Effect of nano-zinc oxide (ZnO NPs) on hematological indices of Koi fish (Cyprinus carpio)

The increased industrial applications of nanoparticles increase the possibility their deposition into aquatic ecosystems and thereby threatening the aquatic life. Therefore, this study aimed to provide the toxicological effects of ZnO NPs (0, 1,2,4,8 mg.L-1) on certain hematological indices of Koi fish for a period of  2 and 10 days, under static bioassay. A significant decrease in hemoglobin (Hb) content 7.3±0.19, red blood cell (RBC) count 1.41±0.03, hematocrit (Hct) value 22±0.66, mean cellular volume (MCV) 155.35±5.29 and mean cellular hemoglobin (MCH) 51.2±2.07 (except on 4 mg.L-1dose) was noticed throughout the study period of 10 days when compared to control groups. In contrast, mean cellular hemoglobin concentration (MCHC) levels 4±0.23 were found to increase during the study period.Our results demonstrate that high ZnO NPs concentrations in the aquatic environment may have adverse effects and cause acute changes on hematological parameters of Koi fish.