Effects of mint (Mentha piperita L.) leaf extract on growth performance, immune and antioxidant responses in green Tiger shrimp (Penaeus semisulcatus).

This study examined the effects of mint (Mentha piperita L.) leaf extract (MLE) on the growth, immune responses, antioxidant activity, and hemolymph biochemical parameters in green tiger shrimp (Penaeus semisulcatus) under standard water chemistry and ammonia stress conditions. Four dietary treatments were established: a control and three MLE concentrations (0.5, 1, and 2 g/kg diet). A total of 240 shrimp (initial weight 9.22 ± 0.97 g) were distributed into 12 tanks and fed for eight weeks before ammonia challenge. The results indicated that MLE supplementation did not significantly affect growth performance. Phenoloxidase (PO) activity decreased at the MLE2 level, while lysozyme (Lys) activity increased in both the MLE1 and MLE2 groups compared to control. Superoxide dismutase (SOD) activity was significantly elevated in the MLE2 group, whereas total antioxidant capacity (TAOC), glutathione peroxidase (GPX) and catalase (CAT) activities remained unchanged. The activities of acid phosphatase (ACP), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) all decreased in at least one MLE exposure group. Lactate dehydrogenase (LDH) activity increased in all MLE groups. After ammonia stress, antioxidant parameters increased in all MLE groups, except for CAT. Activities of ALT and AST were significantly increased in all MLE-supplemented groups. However, LDH and ALP activities were significantly elevated only in MLE1 and MLE2 groups, while ACP activity showed a significant increase solely in MLE1 group compared to control. These results suggest MLE acts primarily as an antioxidant stimulant in P. semisulcatus.