05); 2) the Haugh unit on 28 and 56 days of the experimental group was significantly increased (P<0.05), and the albumen height, yolk color and eggshell thickness on 56 days were extremely significantly increased (P<0.01); 3) the serum albumin (ALB) content and lactate dehydrogenase (LDH) activity of the experimental group were extremely significantly decreased (P<0.01), and the contents of immunoglobulin A (IgA), interleukin-10 (IL-10), interleukin-13 (IL-13) and tumor necrosis factor-α (TNF-α) in serum were extremely significantly increased (P<0.01); 4) the contents of IgA, immunoglobulin G (IgG), IL-10, IL-13 and TNF-α in liver were extremely significantly increased (P<0.01), and the liver immunoglobulin M (IgM) content was significantly increased (P<0.05); 5) the oviduct IgM content of the experimental group was significantly decreased (P<0.05), and the oviduct IgG content was significantly increased (P<0.05). In conclusion, dietary 500 mg/kg silybin can effectively improve the performance, egg quality and immune function of laying hens in late laying period, demonstrating good application potential.

This experiment was aimed to investigate the effects of Aronia melanocarpa pomace (AP) on performance, egg quality, nutrient apparent digestibility and caecal microbiota of laying hens during the peak laying period. A total of 288 Hy-Line Brown laying hens at 28 weeks of age with average body weight of (1 843.33±41.30) g and laying rate of (90.40±0.35)% showing no significant difference (P>0.05) were randomly divided into 4 groups with 6 replicates per group and 12 hens per replicate. Hens in the four groups were fed experimental diets supplemented with 0 (control), 1%, 2% and 3% AP, respectively. The experiment lasted for 33 weeks, with weeks 28 to 45 of age as the early stage of peak laying period and weeks 46 to 60 of age as the late stage of peak laying period. The results showed as follows: 1) during the early stage of peak laying period, compared with the control group, laying rate in 3% AP group was significantly increased (P<0.05), average daily feed intake in 1% and 2% AP groups was significantly decreased (P<0.05), and feed-to-egg ratio in 2% and 3% AP groups was significantly decreased (P<0.05). During the late stage of peak laying period, compared with the control group, laying rate in 3% AP group was significantly increased (P<0.05), and average egg weight and daily egg mass in 2% and 3% AP groups were significantly increased (P<0.05). During the whole peak laying period, compared with the control group, laying rate and daily egg mass in 3% AP group were significantly increased (P<0.05), and average egg weight and daily egg mass in 2% AP group were significantly increased (P<0.05). 2) In terms of egg quality, dietary addition of AP significantly increased yolk color during the early stage of peak laying period (P<0.05). 3) Regarding nutrient apparent digestibility, during the early stage of peak laying period, compared with the control group, apparent digestibility of crude ash and phosphorus in 1%, 2% and 3% AP groups was significantly increased (P<0.05), and apparent digestibility of gross energy in 1% and 2% AP groups was significantly increased (P<0.05). During the late stage of peak laying period, compared with the control group, apparent digestibility of ether extract, crude fiber and ash in 2% and 3% AP groups was significantly increased (P<0.05). 4) At genus level, during the early stage of peak laying period, compared with the control group, the relative abundances of Olsenella, Lactobacillus and Erysipelatoclostridium in cecum of 3% AP group were significantly increased (P<0.05), while the relative abundances of Colidextribacter, Clostridia_vadinBB60_group and Desulfovibrio were significantly decreased (P<0.05). During the late stage of peak laying period, compared with the control group, the relative abundance of Lactobacillus in cecum of 1% AP group was significantly increased (P<0.05), and the relative abundances of Alistipes and Megamonas in 3% AP group were significantly decreased (P<0.05). In conclusion, dietary addition of AP during the peak laying period can modulate the cecal microbiota structure, improve performance and nutrient apparent digestibility of laying hens, with 3% AP addition level showing the best effect.

This experiment was conducted to investigate the effects of dietary calcium (Ca) and non-phytate phosphorus (NPP) levels on laying performance, egg quality, intestinal digestive enzyme activities, nutrient apparent utilization rates and gene expression of osteopontin (OPN) and calbindin (CALB) in eggshell gland of Langya hens during early laying period. A total of 540 healthy 168-day-old Langya chickens were selected and randomly divided into 9 groups according to the principle of equal body weight and laying rate, with 5 replicates per group and 12 chickens per replicate. A 2×3 two-factor orthogonal experimental design was adopted, the dietary Ca levels were set at 2.50%, 3.00% and 3.50%, respectively, and the NPP levels were set at 0.24%, 0.32% and 0.40%, respectively. The experiment included a 7-day pre-trial period and a 35-day formal trial period. The results showed as follows: 1) the average daily egg mass and laying rate of 2.50% and 3.00% Ca groups were significantly higher than those of 3.50% Ca group (P<0.05), and the feed to egg ratio was significantly lower than that of the 3.50% Ca group (P<0.05); dietary Ca and NPP levels had significant interaction effects on the average daily egg mass, laying rate and feed to egg ratio (P<0.05). 2) The Haugh unit of 3.00% Ca group was significantly higher than that of 2.50% and 3.50% Ca groups (P<0.05), and the eggshell strength of 3.00% and 3.50% Ca groups was significantly higher than that of 2.50% Ca group (P<0.05); the eggshell strength of 0.40% NPP group was significantly higher than that of 0.24% and 0.32% NPP groups (P<0.05); dietary Ca and NPP levels had significant interaction effects on albumen height, Haugh unit and eggshell strength (P<0.05). 3) The intestinal trypsin activity of 3.00% Ca group was significantly higher than that of 2.50% and 3.50% Ca groups (P<0.05); the intestinal trypsin activity of 0.32% NPP group was significantly higher than that of the 0.24% and 0.40% NPP groups (P<0.05); dietary Ca and NPP levels had a significant interaction effect on intestinal trypsin activity (P<0.05). 4) The apparent utilization rates of crude protein and Ca of 3.00% Ca group were significantly higher than those of 3.50% Ca group (P<0.05), and the apparent utilization rate of phosphorus of 3.00% Ca group was significantly higher than that of 2.50% and 3.50% Ca groups (P<0.05); the apparent utilization rate of crude protein of 0.32% NPP group was significantly higher than that of 0.24% and 0.40% NPP groups (P<0.05); dietary Ca and NPP levels had significant interaction effects on the apparent utilization rates of Ca and phosphorus (P<0.05). 5) The mRNA relative expression level of CALB in eggshell gland of 3.00% and 3.50% Ca groups was significantly higher than that of 2.50% Ca group (P<0.05); the mRNA relative expression levels of OPN and CALB in eggshell gland of 0.32% and 0.40% NPP groups were significantly higher than those of 0.24% NPP group (P<0.05); dietary Ca and NPP levels had significant interaction effects on the mRNA relative expression levels of OPN and CALB in eggshell gland (P<0.05). In conclusion, the dietary appropriate Ca and NPP levels can improve the laying performance and egg quality of Langya hens during early laying period, enhance the digestive function, and increase the mRNA relative expression levels of OPN and CALB in eggshell gland. The optimal dietary Ca and NPP levels for Langya hens during early laying period are 3.00% and 0.32%, respectively.

The aim of this experiment was to investigate the effects of dietary metabolizable energy (ME) and crude protein (CP) levels on the laying performance, egg quality, serum reproductive hormone contents, follicle numbers and expression of genes [estrogen receptor 1 (ESR1), follicle stimulating hormone receptor (FSHR) and prolactin receptor (PRLR)] related to follicular development of Langya hens during early laying period. A total of 540 healthy 168-day-old Langya chickens were selected and randomly divided into 9 groups according to the principle of equal body weight and laying rate, with 5 replicates per group and 12 chickens per replicate. A 3×3 two-factor and three-level experimental design was adopted, dietary ME levels were 10.8, 11.3 and 11.8 MJ/kg, respectively, and CP levels were 14.5%, 15.5% and 16.5%, respectively. The pre-trial period was 7 days, and the formal trial period was 35 days. The results showed as follows: 1) the average daily egg mass, laying rate, egg weight, albumen height, serum reproductive hormone contents and mRNA relative expression levels of ESR1, FSHR and PRLR of 11.3 MJ/kg ME group were significantly higher than those of 10.8 and 11.8 MJ/kg ME groups (P<0.05), and the feed to egg ratio was significantly lower than that of 10.8 and 11.8 MJ/kg ME groups (P<0.05); the small yellow follicle number and big white follicle number of 11.3 and 11.8 MJ/kg ME groups were significantly higher than those of 10.8 ME group (P<0.05). 2) The average daily egg mass and laying rate of 15.5% CP group were significantly higher than those of 14.5% CP group (P<0.05), and the feed to egg ratio was significantly lower than that of 14.5% CP group (P<0.05); the eggshell thickness and eggshell strength of 16.5% CP group were significantly higher than those of 15.5% CP group (P<0.05), and the egg weight, serum reproductive hormone contents, small yellow follicle number, big white follicle number and mRNA relative expression levels of ESR1, FSHR and PRLR of 15.5% CP group were significantly higher than those of 14.5% and 16.5% CP groups (P<0.05). 3) Dietary ME and CP levels had significant interaction effects on the average daily egg mass, laying rate, feed to egg ratio, eggshell strength, egg weight, albumen height, Haugh unit, serum reproductive hormone contents, small yellow follicle number and mRNA relative expression levels of ESR1, FSHR and PRLR (P<0.05). In conclusion, the dietary appropriate ME and CP levels can improve the laying performance and egg quality of Langya hens during early laying period, promote the secretion of reproductive hormone and follicle development, up-regulate the expression of genes related to follicular development. The appropriate dietary ME and CP levels for Langya hens during early laying period are 11.3 MJ/kg and 15.5%, respectively.

This study investigated the effects of dietary methionine supplementation of meat-type breeder ducks on growth performance and intestinal health of their offspring meat ducks. Forty-eight Beijing breeder ducks (50 weeks of age) with similar egg production rate and body weight were assigned to 2 groups in a completely randomized design with 6 replicates per group and 4 birds per replicate. Breeder ducks in the control group were fed a corn-soybean meal basal diet containing 0.265% methionine, whereas those in the methionine-supplemented group were fed the basal diet supplemented with 0.18% DL-methionine (to reach a dietary methionine content of 0.445%). The trial lasted for 20 weeks, hatching eggs from weeks 18 to 20 were collected for incubation. From each group, 80 healthy ducklings with similar hatch weight were selected (10 replicates with 8 birds per replicate), fed the same methionine-adequate diet, and reared for 49 days. Growth performance, intestinal development, mRNA relative expression levels of jejunal barrier-related genes, and cecal microbial diversity were determined. The results showed as follows: 1) compared with the control group, offspring meat ducks from methionine-supplemented group had a significantly higher body weight at 1 day of age (P<0.05), and had a significantly lower feed-to-gain ratio (P<0.05). 2) Ileal length and ileal weight of offspring meat ducks from methionine-supplemented group were significantly increased (P<0.05), villus height in the duodenum and jejunum was significantly increased (P<0.05), and mRNA relative expression level of zonula occludens-1 (ZO-1) in the jejunum was significantly upregulated (P<0.05). 3) Cecal microbiota β-diversity significantly differed between the 2 groups (P<0.05). At phylum level, the relative abundance of Bacillota was significantly increased and that of Bacteroidota was significantly decreased in the methionine-supplemented group compared with control group (P<0.05). At genus level, the relative abundances of Faecalibacterium, Mediterribacter and Negativibacillus were significantly increased in the methionine-supplemented group compared with control group (P<0.05). In conclusion, dietary methionine supplementation of meat-type breeder ducks can improve growth performance, promote intestinal development, enhance intestinal barrier function, and modulates cecal microbiota composition of their offspring meat ducks.

This experiment was conducted to explore the effects of dietary supplementation of soy isoflavone (SIF) on growth performance, calcium and phosphorus metabolism, and sternal mineralization of Diaobai ducks. A total of 480 one-day-old healthy Cherry Valley meat ducks were selected and randomly divided into 6 groups, with 8 replicates in each group and 10 ducks in each replicate. Diets in each group were supplemented with 0 (basal diet, control group), 2, 4, 8, 16 and 32 mg/kg SIF, respectively. The experimental period was 52 days, divided into the free feeding stage from days 1 to 35 and the restricted feeding stage from days 36 to 52. The results showed as follows: 1) from days 36 to 52, compared with the control group, the average daily gain in 4, 8 and 16 mg/kg SIF supplementation groups was significantly increased (P<0.05), and the feed-to-gain ratio in 4 and 8 mg/kg SIF supplementation groups was significantly decreased (P<0.05). 2) Compared with the control group, the serum alkaline phosphatase (ALP) activity and phosphorus content in 8 mg/kg SIF supplementation group were significantly increased (P<0.05), and the serum calcium content in 4 and 8 mg/kg SIF supplementation groups was significantly increased (P<0.05). 3) Compared with the control group, the sternal calcium content in 2, 4, 8 and 16 mg/kg SIF supplementation groups was significantly increased (P<0.05), and the sternal calcification ratio in each SIF supplementation group was significantly increased (P<0.05). 4) Compared with the control group, the transient receptor potential cation channel subfamily V member 6 (TRPV6) mRNA relative expression level in duodenal mucosa in 4 and 8 mg/kg SIF supplementation groups was significantly increased (P<0.05), the ALP mRNA relative expression level in sternum in 4, 8 and 16 mg/kg SIF supplementation groups was significantly increased (P<0.05), and the estrogen receptor 1 (ESR1) mRNA relative expression level in sternum in 8 mg/kg SIF supplementation group was significantly increased (P<0.05). In conclusion, dietary supplementation of 4 to 8 mg/kg SIF can enhance the growth performance and promote the sternal mineralization of Diaobai ducks.

This study aimed to elucidate the role and molecular mechanisms of ferroptosis in liver injury of laying ducks with fatty liver syndrome (FLS). A total of 48 laying ducks with similar body weight were randomly selected from a flock of 700-day-old Longyan Shanma ducks raised under identical nutritional, environmental and management conditions from the same batch for slaughter and sample collection. The ducks were grouped according to liver anatomical observation and lesion scoring criteria. Six ducks with typical fatty liver lesions (hepatomegaly, hemorrhage and clay-yellow coloration) were assigned to the FL group, and six healthy ducks with normal red and smooth liver appearance were assigned to the control (NL) group. The results showed as follows: 1) compared with the NL group, the FL group exhibited a highly significant increase in percentage area of vacuoles in liver tissue (P<0.01), obvious lipid droplet accumulation, and ultrastructural changes characteristic of ferroptosis, including mitochondrial cristae shrinkage. 2) Compared with the NL group, the FL group showed significantly increased contents of total cholesterol (TC), triglycerides (TG), malondialdehyde (MDA), as well as the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (P<0.05), while glutathione (GSH) content, glutathione peroxidase (GSH-Px) activity, and total antioxidant capacity (T-AOC) of the FL group were significantly decreased (P<0.05). 3) Compared with the NL group, the FL group showed significantly or highly significantly increased contents of liver interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-12 (IL-12) and transforming growth factor-β (TGF-β) (P<0.05 or P<0.01). The contents of total iron ions, ferric iron ions (Fe³⁺) and ferrous iron ions (Fe²⁺) in the liver were highly significantly increased (P<0.01). 4) At the molecular level, compared with the NL group, the FL group showed highly significant downregulation of the mRNA relative expression levels of glutathione peroxidase 4 (GPX4), ferritin heavy chain (FTH1) and solute carrier family 7 member 11 (SLC7A11) (P<0.01), while the mRNA relative expression levels of acyl-CoA synthetase long-chain family member 4 (ACSL4) and transferrin receptor 1 (TFRC) were significantly or highly significantly upregulated (P<0.05 or P<0.01). In conclusion, FLS in laying ducks is accompanied by significant iron metabolism disorders and an imbalance in the antioxidant system. The liver tissue exhibits typical characteristics of ferroptosis, suggesting that ferroptosis is closely associated with hepatocyte injury in FLS and may be one of the important mechanisms mediating pathological liver damage.

This experiment was conducted to explore the effects of dietary supplementation of soy isoflavone (SIF) on performance, egg quality and serum biochemical and antioxidant indices of breeding geese. Six hundred healthy Yangzhou breeding geese at 44 weeks of age with similar laying rate were selected and randomly divided into 5 groups at a male to female ratio of 1∶4, with 6 replicates in each group and 20 geese in each replicate. The dietary supplementation levels of SIF in each group were 0 (basal diet, control group), 50 (S50 group), 100 (S100 group), 150 (S150 group) and 200 mg/kg (S200 group), respectively. The pre-trial period was 1 week, and the formal trial period was 13 weeks. The results showed as follows: 1) compared with the control group, the laying rate in S150 group was significantly increased (P<0.05). 2) Compared with the control group, the albumen height and yolk ratio in S50 group were significantly increased (P<0.05), and the yolk weight and yolk ratio in S150 group and S200 group were significantly increased (P<0.05). 3) Compared with the control group, the serum contents of total protein and albumin in S150 group were significantly increased (P<0.05). 4) Compared with the control group, the serum superoxide dismutase activity in S150 group was significantly increased (P<0.05), while the serum malondialdehyde content in S100 group, S150 group and S200 group was significantly decreased (P<0.05). In conclusion, under the conditions of this experiment, dietary supplementation of 150 mg/kg SIF can increase the laying rate of breeding geese, improve the egg quality and protein metabolism, and enhance the antioxidant capacity of the body.

This study aimed to investigate the effects of dietary different levels of tryptophan on performance, serum biochemical and reproductive hormone indexes and liver antioxidant indexes of breeding geese during laying period. A total of 150 thirty-three-week-old Wulong breeding geese were randomly divided into 5 groups with 6 replicates per group and 5 geese per replicate (one male and four females). The dietary tryptophan levels of 5 groups were 0.14% (control group), 0.19%, 0.24%, 0.29% and 0.34%, respectively. The pre-experimental period lasted for 1 week, and the experimental period lasted for 16 weeks. The results showed as follows: 1) compared with the control group, the average egg weight of 0.24% group was significant increased (P<0.05), and the average daily feed intake (ADFI) and feed to egg ratio of 0.19%, 0.24%, 0.29% and 0.34% groups were significant decreased (P<0.05). 2) Compared with the control group, the serum urea nitrogen (UN) and uric acid (UA) contents of 0.29% and 0.34% groups were significant decreased (P<0.05), the serum total cholesterol (T-CHO) content of 0.29% and 0.34% groups was significant increased (P<0.05), the serum high-density lipoprotein cholesterol (HDL-C) content of 0.29% and 0.34% groups was significant increased (P<0.05), and the serum low-density lipoprotein cholesterol (LDL-C) content of 0.29% group was significant increased (P<0.05). 3) Compared with the control group, the serum follicle-stimulating hormone (FSH) content of 0.24%, 0.29% and 0.34% groups was significant increased (P<0.05), and the serum prolactin (PRL) content of 0.34% group was significant decreased (P<0.05). 4) Compared with the control group, the liver total antioxidant capacity (T-AOC) of 0.24% and 0.29% groups was significant increased (P<0.05), the liver total superoxide dismutase (T-SOD) activity of 0.29% group was significant increased (P<0.05), and the liver malondialdehyde (MDA) content of 0.34% group was significant decreased (P<0.05). In summary, dietary tryptophan can reduce the feed-to-egg ratio, regulate the protein and lipid metabolism, modulate the reproductive hormone content, enhance the body antioxidant capacity, thereby promote the egg production and maintain body health. Under the experimental conditions, the optimal tryptophan level in the diet of laying geese is 0.24% to 0.34%.

This experiment was conducted to investigate the effects of Allium mongolicum Regel ethanol extract (AEE) on amino acid profile, nutritional and flavor quality of milk. A total of 12 healthy multiparous Chinese Holstein cows with similar days in milk [(123±9) d], body weight [(605.9±11.3) kg] and milk performance were selected and randomly divided into 2 groups with 6 replicates per group and 1 cow per replicate. Cows in the control group were fed a basal diet, while those in the AEE group were fed the basal diet supplemented with 54 g/d AEE. The trial lasted for 56 d, including a 14-d preliminary period and a 42-d formal period. The results showed that compared with the control group: 1) the content of total free amino acid (FAA) in milk was significantly increased in the AEE group (P<0.05), whereas no significant differences were observed in milk yield, milk protein content and total hydrolyzed amino acid (HAA) content (P>0.05); 2) for milk HAA, the content of leucine and its amino acid score were significantly elevated in the AEE group (P<0.05), and the contents of methionine and total sulfur-containing amino acids showed an increasing trend (0.05≤P<0.10); 3) the content of glutamic acid in milk FAA was significantly higher in the AEE group (P<0.05), along with notably increased content and proportion of umami amino acids in FAA (P<0.05). In conclusion, supplementation with 54 g/d AEE can optimize milk protein quality by increasing the contents and scores of partial essential amino acids without altering milk yield and milk protein content. Meanwhile, AEE exerts positive regulatory effects on the flavor and nutritional quality of milk via raising the total FAA content as well as the content and proportion of umami amino acids.

This study aimed to investigate the effects of Bacillus subtilis (BS) on performance, serum indices and rumen fermentation parameters of lactating dairy cows. Forty healthy Holstein dairy cows with similar lactation days, parity and milk yield were randomly divided into two groups with 20 cows in each group. Cows in the control group were fed a basal diet, while those in the experimental group were fed the basal diet supplemented with 10 g/(head·d) of BS (with viable count of 2×10⁸ CFU/g). The pre-feeding period lasted for 7 days, and the formal feeding period for 60 days. The results showed as follows: 1) compared with the control group, the milk yield, milk production efficiency, serum glucose (GLU) and urea nitrogen (UN) contents of dairy cows in the experimental group were extremely significantly increased (P<0.01) on day 30, and the serum total protein (TP) content was significantly increased (P<0.05); on day 60, the milk yield, milk production efficiency, serum immunoglobulin A (IgA) and immunoglobulin G (IgG) contents, as well as rumen fluid butyrate, isobutyrate and valerate contents were extremely significantly increased (P<0.01), while the rumen fluid total volatile fatty acids (TVFA) content, serum total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity were significantly increased (P<0.05); the apparent digestibility of ether extract (EE) was significantly increased on days 58 to 60 (P<0.05). 2) Compared with the control group, the serum interleukin-1β (IL-1β) content of dairy cows in the experimental group was significantly decreased (P<0.05) on day 30; on day 60, the milk urea nitrogen content and serum albumin (ALB) content were extremely significantly decreased (P<0.01), and the serum tumor necrosis factor-α (TNF-α) and lipopolysaccharide (LPS) contents were significantly decreased (P<0.05). In conclusion, dietary supplementation with 10 g/(head·d) of BS can increase the milk yield of lactating dairy cows, improve rumen fermentation function, and optimize serum immune function and antioxidant capacity to varying degrees.

This experiment aimed to investigate the effects of dietary rumen-protected glucose (RPG) supplementation on slaughter performance, meat quality, muscle glycolysis and metabolites of yaks under transportation stress. A total of 18 healthy male yaks aged 2 to 3 years with similar body weight [(166.5±9.7) kg] were randomly divided into 2 groups with 9 replicates per group and 1 yak per replicate. Yaks in the conventional transport group (CT group) were fed a basal diet, while those in the RPG group were fed the basal diet supplemented with 1% RPG for 7 days. After the feeding period, all yaks were transported by road for 600 km (approximately 8 h) and slaughtered uniformly. The results showed that after transportation, compared with the CT group: 1) the RPG group had a significantly lower plasma malondialdehyde concentration (P<0.05) and a tendency for lower plasma cortisol concentration (P=0.073), but no significant changes in slaughter performance were observed (P>0.05); 2) the RPG group showed significantly lower pH_{45 min} and pH_{24 h} as well as lactic acid concentration in longissimus dorsi (P<0.05), and significantly higher activities of pyruvate kinase, hexokinase and fructose-6-phosphate kinase, as well as higher concentrations of glycogen and glucose-6-phosphate, and higher glycolytic potential in longissimus dorsi (P<0.05); 3) the RPG group had a significantly higher intramuscular fat content in longissimus dorsi (P<0.05), and optimized the fatty acid composition of the longissimus dorsi by significantly decreasing C18∶1n9t content and significantly increasing C18∶3n3 content (P<0.05); 4) in the RPG group, 24 metabolites such as phosphatidylcholine [15∶0/18∶1(11Z)] and phosphatidylcholine [18∶1(9Z)/15∶0] were significantly up-regulated (P<0.05), while 18 metabolites including 3-hydroxytridecanoyl carnitine were significantly down-regulated (P<0.05). The differential metabolites were mainly enriched in pathways such as reverse endocannabinoid signaling and linoleic acid metabolism. In conclusion, dietary supplementation with 1% RPG before transport can effectively alleviate transportation stress in yaks, regulate key indices of muscle glycolysis, optimize muscle fatty acid composition and lipid metabolism characteristics, thereby improving yak meat quality and nutritional properties.

To investigate the effects of supplemental feeding of concentrate supplement during suckling period on the growth performance, blood indexes and rumen metabolic function of grazing yak calves, fourteen healthy male yak calves with similar body weight [(36.55±1.89) kg] were selected and randomly divided into two groups (seven calves per group, n=7). The control group was fed milk replacer+grazing, while the supplemental feeding group was fed milk replacer+grazing+supplemental feeding of concentrate supplement. The preliminary feeding period lasted for 12 days, and the formal experimental period lasted for 60 days. Prior to the experiment, all calves were suckling with their mothers for (80±7) days. At the beginning of the preliminary feeding period, the calves were separated from their mothers to achieve weaning. The calves were weighed on an empty stomach and randomly assigned to groups, and then milk replacer (milk replacer∶warm water =1∶5) was used to replace maternal milk. During the formal experimental period, the calves were fed milk replacer twice daily (07:00—08:30 and 17:30—18:30). Calves in the supplemental feeding group were fed concentrate supplement once daily at 07:00—08:30. At other times, all calves grazed in natural pasture. The daily feeding amount of milk replacer (on a dry matter basis) was 1.2% of the calf’s body weight, and the daily supplemental feeding amount of concentrate supplement was 2.5% of the calf’s body weight. A single bucket was used for feeding, and the feeding amount was adjusted every 15 days based on body weight gain. The results showed as follows: 1) the final body weight, net weight gain and average daily gain in the supplemental feeding group were extremely significantly higher than those in the control group (P<0.01), and the chest circumference was significantly higher than that in the control group (P<0.05). 2) The serum contents of immunoglobulin A and insulin-like growth factor-Ⅰ in the supplemental feeding group were extremely significantly higher than those in the control group (P<0.01), and the serum contents of blood urea nitrogen, interleukin-2, and insulin were significantly higher than those in the control group (P<0.05). 3) In the rumen, the ammonia nitrogen concentration in the supplemental feeding group was extremely significantly higher than that in the control group (P<0.01), the propionic acid concentration was significantly higher than that in the control group (P<0.05), and the protease activity was extremely significantly higher than that in the control group (P<0.01). 4) 16S rRNA sequencing analysis of rumen microbiota showed that, at the phylum level, the dominant phyla in both groups were Bacteroidota, Firmicutes and Proteobacteria, and the relative abundance of Firmicutes in the supplemental feeding group was significantly higher than that in the control group (P<0.05); at the genus level, the dominant genera were Prevotella, unclassified_F082 and Rikenellaceae_RC9_gut_group, etc., and the relative abundance of Muribaculaceae in the supplemental feeding group was extremely significantly higher than that in the control group (P<0.01). 5) Rumen metabolomics analysis showed that there were 857 differential metabolites between the supplemental feeding group and the control group. KEGG pathway enrichment analysis revealed that the differential metabolites were mainly enriched in pathways such as arginine and proline metabolism, riboflavin metabolism, and protein digestion and absorption. In conclusion, under grazing conditions, supplemental feeding of concentrate supplement to suckling yak calves can improve their growth performance, increase the contents of immune factors in the blood, enhance rumen metabolic function, and ultimately promote the growth and development of yak calves.

This study aimed to investigate differences in rumen microbial community composition and function in Simmental (♀) × Belgian Blue (♂) crossbred beef cattle at 6 and 12 months of age. Eight 6-month-old Simmental (♀) × Belgian Blue (♂) male crossbred cattle were randomly selected and housed until 12 months of age. Body weight and body measurements were recorded, and rumen fluid samples were collected at 6 and 12 months of age for metagenomic sequencing analysis. The results showed as follows: 1) α-diversity analysis revealed that Shannon index and Simpson index of crossbred beef cattle at 12 months of age were significantly higher than those at 6 months of age (P<0.05), while β-diversity analysis showed no distinct separation of ruminal microbiota between 6 and 12 months of age. 2) At the genus level, the characteristic ruminal microorganisms of 6-month-old crossbred beef cattle were Prevotella, Hallella and Bacteroides, while those of 12-month-old crossbred beef cattle were Methanobrevibacter, Mycoplasma and Hungatella. 3) Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the ruminal microbial functions of 6-month-old crossbred beef cattle were mainly associated with amino sugar and nucleotide sugar metabolism, phenylalanine tyrosine and tryptophan biosynthesis, and arginine and proline metabolism; whereas those of 12-month-old crossbred beef cattle were mainly associated with ribosome, aminoacyl-tRNA biosynthesis, and methane metabolism. 4) Carbohydrate-Active Enzymes (CAZy) functional annotation analysis revealed that glycoside hydrolases (GHs) were the predominant carbohydrate-active enzymes in ruminal microbiota at both 6 and 12 months of age, but the relative abundances of specific GH families differed. In conclusion, as crossbred beef cattle grow and develop, the ruminal microbiota becomes more mature and stable, and the ruminal microbial functions gradually shift from self-synthetic metabolism and energy supply to precise regulation of protein. These findings provide theoretical support for implementing stage-specific precision nutrition and management in crossbred beef cattle.

This experiment was conducted to investigate the effects of Sophora flavescens extract on growth performance, immune function and antioxidant capacity of fattening sheep. A total of 75 healthy 3-month-old Hu male lambs with an average body weight of (28.25±2.17) kg were randomly divided into 5 groups, with 3 replicates per group and 5 lambs per replicate. Lambs in group A were fed a basal diet, those in group B were fed the basal diet supplemented with 2 g/(head·d) chlortetracycline, and those in groups C, D and E were fed the basal diets supplemented with 0.25, 0.50 and 0.75 g/(head·d) Sophora flavescens extract, respectively. The experimental period lasted 72 days. The results showed as follows: 1) during days 1 to 72 of the experiment, compared with group A, the average daily gain (ADG) and average daily feed intake (ADFI) in groups B, C and D were extremely significantly increased (P<0.01), and the feed/gain ratio (F/G) in groups C, D and E was significantly decreased (P<0.05); the apparent digestibility of various nutrients in groups C and D was extremely significantly increased (P<0.01). 2) On day 36 of the experiment, compared with group A, the serum immunoglobulin A (IgA) content in groups B, C and D was extremely significantly increased (P<0.01), and the serum immunoglobulin G (IgG) and immunoglobulin M (IgM) contents in group D were significantly increased (P<0.05); the serum interleukin-2 (IL-2) content in groups C, D and E was extremely significantly increased (P<0.01), and the serum tumor necrosis factor-α (TNF-α) content in group C was significantly decreased (P<0.05). On day 72 of the experiment, compared with group A, the serum IgA content in groups B, C, D and E was extremely significantly increased (P<0.01), and the serum IgM content in group C was significantly increased (P<0.05); the serum TNF-α content in group E was extremely significantly lower than that in groups A and B (P<0.01). 3) On days 36 and 72 of the experiment, compared with groups A and B, the serum total antioxidant capacity (T-AOC) in group D was extremely significantly increased (P<0.01); compared with group A, the activities of serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in groups C and D were extremely significantly increased (P<0.01). 4) On day 36 of the experiment, compared with group A, the serum albumin (ALB) content in groups C, D and E was significantly increased (P<0.05); the serum total protein (TP) content in groups D and E was extremely significantly increased (P<0.01), and the serum urea nitrogen (UN) content was extremely significantly decreased (P<0.01). On day 72 of the experiment, compared with group A, the serum ALB content in groups B and D was significantly increased (P<0.05), and the serum UN content in group C was extremely significantly decreased (P<0.01). In conclusion, dietary supplementation with an appropriate dose of Sophora flavescens extract can promote the growth and development, improve immune function and antioxidant capacity, and regulate protein and lipid metabolism of fattening sheep. Under the conditions of this experiment, the optimal supplemental dose of Sophora flavescens extract for fattening sheep is 0.50 g/(head·d).

This study aimed to investigate the effects of high moisture corn on production performance, nutrient apparent digestibility, serum biochemical indices and intestinal metabolism of Kazakh rams. Twenty-four healthy Kazakh rams at approximately 6 months of age with similar body weight [(35.47±1.46) kg] were randomly divided into 2 groups with 12 rams per group. The control group was fed an basal diet, and the experimental group was fed a experimental diet which the common corn in the basal diet was replaced with 50% high moisture corn in equal amounts on dry matter basis. The pre-experimental period lasted for 7 days, and the formal experimental period lasted for 120 days. The results showed as follows: 1) the feed to gain ratio of the experimental group was significantly lower than that of the control group (P<0.05). Compared with the control group, the final body weight, average daily gain, average daily feed intake, carcass weight and slaughter rate of the experimental group were increased by 4.569%, 8.458%, 6.443%, 8.023% and 3.308%, respectively (P>0.05). 2) Compared with the control group, the apparent digestibility of crude protein, ether extract, neutral detergent fiber, acid detergent fiber and crude ash of the experimental group were increased by 7.745%, 8.231%, 5.548%, 6.246% and 7.782%, respectively (P>0.05). 3) On days 40 and 120, the serum urea nitrogen (UN) content of the experimental group was extremely significantly lower than that of the control group (P<0.01). 4) The intestinal non-targeted metabolomics analysis identified 54 differential metabolites in 2 groups, including 25 up-regulated and 29 down-regulated metabolites. The KEGG pathway enrichment analysis indicated that the differential metabolites were significantly enriched in key pathways such as purine metabolism, alanine, aspartate and glutamate metabolism, glycine, serine and threonine metabolism, and nitrogen metabolism (P<0.05). In conclusion, the high moisture corn regulates the intestinal purine and amino acid metabolism of Kazakh rams, optimizes nitrogen utilization efficiency, promotes protein synthesis in the body, thereby increasing feed conversion rate and promoting protein metabolism in the body.

This experiment was conducted to explore the effects of grape seed proanthocyanidins on growth performance,liver antioxidant indices and metabolome of Tan sheep. A total of 40 healthy 3-month-old male Tan sheep with similar body weight of (25.22±2.26) kg were randomly divided into four groups with 10 replicates per group and one sheep per replicate. Sheep in the control group (NC group) were fed a basal diet, and those in experimental groups were fed the basal diets supplemented with 0.3% (LD group), 0.6% (MD group) and 1.2% (HD group) grape seed proanthocyanidins, respectively. The trial lasted for 70 days including a 10-day preliminary trial period and a 60-day formal trial period. The results showed as follows: 1) compared with the NC group, the final body weight of the LD group was extremely significantly decreased (P<0.01), the average daily gain (ADG) was significantly decreased (P<0.05), and the feed/gain ratio (F/G) was extremely significantly increased (P<0.01); no significant changes were observed in final body weight, ADG or F/G in the MD and HD groups (P>0.05). 2) Compared with the NC group, the apparent digestibility of crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) in all experimental groups were significantly or extremely significantly decreased (P<0.05 or P<0.01). 3) Compared with the NC group, the serum aspartate aminotransferase (AST) activity of the LD group was significantly increased (P<0.05), and the liver alkaline phosphatase (ALP) activity was extremely significantly decreased (P<0.01); the liver alanine aminotransferase (ALT) activity of the MD group was extremely significantly decreased (P<0.01); the liver ALT and AST activities of the HD group were extremely significantly decreased (P<0.01). 4) The liver catalase (CAT) activity of the HD group was extremely significantly higher than that of the NC and LD groups (P<0.01). 5) Compared with the NC group, the hepatic differential metabolites in the three experimental groups were mainly glycerophospholipids. Among them, 1,2-tetracosanoyl-sn-glycero-3-phosphocholine and menadione were common differential metabolites across all groups. KEGG pathway enrichment analysis showed that differential metabolites were significantly enriched in pathways such as alpha-linolenic acid metabolism, arachidonic acid metabolism, and choline metabolism in cancer. In conclusion, dietary supplementation with 0.3% grape seed proanthocyanidins reduces the growth performance of housed fattening Tan sheep. When the supplementation dosage is increased to 0.6% and 1.2%, it can enhance the liver antioxidant capacity and improve liver function in Tan sheep. Grape seed proanthocyanidins may regulate liver antioxidant capacity and liver function through pathways including alpha-linolenic acid metabolism, arachidonic acid metabolism, choline metabolism, and key differential metabolites such as 1,2-tetracosanoyl-sn-glycero-3-phosphocholine and menadione.

This experiment was conducted to investigate the effects of supplemental β-hydroxy-β-methylbutyrate calcium (HMB-Ca) at different levels on lactation performance and serum indexes of lactating mares. Eighteen healthy lactating Yili mares (30 days postpartum, with similar parity and body weight) were selected and randomly divided into three groups (six mares per group, n=6). Based on grazing, mares in the control group were supplemented with 500 g of concentrated supplement per head per day. Mares in the test groups Ⅰ and Ⅱ were supplemented with 10 and 20 g of HMB-Ca per head per day, respectively, in addition to 500 g of concentrated supplement. The preliminary feeding period lasted for 7 days, and the formal experimental period lasted for 60 days. The results showed as follows: 1) compared with the control group, on day 30, the milk yield of both test groups Ⅰ and Ⅱ was extremely significantly increased (P<0.01); moreover, HMB-Ca supplementation alleviated the declining trend of milk yield as lactation progressed. 2) On day 60, the casein content in the milk of experimental group Ⅰ was significantly higher than that of the control group (P<0.05); moreover, HMB-Ca supplementation delayed the continuous decline in milk protein percentage, total solids and casein contents in mare milk as lactation progressed. 3) On day 60, the serum contents of glucose, triglyceride and total bilirubin in test groups Ⅰ and Ⅱ were significantly lower than those in the control group (P<0.05), while the serum urea nitrogen content was significantly higher than that in the control group (P<0.05); the serum total protein content in test group Ⅰ was significantly higher than that in the control group (P<0.05). 4) On day 60, the serum superoxide dismutase activity and total antioxidant capacity in test groups Ⅰ and Ⅱ were significantly higher than those in the control group (P<0.05). 5) On day 30, the serum contents of immunoglobulin A, immunoglobulin G and immunoglobulin M in test group Ⅱ were significantly higher than those in the control group (P<0.05). 6) On day 60, the serum estradiol content in test group Ⅰ was significantly higher than that in the control group and test group Ⅱ (P<0.05). In conclusion, under the conditions of this experiment, HMB-Ca supplementation can effectively increase the milk yield of lactating mares, enhance the body’s antioxidant capacity and immune function, and regulate hormone secretion. Based on comprehensive evaluation of various indicators, the appropriate supplemental dose of HMB-Ca for lactating mares is 10 g/(head·d).

This experiment was conducted to study the effects of high cottonseed meal diet adding Lactobacillus casei on the growth performance, serum immune indices, liver antioxidant indices, intestinal histological structure and gene expression of grass carp (Ctenopharyngodon idella). A total of 360 grass carp with initial weight of (28.29±0.04) g were randomly divided into 3 groups with 3 replicates per group and 40 fish per replicate. The control group (CON group) was fed an experimental diet which used fish meal and soy protein concentrate as the main protein sources, the cottonseed meal group (CM group) was fed an experimental diet which used cottonseed meal completely replaced soy protein concentrate, and the Lactobacillus casei group (LC group) fed the experimental diet of CM group supplemented with 1×10⁸ CFU/g Lactobacillus casei. Diets in 3 groups were isonitrogenous and isolipidic (crude protein level was about 28%, crude fat level was about 6%). The experimental period was 8 weeks. The results showed as follows: 1) compared with the CON group, the weight gain rate and specific growth rate of CM group were significantly decreased (P<0.05), and feed conversion rate was significantly increased (P<0.05); the weight gain rate, specific growth rate and feed conversion rate were not significant (P>0.05). 2) Compared with the CON group, the serum complement 3 (C3), complement 4 (C4), immunoglobulin M (IgM) contents and lysozyme (LZM) activity of CM group were significantly decreased (P<0.05); compared with the CM group, the serum C3, IgM contents and LZM activity of LC group were significantly increased (P<0.05). 3) Compared with the CON group, the liver superoxide dismutase (SOD) activity and total antioxidant capacity (T-AOC) of CM group and LC group were significantly increased (P<0.05). 4) Compared with the CON group, the intestinal villi in grass carp of CM group were damage, the apoptosis and inflammation related gene expressions were up-regulated, the tight junction protein gene expressions were down-regulated, inducing intestinal inflammation; compared with the CM group, the integrity of intestinal barrier in grass carp of LC group was restored, relieving intestinal inflammation. 5) Compared with the CM group, the relative abundances of Bacilli and Lactobacillus in intestine of LC group were significantly increased (P<0.05). Overall, dietary Lactobacillus casei alleviates the detrimental effects on growth performance, immune function, antioxidant capacity and intestinal health of grass carp by high cottonseed meal diet.

This experiment aimed to investigate the effects of a high-sugar diet and chronic hypoxic stress on the growth performance, liver histomorphology and antioxidant capacity of largemouth bass (Micropterus salmoides). A 2×2 two-factor randomized crossover experimental design was employed. The two factors were dietary sugar level (normal-sugar diet: digestible sugar level was 10%; high-sugar diet: digestible sugar level was 15%) and water dissolved oxygen (DO) concentration [normoxic water: DO concentration was (7.0±0.5) mg/L; hypoxic water: DO concentration was (3.0±0.5) mg/L]. A total of 240 juvenile largemouth bass with an initial average body weight of (11.50±0.03) g were randomly assigned to four groups. Each group had three replicates (aquariums), with 20 fish per aquarium. The feeding trial lasted for 8 weeks. The results showed as follows: 1) chronic hypoxic stress significantly reduced final body weight, weight gain rate, feed intake and specific growth rate (P<0.05). 2) Dietary sugar level significantly affected whole-body crude protein, ether extract and crude ash contents, as well as the hepatosomatic index and viscerosomatic index (P<0.05). Water DO concentration significantly affected whole-body moisture, crude protein and ether extract contents, as well as the viscerosomatic index (P<0.05). 3) Largemouth bass fed the high-sugar diet exhibited hepatocyte swelling, nuclear displacement, and pronounced vacuolation. 4) The interaction between dietary sugar level and water DO concentration significantly affected liver triglyceride content, as well as serum triglyceride and high-density lipoprotein cholesterol contents (P<0.05). 5) The interaction between dietary sugar level and water DO concentration significantly affected liver total antioxidant capacity, as well as the activities of peroxidase, superoxide dismutase and glutathione peroxidase (P<0.05). Therefore, chronic hypoxic stress reduces the growth performance of largemouth bass, impairs nutrient absorption and deposition, and induces oxidative stress. High-sugar diet leads to hepatic lipid accumulation and oxidative stress in largemouth bass, thereby compromising liver health. Compared with a single stressor, the combination of high-sugar diet and chronic hypoxic stress may exert a synergistic effect, exacerbating the negative impacts on largemouth bass.

This study investigated the effects and mechanisms of Artemisia annua (A. annua) on the growth performance of growth-retarded Japanese eels (Anguilla japonica) using network pharmacology and untargeted metabolomics. A total of 450 growth-retarded eels with an initial body weight of (27.82±0.04) g were randomly allocated into 18 net cages (25 fish/cage), with every 3 cages serving as one group (totaling 6 groups). The groups were fed experimental diets containing 0 (AA0 group, control group), 5 (AA5 group), 10 (AA10 group), 15 (AA15 group), 20 (AA20 group), and 25 g/kg (AA25 group) A. annua for 76 days. The results showed that compared with the AA0 group, all A. annua-supplemented groups (AA5, AA10, AA15, AA20, and AA25 groups) exhibited significantly increased weight gain rate (WGR) and specific growth rate (SGR) (P<0.05), along with a significant reduced feed conversion ratio (FCR) (P<0.05). Compared with AA0 group, muscle lipid content significantly increased in the AA5, AA15, AA20, and AA25 groups (P<0.05), while muscle protein content was significantly decreased in the AA10 and AA20 groups (P<0.05). Moderate A. annua supplementation significantly enhanced foregut trypsin (AA15 and AA20 groups) and α-amylase activities (AA5, AA10, and AA15 groups) compared with the AA0 group (P<0.05). Concurrently, intestinal plica height significantly increased in the AA10, AA15, AA20, and AA25 groups (P<0.05), while plica width significantly increased in the AA15, AA20, and AA25 groups compared with the AA0 group (P<0.05). Network pharmacology analysis identified 213 overlapping targets related to both the active components of A. annua and growth retardation, with key potential regulatory targets including B-cell lymphoma 2-related protein A (BCL2A), Src tyrosine kinase (SRC), epidermal growth factor receptor A (EGFRA), protein tyrosine kinase 2ab (PTK2AB), phosphoinositide-3-kinase catalytic subunit alpha (PIK3CA), and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1). Metabolomic analysis revealed 177 potential active components from A. annua absorbed by the liver. Compared with AA0 group, 109 and 187 differentially expressed metabolites were identified in the AA10 and AA25 groups, respectively, potentially modulating bile secretion and steroid biosynthesis pathways. The above results demonstrate that A. annua promotes the growth of growth-retarded Anguilla japonica by stimulating feed intake, enhancing certain digestive enzyme activities, improving foregut morphology, and facilitating nutrient digestion and absorption, and muscle protein deposition. However, high doses may carry a risk of intestinal structural damage. The effective active components in A. annua likely exert their growth-promoting effects via multi-target regulation.

This experiment was conducted to investigate the effects of replacing fish meal with soybean meal and different proportions of enzymatically hydrolyzed soybean meal on growth performance, muscle growth and development, and meat quality of Chinese soft-shelled turtles (Pelodiscus sinensis). A total of 456 healthy Pelodiscus sinensis with uniform size and an initial body weight of (36.00±0.04) g were selected. Six turtles were randomly chosen for initial body composition analysis, and the remaining 450 turtles were randomly assigned to 5 groups with 3 replicates per group and 30 turtles per replicate. The 5 groups were fed 5 isonitrogenous and isolipidic diets (approximately 46% crude protein and 6.5% ether extract): a basal diet containing 55% fish meal (ESBM0, control), a diet in which 10 percentage points of fish meal were replaced by soybean meal (SBM10), and diets in which 5 (ESBM5), 10 (ESBM10) and 15 (ESBM15) percentage points of fish meal were replaced by enzymatically hydrolyzed soybean meal, respectively. The experiment lasted 56 days. The results showed as follows: 1) compared with the ESBM0 group, the SBM10 group exhibited significantly decreased whole-body crude protein and ether extract contents; muscle contents of glutamate, aspartate, lysine, leucine, valine, total essential amino acids and total flavor amino acids; intestinal amylase, lipase and trypsin activities; muscle catalase (CAT) activity, reduced glutathione (GSH) content and glutathione reductase activity coefficient (GRAC); muscle springiness; and the mRNA relative expression levels of muscle muscleblind-like protein 1 (MBNL1), myogenic factor 5 (MYF5) and uncoupling protein 3 (UCP3) (P<0.05). While muscle hardness, adhesiveness and gumminess, muscle fiber cross-sectional area and diameter, and the mRNA relative expression levels of muscle F-box protein 32 (FBXO32), myostatin (MSTN), UNC-51-like kinase 1 (ULK1), beclin-1 (BECN1), microtubule-associated protein 1 light chain 3 beta (MAP1LC3B) and lysosome-associated membrane protein 1 (LAMP1) in the SBM10 group were significantly increased (P<0.05). Compared with the ESBM0 group, the ESBM10 group showed significantly increased final body weight, weight gain rate, specific growth rate, protein efficiency ratio and protein deposition rate; whole-body crude protein and ether extract contents; muscle contents of glutamate, lysine, leucine, threonine, total essential amino acids and total flavor amino acids; intestinal lipase and trypsin activities; muscle CAT activity and GSH content; and the mRNA relative expression levels of muscle muscle regulatory factor 4 (MRF4), MBNL1, MYF5, UCP3, protein kinase B1 (AKT1), eukaryotic initiation factor 4E (EIF4E) and ribosomal S6 kinase 1 (S6K1) (P<0.05), whereas feed conversion ratio, muscle hardness and the muscle LAMP1 mRNA relative expression level were significantly decreased (P<0.05). 2) Compared with the ESBM10 group, both ESBM5 and ESBM15 groups had significantly decreased whole-body ether extract content, muscle contents of aspartate, lysine, threonine and total essential amino acids, intestinal lipase activity, and the muscle mRNA relative expression levels of MRF4, MBNL1, AKT1 and EIF4E (P<0.05), whereas muscle hardness and the muscle mRNA relative expression levels of MSTN, BECN1 and MAP1LC3B were significantly increased (P<0.05). The ESBM5 group significantly decreased whole-body crude protein content, muscle CAT activity, GSH content and muscle fiber density (P<0.05). The ESBM15 group significantly decreased final body weight, weight gain rate, specific growth rate, protein efficiency ratio and protein deposition rate (P<0.05), and significantly increased feed conversion ratio (P<0.05). In conclusion, under the present experimental conditions, replacing fish meal with enzymatically hydrolyzed soybean meal at levels not exceeding 15 percentage points promotes growth, enhances muscle growth and development, and improves meat quality of Pelodiscus sinensis, with the optimal replacement level being 10 percentage points.

This experiment aimed to investigate the effects of different conditioning temperatures of diets using aged paddy for substituting corn on growth performance, nutrient apparent digestibility and antioxidant capacity of meat rabbits. A total of 288 healthy New Zealand white rabbits aged 35 days with a similar body weight of (702.65±59.17) g were selected and randomly divided into 4 groups, with 18 replicates in each group and 4 rabbits in each replicate. The control group (C80 group) was fed a corn-based diet, and the conditioning temperature was 80 ℃; the experimental groups were fed the aged paddy-based diets that completely replaced corn with aged paddy, and the conditioning temperatures were set at 70 (APR70 group), 80 (APR80 group), and 90 ℃ (APR90 group), respectively. The experiment lasted for 42 days. The results showed as follows: 1) compared with C80 group, there were no significant differences in the average daily feed intake, average daily gain (ADG), and feed to gain ratio of meat rabbits in APR70 group and APR80 group (P>0.05), and the mortality in APR80 group was decreased by 44.48% (P>0.05); the ADG in APR90 group was significantly decreased (P<0.05). Compared with APR90 group, the ADG in APR70 group and APR80 group was significantly increased (P<0.05), and the mortality in APR80 group was decreased by 58.37% (P>0.05). 2) Compared with C80 group, the apparent digestibility of dry matter, crude protein (CP), neutral detergent fiber, acid detergent fiber, acid detergent lignin (ADL), and calcium in APR80 group was significantly increased (P<0.05). Compared with APR70 group, the apparent digestibility of ADL and calcium in APR80 group was significantly increased (P<0.05). Compared with APR90 group, the apparent digestibility of CP, ADL and calcium in APR80 group was significantly increased (P<0.05). 3) Compared with C80 group, there were no significant differences in the total antioxidant capacity, activities of total superoxide dismutase (T-SOD) and glutathione peroxidase, and malondialdehyde content in serum, liver, duodenum, jejunum and ileum in APR80 group (P>0.05). Compared with APR70 group, the serum T-SOD activity in APR80 group and APR90 group was significantly increased (P<0.05). In conclusion, the complete replacement of corn with aged paddy in diet has no negative effects on growth performance, apparent nutrient digestibility and antioxidant capacity of meat rabbits. It is recommended that the suitable conditioning temperature for the aged paddy-based diet of meat rabbits be 80 ℃.

This study employed metagenomics to analyze the differences in composition and function of cecal microbiota of fattening meat rabbits, aiming to investigate the effects of dietary supplementation with different proportions of millet bran on the growth performance and nutrient apparent digestibility of meat rabbits. A total of 320 weaned Ira meat rabbits at 35 days of age with similar body weight were selected and randomly divided into 4 groups, with 80 replicates in each group (half male and half female), and 1 rabbit in each replicate. The control group was fed a basal diet (without millet bran supplementation), while the experimental groups were fed the experimental diets with 6% (test group Ⅰ), 12% (test group Ⅱ), and 18% millet bran (test group Ⅲ) supplementation, respectively, and equally replaced other roughage in the basal diet. The pre-experimental period lasted for 8 days, followed by a formal experimental period of 39 days. The results showed as follows: 1) compared with the control group, the final body weight and average daily gain of meat rabbits in test group Ⅰ were significantly increased (P<0.05), and the feed to gain ratio was significantly decreased (P<0.05). 2) Compared with the control group, the apparent digestibility of crude protein, neutral detergent fiber, acid detergent fiber and crude fiber in test group Ⅰ was significantly increased (P<0.05), while the apparent digestibility of crude protein, neutral detergent fiber, acid detergent fiber, ether extract and crude fiber in test group Ⅲ was significantly decreased (P<0.05). 3) There was no significant difference in each index of cecal microbiota alpha diversity among the groups (P>0.05). 4) Compared with the control group, the relative abundances of Phocaeicola dorei, Phocaeicola, Phocaeicola sp. 002493165 and Caccovivens in cecum in test group Ⅰ were significantly increased (P<0.05), and the Eubacteriaceae relative abundance in cecum in test group Ⅲ was significantly increased (P<0.05). Compared with the test group Ⅲ, the relative abundances of Muribaculum gordoncarteri in cecum in test group Ⅰ and Agathobacter in cecum in test group Ⅱ were significantly increased (P<0.05). 5) Compared with the control group, the relative abundance of cellular processes-transport and catabolism pathway in cecal microbiota in test group Ⅰ was significantly upregulated (P<0.05). Compared with the test group Ⅲ, the relative abundances of environmental information processing, environmental information processing-signal transduction-adenosine monophosphate activated protein kinase (AMPK) signaling pathway, environmental information processing-signal transduction, and cellular processes-cell motility-flagellar assembly pathways in cecal microbiota in test group Ⅰ were significantly upregulated (P<0.05). In conclusion, dietary supplementation with 6% millet bran can enhance the growth performance and apparent nutrient digestibility of fattening meat rabbits, and maintain intestinal health by optimizing the structure of cecal microbiota and improving its function.

This experiment was conducted to explore the effects of dietary supplementation of biological proteins API (containing catfish antimicrobial peptide parasin I) and APL (containing mycelicin antimicrobial peptide plectasin) alone and in combination on growth performance, immune function and intestinal health of meat rabbits. Using a single-factor experimental design, a total of 160 healthy 35-day-old weaned New Zealand white rabbits were selected and randomly divided into 4 groups, with 10 replicates in each group and 4 rabbits in each replicate (half male and half female). The control group (CON group) was fed a basal diet, while the experimental groups were fed the basal diets supplemented with 1 000 mg/kg API (API group), 1 000 mg/kg APL (APL group), and 500 mg/kg API+500 mg/kg APL (CBP group), respectively. The experiment lasted for 35 days, and was divided into two stages: days 1 to 14 and days 15 to 35. The results showed as follows: 1) compared with CON group, the final body weight and average daily gain (ADG) from days 15 to 35 in API group and CBP group were significantly increased (P<0.05), and the feed to gain ratio from days 15 to 35 was significantly decreased (P<0.05); the ADG throughout the entire experimental period in CBP group was significantly increased (P<0.05); the health risk index (HRI, diarrhea rate+mortality) in each experimental group was significantly decreased (P<0.05). 2) Compared with CON group, the serum immunoglobulin A content in each experimental group was significantly increased (P<0.05), the serum immunoglobulin G content in APL group and CBP group was significantly increased (P<0.05), and the serum immunoglobulin M content in CBP group was significantly increased (P<0.05); meanwhile, the secretory immunoglobulin A content in ileum in API group was significantly increased (P<0.05). 3) Compared with CON group, the Claudin-1 mRNA relative expression level in ileum in APL group was significantly increased (P<0.05); the interleukin-10 (IL-10) mRNA relative expression level in duodenum, jejunum and ileum in CBP group was significantly increased (P<0.05), while the tumor necrosis factor-α (TNF-α) mRNA relative expression level in duodenum in API group was significantly decreased (P<0.05); the IL-10 mRNA relative expression level in spleen in each experimental group was significantly increased (P<0.05). 4) Compared with CON group, the total bacterial count in cecum in APL group and CBP group was significantly decreased (P<0.05), and the total volatile fatty acid content in cecum in CBP group was increased (P>0.05). In conclusion, dietary supplementation of biological proteins API and APL can increase ADG, reduce HRI, improve immune function and intestinal barrier function, and decrease the total bacterial count in cecum, thereby enhancing the growth performance and intestinal health of meat rabbits. Moreover, the combined supplementation effect is superior to that of individual supplementation.

The aim of this experiment was to investigate the effects of dietary different proportions of krill oil and krill meal on antioxidant capacity, immune regulation and intestinal health of Beagle dogs. Fifty-six 7 to 9-month-old healthy Beagle dogs with body weight of (7.20±1.09) kg were selected and randomly divided into 7 groups with 8 dogs in each group (half male and half female). The control group (group A) was fed a basal diet without krill ingredients, and the experimental groups were fed basal diets supplemented with 1.0 mL krill oil+1.0% krill meal (group B), 2.0 mL krill oil+1.0% krill meal (group C), 1.0 mL krill oil+2.0% krill meal (group D), 2.0 mL krill oil+2.0% krill meal (group E), 1.0 mL krill oil+4.0% krill meal (group G) and 2.0 mL krill oil+4.0% krill meal (group H). The pre-experimental period lasted for 7 days, and the experimental period lasted for 28 days. The results showed that compared with the control group: 1) the serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities of groups D, E, G and H were significantly increased (P<0.05); 2) the serum total protein (TP) and globulin (GLOB) contents of groups E and G were significantly increased (P<0.05); 3) the serum immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM) contents of groups E, G and H were significantly increased (P<0.05); 4) the serum interleukin-10 (IL-10) content of groups C, D, E, G and H was significantly increased (P<0.05), while the serum interleukin-1β (IL-1β) content of groups E, G and H was significantly decreased (P<0.05); 5) the serum D-lactic acid (D-LA) content of groups D and H was significantly decreased (P<0.05); 6) the fecal microbiota Simpson index of groups B, C, D, E, G and H was significantly increased (P<0.05), and the relative abundances of Lactobacillus and Bifidobacterium were increased. In summary, dietary supplemented with krill oil and krill meal can enhance the antioxidant capacity, anti-inflammatory capacity and immune function of Beagle dogs, and improve the intestinal barrier function and intestinal health. Under the conditions of this experiment, dietary 2.0 mL krill oil+2.0% krill meal, 1.0 mL krill oil+4.0% krill meal and 2.0 mL krill oil+4.0% krill meal have better effects.

This experiment was conducted to explore the effects of dietary supplementation with postbiotics on growth performance, serum indices, and fecal microbiota and metabolites of British shorthair cats. Twelve adult (4 to 5 years old) British shorthair cats in good physical condition were selected and divided into two groups according to the principle of gender and initial weight consistency, with 6 cats in each group (half male and half female). The control group was fed a basal diet, while the experimental group was fed the basal diet+0.5% postbiotics dry powder preparation. The pre-experiment was 7 days and the formal experiment was 56 days. The results showed as follows: 1) compared with the control group, there were no significant differences in the final body weight, average daily feed intake, fecal score, apparent nutrient digestibility and serum biochemical indices in the experimental group (P>0.05). 2) On day 56 of the experiment, compared with the control group, the serum interleukin-8 content in the experimental group was significantly decreased (P<0.05), and the serum catalase (CAT) activity showed an increasing trend (0.05≤P<0.10). Compared with day 1 of the experiment, the serum interleukin-6 content in the experimental group was significantly decreased on day 56 of the experiment (P<0.05), and the serum CAT activity was significantly increased (P<0.05). 3) Compared with the control group, at the phylum level, the Firmicutes relative abundance in feces in the experimental group was decreased; at the genus level, the relative abundances of Leucobacter, norank_f_Atopobiaceae, norank_f_Coriobacteriales_incertae_sedis and Parvibacter in feces in the experimental group were significantly increased (P<0.05), while the relative abundances of Peptococcus and Acinetobacter in feces were significantly decreased (P<0.05). 4) Compared with day 1 of the experiment, the fecal butyric acid content in the experimental group showed an increasing trend on day 56 of the experiment (0.05≤P<0.10), and the contents of fecal isobutyric acid and isovaleric acid were significantly increased (P<0.05). On day 56 of the experiment, compared with the control group, the fecal skatole content in the experimental group was significantly decreased (P<0.05). 5) Metabolomics analysis indicated that compared with the control group, the levels of serum protoporphyrin Ⅸ, citalopram, glycerophosphocholine and riboflavin in the experimental group were significantly upregulated (P<0.05), the levels of fecal phosphohydroxypyruvic acid and benzo[a]pyrene-7,8-diol were significantly upregulated (P<0.05), and the fecal 4-(2-aminophenyl)-2,4-dioxobutanoic acid level was significantly downregulated (P<0.05). In conclusion, dietary supplementation with 0.5% postbiotics has no negative effects on the growth performance, apparent nutrient digestibility and serum biochemical indices of British shorthair cats. At the same time, it can enhance the antioxidant and anti-inflammatory capabilities of the body, regulate the microbiota, improve the composition of serum and fecal metabolites, and have a positive effect on intestinal health.

This study focused on piglets with post-weaning diarrhea (PWD) as the research subjects to systematically evaluate the expression of the pregnane X receptor (PXR) and the pathological changes associated with pyroptosis and necroptosis during PWD-induced intestinal inflammatory injury. Based on the presence or absence of diarrhea 3 days post-weaning, twelve 21-day-old weaned castrated piglets were selected and divided into a diarrhea group (n=6) and a healthy control group (n=6). Following euthanasia, tissue samples from the duodenum, jejunum and ileum were collected. Histological observation, immunofluorescence, immunohistochemistry, and Western blot were employed to evaluate the effects of PWD on intestinal mucosal structure, inflammatory response and programmed cell death. The results showed as follows: 1) PWD led to jejunal villus atrophy and structural disorganization, significantly decreased the expression levels of zonula occludens-1 (ZO-1) and Occludin in the jejunum (P<0.05), indicating damage to the intestinal mucosal barrier. 2) Compared with the healthy group, the expression levels of pro-inflammatory factors [inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), high mobility group box 1 (HMGB1), tumor necrosis factor-alpha (TNF-α), mature interleukin-1β (mature-IL-1β) and mature interleukin-18 (mature-IL-18)] in the jejunum of the diarrhea group were significantly increased (P<0.05), and the Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) signaling pathways were activated. 3) Compared with the healthy group, the expression levels of multiple proteins related to pyroptosis and necroptosis were significantly or extremely significantly upregulated in the jejunum of the diarrhea group (P<0.05 or P<0.01). Pyroptosis-related proteins included NOD-like receptor thermal protein domain associated protein 3 (NLRP3), pro-Caspase-1, cleaved-Caspase-1, gasdermin D-F (GSDMD-F) and gasdermin D-N (GSDMD-N). Necroptosis-related proteins included phosphorylated receptor-interacting protein kinase 1 (p-RIPK1), phosphorylated receptor-interacting protein kinase 3 (p-RIPK3), phosphorylated mixed lineage kinase domain-like protein (p-MLKL), and Fas-associated death domain protein (FADD). 4) Compared with the healthy group, PXR expression in the jejunum of the diarrhea group was significantly downregulated (P<0.05). In conclusion, these findings indicate that PWD exacerbates intestinal inflammation and barrier damage by downregulating PXR expression and activating the pyroptosis and necroptosis pathways in the piglet intestine.

This study aimed to establish a highly sensitive method for the determination of short-chain fatty acids (SCFAs), including acetic acid, propionic acid, butyric acid, valeric acid and hexanoic acid, in pig feces. Pig fecal samples were extracted with acetonitrile. In a pyridine buffer system, under the catalysis of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC·HCl), the SCFAs reacted with Girard reagent P (GP) at room temperature to form amide derivatives with permanent positive charges. Using GP-labeled deuterated SCFAs as internal standards, the derivatives were separated on a hydrophilic interaction liquid chromatography (HILIC) column, detected by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive ion multiple reaction monitoring (MRM) mode, and quantified by isotope internal standard method. The results showed that the limits of detection (LOD) of the five SCFAs ranged from 0.5 to 2.0 pmol/g, and the limits of quantification (LOQ) ranged from 1.0 to 5.0 pmol/g. In the concentration range of 0.001 to 1.000 mmol/L, the correlation coefficients (R²) were all greater than 0.99. The spiked recoveries were in the range of 80.1% to 103.8%, with relative standard deviations (RSD) of 1.8% to 10.0%. It is concluded that the established simultaneous quantification method for five SCFAs based on GP derivatization combined with LC-MS/MS has high sensitivity and good stability, and can achieve accurate determination of trace SCFAs in complex matrices.

This study aimed to systematically elucidate the effectively active components and mechanisms of bamboo leaf flavonoid (BLF) in alleviating oxidative stress injury in the bovine mammary gland by integrating plant untargeted metabolomics, network pharmacology, molecular docking, molecular dynamics, and in vitro cellular molecular biology experiments. Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) was employed to identify the active components of BLF. Potential targets were predicted using Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), SwissTargetPrediction and PharmMapper databases, and then intersected with disease databases to screen for targets related to oxidative stress. Venn diagram was plotted using Venny, and protein-protein interaction (PPI) network was constructed using STRING database. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. The binding modes between core components and key targets were verified via molecular docking and molecular dynamics. Additionally, a hydrogen peroxide (H₂O₂)-induced oxidative injury model in bovine mammary epithelial cells was established. Immunofluorescence and Western blotting were used to verify the effects of BLF on cellular barrier function and mitophagy-related protein expression. The results showed that: a total of 7 main active components in BLF were identified, including homo orientin, isovitexin, luteolin, quercetin, apigenin, tricin and kaempferol. PPI network analysis indicated that epidermal growth factor receptor (EGFR), estrogen receptor 1 (ESR1), matrix metalloproteinase 9 (MMP9), prostaglandin-endoperoxide synthase 2 (PTGS2), and SRC proto-oncogene protein (SRC) were the key targets. GO function enrichment analysis showed that BLF might act in cellular components such as the nucleus, nuclear envelope, and insulin receptor complex, exert molecular functions such as dehydrogenase activity and domain binding, and participate in biological processes such as acetylcholine catabolism and lipoxin A4 biosynthesis. KEGG pathway enrichment analysis revealed that the forkhead box O (FoxO), interleukin-17 (IL-17), and nuclear factor-κB (NF-κB) signaling pathways played key roles in alleviating oxidative stress injury. Molecular docking and molecular dynamics simulation results showed that homo orientin and isovitexin exhibited the lower binding energies with the key target EGFR, indicating the more stable binding. In vitro experiment demonstrated that BLF significantly restored junction protein expression to maintain the cellular barrier. Furthermore, BLF effectively alleviated oxidative stress injury by upregulating key autophagy proteins, promoting P62 degradation, and activating phosphatase and tensin homolog induced putative kinase 1 (PINK1)/Parkin-mediated mitophagy. In conclusion, by combining network pharmacology prediction with in vitro experimental verification, this study systematically elucidates the molecular mechanism by which BLF alleviates the oxidative stress in bovine mammary gland. Specifically, the core active components of BLF, homo orientin and isovitexin, target the EGFR, thereby activating the PINK1/Parkin signaling pathway to mediate mitophagy. This process promotes the degradation of autophagic substrate P62 and the clearance of damaged mitochondria, and ultimately maintains cellular barrier function.

This study conducted a Meta-analysis to evaluate the effects of dietary superoxide dismutase (SOD) supplementation on the growth performance and antioxidant capacity of livestock and poultry. Search keywords were defined using the PICOS (Population, Intervention, Comparison, Outcomes, Study design) framework. Literature searches were performed in four databases: PubMed, Web of Science, CNKI and Wanfang. Eligible studies were screened and data were extracted. Heterogeneity was assessed, and subgroup and publication-bias analyses were conducted. The results showed as follows: 1) for growth performance, SOD dosage was 2 000 to 4 000 U/kg, feeding time was 11 to 30 days, the final body weight (FWB) increased significantly with an initial body weight ( IBW) of below 1 kg (P<0.05); under the same SOD dosage was 2 000 to 4 000 U/kg and IBW<1 kg, average daily gain (ADG) was significantly improved (P<0.05). However, for animals with IBW>10 kg and feeding time>30 days, ADG was significantly decreased (P<0.05). When SOD dosage was<2 000 U/kg and feeding time exceeded 30 days, average daily feed intake (ADFI) increased significantly with IBW<1 kg (P<0.05); conversely, ADFI decreased significantly when SOD dosages were either 2 000 to 4 000 U/kg or >4 000 U/kg (P<0.05). Species-specific analysis indicated that dietary SOD supplementation significantly increased IBW in chickens and ADFI in pigs and sheep (P<0.05), whereas it significantly reduced ADG in sheep and ADFI in chickens (P<0.05). 2) For antioxidant capacity. SOD dosage at 2 000 to 4 000 U/kg significantly increased liver tissue SOD activity with IBW<1 kg (P<0.05). SOD dosage>4 000 U/kg, feeding time with 10 to 30 days significantly enhanced serum glutathione peroxidase activity with IBW>10 kg (P<0.05). In conclusion, dietary SOD supplementation can effectively enhance the growth performance and improve the antioxidant capacity of livestock and poultry.

This study aimed to investigate the protective effect of raffinose (Raf) against aflatoxin B₁(AFB₁)-induced kidney injury in mice and its underlying molecular mechanism, providing a new strategy for livestock nutritional health and the development of functional feed additives. Thirty male C57BL/6 mice (6 to 8 weeks old) were randomly divided into five groups with six mice per group, and treated as follows: Control group, treated with neither Raf nor AFB₁; Raf group, treated with 50 mg/kg BW Raf; AFB₁ group, treated with 1.5 mg/kg BW AFB₁; low-dose Raf intervention group, treated with 25 mg/kg BW Raf+1.5 mg/kg BW AFB₁; high-dose Raf intervention group, treated with 50 mg/kg BW Raf+1.5 mg/kg BW AFB₁. Mice were administered the respective treatments by gavage once every other day for 30 days (15 times in total). At the end of the administration period, blood samples were collected from all mice. Subsequently, the mice were euthanized, and kidney tissues were immediately harvested for biochemical assays, histopathological examination, and detection of relevant protein expression. The results showed as follows: Raf intervention significantly reversed the AFB₁-induced elevation of serum creatinine (Cre) and blood urea nitrogen (BUN) contents in mice (P<0.001 or P<0.000 1). Histopathological examination of kidney tissue sections stained with hematoxylin and eosin (HE) and Paller score revealed that the AFB₁ group exhibited inflammatory cell infiltration, hemorrhage, abnormal kidney tubule structure, and glomerular cell proliferation, with a significant increase in Paller score (P<0.000 1). Following Raf intervention, the aforementioned pathological damage was ameliorated, and the Paller score was significantly reduced (P<0.000 1). 2) Raf significantly reversed the AFB₁-induced decrease in serum glutathione (GSH) content (P<0.05), as well as the increase in malondialdehyde (MDA) content (P<0.000 1) and reactive oxygen species (ROS) fluorescence intensity in mouse kidney tissue. 3) TUNEL staining and Western blot analysis of kidney tissue demonstrated that Raf reduced the number of apoptotic cells induced by AFB₁. Raf significantly upregulated the protein expression of B-cell lymphoma-2 (Bcl-2) (P<0.001) and significantly downregulated the protein expression of Bcl-2-associated X protein (Bax) (P<0.000 1). 4) Compared with the AFB₁ group, high-dose Raf significantly upregulated the protein expression of cystine/glutamate antiporter (xCT), glutathione peroxidase 4 (GPX4), ferroptosis suppressor protein 1 (FSP1) and ferritin heavy chain 1 (FTH1) in kidney tissue (P<0.001). Furthermore, Raf significantly inhibited the AFB₁-induced elevation of serum ferrous ion (Fe²⁺) concentration (P<0.01). 5) Raf significantly reversed the AFB₁-induced downregulation of Kelch-like ECH-associated protein 1 (Keap1) and glutamate-cysteine ligase modulatory subunit (GCLM) protein expression (P<0.001 or P<0.000 1), as well as the upregulation of heme oxygenase-1 (HO-1) protein expression (P<0.000 1) in kidney tissue. In summary, AFB₁ induces oxidative stress imbalance in kidney tissue, activates apoptosis and ferroptosis pathways, and ultimately leads to renal dysfunction and histopathological damage in mice. Conversely, Raf ameliorates AFB₁-induced oxidative stress, inhibits apoptosis and ferroptosis, thereby exerting a protective effect against AFB₁-induced kidney injury in mice.

This study aimed to investigate alleviating effects of selenized Artemisia ordosica polysaccharide on oxidative stress of diquat-induced mice and its regulatory mechanism. A total of 72 four-week-old specific pathogen-free (SPF) mice were randomly divided into 6 groups with 12 replicates per group and 1 mouse per replicate. The control group (CON group) and the diquat group (DQ group) were administered physiological saline by gavage, the Artemisia ordosica polysaccharide group (AOP group) was administered 220.5 mg/kg Artemisia ordosica polysaccharide by gavage, the selenized Artemisia ordosica polysaccharide group (Se-AOP group) was administered 400 mg/kg selenized Artemisia ordosica polysaccharide by gavage, the Artemisia ordosica polysaccharide+sodium selenite group (AOP+Na₂SeO₃ group) was administered 220.5 mg/kg Artemisia ordosica polysaccharide+0.03 mg/kg sodium selenite by gavage, and the sodium selenite group (Na₂SeO₃ group) was administered 0.03 mg/kg sodium selenite by gavage. The daily gavage volume for all groups was 0.2 mL. The pre-experimental period lasted for 7 days, and the experimental period lasted for 21 days. On the last day of the experiment, the CON group was intraperitoneally injected with 0.2 mL of physiological saline, while mice in the other groups were intraperitoneally injected with 1 mg/mL of diquat solution at a dose of 10 mg/kg body weight. The results showed as follows: 1) compared with the CON group, the average daily gain (ADG) of DQ group was significantly decreased (P<0.05), and the feed to gain ratio (F/G) was significantly increased (P<0.05); the total antioxidant capacity (T-AOC) and activities of total superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in serum, liver and liver mitochondria were significantly decreased (P<0.05), and the malondialdehyde (MDA) content was significantly increased (P<0.05); the mRNA relative expression levels of nuclear factor erythroid-2-related factor 2 (Nrf2), CAT, SOD, GSH-Px, PTEN-induced putative kinase 1 (PINK1) and microtubule-associated protein 1 light chain 3-B (LC3-B) in liver were significantly decreased (P<0.05), and the mRNA relative expression levels of Kelch-like ECH-associated protein 1 (Keap1) and p62 were significantly increased (P<0.05). 2) Compared with the DQ group, the ADG of Se-AOP group was significantly increased (P<0.05), and the F/G was significantly decreased (P<0.05); the T-AOC and SOD activity in serum, liver and liver mitochondria and liver CAT activity of AOP group and Se-AOP group were significantly increased (P<0.05); the serum SOD activity of AOP+Na₂SeO₃ group and Na₂SeO₃ group was significantly increased (P<0.05); the serum and liver MDA content of AOP group, Se-AOP group and AOP+Na₂SeO₃ group was significantly decreased (P<0.05); the mRNA relative expression levels of Nrf2, CAT, SOD, GSH-Px, PINK1, Parkin protein (Parkin) and LC3-B in liver of Se-AOP group were significantly increased (P<0.05), and the mRNA relative expression levels of Keap1 and p62 in liver of AOP group, Se-AOP group, AOP+Na₂SeO₃ group and Na₂SeO₃ group were significantly decreased (P<0.05). In conclusion, the selenized Artemisia ordosica polysaccharide can ameliorate the diquat-induced decline in growth performance of mice, enhance the antioxidant enzyme activities, and up-regulate the expression of genes related to antioxidation and mitophagy in the Nrf2/Keap1 pathway and PINK1/Parkin pathway in liver, thereby alleviating diquat-induced oxidative stress in mice.

This study aimed to isolate and identify “autochthonous” Saccharomyces cerevisiae strains adapted to the rumen environment, and to systematically compare their differences in metabolic characteristics and in vitro probiotic potential, thereby revealing the potential links among strain origin, metabolic phenotype, and probiotic function at the metabolite level, so as to provide a basis for developing highly colonizing probiotics specifically for ruminants. One yeast strain was isolated and purified from the rumen fluid of healthy adult beef cattle and one from healthy adult sheep using YPD solid medium. Species identification was performed through morphological observation, methylene blue staining and ITS sequence analysis. Subsequently, the isolated strains were characterized for growth characteristics, acid-producing capacity, tolerance to acid and bile salts, tolerance to artificial gastric and intestinal fluids, surface hydrophobicity, auto-aggregation ability, antimicrobial activity and antibiotic susceptibility. Furthermore, untargeted metabolomics was employed to analyze the differences in metabolites and related pathways between the two isolated strains. The results showed that one Saccharomyces cerevisiae strain was successfully isolated from the rumen fluid of adult beef cattle and one from adult sheep, and they were designated as GRJA008 and GRJA012, respectively. Both strains exhibited good bile salt tolerance (relative survival rate>75% at 24 h) when the bile salt concentration was≥0.2%, showed high tolerance to artificial intestinal fluid (survival rate>95% at 3 h), and possessed strong auto-aggregation ability (auto-aggregation rate>69%). Strain GRJA008 displayed strong antimicrobial activity and a broad antibiotic susceptibility spectrum, whereas strain GRJA012 was insensitive to multiple antibiotics. Untargeted metabolomics analysis revealed a total of 264 differential metabolites between strains GRJA008 and GRJA012, which were primarily involved in lipid metabolism, sterol metabolism and bile acid biosynthesis. The average correlation coefficient between the two metabolic clusters-“lipid-sterol metabolism” and “bile acid-phenolics”, was approximately -0.7, indicating a clear antagonistic relationship between them. The differences in metabolic phenotypes between the two Saccharomyces cerevisiae strains were closely associated with their in vitro probiotic characteristics. In summary, Saccharomyces cerevisiae GRJA008 and GRJA012 isolated from the rumen fluid of ruminants in this study both exhibited excellent in vitro probiotic properties and have the potential to serve as candidate probiotic strains for ruminants. Notably, there were significant differences in metabolic phenotypes between the two strains, a finding that provides a new research perspective for the precise screening and application of probiotics based on metabolic phenotypes.

This study aimed to screen lactic acid bacteria with high adhesion capacity and favorable probiotic properties from milk samples of healthy dairy cows, so as to provide strain resources for the development of feed probiotic additives. Lactic acid bacteria were isolated and purified from cow milk samples using MRS medium supplemented with calcium carbonate (CaCO₃). Hemolysis assay was performed for preliminary screening to obtain safe strains. Strains with high adhesion were further selected by determining auto-aggregation rate, cell surface hydrophobicity, co-aggregation rate with pathogenic bacteria and biofilm formation ability. The strain was identified via morphological observation, biochemical tests and 16S rDNA gene sequencing. Its stress tolerance, antibacterial activity and antibiotic susceptibility were systematically evaluated to characterize probiotic properties. The results showed that a high-adhesion strain A was isolated from milk and identified as Enterococcus faecalis, designated Enterococcus faecalis A. The auto-aggregation rate and cell surface hydrophobicity of this strain were 66.73% and 27.40%, respectively. Its co-aggregation rates against Staphylococcus aureus and Escherichia coli were 85.35% and 81.98%, and it exhibited strong biofilm-forming ability. Probiotic property tests indicated that Enterococcus faecalis A was susceptible to six commonly used antibiotics. Its survival rates in simulated gastric fluid and simulated intestinal fluid were 94.52% and 152.41%, respectively. The survival rates were 46.93% in 0.1% bile salt, 99.96% at 40 ℃ and 37.77% at pH 5.0. In conclusion, Enterococcus faecalis A possesses excellent adhesion performance and desirable probiotic characteristics, which can serve as a promising candidate strain for the preparation of lactic acid bacteria-based microecological preparations.

This experiment was conducted to investigate the effects of supplementation with different amounts of Gracilaria lemaneiformis on methane (CH₄) emission, fermentation parameters, nutrient degradation rates and microbiota in rumen fermentation of beef cattle in vitro. Simmental hybrid cattle were used as rumen fluid donors. Three groups were set up for in vitro fermentation. The control group (CON group) used the basal diet as the fermentation substrate, while the experimental groups were supplemented with 2% and 5% (dry matter basis) of Gracilaria lemaneiformis dry powder, respectively, with 10 replicates in each group. The in vitro fermentation lasted for 48 hours. The gas production parameters, fermentation parameters and nutrient degradation rates were determined, and the microbiota structure was analyzed by 16S rRNA gene sequencing technology. The results showed as follows: 1) compared with CON group, the CH₄ production in 2% Gracilaria lemaneiformis group was significantly decreased (P<0.05), and the CH₄ production per gram of substrate was extremely significantly decreased (P<0.01); the gas production per gram of substrate and CH₄ production per gram of substrate in 5% Gracilaria lemaneiformis group were extremely significantly decreased (P<0.01). 2) There were no significant differences in in vitro fermentation pH and contents of ammonia nitrogen, microbial protein and volatile fatty acids among all groups (P>0.05). 3) Compared with CON group, there was no significant difference in the dry matter degradation rate (DMD) in 2% Gracilaria lemaneiformis group (P>0.05), while the DMD in 5% Gracilaria lemaneiformis group was significantly decreased (P<0.05). There were no significant differences in the degradation rates of neutral detergent fiber and acid detergent fiber among all groups (P>0.05). 4) Compared with CON group, there were no significant differences in the alpha and beta diversities of bacteria and methanogenic archaea in 2% Gracilaria lemaneiformis group (P>0.05). However, the relative abundances of Lachnospiraceae_AC2044_group and Romboutsia were significantly decreased (P<0.05), and the relative abundances of Alistipes and Olsenella were significantly increased (P<0.05). In conclusion, the supplementation of 2% Gracilaria lemaneiformis can reduce the CH₄ production in rumen fermentation of beef cattle in vitro by regulating the microbiota, while maintaining the rumen fermentation homeostasis and feed utilization efficiency.