Classification of essential amino acids for the weanling pig

Feeding experiments with mixtures of purified amino acids show that arginine, leucine, phenylalanine, and valine are required for good growth of weanling pigs. The pig resembles the rat in its ability to synthesize part, but not all of the arginine required. It is now possible to tentatively classify the known amino acids with respect to major growth effects in weanling pigs. The amino acids which must be present in the diet for good growth are arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. The remaining amino acids may be tentatively classed as dispensable.