Alleviation of high fat diet-induced obesity by oligofructose in gnotobiotic mice is independent of presence of Bifidobacterium longum.

SCOPE: Diet-induced obesity is associated with changes in the gut microbiota and low-grade inflammation. Oligofructose was reported to ameliorate high fat diet-induced metabolic disorders in mice by restoring the number of intestinal bifidobacteria. However, this has not been experimentally demonstrated.

METHODS AND RESULTS: We fed conventional mice, germfree mice, mice associated with a simplified human gut microbiota composed of eight bacterial species including Bifidobacterium longum (SIHUMI), and mice associated with SIHUMI without B. longum a low fat diet (LFD), a high fat diet (HFD), or a HFD containing 10% oligofructose (HFD + OFS) for five weeks. We assessed body composition, bacterial cell numbers and metabolites, markers of inflammation, and gut permeability. Conventional mice fed HFD or HFD + OFS did not differ in body weight gain and glucose tolerance. The gnotobiotic mouse groups fed LFD or HFD + OFS gained less body weight and body fat, and displayed an improved glucose tolerance compared with mice fed HFD. These differences were not affected by the presence of B. longum. Mice fed HFD showed no signs of inflammation or increased intestinal permeability.

CONCLUSION: The ability of oligofructose to reduce obesity and to improve glucose tolerance in gnotobiotic mice fed HFD was independent of the presence of B. longum.