Overfeeding a High-Fat Diet Promotes Sex-Specific Alterations on the Gut Microbiota of the Zebrafish (Danio rerio).

Diet modulates the gut microbiota and is one of the main factors promoting obesity and overweight. In the present study, we investigated the effect of a high-fat diet (HFD) on the gut microbiota of the zebrafish (Danio rerio). Fish were separated into three groups and fed in different regimes: low fat, high fat, and high fat overfed; the experiments were performed on males and females separately. We analyzed more than 2.6 million sequences of variable region V3 of the 16S rRNA gene generated by the Illumina Miniseq platform, clustered to 97% similarity with vsearch and classified with the EzBioCloud database. The weight gain, condition factor (K), and body mass index were calculated as indicators of obesity. Multivariate analysis (PERMANOVA and ANOSIM) and diversity indices (Shannon and Dominance) revealed that overfeeding a HFD disturbs the gut microbiota differently in males and females suggesting that sex is a significant factor (p < 0.05) for the composition of the gut microbiota of zebrafish. The results also indicate that a HFD provided in a basal caloric regime does not promote obesity or alterations in the gut microbiota.