Antibacterial Potention of Extract of Rotifers Fed with Different Microalgae to Control Vibrio harveyi

Abstract

Vibrio harveyi is a pathogenic bacteria that can caused high mortality and significant loss in shrimp culture. Application of antibiotic to control vibriosis has negative impact to the environment, people and the shrimp.Therefore, it is important to explore alternative antibiotic from natural substances such as enriched rotifers. The aim of this experiment was to determine the presence of antibacterial compound in rotifer extract fed with different microalgae and to determine the ability of rotifer as an antibacterial to control V.harveyi in vitro. Rotiferswere fed with threedifferent types of microalgae, Porphyridiumsp., Tetraselmis sp., and Chlorella sp.. Cultured rotifers harvested, and the crude extract then obtained with methanol extraction. The antibacterial activity was determined with Kirby-Bauer method and using tetracycline as control. The result showed that rotifer fed with microalgae have antibacterial activityagainst V.harveyi as shown by the formation of inhibition zones in the Kirby-Bauer test. However, the zone was smaller than that produce by tetracycline. It can be concluded that extract of rotifer fed with different microalgae has antibacterial compoundwith moderate antibiotic activity.