Diet supplemented with Saccharomyces cerevisiae from different fermentation media modulates the faecal microbiota and the intestinal fermentative products in dogs

This study aimed at evaluating the coefficients of total tract apparent digestibility (CTTAD) of nutrients, metabolisable energy (ME), diet palatability, faecal fermentative products and microbiota of dogs fed yeasts from different fermentation media and its fractions. Four diets were evaluated: control, without yeast (CO); diet with 10 g/kg brewer's yeast (BY); diet with 10 g/kg brewer's yeast + corn yeast (BCY); and diet with 10 g/kg BCY + cell wall fractions (BCYF). Twelve adult dogs were distributed in a randomized block design (periods). Each of the four diets was fed to a group of three dogs per period of 20 days, totalling two periods and six repetitions per treatment. Sixteen adult dogs were used for the palatability test, which compared the CO diet versus each one of the yeast diets. Data with normal distribution were subjected to analysis of variance (p < 0.05). Means were compared by orthogonal contrasts (p < 0.05): (A) CO diet versus BY, BCY and BCYF diets; (B) BY diet versus BCY and BCYF diets; (C) BCY diet versus BCYF diet. There was no difference in the CTTAD and ME of the diets (p > 0.05). Yeast diets reduced faecal odour and indole peak area (p < 0.05). Faecal short-chain fatty acids concentration was greater in dogs fed yeast diets compared to those fed the CO (p < 0.05). Yeast diets showed a higher intake ratio compared to the CO (p < 0.05). The BCY and BCYF diets resulted in a greater abundance of Bacteroides, Faecalibacterium, Coprococcus, and Phascolarctobacterium in relation to the CO (p < 0.05). Our results suggest that dietary yeast supplementation results in beneficial changes in intestinal functionality indicators, mainly with the combination of yeasts from brewers and corn fermentation media. In addition, yeast supplementation improves diet palatability without compromising nutrient digestibility.