The present invention provides Metschnikowia bicuspidate strains RS550 and LL58, which are isolated from Macrobrachium rosenbergii, have probiotic characteristics and can be applied to aquaculture. The present invention also provides a composition containing said strains and a use of said strains.本發明提供一種分離自淡水長腳大蝦(Macrobrachium rosenbergii)的梅奇酵母菌(Metschnikowia bicuspidate)菌株RS550和LL58,其具有益生菌的特性,可應用於水產養殖方面,本發明另提供一種含有前述菌株的組合物以及該菌株之用途。