Effect of Nanosilver Particles on Bacterial Gut Flora in Common Carp (Cyprinus carpio)

The use of nanotechnology is expanding. The majority of nanoparticles are made of silver nanoparticles. These materials are known for their antimicrobial properties. As these materials are used in aquatic ecosystems and their release in the environment, the present study investigated the median lethal concentration (LC50) and the impact of these particles on the populations of the gut bacterial flora in Cyprinus carpio. For this purpose, 84 fish were exposed to concentrations of (0, 0.1, 0.5, 1, 2.5, 5, 10 ppm) for 96 hours and their mortality were recorded. Using probit analysis, the LC50 was calculated as 0.23 ppm. Next, 84 specimens in four treatments with three replicates were exposed to (1/2 LC50, 1/5 LC50, 1/10 LC50 and control treatment) for 14 days. After 14 days, 2 fish in each replicate was selected randomly and anaesthetized with clove powder. Their intestines were extracted in sterile conditions. Then total mesophil bacteria, acid lactic bacteria and antrobacteriacea were counted. Results showed no significant effect between nanosilver treatments and control treatments (P > 0.05).