Impact of kestose supplementation on the healthy adult microbiota in in vitro fecal batch cultures

Prebiotics are widely used to shape a balanced microbiota in humans and animals. 1-Kestose (kestose) is one of the major components in commercialized short-chain fructooligosaccharide and is a promising prebiotic for infants. We herein studied the impact of kestose on the healthy adult microbiota in an in vitro fecal batch culture model. Stool samples obtained from seven healthy adults were diluted, inoculated into broth supplemented with or without 0.5% (w/v) kestose (kestose group and control group, respectively), and cultured under anaerobic conditions. Microbiota in the groups and stool samples were analyzed using 16S rRNA gene sequencing. At the phylum level, the kestose group showed increases in Bacteroidetes, whereas the control group showed increases in Proteobacteria. At the species level, Bifidobacterium longum was the only species showing significantly higher levels in the kestose group than in the control group and stool samples. On the other hand, levels of Escherichia coli were significantly higher in the control group than in stool samples, while the levels were not significantly different between the kestose group and stool samples. Quantitative PCR assays also revealed significantly higher levels of B. longum and lower tendency of E. coli in the kestose group than in the control group. These results suggest that supplementation with kestose increased the levels of beneficial microorganism and prevented the growth of risk-associated microorganisms related to disease development. Further interventional studies are needed to understand the health benefits of kestose in adult humans.