Effects of dietary astaxanthin and vitamin E and their interactions on the growth performance, pigmentation, digestive enzyme activity of kuruma shrimp (Marsupenaeus japonicus)

Abstract

A 56-day feeding trial was done to investigate the interactive effects of astaxanthin (Ax) and vitamin E (α-Toc) on the performance of kuruma shrimp (Marsupenaeus japonicus). A 2 × 3 factorial experiment was conducted with six experimental diets containing two levels of Ax (0 and 0.6 g/kg diet [Ax0 and Ax0.6]) and three levels of α-Toc (0, 0.2 and 1 g/kg diet [α-Toc0, α-Toc0.2 and α-Toc1]). The results indicated that growth performance was significantly (p < 0.05) increased in shrimp fed with the Ax0.6 × α-Toc0.2 diet. Interactive effects between Ax and α-Toc on the growth parameters were observed. Furthermore, pigmentation performance was significantly (p < 0.05) better in the Ax0.6 groups. Interaction between Ax and α-Toc was also found in the Ax content of shrimp body parts. Interestingly, dietary α-Toc helped to reduce the Ax consumption rate, promote the absorption and increase the deposition of Ax in the muscle. Shrimps from the Ax0.6 groups showed significantly (p < 0.05) improved hepatopancreatic digestive enzyme activities compared with those of the Ax0 groups. Although no interactive (p > 0.05) effects were found between dietary α-Toc and Ax on total haemocyte count and tolerance against freshwater, dietary Ax and α-Toc supplementation showed better performance on these two parameters. It was concluded that dietary Ax and α-Toc functioned synergistically, and the shrimp fed with the diet containing 0.6 g Ax/kg diet Ax and 0.2 g α-Toc/kg diet showed improved growth and pigmentation performance compared with the other groups in the current study.