Similarities and differences of oligo/poly-saccharides’ impact on human fecal microbiota identified by in vitro fermentation

The dietary supplementation of prebiotics is considered a promising strategy for the modulation of gut microbiota. Due to the wide variety of animal models and tremendous inter-individual variability from human investigations, the prebiotic effect of fibers is often difficult to compare between studies. Here, the effects of 11 dietary fibers on human fecal microbiota were studied using an in vitro human fecal fermentation model under well-controlled conditions. All fibers showed positive regulatory effects on short chain fatty acids (SCFAs) and several beneficial bacteria, including Parabacteroides distasonis and Bifidobacterium spp. Cultures supplemented with xylo-oligosaccharide and konjac flour showed the highest SCFAs. According to regulatory effects, fibers were divided into three groups, with 13 indicator OTUs (operational taxonomic units) identified. Fecal microbiota regulated by isomalto-oligosaccharide and chitosan-oligosaccharide were similar to fructo-oligosaccharide and inulin outputs. As a supplement to in vivo studies, our results comprehensively summarized the similarities and distinctiveness of fibers in regulating fecal microbiota structures. KEY POINTS: • Fibers were divided into three groups based on the regulatory effects in microbiota. • Thirteen indicator OTUs were identified using pairwise comparisons. • Fiber similarities and distinctive traits in regulating microbiota effect were identified.