Influence of Age and Dietary Protein on Certain Free Amino Acids in Chick Blood Plasma

DURING the past few years, there has been a great deal of interest in studying the relationship of dietary amino acid levels to the concentrations of free amino acids in the blood plasma. Richardson et al. (1953) demonstrated that the concentrations of the free amino acids in chick plasma were related to the level of the same amino acids in the diet. In an experiment conducted to determine the rate and extent of absorption of amino acids from the intestinal tract of dogs, Denton and Elvehjem (1954) reported that the concentrations of amino acids in the blood corresponded roughly to the amino acid composition of the protein fed. Recently, Tonkinson et al. (1961) have presented data suggesting a correlation of the free amino acids in the blood plasma with the dietary amino acid requirements for turkeys. Since the blood serves as the primary means of transport of constituents to the …