Effects of L‐carnitine supplementation on growth performance, histomorphology, antioxidant and immune function of Rhynchocypris lagowskii fed dietary fish oil replaced with corn oil

摘要

Abstract The effects of L‐carnitine (LC) and dietary lipid on the growth and health of farmed fish are still conflicting. This study aimed to explore the effects of LC supplementation and dietary fish oil replacement by corn oil on growth performance, antioxidant, immune function and histomorphology of Rhynchocypris Lagowskii. Six diets were evaluated as follows: dietary fish oil as 50 and 100 replacement by corn oil, and differing in LC supplementation (0 and 400 mg/kg), were tested in R. Lagowskii for 8 weeks. The highest weight gain rate, specific growth rate and feed efficiency were observed in mix oil diets with LC. The diet with LC significantly increased the total antioxidant capacity level, total superoxide dismutase, alkaline phosphatase, lysozyme activities and immunoglobulin M, complement levels in liver and intestine compared with corn oil diet (p < 0.05). Moreover, the diet with LC significantly up‐regulated the nuclear factor E2‐related factor 2 (p < 0.05), and significantly down‐regulated the interleukin‐1‐beta and tumour necrosis factor‐alpha expression in liver and intestine compared with corn oil diet (p < 0.05). In conclusion, LC supplementation improved the weakening of growth performance, antioxidant capacity, immune function and tissue health caused by R. lagowskii intake of corn oil diets.