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Fructooligosaccharides (FOS) are a well-known class of prebiotic and are considered to selectively stimulate the growth of bifidobacteria in the gut. Previous studies focused on the stimulated growth of Bifidobacterium, but did not further investigate the bifidobacterial composition, i.e. the specific species that was were stimulated. In this study mice were fed with FOS in different doses (0%, 5%, and 25%) for 4 weeks and the composition of fecal microbiota, in particular Bifidobacterium, was analyzed by sequencing the V3-V4 region and the groEL gene on the MiSeq platform, respectively. In the high-dose group (25% FOS) the relative abundance of Actinobacteria was significantly increased, which was mainly contributed by Bifidobacterium. At the genus level the relative abundances of Blautia and Coprococcus were also significantly increased. Through the groEL sequencing 14 species of Bifidobacterium were identified, among which Bifidobacterium pseudolongum (B. pseudolongum) was most abundant. After FOS treatment, B. pseudolongum became almost the sole bifidobacterial species (>95%). We isolated the B. pseudolongum strains and, by high performance liquid chromatography (HPLC), demonstrated their ability to metabolize FOS. Therefore, we concluded that FOS significantly stimulated the growth of B. pseudolongum in mice. Further investigations are needed to reveal the mechanism of selectiveness between FOS and B. pseudolongum, which would aid our understanding of the basic principles of dietary carbohydrates and host health. |
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Keywords:Food science; Fructooligosaccharides; 16S rDNA metagenomic sequencing; intestinal microbiota; Bifidobacterium pseudolongum. |
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