Dichlorvos-induced histoarchitectural changes in the oocytes of a freshwater fish.

The common edible air-breathing catfish Clarias batrachus was exposed to lethal and sublethal concentrations of the organophosphorus insecticide dichlorvos. This produced significant cytoarchitectural changes in the oocytes, including pronounced vacuolation, degeneration and deformation. Clumping of the cytoplasm and karyohypertrophy were also evident and rupture of the cell wall, with extrusion of the cytoplasm and the nuclei, was observed.