Detection and isolation of typical gut indigenous bacteria in ICR mice fed wheat bran and wheat straw fibre

Wheat bran (WB) and wheat straw fibre (WSF) are by-products of the wheat flour industry. To prove the existence of indigenous gut bacteria responsible for WB and WSF, the Institute of Cancer Research (ICR) mice were fed a diet containing no fibre (CS), 10% WB, or 5% WSF for 14 d. The caecal microbiome was analysed by 16S rDNA (V4 region) amplicon sequencing. Typical colonies were isolated and estimated by 16S rRNA gene BLASTn analysis. The predominant amplicon sequence variants in all diet groups belonged to Bifidobacterium pseudolongum- and Faecalibaculum rodentium-like bacteria. Lactobacillus johnsonii- and Limosilactobacillus reuteri-like bacteria were high in the WB group compared with those in the CS group. Lactobacillus johnsonii Wheat-1 and L. reuteri Wheat-12 strains could be isolated. Lactobacillus johnsonii Wheat-1 exhibited good fermentation activity in 10% (w/v) WB suspension. Superoxide anion radical scavenging capacity of the WB suspension was significantly increased by the fermentation.