Supplementation with probiotic/carbon source mixtures in-creased short-chain fatty acid production in the Mucosal Simulator of the Human Intestinal Microbial Ecosystem (M-SHIME®) model

Mixtures containing probiotic bacteria and a carbon source ( Lactobacillus amylovorus [LA] + yeast beta glucan [YBG]; Bacillus subtilis [BS] + wheat flour T55 [WF55]) were evaluated for their ability to modify the gut microbial activity and composition of two healthy human donors in vitro . in vitro Survival of both probiotic strains was shown throughout upper gastrointestinal transit, with the proportion of viable and culturable cells was being a respective 68.0% and 6.9% for LA and 39.9% and 13.1% for BS. Furthermore, after 3 weeks of supplementation with LA+YBG or BS+WT55 using the Mucosal Simulator of the Human Intestinal Microbial Ecosystem (M-SHIME®) model, significant butyrogenic effects were observed in the colonic environment (+33.1% and +73.2% across donors, respectively), likely due to stimulation of members of the Firmicutes phylum. Product-specific effects included significantly elevated acetate production for BS+WT55 (+43.0% across donors), and a consistent propiogenic effect for LA+YBG (+28.6% across donors). These effects could be linked with increased levels of Bifidobacterium spp., particularly Bifidobacterium adolescentis , and enhanced Bacteroides abundance, respectively. The two test mixtures thus demonstrated probiotic-like effects, indicating their potential for gut health. • Both probiotics survived upper GIT transit and sustained within the colonic regions • LA+YBG and BS+WF55 showed consistent and significant butyrogenic properties • LA+YBG specifically enhanced propionate by 28.6%, linked to Bacteroides enrichment • BS+WF55 specifically boosted acetate by 43.0%, driven by Bifidobacterium growth • Both product mixtures enhanced A. muciniphila levels in the distal colonic lumen