We only see very few metabolites, namely trimethylamine N-oxide (Fig. 2E), mannose (Fig. 3C) in zebrafish larvae and 3-aminoisobutyric acid (Fig. 5C) and putrescine (Fig. 6C) in mice of which the levels are changed more severely in the leptin mutant in the presence of infection as compared to the WT. This evidence concerns the gene LEP and infection.