Abstract:

In order to explore the relationship among diet, obesity and intestinal microbiota, high-fat diet was used to
establish obese human flora-associated (HFA) mouse model to investigate the effect of high fat diet on the structure of
gut microbiota in HFA mice. Totally 20 pathogen-free mice were inoculated with fecal suspension derived from a healthy
volunteer to obtain HFA mice. The HFA mice were fed a control or a high-fat diet for 8 weeks. Body weight, blood glucose
and blood fat were determined and the change in gut microbiota was analyzed by PCR-DGGE. Results showed that body
weight, liver weight, fat tissue weight and serum total triglyceride level revealed a significant increase (P ＜ 0.01) in the
high-fat group when compared with the control group. Blood glucose level also increased significantly (P ＜ 0.05) in highfat
diet-fed HFA mice. The gut bacterial diversity index of the high-fat group significantly increased (P ＜ 0.05). The
abundance of the dominant bacteria at zero time reduced, but the abundance of bacteria that were not dominant at zero time
increased. DNA sequencing showed that high-fat diet may induce Staphylococcus lentus, Staphylococcus vitulinus and
Shigella flexneri to bloom in the gut of HFA mice. An obese HFA mouse model was successfully established by feeding a
high-fat diet and high-fat diet obviously altered the structure of gut microbiota in HFA mice. The composition and bacterial
abundance of intestinal flora in high-fat diet-feed HFA mice greatly changed, leading to intestinal dysbacteriosis. It suggests
that human-derived intestinal flora may be involved in the development of obesity caused by imbalanced dietary profile.

Key words: pathogen-free mice, human flora-associated mice, gut microbiota, high-fat diet, obesity, PCR-DGGE