Hubei Yasen Biotechnology Co.,Ltd, as a high & new technical enterprise of China, focuses on the R&D and producing of microecologics and antibiotic fermentation, is one of the largest manufacture of Tywasin(Acetylisovaleryltylosin tartrate) in the worldwide, in addition, is the first company owns Tywasin patent (Patent No. ZL 201010565652.1)in China