Biochemical and histopathological alterations of Oreochromis niloticus fish related to heavy metals in Lake Nasser, Egypt

Abstract

Introduction: Lake Nasser is the one of the longest man-made lakes in the world. The surface area and water level of the lake are depending mainly on the annual flow of flood water comes from the Blue Nile from the Ethiopian highlands, it is a major source used for drinking irrigation, fisheries and other domestic purposes.Material and methods: Fish samples were collected from five stations in lake Nasser including Khor Forgond, Khor Toushka west, Khor Ahmer, Garf Hussen and Khor Ebreem during summer 2019. The determination of blood serum glucose, total protein, albumin, total lipids, creatinine, urea, uric acid AST and ALT were carried. Also, the accumulation of iron, manganese, copper, zinc and cadmium in liver, gills and muscle organs of collected Oreochromis niloticus fish from the above stations were determined. In addition to, the same studied organs were histopathologically examined.Aim of the work: This study aim to investigate the impact of the environmental pollution of Lake Nasser on histology of liver, gills and muscles and biochemical parameters of a commercially important O. niloticus fish and that living in this lake NasserResults and Discussion: The results of the present study exhibited increased levels of glucose, lipid, AST, ALT, urea, uric acid and creatinine, while decreased total protein in blood serum of O. niloticus fish samples at Garf Hussen site. Heavy metals accumulations in O. niloticus fish organs at area under investigation were in following descending order: iron> zinc> manganese> cadmium> copper. While, heavy metals accumulations according to organs were in following descending order: liver > gills>muscle. It was found that the metals accumulation in non-edible organ (liver) more than that in edible organ (muscles), the concentration of heavy metals in the studied fish tissues is dependent upon the type organ as well as the type of metal and concentration of heavy metals in water. The accumulation of these heavy metals in the studied fish organs, give rise to histopathological alteration. These alterations including, hemorraghe, hemosidrin, edema, degeneration, necrosis and hyperplasiae, separation in secondary lamellae. We can concluded that fish samples collected from Garf Hussen were more effected than those obtained from other stations.Conclusion: Oreochromis niloticus samples collected from Garf Hussen were more affected by heavy metals those obtained from other stations. But this impact was still within permissible limit. O. niloticus in lake Nasser is valid for human consumption without any negative effect