Lean rats gained more body weight from a high-fructooligosaccharide diet

Fructooligosaccharides (FOS) are believed to be beneficial to the host growth and its gut health. This article is intended to investigate the different influences of a high-fructooligosaccharide (FOS) diet on the growth and gut microbiota of lean and obese rats. Diet-induced lean and obese rats were fed a high-FOS diet for 8 weeks. Rats' body weight (BW) and feed intake were recorded weekly, and their gut microbiota was analyzed by 16S rDNA sequencing. The results showed that the lean rats gained more BW than the obese ones from the high-FOS diet. In the meanwhile, the gut microbiota in both lean and obese rats was altered by this diet. The abundance of Bacteroidetes was increased significantly (P < 0.05) in the lean rats, while no significant alteration in Firmicutes was observed in all rats after the consumption of a high-FOS diet. In conclusion, this study first reported that the lean rats gained more body weight from a high-FOS diet than the obese ones, and the increase of Bacteroidetes might help rats harvest more energy from the high-FOS diet.