Histopathology of the Gills and Livers on African Catfish (Clarias gariepinus) Juvenile Exposed to Pentachlor

The histopathological effect of pentachlor, an organochlorine pesticide, on the gill and liver tissues of the African catfish (Clarias gariepinus) juvenile was carried out to investigate the toxicity of pentachlor when administered on the test sample within concentrations of 0.073 mg/L, 0.036 mg/L, 0.024 mg/L and 0.018 mg/L and a control in those replicates was used. The fish were acclimatized for 7 days under laboratory conditions before exposure. Sixteen (16) troughs, each of seven (7) juvenile samples of length 2.3 cm and average weight of 10-15 g, were used for the study. Twelve (12) troughs exposed to varying concentrations of pentachlor were used as treatment samples while four (4) troughs served as control. The juveniles were exposed to sub-lethal concentrations for 21 days with a break at every 48 h. The gills and livers were collected for histological examination. Histological data revealed that at 0.1 m/L pentachlor concentration, the gills showed epithelial hyperplasia with heamorrhage in the central venous of the cartilaginous core with the lifting of the epithelia and hypertrophy at 0.2 mg/L. At 0.3 mg/L exposure, epithelia hyperplasia, dilation of the secondary lamellae occurred and severe deformation of the secondary gill lamellae at 0.4 mg/L. However, the control presented normal mucous and epithelial cells with normal secondary and primary gill lamellae. The liver sample treated with 0.1 mg/L showed complete vascular degeneration. Control sample revealed normal blood vessels, sinusoid vessels and hypatocystes. This showed that pentachlor can accumulate in the liver and potentially cause damage to tissue over time.