Effect of Bacillus subtilis DSM29784 on the chicken microbiome

The probiotic Bacillus subtilis strain 29784 (Bs29784) has been shown to improve performance in broilers. In this study, we used a metabolomic and 16S rRNA gene sequencing approach to evaluate effects of Bs29874 in the broiler intestine. Nicotinic acid and hypoxanthine were key metabolites that were produced by the strain in vitro, and were also found in vivo to be increased in small intestinal content of broilers fed Bs29784 as dietary additive. Bs29784 supplementation to the feed significantly altered the ileal microbiome of 13 days old broilers, thereby increasing the abundance of genus Bacillus, while decreasing genera and OTUs belonging to the Lactobacillaceae and Enterobacteriacae families. Moreover, Bs29784 specifically enriched members of family Clostridiales VadinBB60, as well as the butyrate-producing families Ruminococcaceae and Lachnospiraceae. The abundance of various OTUs and genera belonging to these families was significantly associated with nicotinic acid levels in the caecum, suggesting a possible cross-feeding between B. subtilis strain 29784 and these beneficial microbes.