Diet Switch Changes the Composition of the Intestinal Microbiota. (A) Schematic representation of the experimental design. The fecal samples were collected for microbiota analysis at different time points (d0, d49, d51, d53 and d56, d58 and d63) from R23FR and FR mice. (B) Histological scores of the colon and cecum of R23FR mice at d49, d51, d53 and d56. *p<0.05, **p<0.01, *** p<0.001; by nonparametric Mann-Whitney test. (C) Alpha diversity (estimated as number of observed OTUs) at a sequencing depth of 12,000 seqs/sample. Asterisks (colored according to the different genotyping group) indicate a statistically significant difference in the number of observed OTUs compared to OTUs at day 49 within each group. N=8–15 per time point for each group. **p<0.01, *** p<0.001; by nonparametric Mann-Whitney test. (D) Bacterial phylum-level community composition in the stool of R23FR and FR mice at each time point.