Background: The enteric methane inhibitor 3-nitrooxypropanol (3-NOP) inhibits the key enzyme in ruminal methanogenesis, but whether short-term (ST) and long-term (LT) dietary supplementation has similar effects on rumen microbiota in beef cattle and how microbes change after 3-NOP withdrawal have not been studied. This study investigated changes in rumen bacteria, archaea, and protozoa after ST and LT dietary supplementation and removal of 3-NOP using metataxonomic analysis.
Results: A total of 143 rumen samples were collected from two beef cattle studies with 3-NOP supplementation. The ST study (95 samples) used eight ruminally cannulated beef cattle in a 4 × 4 Latin square design with four 28-d of 3-NOP treatments [mg/kg of dry matter (DM)]: control: 0, low: 53, med: 161, and high: 345. The LT study (48 samples) was a completely randomized design with two 3-NOP treatments [control: 0, and high: 280 mg/kg of DM) fed for 112-d followed by a 16-d withdrawal (without 3-NOP). Bacterial and archaeal communities were significantly affected by 3-NOP supplementation but limited effects on protozoal communities were observed. Under ST supplementation, the relative abundances of Prevotella, Methanobrevibacter (Mbb.) ruminantium, Methanosphaera sp. ISO3-F5, and Entodinium were increased (Q < 0.05), whereas those of Mbb. gottschalkii and Epidinium were decreased (Q < 0.05) with 3-NOP supplementation. In LT study, relative abundances of Mbb. ruminantium, and Methanosphaera sp. Group5 were increased (Q < 0.05), while those of Saccharofermentans and Mbb. gottschalkii were decreased (Q < 0.05) with 3-NOP supplementation. Comparison between 3-NOP supplementation and the withdrawal revealed increased relative abundances of Clostridia UCG-014 and Oscillospiraceae NK4A214 group and decreased those of Eubacterium nodatum group and Methanosphaera sp. Group5 (P < 0.05) after 3-NOP withdrawal. Further comparison of rumen microbiota between control and 3-NOP withdrawal showed significantly higher (P = 0.029) relative abundances of Eggerthellaceae DNF00809, p-1088-a5 gut group, and Family XII UCG-001 in control group while no significant differences were detected for archaea and protozoa. Microbial network analysis revealed that microbial interactions differed by both 3-NOP dose and durations.
Conclusions: Both ST and LT supplementation affected overall rumen microbial profile, with individual microbial groups responded to 3-NOP supplementation differently. After 3-NOP withdrawal, not all microbes showed recovery, indicating that the 3-NOP driven shifts were only partially reversible. These findings provide an understanding of the effects of 3-NOP on rumen microbial communities and their adaptability to methane mitigation strategies.
Background: As probiotics, Bacillus strains may regulate some physiological functions in animals. This study aimed to evaluate whether dietary supplementation with a Bacillus-based probiotic could alleviate gut damage induced by rotavirus (RV) infection in piglets. Twenty-four piglets were randomly assigned into 2 groups fed with the basal diet (n = 16) and the diet containing 109 colony-forming unit Bacillus spores/kg (n = 8). On d 8, 8 piglets fed with the diet supplemented with Bacillus-based probiotic and 8 piglets fed with basal diet were orally infused with RV, while the residue piglets had oral gavage of sterile essential medium. The trial duration was 12 d.
Results: RV challenge induced diarrhea, significantly destroyed the morphology of jejunal mucosa (P < 0.05), significantly increased RV-antibody and RV non-structural protein 4 of jejunal mucosa (P < 0.05), significantly impaired antioxidant capacity (including malondialdehyde level, total antioxidant capacity and catalase activity), immunity (such as interleukin 2, interleukin 4 and secreted immunoglobulin A levels), mucins and the mRNA expression of tight-junction-related (such as Zonula occludens 1, occludin) and apoptotic-related (including B-cell lymphoma/leukaemia-2-associated X protein, B cell lymphoma/leukaemia-2, cysteinyl aspartate specific proteinases) genes of jejunal mucosa (P < 0.05), and, to some extents, affected the bacteria community structure and abundance of ileal digesta in piglets. However, Bacillus-based probiotic administration could significantly attenuate the negative effects of RV infection on gut health of piglets (P < 0.05).
Conclusions: These findings suggested that supplementing Bacillus-based probiotic in the diet could decrease diarrhea rate, and improve gut health in weaned piglets, which was associated with regulating intestinal antioxidant capacity, apoptosis, and microbiota.
Background: Inflammatory bowel disease causes intestinal structural damage, impairs gut function, hinders animal growth and development, and reduces farming efficiency. Previous studies demonstrated that lactate alleviates dextran sulfate sodium (DSS)-induced inflammation and mitigates weight loss by enhancing intestinal barrier functions. However, the mechanisms underlying lactate-mediated protection of the intestinal epithelial barrier remain unclear. This study aimed to explore the protective effect of lactate on intestinal barrier damage in colitis piglets and the possible underlying mechanisms through in vivo and in vitro experiments.
Methods: A total of 60 21-day-old weaned female piglets were randomly assigned into three groups based on weight: the control group (basal diet with physiological saline gavage), the DSS group (basal diet with 5% DSS gavage), and the DSS + LA group (2% lactate diet with 5% DSS gavage). There were 10 replicates per treatment, with 2 piglets per replicate. Jejunal morphology was assessed via hematoxylin and eosin staining, while Western blotting quantified the protein levels of proliferation markers, including cluster of differentiation 24 (CD24), cyclin D1, and wingless/integrated (Wnt)/β-catenin signaling components. In vitro, 0.08% DSS and 2-32 mmol/L sodium lactate-treated intestinal porcine epithelial cell line-J2 (IPEC-J2) cells (n = 4) were assessed for viability (Cell Counting Kit-8 assay), apoptosis (flow cytometry), and proliferation parameters, including cell cycle analysis and Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5+) stem cell quantification.
Results: In vivo, DSS administration induced jejunal villus shortening (P < 0.05), downregulated protein levels of CD24, cyclin D1, casein kinase 1 (CK1), and dishevelled-2 (DVL2) (P < 0.05). In vitro, DSS promoted apoptosis, inhibited proliferation, diminished the Lgr5+ cell populations (P < 0.05), and reduced S-phase cell proportions (P < 0.05). Conversely, lactate supplementation ameliorated DSS-induced villus atrophy (P < 0.05), restored CD24, cyclin D1, CK1, and DVL2 protein levels (P < 0.05). Furthermore, in vitro, sodium lactate attenuated DSS-induced apoptosis (P < 0.05), enhanced IPEC-J2 proliferation (P < 0.05), expanded Lgr5+ cells (P < 0.05), and increased S-phase progression (P < 0.05).
Conclusions: In summary, lactate ameliorated intestinal barrier damage in DSS-induced colitis by activating the Wnt/β-catenin pathway and restoring the balance between epithelial cell proliferation and apoptosis. This study provides novel mechanistic evidence supporting lactate's therapeutic potential for IBD management.

