Biochemical responses of oncorhynchus mykiss to the stress induced by phosmet

Organophosphorus pesticide phosmet is an anticholinesterase showing its toxicity following contact, ingestion and inhalation. It finds a use in agriculture for apple, peach and olive trees against pests in our country and there are limited numbers of study related to its sublethal effects of on non-target organisms. Therefore this investigation was performed to evaluate oxidative stress inducing potential and anticholinesterase activity of phosmet together with biochemical blood parameters on liver and brain tissues of juvenile O. mykiss following 24h, 48h, 72h and 96h of exposure to 5 µg/L, 25 µg/L and 50 µg/L concentrations. Phosmet application resulted in important decrease in the levels of serum glucose, protein and cholesterol while a significant increase in the activities of ALT, AST and ALP were recorded. Its anticholinesterase activity was confirmed in both liver and brain tissues being more pronounced in brain possibly due to abundant tissue concentration. In both tissues, the activities of SOD, CAT and GPx and level of GSH were increased. Similarly, TBARS level exerted ascending tendency. Obtained findings reveal the inhibitory effect of phosmet on AChE activity and its oxidative stress potency. The observed changes in ALT, AST and ALP activities present the hepatotoxic potential of phosmet meanwhile determined hypoproteinemia and hypoglycaemia were evaluated as adaptive responses to cope with the applied stress.