Multibiomarker assessment of greenly synthesized silver nanoparticles toxicity in the Tor putitora

Siver nanoparticles (AgNPs) are widely used worldwide due to their diverse application history; however, concerns are raising about their potential toxicity in aquatic organisms such as fish. Therefore, the current study aims to evaluate the impact of greenly synthesized AgNPs on the health of Himalayan Mahseer (Tor putitora). Selected fish were exposed to different groups based on the concentrations of AgNPs (0.5 mg/L, 1 mg/L, and 2 mg/L) for two weeks, and behavioral, haematological, biochemical, oxidative stress, histopathological and genotoxic effects were assessed. Significant behavioral alterations, including abnormal operculum movement, irregular swimming patterns, convulsions, and fin tilting were observed at the highest concentration (2 mg/L). Haematological analysis showed a notable decline (p < 0.05) in erythrocytes, hemoglobin, hematocrit, leukocytes, and mean corpuscular hemoglobin concentration, with an increase in mean corpuscular volume. Biochemical findings indicated elevated levels of enzymes, while calcium, potassium, phosphorus, and iron decreased in all treated groups. Metabolites increased, whereas triglycerides decreased. The results on oxidative stress biomarkers and antioxidant enzymes in gils, liver and kidney tissues resulted in significantly (p < 0.05) higher quantity of oxidative stress biomarkers, while lower concentrations of antioxidant enzymes in treated fish. Histopathological analysis demonstrated the damaged gill structure with cartilage core destruction, necrosis and telangiectasia, while the liver tissues included blood coagulation, pyknotic nuclei, and melanomacrophages formation. In the intestinal tissues, abnormalities noted include serosa destruction, detached villi, villi fusion, and necrosis. Genotoxicity analysis using the comet assay revealed significant DNA damage in erythrocytes, especially at 2 mg/L. These findings demonstrate that greenly synthesized AgNPs can cause severe physiological and genetic alterations in fish, highlighting their potential risk to aquatic ecosystems.