In recent years, the release of nano-materials into the environment has been a source of concern. On the other hand, these materials can be widely used in many fields, including aquaculture nutrition. Although zinc oxide nanoparticles (ZnO NPs) have potential for use in aquatic nutrition as a feed supplement, their negative effects on fish following dietborne exposure are not well known. The purpose of this study was investigating the relationship between the dietary ZnO NPs doses with zinc bioaccumulation in different tissues of common carp (Cyprinus carpio). Juvenile carps with an average weight of 25.26±2.07 were fed the experimental diets supplemented by 0 (control), 30, 100 and 500 mg kg-1 ZnO NPs for two months. At the end of the experiments, sampling was conducted to measure the bioaccumulation of zinc in liver, skin, muscle, bone and intestine tissues. Based on the results of this study, zinc bioaccumulation following feeding with ZnO NPs was both dose- and tissuedependent. The highest bioaccumulation of zinc was observed in the liver tissue and in fish fed with 500 mg kg-1 of ZnO NPs. Diet-borne exposure to 30 and 100 mg kg-1 of ZnO NPs didn’t significantly increased zinc bioaccumulation in interior and posterior intestine compare to control, but there was a significant difference in the dose of 500 mg kg-1. There was no significant increase in zinc bioaccumulation in skin tissue in any of the tested doses. Because of the accumulation of zinc in various tissues of the fish due to nutrition on a diet supplemented with ZnO NPs, especially at high doses, further studies are needed to investigate the side effects of accumulated zinc on the vital factors of exposed fish.
