Feruloylated oligosaccharides modulate the gut microbiota in vitro via the combined actions of oligosaccharides and ferulic acid

The effects of wheat bran feruloylated oligosaccharides (FOs) on the gut microbiota were studied. Furthermore, xylo-oligosaccharides (XOs) and ferulic acid (FA) as the two major moieties were used to demonstrate the structural influence of FOs on microbiota modulation effects. FOs promoted the phylum Firmicutes and Actinobacteria and decreased the relative abundance of Bacteroidetes and Proteobacteria. FA significantly increased the phylum Bacteroidetes. At the genus level, FOs promoted beneficial microorganism such as Bifidobacterium and Faecalibacterium, and inhibit the growth of disease-related bacteria such as Alistipes, Bilophila, Dorea, Enterobacteriaceae, and Oscillopira. FA significantly increased Bacteroides, Dialister and decreased Coprococcus, Enterobacteriaceae, Megamonas, Oscillospira. In terms of metabolites, FOs and XOs increased the content of short-chain fatty acids (SCFAs) but inhibited the production of branched-chain fatty acids (BCFAs). However, FA inhibited the production of both SCFAs and BCFAs. In conclusion, wheat bran FOs showed the prebiotic effects and further promoted the production of SCFAs due to the combined actions of oligosaccharides and FA moieties. Our findings highlighted that composition and structure should be taken into consideration for selecting FOs as prebiotics.