Effect of five dietary carotenoids on antioxidant capability and high temperature tolerance of juvenile Chinese mitten crab, Eriocheir sinensis

This study was designed to determine the effect of different dietary carotenoids on growth, antioxidant status, high-temperature tolerance, color parameters, and carotenoid composition of juvenile Chinese mitten crab Eriocheir sinensis. Five diets were formulated to contain around 100 mg/kg dry diets of each carotenoid: astaxanthin (Axn), β-carotene (β-car), canthaxanthin (Cxn), lutein (Lut) and zeaxanthin (Zxn), and a control treatment without any carotenoid supplementation was also included in the study. The results showed that: (1) Dietary carotenoid supplementation did not significantly affect growth performance, survival and hepatosomatic index (HSI) of juvenile E. sinensis among six treatments. (2) Indicators of antioxidant capacity (T-AOC, MDA), immunity (AKP, ACP) and physiological status (GPT, GOT) were significantly improved in the hepatopancreas and hemolymph of carotenoid supplemented treatments with the order of Axn > Cxn > β-car > Lut ≈ Zxn. (3) The thermal stress test indicated the control treatment had the highest mortality among all treatments, and the lowest mortality was found on Axn treatment during the stress test. (4) For colour enhancement, dietary carotenoid supplementation significantly increased the redness of carapace and hepatopancreas with the order of Axn > β-car ≈ Cxn > Lut ≈ Zxn. In conclusion, the results of this study suggested that the all five carotenoid types could enhance pigmentation and antioxidant capacity for juvenile E. sinensis, and the dietary Axn was more effective than the other carotenoids in terms of antioxidant properties, thermal tolerance and colour enhancement for this species.