Effects of Oat Bran Addition on the Growth Performance and Intestinal Health of Nile Tilapia ( Oreochromis niloticus ) Exposed to Copper Ions.

This study investigated the effects of the oat bran addition on the growth performance and intestinal health of Nile tilapia ( Oreochromis niloticus ) exposed to copper ions. Four groups of diets containing 0%, 5%, 10%, and 20% oat bran were fed to Nile tilapia for four weeks. The results showed that oat bran had a dose-dependent effect on the growth performance of Nile tilapia. The addition of oat bran can increase the relative abundance of Delftia , which is capable of degrading heavy metals in the intestinal tract and alleviating the intestinal damage caused by copper ion stress. Compared to the control group, the 5% oat bran group had an increased intestinal antioxidant capacity. The relative gene expression of proinflammatory factors (NF- κ B, IL-1 β ) was significantly downregulated in the 5% oat bran group ( P < 0.05), and the relative gene expression of anti-inflammatory factors (TGF- β ), HIF-1 α , occludin, and claudin was significantly upregulated ( P < 0.05). In conclusion, we suggest that 5% oat bran should be added to the diet to improve the growth performance of Nile tilapia and alleviate the negative effects of copper ion stress on intestinal health.