Fig. 7

Untargeted metabolomics analysis reveals a metabolic candidate regulating the motivation for food reward. Volcano plots showing metabolites discriminant between gut microbiota recipient mice from lean and obese donors in a the plasma and b in the cecal content. Metabolites with labeled point were significantly down (red) or up (blue) in gut microbiota recipient mice from obese donors (DIO_rec) after non-parametric Wilcoxon test (p-value < 0.05) and were more than 2-fold changed compared to lean gut microbiota recipient mice (Lean_rec). Metabolites that did not satisfy the threshold of significance at Wilcoxon test and that were less than 2-fold changed compared to the lean gut microbiota recipient mice, appear in gray and are not labeled. The horizontal line corresponds to the p-value cutoff of 0.05 at non-parametric Wilcoxon test, the vertical lines correspond to the fold change cutoff of 2. See also Table 1 for the detailed list of the significantly different metabolites between gut microbiota recipient mice from lean and obese donors. Metabolites with a star (*) are partially characterized, and X metabolites are unidentified. Pearson’s correlations between 3-(3’-Hydroxyphenyl)propanoic acid concentrations in c the plasma or in d the cecal content of donor and gut microbiota recipient mice and the mean number of lever presses on the active lever during the progressive ratio (PR) sessions of the operant wall test