The potential of yeast culture for alleviating enterotoxigenic Escherichia coli-induced diarrhea in neonatal livestock: Insights from intestinal barrier mechanisms.

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.