Herbs mixture improves growth performance, intestine and liver histology, and immunity of juvenile large yellow croaker (Larimichthys crocea)

The present study aims to investigate the effects of dietary Chinese herbs mixture (CHM) including Artemisia capillaris, Gardenia jasminoides, Scutellaria baicalensis, Reynoutria japonica and Uncaria rhynchophylla on the growth performance, anti-oxidative and immune responses, and intestine and liver histology of juvenile large yellow croaker Larimichthys crocea (initial body weight: 17.03 ± 0.03 g), which were fed graded levels of CHM (0 (control group), 250, 500 and 750 mg/kg, respectively) for 60 days. The results indicated that supplementing 250 and 500 mg/kg CHM in diet significantly increased the weight gain rate and decreased the feed conversion ratio of juvenile large yellow croaker (P < 0.05). The activities of lipase, chymotrypsin, γ-glutamyl transferase and Na+, K+-ATPase were significantly increased in CHM250 and/or CHM500 groups (P < 0.05). Besides, the levels of total anti-oxidative capacity, immunoglobulin M, complement 3 and complement 4 were significantly increased in the CHM250 and/or CHM500 groups (P < 0.05). The expressions of anti-oxidation gene (nuclear factor erythroid 2-related factor 2, nrf2), anti-inflammatory cytokines (interleukin-10, il-10 and transforming growth factor-β, tgf-β) and anti-apoptotic gene (B-cell lymphoma-2, bcl-2) in liver were significantly up-regulated, while the malondialdehyde content and the expressions of kelch like ECH associated protein 1 (keap1) and nuclear factor κB p65 (nf-κb p65) were significantly down-regulated after supplementing 250 and/or 500 mg/kg CHM in diet (P < 0.05). The histological analysis of liver and intestine showed the better morphology in CHM250 and CHM500 groups than the control group. In conclusion, above results indicated that dietary CHM (250 – 500 mg/kg) significantly improved the growth performance, anti-oxidative capacity, immunity and histology of liver and intestine of juvenile large yellow croaker.