The addition of vitamin supplementation to a diet could control melanization syndrome of the gonads. A formulated feed with high nutritional quality served as a basal diet (149 mg/kg) and treatment diets were prepared with 3 vitamin E levels: 894 mg/kg (diet A), 1639 mg/kg (diet B), and 2384 mg/kg (diet C). Three 500 L tanks were set up for each treatment, and seven individuals were set in each tank. Sperm quantity and quality were classified as normal, abnormal, or dead. The cholesterol, triglycerides, glucose , total protein and antioxidant enzyme activity from hemolymph were quantified. The differential expression of immune system genes and genes coding for antioxidant enzymes in the reproductive system was determined. Sperm quantity and quality were higher in the shrimp fed diet A. The addition of vitamin E to diet A, led to a decrease of cholesterol and triglycerides. Lipid peroxidation and differential immune system gene expression were also lower in diet A, which suggests that this diet contributes to a good physiological status, where immune system activation and the genes that code for antioxidant enzymes are not necessary. However, with the increased vitamin E in diets B and C, the triglyceride content and lipid peroxidation in hemolymph increased. Males fed diets B and C presented a high activity of antioxidant enzymes and a low level of sperm, which suggested a state of oxidative stress. Therefore, basal diet A supplemented with 894 mg/kg vitamin E is recommended for the cultivation of broodstock males of L. vannamei.
Keywords: Peneid; Immunity; Sperm quality; Antioxidant enzymes; Vitamin E.