Journal of Animal Science and Biotechnology最新文献

Background: Piglets are highly susceptible to oxidative stress, which can reduce growth performance and cause intestinal damage. Piceatannol (PIC), a natural bioactive substance enriched in Chinese rhubarb (Rheum officinale) and certain dark purple fruits, shows excellent antioxidant properties in our previous cell-based high-throughput screening. However, its effect on piglet growth performance and antioxidant capacity as well as underling mechanism has not been thoroughly investigated.

Methods: One hundred weaned pigs (28 days of age, 8.71 ± 0.20 kg) were randomly assigned to 4 treatments with 5 replicates of 5 pigs per replicate. The experimental diets consisted of: 1) basal diet, 2) basal diet + 100 mg/kg PIC, 3) basal diet + 200 mg/kg PIC, and 4) basal diet + 300 mg/kg PIC. On d 15 and 35, one pig from each replicate was selected for sampling. The growth performance was monitored during a 35-day trial. In addition, H₂O₂-challenged IPEC-J2 cells served as an in vitro model to investigate the antioxidant mechanisms of PIC. IPEC-J2 cells were treated with 1,000 μmol/L H₂O₂ in the presence or absence of 10 μmol/L PIC.

Results: Dietary PIC at 200 mg/kg significantly enhanced growth performance, as evidenced by increased average daily gain and feed conversion rate (P < 0.05). PIC supplementation markedly improved systemic antioxidant capacity, with elevated serum total antioxidant capacity, catalase activity, and glutathione levels, along with reduced malondialdehyde content (P < 0.05). Notably, PIC modulated the gut microbiota composition, increasing the amounts of beneficial genera (e.g., Blautia and Faecalibacterium), and these microbial shifts significantly correlated with improved antioxidant indices. In vitro, PIC pretreatment effectively protected IPEC-J2 cells against H₂O₂-induced oxidative damage by reducing reactive oxygen species generation and lipid peroxidation (P < 0.01). Mechanistically, PIC exerts its antioxidant effects through Nrf2 pathway activation, upregulating endogenous antioxidant enzymes (P < 0.05) while simultaneously inhibiting apoptosis via the regulation of the Bcl-2/Bax ratio and caspase-3 cleavage (P < 0.01).

Conclusions: PIC improved the growth performance and health status of weaned piglets through the regulation of Nrf2-mediated redox homeostasis and modulation of the related gut microbiota, offering a potential new natural antioxidants for mitigating weaning stress in piglets.

Background: Efficiency is characterized by maximum productivity with lower inputs and minimal waste, resulting in greater output with the same or even fewer resources. In livestock, more efficient animals in converting food into protein may improve the economic efficiency of production systems, as feed costs represent a significant expense in beef production. Thus, the present study aimed to use imputed whole-genome sequencing (WGS) data to perform a genome-wide association study (GWAS) in order to identify genomic regions and potential candidate genes involved in the biological processes and metabolic pathways associated with feed efficiency-related traits (RFI: residual feed intake, DMI: dry matter intake, FE: feed efficiency, FC: feed conversion, and RWG: residual weight gain) in Nellore cattle.

Results: The GWAS identified significant SNPs associated with feed efficiency traits in Nellore cattle. A total of 42 SNPs were detected for RFI, 10 for DMI, 99 for FC, 15 for FE, and 3 for RWG, distributed in different autosomes. Annotation analysis identified several candidate genes, and the prioritization highlighted 21, 9, 68, 23, and 8 key genes for RFI, DMI, FC, FE, and RWG, respectively. The prioritized candidate genes are involved in muscle development, lipid metabolism, response to oxidative stress, nutrient metabolism, neurotransmission, and oxidative phosphorylation. Additionally, enrichment analysis indicated that these genes act in several signaling pathways related to signal transduction, the nervous system, the endocrine system, energy metabolism, the digestive system, and nutrient metabolism.

Conclusion: The use of imputed WGS data in GWAS analyses enabled the broad identification of regions and candidate genes throughout the genome that regulate expression of feed efficiency-related traits in Nellore cattle. Our results provide new perspectives into the molecular mechanisms underlying feed efficiency in Nellore cattle, offering a genetic basis to guide the breeding of efficient animals, thereby optimizing resource utilization and the profitability of production systems.

Background: Zearalenone (ZEN), a common mycotoxin in ruminant diets, could disturb the rumen ecosystem and impair rumen fermentation. Noticeably, ZEN has been shown to reduce the relative abundances of specific bacterial taxa that potentially possess quorum sensing (QS) functions, which are deemed essential for the microbial interactions and adaptations during rumen fermentation. Nonetheless, whether QS communications participate in the responses of rumen microbial fermentation to ZEN remains unknown. Therefore, the present trial was performed to explore the potential roles of QS during the alterations of rumen microbial fermentation by ZEN through a rumen simulation technique (RUSITEC) system, in a replicated 4 × 4 Latin square design.

Results: ZEN significantly (P < 0.05) reduced QS signal autoinducer-2 (AI-2), and tended to (P = 0.051) downregulate QS signal C4-homoserine lactone (HSL). ZEN also significantly (P < 0.05) decreased total volatile fatty acid (TVFA), acetate, propionate, isobutyrate, isovalerate, organic matter disappearance (OMD), neutral detergent fiber disappearance (NDFD), and acid detergent fiber disappearance (ADFD) in different manners. The linear discriminant analysis effect size (LEfSe) analysis indicated significantly (P < 0.05) differential enrichments of a series of bacterial taxa such as Butyrivibrio_sp_X503, Rhizobium daejeonense, Hoylesella buccalis, Ezakiella coagulans, Enterococcus cecorum, Ruminococcus_sp_zg-924, Polystyrenella longa, and Methylacidimicrobium fagopyrum across different treatments. The phylogenetic investigation of communities by reconstruction of unobserved states 2 (PICRUSt2) analysis suggested that QS were predicted to be significantly (P < 0.05) affected by ZEN. The metabolomics analysis detected considerable significantly (P < 0.05) differing metabolites and implied that ZEN challenge significantly (P < 0.05) influenced the indole alkaloid biosynthesis, biosynthesis of alkaloids derived from shikimate pathway, and sesquiterpenoid and triterpenoid biosynthesis. Significant (P < 0.05) interconnections of QS molecules with the differential rumen fermentation traits, differential bacterial taxa, and differential metabolites were exhibited by Spearman analysis.

Conclusions: ZEN negatively affected the QS signals of AI-2 and C4-HSL, which was found to correlate with the fluctuations in specific rumen fermentation characteristics, ruminal bacterial populations, and ruminal metabolisms. These interrelationships implied the potential involvement of QS in the reactions of rumen microbiota to ZEN contamination, and probably contributed to the inhibition of rumen fermentation.

Background: The rapid emergence of multidrug-resistant Salmonella in poultry demands alternative control strategies beyond conventional antibiotics. In this study, we evaluated a combination of lytic Salmonella-infecting bacteriophages (SLAM_phiST45 and SLAM_phiST56) and a probiotic bacterium Limosilactobacillus reuteri (SLAM_LAR11) in a chick model challenged with Salmonella enterica serovar Typhimurium infection.

Results: Co-administration with two-phage cocktail and a probiotic showed markedly reduced Salmonella colonization in the gut and systemic organs of chicks, comparable to the effect of phage-only treatment. In contrast with phage-only treatment, the combined therapy significantly improved the rate of body-weight change from the day of infection to necropsy (P < 0.0001) and alleviated infection-associated splenomegaly (P = 0.028) and hepatomegaly (P = 0.011). In the ileum, the villus height-to-crypt depth ratio (VH/CD) increased significantly (P = 0.044). In the colon, expression of tight-junction genes OCLN (P = 0.014), TJP1 (P < 0.0001), and MUC2 (P = 0.011) was elevated, whereas the pro-inflammatory cytokine IL6 was reduced (P = 0.018). These improvements were accompanied, in the cecum, by trends toward decreases in Escherichia-Shigella (P = 0.09) and Clostridium (P = 0.16) and a trend toward an increase in Blautia (P = 0.11); additionally, in the ileum, Lactobacillus (P = 0.037) and Blautia (P = 0.016) increased significantly, yielding a more balanced microbiota than with phage-only treatment. Consistently, levels of functional metabolites, including acetic acid (LDA = 3.32) and lactic acid (LDA = 5.29), were increased.

Conclusion: Taken together, these findings demonstrate that phage-probiotic co-administration not only enhances the clearance of multidrug-resistant Salmonella more effectively than phage treatment alone but also promotes intestinal health, highlighting its potential as an antibiotic-alternatives strategy to improve intestinal health and ensure food safety in poultry production systems.

Pork is rich in various nutrients and serves as a pivotal source of protein in the human diet, accounting for a substantial portion of worldwide meat consumption. With the rapid development of the national economy and the improvement of people's living standards, the demand for high-quality meat is continuously increasing. However, the production of high-quality pork still faces critical challenges. At present, improving pork quality through probiotics and their fermented feed has become a hot topic of interest and concern. Fermented feed can enhance pork quality by improving meat color, drip loss, tenderness, flavor, intramuscular fat (IMF) content, and nutritional value. In this review, we summarized and discussed the recent advances in fermentation strains, fermentation technology, fermented feed characteristics, and their effects and regulatory mechanisms on pork quality, aiming to provide a theoretical foundation and technical insights for the application of fermented feed in the production of high-quality pork.

Fiber, the most abundant organic polymer in nature, is widely recognized as a foundational sustainable material with diverse applications across industrial, medical, and consumer domains. Owing to its renewability and widespread availability, it also serves as a critical alternative energy source in agriculture, enabling more sustainable livestock production through the efficient conversion of fibrous feedstuffs, thereby supporting the principles of a circular bioeconomy. Cellulose, which constitutes up to 80% of plant fiber, contains tightly packed crystalline regions that confer strong resistance to microbial degradation. Other key obstacles to efficient cellulose digestion in the gut include the absence of critical cellulolytic genes, low enzymatic activity, a lack of natural activators, and the presence of cellulase inhibitors. Synthetic biology provides innovative molecular-level strategies to overcome key technical barriers in cellulose degradation. These approaches employ targeted modifications at nucleic acid and protein levels, including the introduction of engineered genes, synthetic regulators, and optimized enzymes, to develop high-performance microbial systems with enhanced cellulose-degrading capabilities. Furthermore, genetic modifications like the knockout of inhibitory genes and knock-in of activator genes, combined with rational redesign of multi-enzyme complexes, can significantly improve the secretion and catalytic efficiency of cellulases. When integrated with artificial intelligence, synthetic biology enables predictive screening and precision engineering of microbial strains for highly efficient cellulose degradation. This review comprehensively summarizes recent advances in synthetic biology approaches for improving cellulose degradation and highlights how these tools can optimize fiber utilization in sustainable agricultural and industrial applications.

Background: Post-weaning diarrhea (PWD) in piglets, primarily caused by enterotoxigenic Escherichia coli (ETEC) K88 (F4) infection, presents a major challenge in swine production. This study aimed to isolate bacteriophages (phages) specific to ETEC K88, utilizing ETEC K88 as the host strain, and to assess the efficacy of dietary supplementation with the isolated phages in weaned piglets over a two-week period using an ETEC K88 challenge model in a pilot study.

Results: Three ETEC K88-specific phages (EC-P1, EC-P2, and EC-P3) were isolated and identified as tailed phages. These phages displayed a short latency period, broad acid-base stability, and thermal stability, effectively inhibiting ETEC K88 growth and disrupting ETEC K88 biofilms in vitro. Lyophilized phage powder was prepared and supplemented at 400, 600 or 800 mg/kg in the diets. Compared to the ETEC K88 group, piglets in the ETEC K88 + 600 or 800 mg/kg phages group exhibited markedly lower diarrhea scores and rectal temperatures at 12, 24, and 48 h post-infection. Supplementation with 600 mg/kg phages enhanced intestinal integrity of ETEC K88-infected piglets, as evidenced by an increased jejunal villus height and villus height-to-crypt depth ratio, reduced serum diamine oxidase and D-lactate levels, and upregulated jejunal ZO-1 protein expression. Concomitantly, systemic and jejunal inflammatory responses were attenuated by supplementation with 600 mg/kg of phages, as evidenced by decreased serum LPS, IL-1β, IL-10 and TNF-α levels, down-regulated jejunal IL-1β and IL-6 mRNA expression, and suppressed NF-κB signalling (downregulated p-IκBα/IκBα and p-p65/p65 ratios). Supplementation with 600 mg/kg phages also shifted the faecal microbiota toward eubiosis, increasing the Shannon index, decreasing Proteobacteria and Enterobacteriaceae abundances, and elevating beneficial taxa (Patescibacteria, Muribaculaceae, and Subdoligranulum). Correlation analysis further revealed that Proteobacteria and Enterobacteriaceae abundances were positively associated with diarrhoea characteristics, whereas Muribaculaceae showed a negative correlation.

Conclusions: Three ETEC K88-targeting phages were successfully isolated, characterized, and prepared as lyophilized phage powder for dietary supplementation. Dietary supplementation with 600 mg/kg of lyophilized phage powder alleviated PWD in piglets by modulating gut microbiota and inflammatory responses.

Background: Normal testicular development is essential for maintaining male fertility and reproductive performance in livestock. Leydig cells (LCs) play a central role in testicular physiology; however, the epigenetic mechanisms regulating their development remain largely unclear. Methyltransferase-like 3 (METTL3), a key m⁶A methylation enzyme, and microRNAs are increasingly recognised as critical regulators of this process.

Results: METTL3 expression in goat LCs markedly decreased during testicular development. This downregulation reduced m⁶A modification on pri-miR-145, impairing DiGeorge syndrome critical region 8-mediated processing and resulting in decreased levels of mature miR-145-3p. This reduction in miR-145-3p increased the expression of phosphoenolpyruvate carboxykinase 1 (PCK1), which activated gluconeogenesis, increased intracellular glucose levels, and increased mitochondrial membrane potential. Consequently, this metabolic shift upregulated cell cycle-related genes (cyclin B1 and cyclin E2), promoting LC proliferation and testicular growth.

Conclusions: Our findings demonstrate that the METTL3/miR-145-3p/PCK1 axis is a key regulatory pathway linking epigenetic modification to the metabolic activity and proliferation of LCs. This mechanism provides novel insights into the molecular control of testicular development in male goats and may offer new targets for improving male reproductive capacity in livestock.

Background: During the weaning phase, piglets are exposed to significant physiological and environmental stressors, which disrupt the balance of their intestinal microbiota and often lead to severe diarrhea. Previous studies have demonstrated that alfalfa fiber, derived from the stems and leaves of alfalfa, can effectively alleviate diarrhea in piglets. Additionally, multiple studies have highlighted the potential of fecal microbiota transplantation (FMT) in mitigating diarrhea in various models of intestinal diseases in young animals. However, the specific mechanisms by which FMT from targeted sources alleviates diarrhea in weaned piglets remain to be fully elucidated.

Results: In this study, FMT from donor piglets fed an alfalfa fiber-supplemented diet effectively alleviated diarrhea, improved intestinal morphology, and enhanced gut barrier function in weaned piglets. FMT further promoted the colonization of beneficial bacterial genera (including UCG-005, unclassified Lachnospiraceae, Lachnospiraceae AC2044 group, UCG-002, Candidatus Saccharimonas, and Lachnospiraceae ND3007 group) while inhibiting the detrimental genus Tyzzerella, consequently enhancing the production of short-chain fatty acids (SCFAs). Additionally, FMT upregulated riboflavin metabolism, leading to elevated flavin adenine dinucleotide (FAD) levels and increased glutathione reductase activity, thereby collectively attenuating lipopolysaccharide (LPS)-induced oxidative stress and contributing to intestinal health.

Conclusions: We found that FMT modulates the structure of the gut microbiota, enhances microbial diversity and composition, increases the production of SCFAs, and upregulates riboflavin metabolism to elevate FAD levels. These changes collectively enhance immune and antioxidant capacities, thereby alleviating diarrhea.

Background: The gut is primarily responsible for digestion and nutrient absorption, plays essential roles in immune regulation and metabolic balance, and is supported by a diverse microbiome essential for digestion, absorption, and defence from pathogens. Understanding gut physiology and pathophysiology in pre-weaned calves is essential, as infections like cryptosporidiosis can lead to gut dysbiosis, impair growth, and negatively affect long-term productivity. Faeces are considered easily accessible biological specimens that can be used to monitor gastrointestinal disorders. The methods employed in this study aimed to investigate the potential use of faecal extracellular vesicles (fEVs) as a non-invasive tool for assessing gut health and infections in calves. Particularly, considering Cryptosporidiosis as a model for gut infectious disease.

Results: The analysis using a hybrid reference-based metaproteomic approach revealed that the proteomic profiles of fEVs significantly differed from that of faecal crude (FC) suspensions. Both sample types contained microbial and host proteins, which are important for maintaining gut defence and microbial homeostasis. However, Cryptosporidium spp. infection significantly shifted the fEV proteome, reducing both host and microbial proteins involved in gut defence. It also reduced proteins from microbes that are important for maintaining microbial homeostasis, while increasing stress-related proteins. Further, lyophilisation of fEVs significantly altered the protein profiles.

Conclusion: These findings underscore that fEVs contain host and microbial proteins that are a valuable resource for studying gut physiology, pathophysiology, host-microbe-pathogen interactions, and microbiome dynamics. Changes in the proteomic profile of fEVs during Cryptosporidium spp. infection demonstrates the pathogen's ability to manipulate host immune defences and microbiome composition for its survival and replication. Overall, these findings support the utility of fEV proteomics as a non-invasive platform for biomarker discovery and advancing research in gastrointestinal health and disease in livestock.