To study whether the effluents of Sabal drain could affect the health status of Oreochromis niloticus; site2 (south part of main canal), site3 (at the canal outlet), site4 (north part of main canal) and site1 (reference site) were selected. Compared to the reference fish, activities of superoxide dismutase and glutathione peroxidase in addition to glutathione reduced and thiobarbituric acid reactive substances concentrations of the gills showed significant (p < 0.05) increase with different levels in all studied sites. Whereas, catalase activities revealed significant (p < 0.05) decrease in all studied sites with maximum decrease in site3. The recorded histopathological lesions were correlated with the distance from discharge point. Gills, liver and kidney of site3 had the worst histopathological conditions based on the frequency of alterations appearance and size of the affected areas. While, the regressive alterations that recorded in site2 and site4 suggest the onset of adaptive histological mechanisms.
Keywords: Antioxidant responses; Drain water; Histopathological alterations.