Lysine is the necessary amino acid for the animal but which can not be synthesized by themselves. Therefore, it is called “the most restrained amino acid”.L-lysine monohydrochloride is a kind of feed additives which is made from corn starch and other raw materials.The producing of L-lysine monohy-drochloride depends on bioengineering principle through the processing of liquid deeplevel fermentation and refining.