Effect of Handling Stress on Selected Antioxidants in two Sizes of African Catfish (Clarias Gariepinus)

Variations in some antioxidants (Catalase, Superoxide dismutase and Glutathione-S-Transferase) in the plasma of juveniles and adult sizes of Clarias gariepinus exposed to three on-farm procedures (starvation, overcrowding and sorting) were determined spectrophotometrically to evaluate oxidative stress in fish exposed to these aquaculture operations. Blood samples were collected from juveniles and adults of catfish exposed to these conditions. The samples were analyzed with Randox test kits. Results from antioxidants analysis showed that the control values of catalase (CAT) superoxide dismutase (SOD) and Glutathione-S-transferase (GST) enzymes activities in the plasma of C.gariepinus (juveniles and adults) from control farm ranged between (0.71 – 0.85Umg/protein); (0.38 – 0.50Umg/protein) and (0.34 – 0.37Umg/protein) respectively. In juvenile and adult fish exposed to these handling stress, the catalase reduced significantly (P<0.05) in both sizes when compared to the control, while Superoxide dismutase and Glutathione transferase values increased significantly. These alterations were more pronounced in the juvenile fish than adult. An indication that juvenile fish were more stressed than adult fish in the rearing facilities.