Effects of dietary supplementation of zinc oxide nanoparticles on some biochemical biomarkers in common carp (Cyprinus carpio)

If the dose and duration of zinc oxide nanoparticle (ZnO-NPs) supplementation optimize, low concentrations of Zn nanoparticles can replace conventional Zn sources in diets of different species of fish. Since evaluating the cytotoxicity of any nutritional supplement is one of the requirements for optimizing the dose for a specified time, we conducted this study to investigate the effects of oral administration of ZnO-NPs on oxidative stress and certain biochemical biomarkers in common carp, Cyprinus carpio, as an experimental model. For this purpose, ZnO-NPs were orally administered to fish for 21 days at 0 (control), 5, 10 and 15 mg kg^-1 feed. Administration of ZnONPs (15 mg kg^-1) significantly enhanced aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) activities in liver, and alanine aminotransferase (ALT), alkaline phosphatase (ALP), and LDH activities in kidney. Dietary ZnO-NPs increased glucose-6-phosphate dehydrogenase (G6PDH) activity in liver of fish. The results indicated that administration of 10 mg kg-1 and 15 mg kg^-1 ZnO-NPs caused a significant increase in ALT and catalase (CAT) activities and malondialdehyde (MDA) levels in liver, AST and CAT activities and MDA levels in kidney. ZnONPs decreased the liver ALP activity. Administration of 5 mg kg^-1 ZnO-NPs significantly increased the cellular total antioxidant (TA) levels in various tissues. Therefore, we suggest that oral administration of 10 and 15 mg kg^-1 ZnO NPs caused cytotoxicity and alterations in oxidative biomarkers, but 5 mg ZnO-NPs per kg feed had no side effects on oxidative stress and biochemical biomarkers in fish.