The effects of sub-lethal concentrations of silver nanoparticles and silver nitrate on common carp (Cyprinus carpio L.): changes in hematology and antioxidants

Considering the high application of silver as well as the risk of exposure of aquatic organisms, the possibility of exposing these animals to this metal is high. Therefore, the aim of this study was to investigate and compare the sub-acute effects of silver nanoparticle and silver nitrate on survival, various indices of blood and also antioxidant biomarker in common carp. For this purpose, at first, Lethal Concentration (LC50-96 h) for two silver forms was obtained and then fish were exposed to 15 and 30% of the calculated concentration (0.4 and 0.8 mg / L nanoparticles as well as 0.025 and 0.045 mg / L silver nitrate) for 21 days. LC50-96 h for silver nanoparticles and silver nitrate were 0.29 ± 0.02 and 0.15 ± 0.05 mg/L respectively. The results showed that after exposure to silver nanoparticles and silver nitrate, different disorders were observed in hematologic indices including reducing the RBC and WBC count. The results showed that the SOD enzyme activity in most exposed groups were induced in compare to the control group. This study showed that silver nitrate at lower concentrations show its destructive effects and both forms of silver almost identically changed immunity factors and also oxidative stress in exposed fish, but in the SOD enzyme, these changes were slightly higher in groups exposed to silver nitrate.