Journal of Animal Science and Biotechnology最新文献

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.

Background: Heat stress (HS) can impair boar testicular function, leading to reproductive issues. However, chlorogenic acid (CGA) has been shown to mitigate HS-induced damage in various livestock and poultry species. Prepuberty is an important stage of testicular development in boars after birth. However, the protective effect of CGA on testicular HS injury during prepuberty boars and the underlying mechanisms are still not fully understood.

Results: In vivo, a total of 30 healthy boars with similar body weights and ages were obtained and randomly divided into 3 groups, which were fed a basal diet supplemented with CGA 0 (the ND_TN group), 0 (the ND_HS group) or 1,000 (the CGA_HS group) mg/kg. After being fed for 28 d, all the groups, except the ND_TN group, were treated with high temperature for 7 d, after which samples were collected from the boars and analysed. The results showed that CGA significantly mitigated the HS-induced reduction in T-AOC content in testicular tissue and sperm density. Mechanistically, multiomics analysis revealed that the genes differentially expressed by CGA and HS were predominantly associated with the glutathione metabolism pathway. The combined analysis of transcriptomics and proteomics revealed that only BLVRA was affected by both HS and CGA when the mRNA and protein levels of a gene showed differential expression with the same trend. In vitro studies confirmed that CGA modulated GPX3 expression via BLVRA, affected GPx activity, and attenuated HS-induced ROS accumulation.

Conclusions: In conclusion, prepubertal HS impairs the spermatogenic capacity of boars. BLVRA may mediate the testicular protective effect of CGA, although in vivo validation of this pathway is needed. This study contributes to elucidating the mechanisms underlying the effects of HS on prepubertal boar testicular development using multiomics approaches, laying a foundation for the potential utilization of CGA in swine production.

Background: Sphingolipids (SL) are key regulators of inflammatory processes, yet their roles in dairy cows remain poorly understood. This study investigated the effects of inflammation (plasma haptoglobin concentration), ketosis, and mastitis on plasma SL profiles in Holstein cows sampled seven days postpartum. From a cohort of 427 cows across 25 farms, 80 animals were classified into four groups: inflammation (n = 20), ketosis (n = 19), mastitis (n = 21), and healthy controls (n = 20). Plasma SL were quantified by targeted HPLC-MS/MS, while cytokines were quantified with a 15-plex bead-based assay. Both univariate and multivariate analyses were applied to assess pathological effects, along with SL ratios and correlations between SL and cytokines.

Results: Systemic inflammation detected through the haptoglobin measure induced the most pronounced alterations in SL metabolism, characterized by elevated dihydrosphingomyelins (DHSM) and lactosylceramides (LacCer), higher C22-24:C16 ratios, and lower unsaturated:saturated ratios in ceramides (Cer) and sphingomyelins (SM). Although total Cer, SM, and the Cer:SM ratio remained unchanged, specific reductions were observed in both Cer and SM in C14, Cer C18:1, SM C16:1, and SM C23:1, whereas SM C25:0 and C26:0 increased. Sphingosine-1-phosphate (So1P) was positively correlated with IL-10 as well as IL-1α and TNFα, while C18-20 Cer correlated positively with multiple pro-inflammatory cytokines and chemokines such as CXCL8 and CCL2. Ketosis induced subtler changes, primarily an increase in plasma DHSM and DHSM:SM ratio (driven by C16:0), an increase in C22-24:C16 DHCer ratio, and a decrease in both LacSo:LacCer and unsaturated:saturated ratios in C23-SM. In this group, So1P correlated positively with CXCL8 and CCL2. Moreover C18-20 Cer and DHCer were positively associated with CXCL8, CCL2, CCL3, and CCL4, which also showed correlations with most LacCer species. Analysis of chronic mastitis cases yielded a clear separation from controls in multivariate analysis but only minimal changes in SL concentrations and ratios, maybe due to the localized nature of the inflammatory response.

Conclusions: In summary, heightened inflammatory response in early post-partum is associated with the strongest systemic effects on SL metabolism, followed by ketosis, while mastitis induced only modest alterations. These findings highlight condition-specific patterns of SL regulation postpartum and suggest potential immunometabolic biomarkers of disease.

Background: Selective breeding for disease resistance is an effective strategy to control duck hepatitis A virus type 3 (DHAV-3) in waterfowl. However, the mechanism underlying resistance remains poorly understood, particularly those associated with antioxidant defense, intestinal development and host-microbiota interactions.

Method: A total of 100 1-day-old Pekin ducklings were used in this study with 50 DHAV-3 susceptible and resistant ducks, respectively. Samples were collected at 7 days post-hatching (D7), D21 and D42, 10 birds per group. We compared DHAV-3 resistant and susceptible ducks during early development with respect to immune organ indices, antioxidant capacity, intestinal morphology, barrier-related gene expression and cecal microbiota.

Result: Resistant ducks exhibited higher spleen indices and stronger antioxidant capacity, characterized by increased superoxide dismutase, reduced glutathione, and total antioxidant capacity, along with lower malondialdehyde levels at D7 and D21. In contrast, susceptible ducks showed compensatory thymus hypertrophy and delayed development of antioxidant defense and intestinal maturation. Ileal morphology revealed greater villus height and width with more regular arrangement in resistant ducks at D7, whereas these differences diminished at D21 and D42. Gene expression analysis demonstrated higher early expression of the tight junction proteins CLDN1 and CLDN3 in resistant ducks, while susceptible ducks displayed elevated MUC2 and OCLN, suggesting stress induced compensatory responses. Cecal microbiota analysis revealed distinct colonization patterns in early development. Resistant ducks were enriched with Firmicutes and beneficial genera such as Enterococcus and Lactobacillus, whereas susceptible ducks harbored higher abundances of Bacteroidota and potentially opportunistic taxa. Microbial diversity increased with age in both groups, but resistant ducks displayed more orderly succession and enrichment of SCFA producing genera, including Subdoligranulum and Phascolarctobacterium, which positively correlated with plasma antioxidant indices.

Conclusion: DHAV-3 resistant ducks exhibit early advantages in antioxidant defense, intestinal barrier development and colonization by beneficial microbiota, which collectively contribute to enhanced disease resistance. These findings highlight the synergistic roles of host physiology and gut microbiota in shaping resistance. In the future, integrating genomic selection with microbiota modulation and antioxidant interventions may accelerate the breeding of highly resistant duck lines and provide scientific evidence and practical strategies for controlling duck viral hepatitis.

Background: Endometrial receptivity (ERE) is a transient uterine state that determines the success of blastocyst implantation; however, the epigenomic regulation underlying ERE establishment in goats remains unclear. Here, we profiled transcriptional and epigenomic features of endometrial tissues from pregnant goats during the peri-implantation window and nonpregnant control goats in the regressed luteal phase to uncover the transcriptional regulatory networks responsible for ERE establishment in goats, utilizing RNA-seq, ATAC-seq, and H3K27ac CUT&Tag.

Results: A total of 3,143 differentially expressed genes (DEGs) were identified, accompanied by significant alterations in chromatin accessibility and H3K27ac modifications between receptive and non-receptive endometria. The targeted genes associated with these epigenetic changes were significantly enriched in pathways related to cell adhesion, immune tolerance, and embryo attachment. Motif enrichment and transcription factor (TF) footprinting analyses identified members of the FOS/JUN, SOX, HNF1, CEBP, and BATF families as candidate regulators, implicating downstream genes involved in ERE establishment, including SPP1, FOXO1, KLF4/6, STAT1, IFI6, ITGB8, PLAC8, DUSP4, NR1D1, ISG15, RUFY4, and PIK3R3. In addition, numerous super-enhancers were identified, indicating regions of high regulatory activity and potential long-range gene-enhancers interactions in the endometrium. Integration of multi-omics datasets revealed a strong correlation (r > 0.7) among chromatin accessibility, H3K27ac activation, and the expression of 172 DEGs. Furthermore, a set of hub genes (KLF6, IFI6, MCL1, SDC4, SUSD6, MAFF, and IL6R) that appear to coordinate TF binding and distal super-enhancers activity associated with ERE establishment.

Conclusions: Our data provided an integrated epigenomic atlas of endometrial receptivity establishment in goats and identify candidate regulatory elements and transcription factors that may orchestrate uterine preparation for implantation. These findings offer valuable insights and testable targets for improving fertility in ruminant livestock.

Background: Undernutrition disrupts pregnant ewe's metabolic homeostasis and severely inhibits fetal growth and development. In this study, undernourished and nutrition-recovery pregnant sheep models and rumen epithelial cells were utilized to investigate the mechanisms behind undernutrition-induced disruptions in male fetal rumen metabolism and development.

Results: Maternal undernutrition significantly reduced male fetal rumen weight and papilla length, width and surface area. Maternal undernutrition extremely suppressed nutrient metabolism and energy production in male fetal rumen via JAK3/STAT3 signaling to inhibit cell cycle progression and male fetal rumen development, while maternal nutritional recovery partially restored metabolic inhibition but failed to alleviate male fetal rumen development. Meanwhile, 64 differentially expressed miRNAs (DEMs) were identified in male fetal rumen between undernourished ewes and controls. Novel miR-736 was overexpressed both in male fetal rumen of undernourished and nutrition-recovery models. E2F transcription factor 2 (E2F2) and MYB proto-oncogene like 2 (MYBL2) were the intersection of male fetal rumen differentially expressed genes (DEGs) and DEMs target genes integrated analysis and were predicted as novel miR-736 target genes. Further, we confirmed that novel miR-736 targeted and downregulated E2F2 and MYBL2 expression levels. Silencing E2F2 and MYBL2 promoted apoptosis and inhibited S-phase entry in rumen epithelial cells.

Conclusions: In summary, maternal undernutrition disrupted male fetal rumen metabolism and elevated novel miR-736, which targeted and downregulated E2F2 and MYBL2 to inhibit cell cycle progression and promote apoptosis, finally inhibited male fetal rumen development. This study provides new insights into the epigenetic mechanisms underlying maternal undernutrition-induced male fetal rumen developmental deficits.