Effect of live yeast supplementation on gastric ecosystem in horses fed a high-starch diet

The observation of the stomach with the video-endoscope did not reveal any alteration of the squamous gastric mucosa. Total anaerobic bacteria and amylolytic concentrations were lower with Sc47 dose 10 compared to placebo (P = 0.03 and 0.04, respectively). With dose 10 of Sc47, lactate-utilizing bacteria concentrations decreased compare to Sc47 dose 1 (P = 0.03) and placebo (P = 0.004). No treatment effect was observed on total VFAs and lactic acid concentrations. Butyric and valeric acids concentrations showed higher concentration with Sc47 dose 1 compared to other treatments during period 1. Although, the pHs were numerically less acidic with live yeast, they were not significantly modified by the treatment. Globally, there was a dose effect of Sc47 on bacteria concentrations which all decreased or tended to decrease when the level of yeast increased in the diet. Further investigation is required to know whether live yeast supplementation could be part of the strategy to reduce gastric fermentation of starch and thereby help reducing the risk of ESGD.