Effect of Vitamin C on the Antioxidant and Immune Response of Male White Shrimp (Penaeus vannamei) Broodstock

This study evaluated the effect of vitamin C (L-ascorbyl-2-polyphosphate) on the physiological condition, biochemical antioxidant activity, immune responses, and gene expression in the reproductive tract, as well as on sperm quantity and quality in male white shrimp <i>Penaeus vannamei</i> broodstock. Four diets containing 42.5% protein, 11.5% lipids, and 23.5% carbohydrates were formulated with L-ascorbyl-2-polyphosphate as a source of vitamin C at the following concentrations: 0.016 g/kg (Basal), 0.322 g/kg (A), 0.628 g/kg (B), and 0.934 g/kg (<b>C</b>). Shrimp fed diet <b>C</b> exhibited the highest SOD and CAT activity and serum cholesterol levels, but the lowest expression of hemocyanin (Hemo) mRNA transcripts (<i>p</i> ˂ 0.05). Shrimp fed diet A showed the highest Hemo mRNA expression and phenoloxidase (PO) activity, while those fed diet B had the highest serum triglyceride levels (<i>p</i> ˂ 0.05). In contrast, shrimp fed diets A and B exhibited the lowest serum cholesterol levels (<i>p</i> ˂ 0.05). There were no differences in sperm quality between the diets. In relation to sperm quantity, the shrimp fed diet B had the highest sperm cell count (2,750,000 cel/mL), and those fed diet A had the lowest (585,000 cel/mL) (<i>p</i> ˂ 0.05). These results indicate that vitamin C influences the reproductive aspects of male <i>P. vannamei</i> broodstock. A dietary inclusion level of 0.628 g/kg promotes optimal physiological, oxidative stress, and immunological conditions for increased sperm cell production, whereas an excessive level may promote oxidative stress.