Inhibitory Rate of Chitosan Against Vibrio harveyi use in vitro method

The intensification of the penaeid shrimp culture industry have been accompanied over the last two decades by an increased incidence of infectious pathogens. Vibrio sp. has become a major source of concern for shrimp culture because of their close association with low survival rates in hatcheries or growout ponds. The antibioctic use to aim this disease but it harmful to use continuously. Resistance of pathogen and retention are such side effect left after antibiotic used. Chitosan is a biocompatible and biodegradable natural polymer with established antimicrobial properties against specific microorganisms. This research demonstrates its antibacterial activity to inhibit growth of Vibrio harveyi comparing with oxoninic acid. Inhibition growth of Vibrio harveyi was tested using diffusion method on TSA added 2% NaCl by additional disc paper which has been soaked in chitosan suspension consentrations 0,8; 1,0; 1,2; 1,4; 1,6% (w/v), asetic acid 1%, and oxolonic acid disc (2µg), each treatment was repeated three times. In this study chitosan showed an antibacterial activity. The lowest antibacterial activity showed by the lowest concentration 0,8% (w/v) and the higest antibacterial activity showed by the highest concentration 1,6% (w/v).