Phagocytosis and ROS production as biomarkers in Nile tilapia (Oreochromis niloticus) leukocytes by exposure to organophosphorus pesticides

Abstract Organophosphorus pesticides (OPs) are broad-spectrum insecticides. One of the commonly used OPs is diazinon (DZN). The aim of this study was to evaluate the immunotoxic effect of DZN on phagocytic parameters of blood leukocytes using the teleost fish Oreochromis niloticus as a study model. For this purpose, fish were exposed in vivo to 0.97, 1.95 and 3.97 mg/L of DZN for 6 and 24 h. Our results indicated that phagocytic active cells decreased in fish exposed in vivo to 0.97 and 1.95 mg/L of DZN for 6 and 24 h. Regarding ROS production, H 2 O 2 and O 2 − levels were higher on fish exposed to 1.95 mg/L for 6 and 24 h, while H 2 O 2 production increased at 0.97 mg/L for 24 h. From this we can conclude that phagocytic parameters are sensitive to assess the effect of acute intoxication with organophosphorus pesticides on Nile tilapia.