The Potential Of Nanosilver As An Antibacterial Agent For Grouper Aquaculture

Abstract

This study evaluated the efficacy of nanosilver in grouper aquaculture. The commercial nanosilver solution was trailed for antibacterial activity against Vibrio alginolyticus, one of the most serious threats for grouper survival. The in vitro studies showed that nanosilver possessed Minimum Inhibitory Concentration (MIC) value of 8 ppm, Minimum Bactericidal Concentration (MBC) value of 16 ppm and Zone of Inhibition (ZOI) of 14 mm (20 mu g silver loading). In addition to assessment of antibacterial activity in culture medium, it was also found that the dosage of nanosilver above 8 ppb were effective for growth inhibition of V alginolyticus in seawater (10(3) CFU mL(-I)). The growth inhibition was more significant with the lower salinity in seawater. In the disinfectant application of living feed, exposure of 16 ppb nanosilver to Brachionus plicatilis for 15 minutes could accomplish a good sterile effect as well as maintain the vitality. In the safety issues, it was shown that the growth and survival of Epinephelus coioides were not affected after 8 weeks of dietary addition of nanosilver. Moreover, the accumulation of silver in the muscle tissues was not observed by the analysis of inductively coupled plasma mass spectrometry (ICP-MS). Therefore, nanosilver can be used as a suitable antibacterial agent in grouper aquaculture.