HISTOPATHOLOGY STUDIES OF SELECTED ORGANS OF Hemichromis fasciatus INHABITING IGUN GOLD MINING AND OPA RESERVOIRS, OSUN STATE, NIGERIA: A COMPARATIVE STUDY
This study examined the histopathological alterations in the gills, fillet and liver of Hemichromis fasciatus in Igun reservoir (located in an abandoned goldmine area) compared to those of Opa reservoir. Life fish species were collected from Opa and Igun reservoirs and identified in the laboratory. Techniques based on histological analyses were done on the organs and photomicrographs taken using digital binocular compound LED microscope. Epithelial lifting and hypertrophy of lamellae were observed in the gills of H. fasciatus in Opa reservoir and compared to rupture of gill epithelium, rupture of chloride cell, fusion, hyperplasia, curling of lamellae in H. fasciatus of Igun reservoir. The fillet of H. fasciatusin Opa and Igun reservoirs revealed splitting and atrophy of muscle bundles. Also, parasite cyst and necrosis were observed in the fillet of H. fasciatus of Igun reservoir compared to degeneration in muscle bundles in the fish of Opa reservoir. Similarly, the liver of H. fasciatus in Igun and Opa reservoirs showed splitting at the wall of central vein, hepatopancreas and liver cells degeneration. Moreover, nucleus hypertrophy was also identified in the liver of H. fasciatus in Opa reservoir compared to vascular congestion in the central vein, bile duct, portal vein and portal artery of H. fasciatus in Igun reservoir. The study therefore concluded that H. fasciatus specimens in Igun reservoir were histopathologically unhealthy as compared with those of Opa reservoir probably due to the high level of pollution resulting in bioaccumulation of heavy metals in Igun reservoir samples. Obayemi, O. E | Department of Zoology, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria