E. Chahardeh Baladehi
S.A.A. Hedayati

The aim of this study was to examine the adverse effects of zinc nanoparticles on hematological indices of trout and investigate the improvement of these indices after vitamin C treatments. This study assesses the protective role of vitamin C in fish exposed to ZnO NPs. Two concentrations of ZnO-NPs (۴۰ and ۸۰ mg L-۱) and two doses of vitamin C (۴۰۰ and ۸۰۰ mg per kg of feed) were used to treat ۱۶۲ specimens of Oncorhynchus mykiss. No mortality was observed during the test. After ۵ and ۱۰ days of exposure, hematological data were analyzed according to routine clinical methods. Statistical analysis showed significant changes in WBCs and RBC on day ۱۰ (p<۰.۰۵). Values for HT and MCH were significantly higher in treatment ۲ (normal diet+۴۰ mg L-۱ ZnO-NPs) and ۹ (۸۰۰ mg/kg Vit + ۸۰ mg L-۱ ZnO-NPs), and lower in treatment ۳ (normal diet+۸۰ mg L-۱ ZnO-NPs) in comparison with the control group (normal diet+۰ mg L-۱ ZnO-NPs) (P<۰.۰۵). No significant differences of MCV and MCHC were observed (p>۰.۰۵), while significant increase in neutrophils and monocytes, and decrease in lymphocyte cells were recorded (p<۰.۰۵). ZnO-NPs stimulated the immune system of O. mykiss, but this effect did not have any lethality on this species at ۴۰ and ۸۰ mg L-۱. Vitamin C in different concentrations could help to prevent rainbow trout from the toxic effects of this nano metal. 

Fish, Hematology, Nano particle, Toxicity, Vitamin C