Hematological, biochemical, and behavioral responses of Oncorhynchus mykiss to dimethoate.

The effects of dimethoate on hematological, biochemical parameters, and behavior were investigated in Oncorhynchus mykiss exposed to sublethal concentrations of 0.0735, 0.3675, and 0.7350 mg/l for 5, 15, and 30 days. Significant decrease was determined in erythrocyte and leukocyte counts, hemoglobin, hematocrit, MCV, and MCH, which was pronounced after prolonged exposure indicating the appearance of microcytic hypochromic anemia. There were no prominent changes in thrombocyte and MCHC. The glucose concentration showed an ascending pattern that proved to be positively correlated with duration. The protein concentration declined in higher dimethoate concentrations following 15 and 30 days. Negative and significant correlation was detected between glucose and protein concentrations. The fish showed remarkable behavioral abnormality such as loss of balance, erratic swimming, and convulsion. Present findings revealed that dimethoate exerts its toxic action even in sublethal concentrations and hematological parameters and abnormal behavior may be sensitive indicators to evaluate pesticide intoxication.