Impact of Saccharomyces boulardii RC009 administration on clinical and microbiological parameters in Thoroughbred racehorses: a controlled study

Abstract

This study evaluated the effect of Saccharomyces cerevisiae var. boulardii RC009 on body condition, coat quality, fecal score, and fecal microbiota profile in 25 Thoroughbred racehorses over 30 days. Animals were divided into a control group (CG) and a treated group (TG), the latter supplemented with 2x1010 CFU/day. In the TG, coat condition improved significantly: 53.8 % increased by one grade, and the remaining 46.2 % by two grades. Regarding faecal consistency, 58.3 % of the CG and 53.8% of the TG increased their score by one point. Microbiologically, TG showed a relative increase in the families Lactobacillaceae and Prevotellaceae, taxa associated with optimized digestion. The results indicate that S. boulardii RC009 supplementation positively impacted body condition, coat appearance, and faecal microbiota profile. These findings suggest that the probiotic favorably influences host physiology and microbial composition, supporting the need for further longitudinal studies with larger cohorts to further explore these mechanisms.