Synergistic Effect of Dietary Inactivated Lactobacillus plantarum and Berberine Supplementation on Growth Performance, Antioxidant Capacity, and Immune Function of Juvenile Black Sea Bream (Acanthopagrus schlegelii)

The interactive effect of dietary inactivated Lactobacillus plantarum and berberine on black sea bream, Acanthopagrus schlegelii, was investigated with three diets designated as D1 (Con: basal diet), D2 (LP: basal diet + 400 mg/kg L. plantarum), and D3 (LPBB: basal diet + 400 mg/kg L. plantarum + 50 mg/kg berberine) and fed to juvenile black sea bream ( 5.67 ± 0.05  g) for 56 days. The growth performance and feed utilization parameters, as well as intestinal trypsin activity, were significantly improved in the LP and LPBB groups ( P < 0.05 ). Fish fed the LPBB diet showed better serum and hepatic antioxidant capacity, whilst the LP group had better hepatic antioxidant capacity, than the control fish ( P < 0.05 ). Intestinal IgM and C3 levels significantly increased in the LPBB fish than the rest of the groups ( P < 0.05 ). NF-κB was significantly upregulated in the LP group ( P < 0.05 ). Nrf2 and IL-10 were significantly upregulated, whilst Keap1b and NF-κB were significantly downregulated in the LPBB group ( P < 0.05 ). These findings show that a combination of inactivated L. plantarum and berberine in the diet of black sea bream can improve the immune response and antioxidant capacity than a diet with only the inactivated probiotic, whilst both diets can equally improve growth performance.