Dietary astaxanthin supplementation improves the growth performance, immune response, and immunity-related gene expression of sea cucumber (Apostichopus japonicas)

Astaxanthin has potent antioxidant activity and is frequently used for feed supplementation. This study investigated the effects of dietary astaxanthin on the growth performance and innate immune index of juvenile sea cucumbers (Apostichopus japonicas). Astaxanthin was replaced 0 g/kg, 0.1 g/kg, 0.3 g/kg, and 0.5 g/kg of cellulose to formulate four kinds of test feeds with equivalent nitrogen and energy. Dietary astaxanthin supplementation improved body weight gain, specific growth rate, feed efficiency, intestinal trypsin, and amylase and lipase activities and enhanced the activities of lysozyme, alkaline phosphatase, and acid phosphatase in the coelomic fluid and the expression of intestinal immunity-related NF-κB p105, p50, and rel and lysozyme gene lys and disease resistance ability of juvenile sea cucumbers against the pathogen, Vibrio splendidus. The optimal dose of dietary astaxanthin supplementation required for the maximal growth of sea cucumbers was 0.29 g/kg, which was obtained by quadratic regression analysis. The results indicate that astaxanthin may be a promising feed supplementation for sea cucumbers.