RESUMO
The effect of paraquat on Clarias gariepinus (220.50 ± 15.33g mean weight and 30.43 ± 1.22cm mean total length) was examined by the assessment of the organ indices and haematological parameters after twenty one days of exposure. It was observed that paraquat caused decline in the fish condition, renatosomatic index, splenosomatic index and cardiosomatic index. However, there was an increase in the hepatosomatic index. There was decline in most of the blood parameters measured such as packed cell volume (PCV), haemoglobin (Hb), red blood cells (RBC) and RBC indices, though the decline were not significant (P≥0.05). Leucocrit fluctuated significantly (P≥0.05) in all the exposure concentrations. Platelets increased in level above the control value. White blood cells (WBC) declined slightly in all the exposure concentrations. The WBC counts, mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and mean corpuscular volume (MCV) did not show any appreciable decline in levels, while lymphocytes showed slight decline in the lower concentrations and appreciated slightly in the highest concentration. Neutrophils increased in levels above that of the control value in all the concentrations except at the highest concentration where decline in level was observed.