L-Tryptophan is one of essential amino acids and the fourth limiting amino acid in animal diets, which means it could not be synthesized by the body, in addition, dietary supply through feed materials is usually insufficient.
The deficiency of L-Tryptophan was generally characterized as decreased feed intake and efficiency, and slow growth rate. Considering L-Tryptophan playing a key role in growth performance and feed efficiency, it is recommended to add L-Tryptophan in diet to achieve the optimal amino acid balance and fulfill the digestible tryptophan requirement of animals, especially piglets, sows and poultry etc.