Effects of dietary fiber supplementation on fatty acid metabolism and intestinal microbiota diversity in C57BL/6J mice fed with high fat diet.

This work was to assess possible impacts of novel insoluble fiber BC (8% bacterial cellulose), soluble fiber KGM (8% Konjac glucomannan) and their mixture (4% BC/4% KGM) on fatty acid metabolism and intestinal microbiota of C57BL/6J mice fed with high-fat diet (HFD). HFD-fed mice receiving the dietary fibers (DFs) for 16 weeks exhibited an improvement in lipid-associated cytokines and a decrease in inflammation factors, which was associated with the improved the hepatic and serum fatty acids composition. The DFs, notably the mixed BC/KGM, elevated the HFD-caused decrease in the contents of acetic acid (from 23.9±0.85 to 32.2±0.84 mM/g, p<0.05), propionic acid (from 6.53±0.28 to 12.8±0.58 mM/g, p<0.05) and butyric acid (from 7.73±0.43 to 13.5±0.47 mM/g, p<0.05). Furthermore, the mixed BC/KGM significantly decreased the abundance of Firmicutes (from 90.4% to 67.6%) and Mucispirillum (from 4.77% to 1.58%), and dramatically increased the abundance of Bacteroides (from 7.83% to 25.0%) and Akkermansia (from 0.69% to 2.80%) in the gut of HFD-fed mice at genus level. Moreover, correlation analysis revealed that the multiplicity of gut microbiota was useful in sustaining colonic integrity through producing short chain fatty acids to some extent. This finding suggests that a mixture of insoluble BC and soluble KGM has positive effects on modulation of intestinal microecosystem in mice.