Histopathology of liver and gill of C.gariepinus– (Burchell 1822) with swollen abdomen following exposure to acute and sublethal concentrations of chlorpyrifos-ethyl

Abstract

Chlorpyrifos-ethyl, an organophosphate insecticide, was evaluated for its histopathological effects on African catfish Clarias gariepinus, by light microscopy. Juveniles were exposed to acute (0.64mg/l, 0.80mg/l, 0.96mg/l, 1.12mg/l, 1.28mg/l, and a control) and sublethal (0.045mg/l, 0.096mg/l and 0.192mg/l and control) concentrations of chlorpyrifos-ethyl for a duration of 96hrs and 8 weeks respectively. The gills and liver samples of control and treated fish with swollen abdomen were removed at the end of 96hrs and 4 weeks durations of exposure for histological examinations. No degenerations were observed in the control samples. The highest acute and sublethal doses of the toxicant induced occasionally on the fish, morphological degeneration characterized by swollen abdomen. The histopathological degenerations in the gill was characterized as mucous cell secretion in the gill, lamella hyperplasia/hypertrophy, oedema, occlusion of interlamella spaces; Degenerations in the liver included: enlargement of sinusoids, massive infiltration of sinusoidal spaces and central vein by mono and polymorphonuclear leukocytes and RBC’s, pyknotic nuclei and coagulation necrosis.