PSVIII-13 Evaluating the Effects of a Dried brewer’s Yeast Product on the Fecal Characteristics, Metabolites, and Microbiota Populations of Adult Dogs

Abstract

Abstract Inclusion of brewer’s yeast in pet foods has become popular because of the potential health benefits it provides. However, more research is needed to evaluate the effects of different brewer’s yeast products on canine gut health outcomes. This study aimed to investigate the effects of a brewer’s yeast product on the fecal characteristics, metabolites, and microbiota populations of adult dogs. Sixteen healthy adult dogs (BW: 9.0 ± 1.7 kg) were acclimated for 7 days and then randomly assigned to a control diet containing no yeast or a brewer’s yeast-containing diet (n = 8/group) for a 21-day period. Fresh fecal samples were collected before and after treatment for measurement of fecal scores, pH, dry matter content, metabolite concentrations [short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), ammonia, phenols, indoles], and microbiota populations. All data were analyzed as a percent change from baseline using the PROC MIXED procedure of SAS, with treatment as the main effect and dog as a random effect. Significance was declared at P ≤ 0.05, and trends reported if 0.05 < P ≤ 0.10. The brewer’s yeast treatment tended to increase (P = 0.10) fecal butyrate concentrations more than that of controls, but fecal characteristics (pH; dry matter; fecal scores) and other metabolite concentrations were not affected by treatment. Fecal bacterial alpha diversity metrics were not affected by treatment, but beta diversity analysis (unweighted UniFrac distances) tended (P = 0.09) to show a shift between treatments. Change in relative abundance of fecal Blautia was less (P = 0.05) in dogs fed brewer’s yeast than controls, but other bacterial genera were unaffected by diet. In conclusion, this study suggests that the dried brewer's yeast products tested had little impact on fecal characteristics, metabolites, or microbiota populations of adult dogs. The tendency of greater fecal butyrate concentrations in dogs fed brewer’s yeast is encouraging, but further research is needed to identify the potential health benefits of these products in canine diets.