Toxicological effects of dichlorvos (DDVP) on brain and liver acetylcholinesterase (AChE) activity of Tilapia mossambica, Peters.

Acetylcholinesterase (AChE) activity of T. mossambica in relation to the interacting effects of aging and sub-lethal concentrations of Dichlorvos was studied. The enzyme activity of brain and liver decreased with increasing size (and age) and DDVP-exposed fish showed considerable inhibition of brain and liver AChE. The degree of enzyme inhibition followed a positive correlation with the insecticide concentration and the time of exposure. Brain exhibited a higher degree of enzyme inhibition in all age groups of fish as compared to liver. Small fish were more susceptible to the insecticide with respect to AChE activity. When transferred to clean water most of the exposed fish recovered their AChE activity and the recovery was greater in liver than in brain. Small fish exhibited comparatively a high level of recovery in the AChE activity. The degree of recovery followed an inverse relationship with the time of exposure.