Oxidative damage and changes in Glutathione S-transferase activity in
juvenile African catfish, Clarias gariepinus exposed to cypermethrin
and chlorpyrifos
Cypermethrin and chlorpyrifos are broad-spectrum insecticides routinely
used as household and agricultural insecticides. Since aquatic
environments serve as sinks for numerous environmental pollutants, the
effects of these substances on the resident aquatic organisms can be
quite serious. In this study, we investigated the effects of exposure
of African catfish to cypermethrin and chlorpyrifos on oxidative damage
and the activity of glutathione S-transferase (GST). Juvenile African
catfish were exposed to 1.25 \ub5g/L cypermethrin, 1.25 \ub5g/L
chlorpyrifos, 2.5 \ub5g/L cypermethrin or 2.5 \ub5g/L chlorpyrifos
for 96 h. Control fish were maintained in borehole water. At the end of
the 96 h exposure, tissue lipid peroxidation (LPO), protein
carbonylation and GST activities were determined. Contaminant exposure
resulted in a significant increase (p < 0.05) in the levels of LPO
and protein carbonylation and the activity of GST in the gills, liver
and muscle of exposed fish compared to the controls. Oxidative damage
was more serious in the groups exposed to chlorpyrifos compared to
those exposed to cypermethrin, thus implying that chlorpyrifos is more
toxic to these fish than cypermethrin. The results of this study
indicate that the pollution of aquatic ecosystems with cypermethrin and
chlorpyrifos may cause oxidation of biomolecules (lipids and proteins)
that are involved in essential physiological and biochemical activities
in animals