Introduction: In lambs, the function of the rumen is incompletely developed at weaning, and the inclusion of yeast cultures in the diet can profoundly influence the morphological and functional development of the rumen.Methods: In this study, the effects of Saccharomyces cerevisiae and Kluyveromyces marxianus (NM) yeast co-cultures on ruminal histomorphology were assessed, and corresponding transcriptomic changes within the rumen epithelium were identified. In total, 24 lambs were grouped into four groups of six lambs including a control (C) group fed a basal diet, and N, M, and NM groups in which lambs were fed the basal diet, respectively, supplemented with Saccharomyces cerevisiae yeast cultures (30 g/d per head), Kluyveromyces marxianus yeast cultures (30 g/d per head), and co-cultures of both yeasts (30 g/d per head), the experiment lasted for 42 d.Results: In morphological analyses, lambs from the NM group presented with significant increases in papilla length, papilla width, and epithelial thickness in the rumen relative to lambs in the C group (p < 0.05). Transcriptomic analyses revealed 202 genes that were differentially expressed between samples from the C and NM groups, with the largest proportion of these genes being associated with the oxidative phosphorylation pathway. In a weighted gene coexpression network analysis, a positive correlation was observed between the MEgreen and MEpurple modules and rumen morphology. Of these modules, the MEgreen module was found to be more closely linked to fatty acid metabolism and oxidative phosphorylation, whereas the MEpurple module was linked to oxidative phosphorylation and fatty acid degradation. Ultimately, these results suggest that dietary supplementation with NM has driven the degradation of fatty acids, the induction of oxidative phosphorylation, the acceleration of lipid metabolism, the production of ATP to sustain ruminal growth, and the maintenance of intracellular NADH/NAD+ homeostasis on weaned lambs and is superior to single yeast fermentation.Discussion: These results thus offer a theoretical foundation for further studies examining the mechanisms through which NM cultures can influence ruminal development in lambs.

Enterotoxigenic Escherichia coli (ETEC) remains a leading cause of neonatal diarrhea in piglets, calves, and lambs, yet antibiotic curtailment demands nutrition-based solutions. This review takes a novel barrier-centric perspective to evaluate how yeast culture mitigates neonatal livestock diarrhea caused by ETEC. Unlike previous probiotic or prebiotic reviews, this review focuses specifically on multifaceted components of yeast culture and map their protective effects on each intestinal barrier layer. Across challenge and field studies, yeast culture supplementation reduced neonatal diarrhea incidence relatively by up to 40% to 60% and improved weight gain, highlighting its practical efficacy. Consistent biological correlates include preserved tight junction protein expression and epithelial permeability, thicker mucus and higher goblet-cell count, increased mucosal secretory immunoglobulin A (sIgA) with tempered cytokine responses, and microbiota shifts toward colonization enhanced colonization resistance and short-chain fatty acid production, thereby collectively fortifying the gut against ETEC adhesion and toxin-induced damage. Despite these promising outcomes, challenges remain in optimizing yeast formulation and dosage, and further research is needed to address gaps in species-specific application and long-term efficacy. Overall, yeast culture may provide a multi-target, antibiotic-free strategy to reduce ETEC-associated diarrhea by restoring barrier function and microbiota homeostasis.

INPLASY202440104 Efficacy of monensin, 15 types of direct-fed microbials（DFM）or their fermentation products in milk performance in dairy cows: A systematic review and network meta-analysis (NMA) Ke…

Compound yeast culture (CYC) is known to enhance animal health, but its effects on hepatic immune function are unclear. This study systematically examined CYC’s regulatory effects on the liver of weaned lambs using transcriptomics and integrative bioinformatics. Ten lambs were randomly assigned to a control diet or a basal diet supplemented with 30 g/d per head of Saccharomyces cerevisiae and Kluyveromyces marxianus co-culture (CYC group) for 42 days. Histological analysis showed that CYC improved hepatocyte arrangement and sinusoidal integrity, suggesting enhanced hepatic tissue stability. Cytokine analysis revealed CYC significantly increased IL-6 and IL-1β while reducing IL-10, TGF-β1, TNF-α, and CXCL9, indicating a bidirectional modulation of the immune response. Additionally, CYC enhanced antioxidant defenses by increasing T-SOD, GSH-Px, and T-AOC activities and decreasing MDA content. Transcriptomic sequencing indicated that CYC reshaped hepatic gene expression. Upregulated genes were enriched in immune-regulatory and structural pathways, including PI3K-AKT signaling, ECM–receptor interactions, Toll-like receptor pathways, and cell adhesion molecules. Protein-level validation further confirmed activation of PI3K and AKTAKT phosphorylation with limited engagement of NF-κB signaling. Conversely, downregulated genes were mainly associated with oxidative stress and energy metabolism, such as ROS-related pathways and MAPK signaling. WGCNA identified key hub genes (PTPRC, CD86, and ITGAV), which correlate with pro-inflammatory factors and participate in immune recognition, T-cell activation, and cell adhesion. These data suggest that CYC promotes hepatic immune homeostasis by enhancing immune signaling, stabilizing tissue architecture, and modulating oxidative stress/metabolic processes. This study provides mechanistic insights into CYC’s regulation of liver immune function and supports its targeted application as a functional feed additive for ruminants.

The objective of this study was to evaluate the effects of dietary supplementation with a composite yeast culture (CYC) on the immune status and splenic ge