With the development of large-scale and intensive livestock and poultry breeding, and the pollution of the breeding environment, animals have low immunity and are vulnerable to pathogenic bacteria. Adding antibiotics to livestock and poultry feeds can enhance the animal's own immunity, but it leads to problems such as antibiotic residues and bacter

L-threonine is an essential amino acid, and threonine is mainly used in medicine, chemical reagents, food fortifiers, feed additives, etc. In particular, the amount of feed additives has grown rapidly. It is often added to the feed of young piglets and poultry, and is the second limiting amino acid in pig feed and the third limiting amino acid in