Cerium oxide nanoparticles induced physio-biochemical, neurochemical, and morphological responses in Cirrhinus mrigala during short term exposure

Cerium oxide nanoparticle (CeO2NPs) has wide applications in pharmaceutical, biomedical and chemical industries. Albeit of their uses, bioavailability followed by toxicity of CeO2NPs in fresh water fishes, are yet to be understood in detail. In this evaluation, we have synthesized, characterized and assessed the biological effects (hematology, ionoregulatory, oxidative stress, histological and glutamate indices) of CeO2NPs at different doses (2.5mg/L and 25mg/L based on 1/10th LC50) on freshwater carps Cirrhinus mrigala, for short term exposure of 96 h. Impact of CeO2NPs at low concentration (2.5mg/L) confirmed a significant decrease in hematological parameters and also affecting serum Na+, Cl-, K+ levels along with gill Na+/K+-ATPase activity. The indicated variations oxidative stress enzymes superoxide dismutase, Catalase, glutathione peroxidase with relative elevation in lipid peroxidation (LPO) (22.47±0.198) compared to control groups. CeO2NPs at high concentration (25mg/L) revealed the alterations in neurotransmitter glutamate levels compared to control groups. Rise in glucose and decrease in plasma protein levels in response to both the concentrations was noted. Microscopic observations confirmed the tissue damages and alterations in gill architecture. By integrating all results obtained by short term exposure of juvenile carps to CeO2NPs at different doses, we reported nanoparticles have considerable deleterious effects on physiological and morphological condition of fishes.