In vitro effects of Sargassum latifolium (Agardeh, 1948) against selected bacterial pathogens of shrimp

During the last decade, shrimp aquaculture has developed rapidly in many developing countries. Antibiotic resistance is a major problem in shrimp aquaculture. Seaweeds are considered as potent source of bioactive compounds that are able to produce biological activities. The aim of this study was to evaluate the antibacterial activity of ethanolic and chloroformic crude extracts of the brown algae, Sargassum latifolium derived from Persian Gulf waters. The extractions against shrimp selective pathogen bacteria including Vibrio alginolyticus, V. parahaemolyticus and V. harveyi were used by disk diffusion agar method. Results revealed that all mentioned bacteria were sensitive to both ethanolic and chloroformic crude extracts of S.latifolium. The minimum inhibitory concentration of chloroformic extract of S. latifolium against the bacteria was performed by tube dilution technique. MICs were 5, 10 and 10 mg ml-1 for V. alginolyticus, V. parahaemolyticus and V. harveyi, respectively while minimum bactericidal concentrations (MBC) were 5, 15 and 20 mg ml-1. This study recommended that S.latifolium isolated from Persian Gulf waters has antibacterial activity potential against shrimp pathogen bacteria.