Dietary supplementation with Bacillus subtilis C-3102 improves gut health indicators and fecal microbiota of dogs

Abstract This study aimed to evaluate the effects of Bacillus subtilis C-3102 on diet digestibility, fecal characteristics, and fecal microbiota of dogs. Sixteen adult Beagle dogs were randomly assigned to one of the two dietary treatments for 33 days: control (no B. subtilis C-3102, n = 8) and B. subtilis C-3102 (1 × 106 CFU of B. subtilis C-3102/g of diet, n = 8). Diets were offered for an adaptation period of 28 days followed by five days of total fecal collection. The coefficients of total tract apparent digestibility (CTTAD) of nutrients and metabolizable energy (ME) content of diets were evaluated. Fecal characteristics were evaluated at the end of the study by dry matter content, fecal score (1 = watery to 5 = firm stools), pH, ammonia concentration, odor, short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), and sialic acid concentrations. The fecal odor was evaluated by 50 volunteers by comparing the odor of fresh feces of the B. subtilis C-3102 vs the control group. Fecal microbiota was evaluated by sequencing the 16S rRNA gene. No difference was observed between the groups for CTTAD and ME (P > 0.05). Likewise, no differences were observed for fecal pH and sialic acid (P > 0.05). However, firmer stools (P