Gills and skin histopathological evaluation in African sharptooth catfish, Clarias gariepinus exposed to ethanol extract of Adenium obesum stem bark

Histopathological effects of ethanol extract of Adenium obesum stem bark was investigated in the gills and skin of African sharptooth catfish, Clarias gariepinus over a 96-h exposure period as an endpoint of toxicity. There was a significant (p < 0.05) concentration-dependent mortality in some of the exposed fish. The median lethal concentration of the extract was 7.15 mg L−1. The extract caused some histopathological lesions in the gills and skin of the exposed fish. However, the severity but not the type of the lesions observed in the gills and skin of the exposed fish was concentration-dependent. Although the degree of tissue change (DTC) grading indicated moderate damage in the gills of the exposed fish, there were no significant (p > 0.05) differences between gills DTC of the exposed and unexposed fish. However, lesions in the skin did not affect the normal functioning of the tissue but significant (p < 0.05) differences were recorded in the DTC between the skin of the exposed and the unexposed fish. The extract was toxic to the exposed fish and therefore, A. obesum can be used as a potent organic piscicide for effective fish pond management.