Deltamethrin-induced oxidative stress and biochemical changes in tissues and blood of catfish (Clarias gariepinus): antioxidant defense and role of alpha-tocopherol

Background: The pyrethroid class of insecticides, including deltamethrin, is being used as substitutes for organochlorines and organophosphates in pest-control programs because of their low environmental persistence and toxicity. This study was aimed to investigate the impact of commonly used pesticides (deltamethrin) on the blood and tissue oxidative stress level in catfish (Clarias gariepinus); in addition to the protective effect of alpha-tocopherol on deltamethrin induced oxidative stress. Catfish were divided into three groups, 1st control group include 20 fish divided into two tanks each one contain 10 fish, 2nd deltamethrin group, where Fish exposed to deltamethrin in a concentration (0.75 mu g/l) and 3rd Vitamin E group, Fish exposed to deltamethrin and vitamin E at a dose of 12 mu g/l for successive 4 days. Serum, liver, kidney and Gills were collected for biochemical assays. Tissue oxidative stress biomarkers malondialdhyde (MDA) and catalase activity in liver, kidney and gills tissues, serum liver enzymes (ALT and AST), serum albumin, total protein, urea and creatinine were analysed. Results: Our results showed that 48 h. exposure to 0.75 mu g/l deltamethrin significantly (p < 0.05) increased lipid peroxidation (MDA) in the liver, kidney and gills while catalase activity was significantly decreased in the same tissues. This accompanied by significant increase in serum ALT, AST activity, urea and creatinine and a marked decrease in serum albumin and total proteins. Conclusions: It could be concluded that deltamethrin is highly toxic to catfish even in very low concentration (0.75 mu g/l). Moreover the effect of deltamethrin was pronounced in the liver of catfish in comparison with kidneys and gills. Moreover fish antioxidants and oxidative stress could be used as biomarkers for aquatic pollution, thus helping in the diagnosis of pollution. Adminstration of 12 mu g/l alpha-tocopherol restored the quantified tissue and serum parameters, so supplementation of alpha-tocopherol consider an effective way to counter the toxicity of deltamethrin in the catfish.