環境および分析毒性学

Biochemical Response of Clarias gariepinus to Cypermethrin

Abstract

Adeyemi Olalekan

The biochemical responses of Clarias gariepinus to cypermethrin was assessed in this study. C. gariepinus was reared in various concentrations of cypermethrin-contaminated dechlorinated water (0, 5, 10, 15 and 20) μg/L over a period of five days and designated A (Control), B, C, D and E respectively. The levels of protein and carbohydrate metabolites, protease, cholinesterase and cytochrome oxidase of liver and muscle of fish were assayed. The total protein (TP) level of liver and muscle of Group E decreased by 20% and 29% respectively relative to the control. Conversely, free amino acid (FAA) of liver and muscle of Group E increased by about 38% and 43% respectively compared with the control. Relative to the control, the levels of glycogen and pyruvate of tissues of the liver and muscle of Clarias gariepinus reared in contaminated water was significantly (p<0.05) lower while the level of lactate in the tissues was significantly (p<0.05) higher. Activity of cholinesterase of the tissues of Group E animals was 1/3 that of control. In contrast, protease activity of tissue of Group E animal was about 2 folds that of control. Cypermethrin inhibited activities of cholinesterase and cytochrome oxidase by a mechanism that inhibited oxidative metabolism of carbohydrate and shifting to protein catabolism for energy requirement. Thus it may be inferred that there is a tendency to shift the aerobic pathway to anaerobic pathway of fish respiration, to meet energy demands for the physiological and metabolic activities augmented by Cypermethrin induced stress.