Dietary Haematococcus pluvialis powder supplementation affect carotenoid content, astaxanthin isomer, antioxidant capacity and immune‐related gene expression in Pacific white shrimp, Litopenaeus vannamei

This study was conducted to evaluate the effect of Haematococcus pluvialis powder on astaxanthin content and isomer composition, antioxidant ability and immunity of Litopenaeus vannamei after short-term feedings. Experimental diets include a commercial diet (control) and diets containing H. pluvialis powder (HP-35 and HP-70, 35 and 70 mg of carotenoids kg(-1)). After feeding for 15 days, the content of astaxanthin in the muscle, cephalothorax and shell of shrimp increased significantly with increasing addition of H. pluvialis powder (p < 0.05). Dietary addition of H. pluvialis powder significantly increased the activity of total antioxygenic capacity (T-AOC), superoxide dismutase (SOD) and glutathione S-transferase (GST) as well as the relative mRNA levels of immune-related genes, Toll, MyD88, IMD, Crustin, PO and Lysozyme in hepatopancreas (p < 0.05). The proportion of astaxanthin isomers in different body parts was different, whereas it has no significant difference between same body parts of different groups. This indicated that the accumulation of astaxanthin among body parts may be accompanied with selection and isomerization. In conclusion, feeding with H. pluvialis powder diets containing 35 and 70 mg of carotenoids kg(-1) can enhance the carotenoid and astaxanthin content, antioxidant and immune capacity of L. vannamei.