Abstract: To investigate the effect of dietary fructooligosaccharides (FOS) in preventing obesity and regulating the gut?microbiota in C57BL/6 mice, 50 male five-week-old C57BL/6 mice were randomly divided into five groups. One group received a normal diet as a control group, while the other four groups were fed a high fat diet to induce obesity. The mice in the normal and model groups were given normal saline intragastrically, those in the experimental groups were given high and low doses of FOS intragastrically, and those in the positive control group were given orlistat intragastrically. The experiment lasted for six weeks. High-throughput 16S rRNA gene amplicon sequencing and enzyme-linked immunosorbent assay (ELISA) were carried out in this study. The results showed that both high- and low-dose FOS significantly reduced the Lee’s index and epididymal?adipose index (P < 0.05), and significantly increased the high density lipoprotein cholesterol (HDL-C) level of the obese mouse model (P < 0.05). High-dose FOS significantly reduced the body mass gain, and the levels of serum low density lipoprotein cholesterol (LDL-C), tumor necrosis factor α (TNF-α) and lipopolysaccharide (LPS) in the obese mouse model. The gut microbiota analysis showed that compared with the normal group, the relative abundance of Firmicutes in the model group was significantly increased (P < 0.05), and the relative abundance of Bacteroidota was significantly decreased (P < 0.05). The gut microbiota of mice in the FOS intervention group was restored to a certain extent, and the composition of gut microbiota was close to that of the normal group. Therefore, FOS can control obesity and improve the gut microbiota in mice.

Key words: fructooligosaccharides; obesity; prebiotics; gut microbiota; endotoxin