There are essential and non-essential amino acids. The essential amino acids either cannot be synthesized by the shrimp or are synthesized at a rate which results in less than optimal growth. Thus, essential amino acids must be provided in the diet. On the other hand, non-essential amino acids are readily synthesized by the animal for optimum growth. Amino acids considered dietary essentials for shrimp are methionine, arginine, threonine, tryptophan, histidine, isoleucine, leucine, Iysine, valine and phenylalanine. Arginime and lepine appear to be the essential amino acids that would be the first limiting in the diet (Akiyama et al., 1992).