Some Haematological Responses of O. Niloticus to Acute and Sublethal Concentrations of Paraquat

Abstract

Haematological characteristics have been used widely in clinical diagnosis in man .The application of haematological techniques is valuable for fishery biologists in assessing fish health and monitoring stress. The results of the study showed that of acute toxicity test, O. niloticus exposed to (0.00,9.60,10.40,11.20,12.00,14.20,15.20 and 16.00 mgL-1) of paraquat showed that fish were put under stress as evidenced by a dose –dependent reduction in haematocrit value, haemoglobin content, mean corpuscular haemoglobin concentration, and % neutrophil as compared to its baseline values. The acute effect on the blood was further confirmed by the photomicrograph of the blood cells at 96-hour, which showed total destruction and senility of blood cells. In the sub-lethal toxicity tests of paraquat to 0reochromis.niloticus, the study showed a significant decrease in the haemoglobin (Hb), haematocrit (Hct) and mean corpuscular haemoglobin concentration (MCHC) with increase in concentrations and in exposure periods of 8-weeks which could be due to haemodilution and an increase in erythrocyte destruction. This may indicate that the herbicide induced an effect similar to production of anaemia.