The present invention relates to a fusion protein in which a myostatin mature protein is fused to a multimer of myostatin-derived antigenic peptide Myo-2, a surface expression vector containing a polynucleotide encoding the fusion protein, a recombinant microorganism transformed with the vector, and a feedstuff additive or a pharmaceutical composition containing the microorganism as an effective ingredient. The feedstuff additive or pharmaceutical composition according to the present invention can be used for muscle development and regulation of muscle growth in livestock and poultry, as well as for preventing and treating muscle-wasting diseases and degenerative diseases such as muscular dystrophy, muscular atrophy and the like. In addition, the transformed strain shows the same effect even if the strain itself after culture thereof is directly used, and thus it is very economical.
