Evaluation of Haematological and Biochemical Parameters of Juvenile Oreochromis niloticus   after Exposure to Water Soluble Fractions of Crude Oil

The influence of water soluble fraction of crude oil from Afiesere oil field on water quality components and its consequent effect on haematological and biochemical parameters in juveniles of Oreochromis niloticus were evaluated. After a preliminary determination of the 96 h-LC₅₀ of crude oil by probit regression was found to be 92.38 mg/l, fish were exposed to 4 sub-lethal concentrations (30, 45, 60 and 75% of the LC₅₀ corresponding to 28, 41, 55 and 69 mg/l respectively) of the oil and a control. After 84 days of exposure, blood was collected and used in conducting haematological and biochemical analyses. Exposure of water to crude oil caused increased levels in chloride, conductivity, salinity, magnesium, biochemical oxygen demand, chemical oxygen demand, turbidity and Nitrate. The crude oil contaminated water resulted in a significant reduction (p<0.05) in the values of red blood cells, packed cell volume and haemoglobin. Although no definite trend in the values of computed haematological indices was observed, MCHC, however, decreased with increased concentration. Also, Glucose, ALP, ALT, AST, Urea and creatinine activities of all the affected set of fish, which have been exposed to the crude oil were significantly higher (p<0.05) in comparison to their respective control.

Keywords
Crude oil; Afiesere oil field; blood; toxicity; water quality; Oreochromis niloticus