Abstract
The present work aimed to study the hestopathological alteration in liver and gills of O. niloticus exposed to Zinc oxide nanoparticles. Two hundred male O. niloticus were equally divided into 5 groups. Group (1) was the control. Groups (2 and 3) were exposed to 1 and 2 mgL(-1) of ZnONPs. Meanwhile, the groups (4 and 5) were exposed to 1 and 2 mg/L of ZnONPs and treated with 500 mg of a mixture of vitamin C and E /kg diet. The obtained data indicated that, the gene expression and activities of catalase (CAT) and superoxide dismutase (SOD) were altered due to ZnONPs in a relation to the concentration and exposure time. Histopathologically, acute cell injury of hydropic degeneration and fatty change and irregular areas of coagulative necrosis were noticed in the liver in addition to congestion, telangiectasia and aneurysm, with hypertrophy and hyperplasia of the mucous cells in the gills. In presence of vitamin mixture such alterations in the antioxidant system and histology were alleviated or completely absent particularly with the low ZnONPs concentrations and short exposure time. Finally it could concluded that the supplementation of a mixture of vitamin C and E has a beneficial effect against the ZnONPs toxicity in O. niloticus.