PSV-B-18 - Characterization of the fecal microbiome of healthy adult Beagle dogs supplemented with graded levels of Bacillus coagulans GBI-30, 6086

This study aimed to evaluate the effect of Bacillus coagulans GBI-30, 6086 on the fecal microbiome of healthy adult dogs. Extruded diets containing graded levels of probiotic applied either to the base ration before extrusion or as a topical coating post-extrusion were randomly assigned to ten individually-housed Beagle dogs (7 castrated males, 3 spayed females) of similar age (5.75 ± 0.23 yr) and body weight (12.3 ± 1.5 kg) in a 5 x 5 replicated Latin square with 16-d adaptation and 5-d total fecal collection for each period. Five dietary treatments were formulated to deliver a dose of 0-, 6-, 7-, 8-, or 9-log₁₀ CFU·dog^-1·d^-1. Fresh fecal samples (n=50) were analyzed by 16S rRNA gene pyrosequencing. Community diversity was evaluated in R (v4.0.3, R Core Team, 2019). Relative abundance data were analyzed using a mixed model (v9.4, SAS Institute, Inc., Cary, NC) with treatment and period as fixed effects and dog as a random effect. Results were considered significant at P < 0.05. Predominant phyla were Firmicutes (mean 81.2% ± 5), Actinobacteria (mean 9.9% ± 4.4), Bacteroidetes (mean 4.5% ± 1.7), Proteobacteria (mean 1.3% ± 0.7), and Fusobacteria (mean 1.1% ± 0.6). No evidence of shifts in predominant phyla, class, family, or genus taxonomic levels were observed except for the Bacillus genus, which had a greater relative abundance (P = 0.0189) in the low probiotic coating and high probiotic coating treatment groups compared to the extruded probiotic group. Alpha-diversity indices (Richness, Chao1, ACE, Shannon, Simpson, Inverse Simpson, and Fisher) and beta-diversity metrics (principal coordinate analysis and multi-dimensional scaling) were similar for all treatments. This data indicates that supplementation with Bacillus coagulans GBI-30, 6086 at a dose of up to 9 log₁₀ CFU·d^-1 did not alter the overall diversity of the fecal microbiome of healthy adult dogs over a 21-d period.