Rhizophora apiculata is a type of mangrove plant that contains many secondary metabolites, such as flavonoid, saponin, tanin, terpenoid, and steroid. The aim of this study was to obtain the best dose of mangrove oil leaf extract (R. apiculata) added to the feed to prevent Motile Aeromonas Septicemia (MAS). The method used is the experimental method with Completely Randomized Design (CRD), one f…