Feed additive 1: l-tryptophan 98% feed grade 2: cas no: 73-22-3 3: white to yellow-white crystal or crystalline powder Molecular formula: c11h12n2o2 L-tryptophan need to be stored in cool, dry and well-ventilated place 2, useage: 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