Gossypol, the main antinutritional factor in cottonseed protein concentrate (CPC), could affect the growth conditions of fish, but the underlying mechanism remains unclear. In this study, an 8-week feeding trial was carried out to investigate the effects of gossypol on Nile tilapia (Oreochromis niloticus). Three experimental diets were designed, including control diet (CON), control diet supplemented with 150 mg/kg gossypol (ML), and 300 mg/kg gossypol (MH). 16S rRNA gene sequencing showed that gossypol significantly reduced the richness and diversity of the gut microbiota. Untargeted metabolite analysis revealed that most metabolites were down-regulated by gossypol, and riboflavin was the key metabolite with significant difference between CON-treated and gossypol-treated groups. Gossypol caused intestinal inflammation, oxidative stress, and apoptosis. Through fecal bacteria transplantation experiments, we demonstrated that intestinal microbiota mediated gossypol-induced negative effects, suggesting that intestinal microbiota and its metabolite may account for the harmful effects of gossypol.
Keywords: Nile tilapia; gossypol; gut microbiota; intestinal health; metabolites.