Effect of dietary lycopene supplementation on growth, antioxidant and immunity of juvenile hybrid grouper (♀Epinephelus fuscoguttatus ×♂E. lanceolatus) fed with high lipid diets

The aim of this experiment was to investigate the effects of dietary lycopene (LCP) on growth performance, antioxidant, and immunity of hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂) fed with high-lipid diets (HLD, CL16 %). Hybrid groupers (20.56±0.17 g) were selected and fed four diets containing 0, 100, 200 and 400 mg/kg of LCP, named L0, L1, L2 and L3. The results showed that: FBW and SGR were significantly higher in all dietary LCP group compared to the L0 group (P< 0.05). In serum, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) content were significantly higher in group L2 than in group L0, and alkaline phosphatase (AKP) content in L3 group was significantly lower (P< 0.05). In the liver, malondialdehyde (MDA) content were significantly lower in all LCP groups than in the L0 group (P< 0.05); catalase (CAT), AKP, and acid phosphatase (ACP) activities were significantly higher in all LCP group than in the L0 group (P< 0.05); SOD, Aspartate aminotransferase (GOT) and glutamate-pyruvate transaminase (GPT) activities in the liver were significantly higher in the L2 group than in the L0 group (P< 0.05). Dietary supplementation of 200–400 mg/kg LCP significantly up-regulated mRNA levels of hepatic sod, gsh-px, cat, nuclear factor erythroid 2-related factor 2 (nrf2), heat stimulating protein 90 (hsp90) and transforming growth factor-β (tgfβ), and significantly down-regulated mRNA levels of hepatic kelch-like ECH-associated protein 1 (keap1) and interleukin-1β (il1β) (P< 0.05). The optimal levels of LCP were 282.22 mg/kg, 246.83 mg/kg and 248.5 mg/kg for FBW, serum GSH-Px activity and hepatic immunoglobulin M (IgM) content, respectively. In conclusion, the addition of 200–300 mg/kg LCP could promote the growth performance of hybrid grouper, improve the antioxidant capacity, and alleviate the oxidative damage of liver caused by HLD.