Organosomatic indices, haematological and histological assessment as biomarkers of health status in feral and cultured Clarias gariepinus

The project was designed to study the physiological differences and histological changes in cultured and feral Clarias gariepinus. The quality of the culture water was also compared. Water samples and live specimens of Clarias gariepinus of both sexes were purchased weekly for five weeks from fishermen at Eleyele River (feral) and a commercial fish pond (cultured) in Ibadan, Nigeria. The samples were subjected to haematological and histological assessments. Water and milt qualities were also determined. There were no significant differences in the organosomatic indices and haematological parameters. The spermatozoa count was significantly higher in cultured fish. However, the dissolved oxygen content of the cultured pond was significantly lower (p< 0.05) than feral. Histological assessment revealed macrophage hyperplasia and severe fatty degeneration with sinusoid dilation of the liver of cultured fish; which respectively, can be attributed to reaction to the presence of an antigen and malnutrition from the supplementary diet fed cultured fishes.