Impact of Green‐Synthesized Zinc Oxide Nanoparticles (ZnO NPs) on the Biochemical and Histological Profiles of <i>Cyprinus carpio</i>

This study investigated the impact of varying concentrations, including 0.5 mg L −1 ( T 1 ), 1 mg L −1 ( T 2 ), and 2 mg L −1 ( T 3 ) of zinc oxide nanoparticles (ZnO NPs) on hematological, biochemical, and histological indices of Cyprinus carpio . As the use of ZnO NPs grows, there are rising concerns about their potential environmental impacts, particularly on aquatic ecosystems. When released into water bodies, these NPs can be ingested by aquatic organisms, leading to bioaccumulation and potential toxicity. Therefore, understanding their effects on aquatic species, like C. carpio , is crucial. Significant alterations in the erythrocyte count, hemoglobin (Hb), and hematocrit (Ht) levels were found. Compared to the control group, the number of lymphocytes, EOSO, monocytes, and platelets in the Zn NPs‐exposed groups dramatically increased. The biochemical analysis found considerable changes in blood total protein, albumin, globulin, and glucose levels. Histological examinations of the gills, intestines, and kidneys were conducted to assess structural or pathological changes. Treated fish showed progressive architectural distortions like necrosis (N), hyperplasia (HP), hypertrophy (HT), fusion of gill lamella (FGL), and proliferation of mucocytes (PM) in gills. Distension of the intercellular space (DIS), increased rate of the mucous cell (IMC), villous atrophy (VA), HP, and dysplasia (DP) were found in the intestines of ZnO NPs treated C. carpio . Tubular dilatation, tubular necrosis, severe congestion, hematopoietic tissue degradation, constricted lumen, glomerulopathy, and bowmans capsule dilution in kidneys of ZnO NPs treated C. carpio were noted. The findings from this study shed light on the biochemical and histological effects of ZnO NPs on C. carpio , contributing to a better understanding of the potential risks associated with NP exposure in aquatic environments. The results highlight the need to regulate the use of these NPs as well as their disposal in order to reduce the potential impact that they could have on aquatic ecosystems and public health.