Influence of long-term feeding of different purified dietary fibers on cecal microflora composition and its metabolizing activity on bile acids

The aim of the study was to investigate the effect of four weeks ingestion of 10% fiber diets (cellulose, lignocellulose, pectin and guar gum) and a fiber-free diet on cecal microflora composition and its primary bile acid metabolizing activity in vitro in female Sprague Dawley rats. There was no difference in the qualitative and quantitative cecal microflora composition in rats fed cellulose and lignocellulose diets and those fed fiber-free diet. Guar gum and pectin diets significantly increased Bacteroidaceae compared to cellulose and lignocellulose diets. The counts of bifidobacteria were significantly higher in rats fed guar gum than in all the other groups. Clostridia were present in high counts in rats fed guar gum and pectin and generally absent in all the other groups. As regards 7α-dehydroxylating cholic and chenodeoxycholic microorganisms, cellulose and lignocellulose diets significantly decreased these microbial counts compared to all the diets. The results show that dietary fiber can induce alterations of cecal microflora composition and intestinal bile acid metabolism.