Assessment of the potential threat of nickel(II) oxide nanoparticles to fish Heteropneustes fossilis associated with the changes in haematological, biochemical and enzymological parameters.

The present study has been conducted to evaluate the potential threat of NiO nanoparticles (NiO NPs) on an edible fish Heteropneustes fossilis. Fishes selected for the study were exposed to four concentrations of NiO NPs (12, 24, 36 and 48 mg/l) for the period of 14 days, and various haematological, biochemical and enzymological changes in the exposed fishes were examined. Results revealed that maximum fluctuations were seen in 48-mg/l-exposed fishes when compared with the control in terms of the haematological parameters (RBC count, WBC count, Hb content, Ht% and O2 carrying capacity of blood), enzymatic activities (AST, ALP, ALT and LDH) and biochemical parameters (level of cholesterol, triglycerides, glucose, total protein, albumin, globulin, bilirubin and creatinine). However, 12 mg/l treatment to the fishes showed its least impact on aforesaid parameters. Furthermore, Ni accumulation and changes in cortisol level in the blood were also noticed in all the treated fishes. Structural changes, such as membrane and nuclear disintegration, micronucleus, deformed and vacuolated cells, and enucleation were also observed in RBCs of NiO NP-treated fishes. Conclusively, our study provides useful information and insight for the possible ecotoxicity of NiO NPs on aquatic organisms and emphasizes upon the importance of treatment of effluents containing nanoparticles before their release into the aquatic system.