Fate of chitin-glucan in the human gastrointestinal tract as studied in a dynamic gut simulator (SHIME)®

Despite the availability of in vivo data showing the positive effect of chitin-glucan (CG), an insoluble dietary fiber extracted from the cell wall of fungi, its fate after ingestion remains unknown. In this study, we made use of the in vitro Simulator of the Human Intestinal Microbial Ecosystem (SHIME) to assess the impact of two different doses of CG (1.5 and 4.5 g/day) on the physiology of the upper GIT and on the gut microbiota activity and composition. CG reduced the fractions of bioaccessible iron, bile salts and had a strong water retention capacity. Daily doses of CG for at least 2 weeks were needed to induce gradual changes in the gut microbiota composition and activity. The gradual fermentation along the entire colon was linked to a propionogenic and butyrogenic effect, mild gas production, decrease of the ratio Firmicutes/Bacteroidetes and delayed increase in the concentration of Roseburia spp. (C) 2017 Elsevier Ltd. All rights reserved.