Effects of cypermethrin and carbofuran on certain hematological parameters and prediction of their recovery in a freshwater teleost, Labeo rohita (Hamilton).

Sublethal effects of cypermethrin and carbofuran on hematological parameters and their complete recovery were studied in Labeo rohita as a function of exposure time. Exposure of Labeo rohita to sublethal levels of cypermethrin and carbofuran resulted in significantly (P<0.05) lower values for erythrocyte count (RBC), hemoglobin content (Hb), and hematocrit compared with the control group. In contrast, there was a significant increase (P<0.05) in leukocyte count (TLC) in the pesticide-treated group. Mean cell volume (MCV) and mean cell hemoglobin (MCH) increased in response to both pesticides during the study. The rate of recovery or extrapolation time between Days 0 and 28 of the recovery period revealed that RBC completely recovered from cypermethrin toxicity on Days 80, 86.6, and 90 and TLC recovered on Days 60, 62.7, and 63.3 in fish exposed to 0.16, 0.40, and 0.80 microL/L cypermethrin, respectively. In the case of carbofuran toxicity, the complete recovery for RBC was on Days 100, 101.5, and 102, and for TLC, on Days 77, 77.6, and 79.3 in fish exposed to 0.06, 0.15, and 0.30 mg/L carbofuran, respectively. TLC recovered faster than RBC. RBC and TLC of fish exposed to carbofuran took more time to complete recovery than RBC and TLC in fish exposed to cypermethrin.