ABSTRACT
Background:Zeolites containing silver ion, in combination with synthetic fibers, show antibacterial activity
Objectives: The purpose of this study was to use silver zeolite indirectly as antimicrobial agents to control Streptococcus iniae infection which recently has caused disease in some of rainbow trout farms in Iran
MethodsS: In this context polyurethane foams containing silver zeolite [10 and 20%] were used in water filtration of semi circulation culture system of rainbow trout fry. After addition of Streptococcus iniae[105 Cell/ml] to water in culture systems, the filters were evaluated for efficacy in inhibiting bacteria through measuring bacterial loading in water, monitoring disease symptom and culture of bacteria from kidney and spleen
Results: The results indicated that filters containing silver compounds could significantly reduce load of bacteria from the water to 102 [p<0.05] compared to the control. Filter with 10% silver zeolite had higher efficiency among others
Conclusions: According to the results of this study, it seems that silver zeolite in combination with polyurethane foams has the sufficient potential to control bacterial infection and disease prevention in semi circulation system of Rainbow trout. Development of these filters and their application in control of aquatic animal diseases can result in reduction of using chemical drugs
ABSTRACT
Increasing developments in nanotechnology in recent years have raised the possible risk of release of nanoparticles into the aquatic environment, which could adversely affect organisms. Silver nanoparticles possess antibacterial activities and constitute almost 567o of total manufactured nanoparticles which are currently in use. The aim of this study was to evaluate the effects of colloidal silver nanoparticles on bacterial flora of rainbow trout gut. The Induced Coupled Plasma [ICP], Zetasizer and Transmission Electron Microscope [TEM] methods were used in order to ensure the quality of silver nanoparticles. 90 Fish [25 +/- 0.5 g] in Faculty of Marine Sciences were exposed to zero and 1 mg/L of silver nanoparticles over 14 days. Total viable bacterial counts and psycrotrophic bacteria, entrobacteriaceae and lactic acid bacteria counts of fish's gut and total viable bacterial counts and psycrotrophic bacteria counts of water were determined. There was not any effect of nonoparticles on the bacterial counts [lactic acid bacteria, psycrotrophic and enterobacteriaceae] of the fish's gut and bacterial counts [psycrotrophic and total viable of the water. However, there were significant differences between control and 1 ppm treatments based on the size and color of psycrotrophic colonies. Furthermore, the psycrotrophic bacterial counts of fish's gut in the 1 ppm treatment showed significant increase [6.49 +/- 0.02 1og cfu/g] compared to the control group [5.72 +/- 0.17 log cfu/g] [p<0.05]. The psycrotrophic bacteria represented the most sensitivity to nanoparticles among all studied bacterial groups [p<0.05]; so, changes in the number of these bacteria may be considered as an indicator in monitoring the release and presence of silver nanoparticles in aquatic ecosystems.