Beneficial effects of fermented vegetal beverages on human gastrointestinal microbial ecosystem in a simulator.

The aim of this study was to evaluate the effects of four beverage formulations (prebiotic - fructooligosaccharide, probiotic - Lactobacillus casei Lc-01, synbiotic - fructooligosaccharide and L. casei Lc-01 and placebo) based on aqueous extracts of soy and quinoa, towards the human intestinal microbiota using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®), a dynamic model of the human gut. To monitor the effects on microbial community composition, plate counts on specific growth media and a PCR-DGGE analysis were performed on samples from all colon compartments - ascending, transverse and descending. To verify the effects on microbial metabolism, we analyzed the ammonium and short chain fatty acids (SCFAs) concentrations. The synbiotic beverage showed the best microbiological results in the ascending colon compartment, stimulating the growth of Lactobacillus spp. and Bifidobacterium spp., and reducing Clostridium spp., Bacteroides spp., enterobacteria and Enterococcus spp. populations in this compartment. A larger reduction (p<0.05) of ammonia ions in the ascending colon was observed during the synbiotic beverage treatment. No statistical difference was observed in SCFA production among the treatments and the basal period. Plate count and DGGE analysis showed the survival of L. casei Lc-01 in the colon. DGGE analysis also showed higher richness and diversity of the Lactobacillus spp. community during the treatment with synbiotic beverage, with higher accentuation in the ascending colon.