The putative effect of a SOD-rich melon pulp concentrate on growth performance and antioxidant status of Nile tilapia under heat/dissolved oxygen-induced stress

This study evaluated the effects of SOD-rich melon pulp concentrate (SOD-rich MPC) on growth performance, hematological profile and antioxidant enzyme activity of Nile tilapia subjected heat/dissolved oxygen-induced stress (HDOIS). A group of 462 male Nile tilapia (8.87 g ± 0.12) was randomly distributed in 42 250-L aquaria (11 fish/tank) and fed seven practical diets with graded levels of SOD-rich MPC at 0, 0.1, 0.2, 0.3, 0.4, 0.5 and 1.0% for 60 days. The diets were formulated to contain 30% crude protein and 18 MJ kg-1 crude energy. After the feeding period, growth performance was evaluated and six fish per treatment were sampled for hematological profile and antioxidant enzyme activity. Then, fish were subjected to HDOIS (34°C/1.87 mg/L-1 dissolved oxygen) for two days and the same hematological profile and antioxidant enzyme activity were determined. In the present study, SOD-rich MPC was able to keep erythropoiesis and antioxidant capacity under HDOIS, but did not affect growth performance. The concentration of MDA in fish fed diets supplemented with SOD-rich MPC decreased by 1.5 fold after HDOIS. The results of the present study suggest that 0.5% SOD-rich MPC dietary supplementation was appropriate to maintain Nile tilapia health and improve their antioxidant capacity under HDOIS. (AU)