The effect of copper on some laboratory indices of Clarias gariepinus (Burchell 1822)

Abstract

Haematological studies were carried out on the blood of Clarias gariepinus broodstock fed different diets. Five
isonitrogenous diets, prepared from locally available feedstuffs were fed to 150 broodfish for 10 weeks in
triplicate laboratory aquaria tanks at 10 fish per tank. Four of the diets contain different inclusion levels of
copper sulphate tagged CSD1 (1.0mg CuSO4/g), CSD2 (2.5mg CuSO4/g), CSD3 (5.0mg CuSO4/g) and CSD4
(7.5 mg CuSO4/g) while the control diet, CSD0 contained no copper sulphate. The haematological parameters
measured; haematocrit (HCT), red blood cells, haemoglobin and glucose concentrations were significantly
higher (p<0.05) in the broodfish fed CSD0 and CSD1 diets than the other diets. Exposure of Clarias gariepinus
fish to copper in water, at concentrations above 1.0mg CuSO4/g elicits adverse haematological responses and
causes homeostatic imbalance. To prevent pollution, it is expedient that there be regulation of the amount of
copper sulphate used in cocoa farms, as occurs in south western Nigeria.

Key words: Clarias gariepinus, Copper sulphate, Haematological, Fish