The beneficial effect of exopolysaccharides from Bifidobacterium bifidum WBIN03 on microbial diversity in mouse intestine

BACKGROUND The structure of exopolysaccharides (EPS) produced by Bifidobacterium and their beneficial effects on human health have been fully studied, but only a few studies have investigated their influence on microbial diversity in the human/animal intestine. RESULTS The strain named Bifidobacterium bifidum WBIN03 with high growth rate and exopolysaccharide (EPS) yield was selected to study the effect of its EPS on modifying the intestinal microbiota of mice. The results indicated that EPS significantly increased the growth of lactobacilli and total anaerobic bacteria, and exerted their inhibition effect on the growth of enterobacteria, enterococci and Bacteroides fragilis. Denaturing gradient gel electrophoresis (DGGE) analysis indicated that the EPS significantly increased the diversity of total bacteria and lactobacilli, but significantly decreased the diversity of enterobacteria. When receiving a low dose of EPS, Bacteroidales sp./Lactobacillus sp. occupied the dominant position, and L. johnsonii, L. animalis and L. reuteri were identified as the dominant strains when receiving a high concentration of EPS. CONCLUSION The combination of viable cell count, DGGE and sequencing was used as an effective method to assess the microbial diversity in mouse intestine, and the benefit effect of EPS from B. bifidum WBIN03 on probiotics and antagonistic effect against pathogens would guaranteed the health of their hosts. © 2013 Society of Chemical Industry