Plasma Amino Acid Pattern of Chicks in Relation to Length of Feeding Period

Abstract

The concentration of either lysine or valine was varied from deficient to excessive dietary levels in a basal diet containing crystalline amino acids in order to study the relationship between amino acid levels and the accumulation of free amino acids in the blood plasma of chicks. In separate assays where the feeding phase was restricted to 30 minutes, increasing the dietary concentration of valine or lysine resulted in the accumulation of these amino acids in the plasma even though the lower dietary amino acid levels were known to be well below the concentration needed to maximize weight gain. Plasma lysine also increased when the feeding period was lengthened to 6 hours. In contrast, valine did not start to accumulate in plasma until the dietary concentration approached or exceeded the level known to be required for maximal gain.