Effects of Bacillus coagulans (GBI-30, 6086) supplementation on apparent total tract nutrient digestibility and the fecal characteristics and metabolites, immunity, and microbiota of healthy adult dogs.

Bacillus coagulans GBI-30, 6086 is a lactic acid-producing, spore-forming bacteria with diverse characteristics that lend it resiliency through commercial pet food processing, storage, and chemical and enzymatic digestion through the gastrointestinal tract. The objective of this study was to determine the effects of B. coagulans on dietary apparent total tract nutrient digestibility (ATTD) and the hematology, immunoglobulin concentrations, and fecal characteristics, metabolites, and microbiota populations of healthy adult dogs. Adult English Pointer dogs (n = 12; age = 5.9±2.5 yr; body weight = 26.6±6.1 kg) were fed the same diet but supplemented with B. coagulans or a placebo via gelatin capsules in a replicated 3×3 Latin square design. Capsules were administered daily before each feeding, with the following treatments tested: 1) basal diet + placebo (control; 250 mg maltodextrin); 2) basal diet + B. coagulans [low dose; 5×108 colony-forming units (CFU)/d]; and 3) basal diet + B. coagulans (high dose; 2.5×109 CFU/d). Fecal, blood, nasal, and pinnae samples were collected after a 22-d adaptation phase in each period. Data were analyzed using the Mixed Models procedure of SAS 9.4, with P<0.05 being significant and P<0.10 being trends. B. coagulans supplementation did not affect ATTD, food intake, fecal metabolites, immunoglobulin concentrations, or hematology, but did lower fecal scores (P<0.05; firmer stool). Using qPCR, fecal Faecalibacterium spp. abundance was greater (P<0.05) and fecal Bacteroides spp., Bifidobacterium spp., and Ruminococcus gnavus abundances tended to be greater (P<0.10) in dogs fed the low B. coagulans dose than those fed the placebo. Overall, our results demonstrate that this bacterial species can be safely supplemented to healthy dogs without a negative impact on nutrient digestibility or canine health parameters, and supplementation with the low dose treatment may help maintain fecal consistency and positively influence gastrointestinal microbiota.