Assessment of hematological and biochemical alterations as markers in an Indian major carp Catla catla exposed to various concentrations of zinc oxide nanoparticles

Fingerlings of Catla catla were exposed to 1, 5, and 25 mg/L of zinc oxide nanoparticles (ZnO NPs) for 15 days, and specific hematological and biochemical parameters were evaluated to assess the toxicity. During the exposure period, red blood cell (RBC) count was found to decrease (except at the end of the 5th day in 1 mg/L) whereas white blood cell (WBC) count was found to increase in ZnO NPs treated fishes. A significantly higher hematocrit (Hct) level was recorded in fish exposed to 1 mg/L when compared with control and a higher concentration of ZnO NPs (5 and 25 mg/L). Erythrocyte indices such as mean cellular volume (MCV) and mean cellular hemoglobin (MCH) values (except at the end of 5 and 10th day at 1 and 10 mg/L exposed groups) were significantly increased. Mean cellular hemoglobin concentration (MCHC) level was found to be increased at 1 and 25 mg/L treated groups compared to 10 mg/L. Compared to the control group, plasma glucose level was increased significantly in fish exposed to 5 and 25 mg/L concentrations of ZnO NPs, while the plasma glucose level was decreased at the end of the 15th day in all the concentrations. Plasma protein level was increased at the end of the 5th day while the level of plasma protein was decreased on the 10 and 15th day. A significant increase in glutamate oxaloacetate transaminase (GOT) (except at the end of 10th day) and glutamate pyruvate transaminase (GPT) activity in gill and liver (except at the end of 10 and 15th day in gill) were noted in all the concentrations tested when compared to control groups. The results of the present study indicate that ZnO NPs at 1, 5, and 25 mg/L can alter the hematological and biochemical parameters of fish and the toxicity data may provide the ecotoxicological impact of ZnO NPs on the aquatic environment.