Nondigestible Fructans Alter Gastrointestinal Barrier Function, Gene Expression, Histomorphology, and the Microbiota Profiles of Diet Induced Obese C57BL/6J Mice.
BACKGROUND Obesity is associated with compromised intestinal barrier function and shifts in gastrointestinal microbiota that may contribute to inflammation. Fiber provides benefits, but impacts of fiber type are not understood. OBJECTIVE We aimed to determine the impact of cellulose compared with fructans on the fecal microbiota and gastrointestinal physiology in obese mice. METHODS Eighteen wk old male diet induced obese C57BL/6J mice (n 6/group; 40.5 g) were fed high fat diets (45% kcal fat) containing 5% cellulose (control) 10% cellulose, 10% short chain fructooligosaccharides (scFOS) or 10% inulin for 4 wk. Cecal and colon tissues were collected to assess barrier function, histomorphology, and gene expression. Fecal DNA extracts were subjected to 16S ribosomal RNA amplicon based Illumina MiSeq sequencing to assess microbiota. RESULTS Body weight gain was greater (P 0.05) in scFOS fed than in 10% cellulose fed mice. Both groups of fructan fed mice had greater (P 0.05) cecal crypt depth (scFOS: 141 mm; inulin: 145 mm) than both groups of cellulose fed mice (5% and 10% 109 mm) Inulin fed mice had greater (P 0.05) cecal transmural resistance (101 O x cm(2) than 5% cellulose fed controls (45 O x cm(2) Inulin fed mice had lower (P 0.05) colonic mRNA abundance of Ocln (0.41) and Mct1 (0.35) than those fed 10% cellulose (Ocln: 1.28; Mct1: 0.90) Fructan and cellulose groups had different UniFrac distances of fecal microbiota (P 0.05) and a diversity, which demonstrated lower (P 0.01) species richness in fructan fed mice. Mice fed scFOS had greater (P 0.05) Actinobacteria (15.9% and Verrucomicrobia (Akkermansia) (17.0% than 5% controls (Actinobacteria: 0.07% Akkermansia: 0.08% Relative abundance of Akkermansia was positively correlated (r 0.56, P 0.01) with cecal crypt depth. CONCLUSIONS Fructans markedly shifted gut microbiota and improved intestinal physiology in obese mice, but the mechanisms by which they affect gut integrity and inflammation in the obese are still unknown.
The Journal of nutrition