The influences of low protein diet on the intestinal microbiota of mice

Recent research has suggested that protein deficiency symptoms are related to the intestinal microbiota. We investigated the influence of a low protein diet on composition of the intestinal microbiota by animal experiments. We divided SPF mice into four groups fed diets containing 3, 6, 9, or 12% protein for 4 weeks. The intestinal microbiota of mice before and after feeding the 3% and 12% protein diets were investigated by 16S rRNA gene sequencing. Mice fed the 3% protein diet showed protein deficiency symptoms such as weight loss, the low level of albumin-globulin ratio and blood urea nitrogen concentration in their serum. On the other hand, the microbiota composition of mice fed the 3% protein diet changed over the course of the experiment: the abundance of some bacterial species that may be correlated with nitrogen recycling in the host was higher at the end of the experiment than at the beginning of the experiment. The present results suggest that a low protein diet led to adaptation of the intestinal microbiota in mice in response to protein deficiency.