In the catabolism of l threonine powder (l threonine powder) in the body, it is the only one that does not undergo deamination and transamination, but directly passes through threonine dehydratase, threonine dehydrogenase and threonine aldehyde Amino acids that are catalyzed by the contraction enzymes are converted into other substances, for example, l threonine powder can be converted into butyryl-CoA, succinyl-CoA, serine, glycine, and the like.In addition, excessive threonine can increase the activity of lysine-α-ketogluconate reductase. Adding an appropriate amount of threonine in the diet can eliminate the weight gain caused by excessive lysine, and the protein in liver and muscle tissue can be eliminated. Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)/DNA ratios decreased. Addition of threonine also alleviated growth inhibition caused by excess tryptophan or methionine. According to reports, most of the absorption of threonine by chickens is in the duodenum, and the threonine absorbed by the crop and glandular stomach is rapidly converted into liver protein and deposited in the body.