ABSTRACT
Five isonitrogenous diets were formulated to comprise two forms of zinc (Zn): convention zinc oxide named Bulk-ZnO or zinc oxide nanoparticles (Nano-ZnO) supplemented at two levels 30 and 60 mg kg-1 compared to the control diet. Nile tilapia, Oreochromis niloticus, fingerlings (5.02-5.05 g) were fed tested diets two times a day for 84 days. The results displayed that the best growth and digestive enzyme activity (P < 0.05) were noticed in fish fed 60 mg kg-1 Nano-ZnO. Moreover, significant (P < 0.05) improvement in intestinal topography was observed in 60 mg kg-1 Nano-ZnO group versus other treatments. Furthermore, fish fed 30 mg kg-1 Nano-ZnO recorded the best values of hematological indices (P < 0.05). The alanine and aspartate aminotransferase (ALT and AST) values were lower, while total serum protein, albumin, and globulin contents were clearly higher in fish fed diet that contained 30 mg kg-1 Nano-ZnO versus other groups. The significant highest values of oxidative enzyme activity escorted with lower malondialdehyde value recorded of fish fed diet supplemented with 60 mg kg-1 Nano-ZnO. The results indicated that inclusion of Nano-ZnO at 60 mg kg-1 was the recommended source to enhance growth, feed utilization, amylase and lipase enzymes activity, intestinal morphology, hemato-biochemical, and oxidative response biomarkers of Nile tilapia compared with Bulk-ZnO in commercial tilapia feeds.
