Fish Nutrition & Feed Technology

Unit 3 - Proteins and Amino acids

3.7. Amino acid Classification

For nutritional purposes, amino acids may be divided into two groups; the essential amino acids (EAA), and the non-essential amino acids (NEAA). EAA are those amino acids that cannot be synthesized within the animal body or at a rate sufficient to meet the physiological needs of the growing animal, and must therefore be supplied in a ready made form in the diet. NEAA are those amino acids that can be synthesized in the body from a suitable carbon source and amino groups from other amino acids or simple compounds such as diammonium citrate, and consequently do not have to be supplied in a ready made form in the diet.

The ten important EAA and a few important NEAA are listed below:

From a feed formulation viewpoint, it is important to know that the NEAA's cystine and tyrosine can be synthesized within the body from the EAA's methionine and phenylalanine respectively, and consequently the dietary requirement for these EAA is dependent on the concentration of the corresponding NEAA within the diet.