Effects of silver nanoparticles synthesized by bioreduction method on gill antioxidant defense system response of common carp, Cyprinus carpio

Nanoparticles are already widely used in technology, medicine and consumer products, but there are limited data on their effects on the aquatic environments. The aim of this study was to evaluate the response of antioxidant defense system in common carp gills exposed to silver nanoparticles, which are produced by bioreduction method.
Common carp fish were exposed to the silver nanoparticles at concentrations of 0.11, 1.13 and 5.67 mg/L for 14 days. A treatment without silver was considered as a control. After sampling, 1 g of gill was weighed and homogenized in 5 mL phosphate buffer. The homogenized samples were analyzed for measuring the activity of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), total antioxidant capacity (TAC) and malondialdehyde (MDA).
CAT activity in gill at the concentrations of 1.13 and 5.67 mg/L AgNPs was significantly reduced compared to that of the control (p0.05) was observed. Activity of SOD and MDA of all treatments sampled at different days was fluctuated, that is, it was either increased or decreased. However, superoxide dismutase activity was significantly higher in exposure to concentrations of 5.67 mg/L and 1.13 mg/L.
According to the results, fish gills are one of the most susceptible organs of oxidative damage in exposure to silver nanoparticles. This can affect the health of common carp and thus increase the risk of disease in the fish.