Superior Probiotic Potential of Saccharomyces cerevisiae YH14: In vitro and In vivo Evaluation for Animal Nutrition and Health

The gastrointestinal tract of native animals represents a valuable reservoir of probiotic candidates. In this study, yeast strains were isolated from the feces of healthy native pigs raised in southern Thailand and evaluated for probiotic potential, safety, and extracellular enzyme production in vitro. The most promising isolate, Saccharomyces cerevisiae YH14, was selected for in vivo evaluation in a murine model. YH14 exhibited robust growth at 37°C and demonstrated high tolerance to acidic (127.38%) and bile salt (139.94%) conditions. The strain showed strong auto-aggregation (90.09%), cell surface hydrophobicity (59.21%), and notable adhesion to Caco-2 cells (43.18%). Co-aggregation with enteric pathogens—including enterohemorrhagic E. coli (55.37%), enteropathogenic E. coli (57.91%), and Salmonella Typhimurium (56.62%)—was observed at intermediate levels. YH14 was non-hemolytic and produced beneficial feed enzymes, including xylanase and phytase. In vivo , administration of YH14 induced no mortality, behavioral changes, or adverse effects on feed intake and body weight gain. Histological examination revealed preserved tissue architecture in the intestine, liver, and spleen, with no signs of inflammation. Moreover, YH14 modulated the gut microbiota by promoting beneficial bacterial populations and suppressing potential pathogens, without significantly altering overall microbiome diversity. These findings support the potential application of S. cerevisiae YH14 as a probiotic feed additive for improving gut health and digestive efficiency in livestock.