Evaluation of Histopathological Effects of Sub-lethal Concentrations of Chloramphenicol Antibiotic on the Gill of Clarias gariepinus Juvenile (Burchell, 1822)

Abstract

An investigation on the effect of Chloramphenicol on the gill tissues of Clariasgariepinus juveniles was carried out in the laboratory using static renewal bioassaytechniques. Two hundred and seventy fish with length 7.39±39cm and weight12.37±65g were exposed to sub lethal concentrations of chloramphenicol for 70 days.The gills were removed for histopathological examination. The observedhistopathological changes in the gills were occlusion of tubular lumen, congestion ofblood vessels, degeneration of primary and secondary gill lamellar, fragmentation ofcentral axis, lamellar fusion and degeneration of epithelial and marginal cells in thetest organs. The severity of the lesions along the concentration gradients was observedto be proportional to dosage. The effect was most severe at the highest concentration(12.5 mg/l). The observed abnormalities in the gills of Clarias gariepinus juvenilesexposed to chloramphenicol shows the suitability of Clarias gariepinus in the toxicitytesting of antibiotics.