Brewer's yeast (BY), autolysed sugarcane yeast (ASCY) and integral sugar cane yeast (ISCY) were studied in two experiments as ingredients for dog diets.
In the first experiment, 28 dogs were randomly assigned to four diets; one reference diet and three test diets containing 15% of BY, ASCY or ISCY and 85% of the reference diet. The digestibilities of the yeasts were calculated by the substitution method. In the second experiment, 35 dogs were randomized to five diets with similar chemical composition but different levels of sugarcane yeast inclusion. In both experiments, the coefficient of total tract apparent digestibility (CTTAD) of nutrients was determined through total collection of feces. During experiment, two additional analyses of food palatability, nitrogen balance and urea postprandial responses were performed.
In experiment 1, CTTAD of protein was lower for both sugarcane yeasts than for BY, as was metabolizable energy content. In experiment 2, a linear reduction in energy digestibility with ASCY inclusion was verified. Furthermore, fecal score and DM content were reduced with ISCY inclusion. No effect of yeast inclusion on nitrogen balance or postprandial urea response was found.
Yeasts present adequate digestibility by dogs, but its effect on fecal formation needs to be considered. No clear advantage for the use of ASCY over ISCY was found. In conclusion, we find that sugarcane yeast is suitable for inclusion in dog food and can enhance the overall palatability of the diet.