Alterations in the hematological parameters of rainbow trout, Oncorhynchus mykiss, exposed to cypermethrin

Rainbow trout were exposed to sublethal concentrations of the pesticide cypermethrin (1/8, 1/4 and 1/2 of the LC50, 0.0082 mg/l) for 21 days at 24-hour intervals. At the end of the exposure period, hematological parameters were investigated. As the concentration of cypermethrin increased, there were increases in red blood cells, hemoglobin concentration, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, thrombocyte count and erythrocyte sedimentation rate. As the exposure increased, there were decreases in packed cell volume, mean corpuscular volume and white blood cell count. Differences among treatments were significant (p<0.05) only for red blood cells, mean corpuscular volume, thrombocyte count and erythrocyte sedimentation rate when exposure rose from 1/8 to 1/2 of the LC50 concentration.