Animal nutrition 1: l-tryptophan 98% feed grade 2: cas no: 73-22-3 3: white to yellow-white crystal or crystalline powder Lgnition residue acuities 0.1%; Animals: to promote animal feed, weaken the stress reaction, improve animals sleep, still can increase fetal and cubs of antibodies, improve the dairy cattle lactation. Reduce the ration of high-quality protein dosage, save feed costs, reduce ration protein feed consumption, save formula space and so on 20kg/bag or 10kg/bag