Sequence in Which the Amino Acids of Fish Meal Proteins Become Limiting for the Growing Rat, as Determined by “The Complete Protein Evaluation Method”

Abstract

The sequences of limiting amino acids in two fish meals were determined in rat growth experiments by the procedure proposed by Schelling (1975) for the complete evaluation of dietary protein (CPE). In preliminary studies the fish meals had been found not to have methionine as the first limiting amino acid. The results showed that histidine, methionine, tryptophan and threonine were the most limiting amino acids in both meals. For practical purposes histidine and methionine were first co-limiting in both, tryptophan came next in one followed by threonine; in the other the two latter were co-limiting. The further sequences were not clearly identified by the procedure used. Calculations of chemical scores identified methionine, tryptophan and histidine as the most limiting in that order, but limitations in threonine were not detected. The experience gained indicates that the procedure has a potential for detecting the most limiting amino acids in animal protein.

Key Words:

• relative excess
• growth