Two trials were conducted to evaluate the effects of chemically synthesized astaxanthin (Ax) on growth performance, survival, and stress resistance in larval and postlarval kuruma shrimp (Marsupenaeus japonicus). Six dietary levels of Ax (0, 50, 100, 200, 400 and 800 mg/kg diet) were added to a baseline diet. As a first study, an 8-day feeding trial was conducted on larval kuruma shrimp, with results showing that larvae-fed diets supplemented with different Ax levels exhibited better performance during developmental and metamorphosis to postlarvae. Broken-line regression analysis indicated that the optimal levels for growth and stress resistance of larvae were 168.9 mg/kg and 82.1 mg/kg diet, respectively. Second, a 30-day feeding trial was conducted on post-larval shrimp. Supplementation with 100 and 200 mg/kg Ax yielded significantly higher final body weight, body weight gain and specific growth rate than that in a control group. A cumulative mortality index for osmotic stress revealed significantly better performance in a group fed 200 mg/kg supplementation than in controls. Broken-line regression analysis indicated that the optimal levels for growth and stress resistance of postlarvae were 108.7 mg/kg and 178.1 mg/kg diet, respectively. Based on these results, we suggest that carefully dosed Ax supplementation is a beneficial nutritional strategy for the early developmental stages of kuruma shrimp.
K E Y W O R D Sastaxanthin, kuruma shrimp, larval, optimal level, post-larval