Effect of direct-fed microbial supplementation on dietary nutrient digestibility and fecal characteristics of dogs

The nutritional composition of a diet influences gut microflora, which in turn influences digestion of food and absorption of nutrients. Direct-fed microbes are often supplemented in the diet to improve the health of animals; however, the effect of direct-fed microbial supplementation on nutrient digestibility and fecal characteristics in dogs, as well as how it affects palatability, is not well known. The objective of this study was to determine the effect of a direct-fed microbial supplementation in dogs on the following characteristics: dry matter, organic matter, apparent total tract nutrient and energy digestibility, fecal pH, and fecal score. Twelve dogs, fed a premium commercial diet, were divided into two groups which were randomly assigned the following treatments: a) Control (no Direct Fed Microbes [DFM]), and b) DFM (Bacillus subtilis (2×109 CFU/g), Bifidobacterium bifidum (2×109 CFU/g), Enterococcus faecium (4×109 CFU/g), Lactobacillus acidophilus (3×109 CFU/g), and Lactobacillus casei (4×109 CFU/g). Dogs underwent their assigned treatment for 33 days. Overall, the supplementation of the direct-fed microbes did not affect dry matter, organic matter, or gross energy digestibility, as well as fecal scores or fecal pH. Our results did show a clear food preference for the food with the direct-fed microbes. These results highlight that the DFM had a positive impact on palatability, but in our sample of healthy dogs fed a high-quality diet, enhancements in digestibility were not evident.