Zeng, Huawei

High‐fat diets induce changes in the gut microbiome and induce nonalcoholic fatty liver disease. This study tested the hypothesis that high‐fat feeding increases certain predominant hind gut bacteria in a C57BL/6 mouse model of obesity. We found that a high‐fat diet produced significant increases in both body weight and body fat percentage in C57BL/6 mice compared with a control group fed a low‐fat diet. With an immunohistochemical approach, we found that these changes were associated with increases in lipid droplets, inflammatory cell infiltration and inducible nitric oxide synthase (iNOS) level in the livers of mice fed the high‐fat diet. In addition, plasma leptin and tumor necrosis factor (TNFα) levels were elevated in mice fed the high‐fat diet, indicative of chronic inflammation. Eight out of twelve bacterial species that typically predominate hind gut microbial ecology were detected in fecal samples by DNA analysis. The DNA amount of one of these species, Lactobacillus (L.) acidophilus , was 6900‐fold greater in high‐fat fed mice compared to controls. L. acidophilus can promote inflammatory production of cytokines such as TNFα, which was also elevated in high‐fat fed mice. These results suggest that changes in the hindgut microbiome which accompany high fat feeding may contribute to the development of steatohepatitis in obese mice.