Effects of dietary different canthaxanthin levels on growth performance, antioxidant capacity, biochemical and immune-physiological parameters of white shrimp (Litopenaeus Vannamei)

Abstract

An 8-week feeding trial was conducted to evaluate the effects of different dietary canthaxanthin (CX) levels on growth performance, pigmentation, antioxidant capacity, hemolymph biochemical parameters, immune response, and resistance to hypoxia stress of white shrimp (Litopenaeus vannamei). Juveniles (initial weight 1.15 ± 0.12 g) were fed with five iso‑nitrogenous and isolipidic diets supplemented with/without CX: 0 (control), 50, 100, 200, and 400 mg kg−1 diet. Results showed that the growth performance, survival, and feed conversion ratio improved significantly in CX supplemented treatments compared to the control. The redness of cooked shrimp tended to increase with increasing CX level; however, no significant difference was observed among the treatments that received CX of more than 100 mg kg−1. Further, the activities of digestive enzymes, total antioxidant capacity, and peroxidase increased significantly (P < 0.05), while the activities of glutathione peroxidase, catalase, and malondialdehyde decreased significantly (P < 0.05) in the hepatopancreas with increasing dietary CX levels. The immune-related enzymes (alkaline phosphatase, lysozyme, alanine aminotransferase, and aspartate aminotransferase) and hemolymph biochemical parameters (cholesterol, high-density, and low-density lipoprotein) are significantly affected by different dietary CX levels. Total carotenoids and astaxanthin contents in shrimp muscle, shell, head, and whole-body showed an upward trend with the increment of dietary CX. After exposure to hypoxia stress, juveniles in 200 mg kg−1 supplementation treatment exhibited the highest LT50 value among all the treatments. Moreover, broken-line regression analysis indicated that a dose of 173.73 to 202.13 mg kg−1 of CX was suitable in the diet of L. vannamei as a potential carotenoid source for substituting dietary astaxanthin in the shrimp feed industry.