Effect of Starvation and a Nonprotein Diet on Blood Plasma Amino Acids, and Observations on the Detection of Amino Acids Limiting Growth of Chicks Fed Purified Diets

Effect of low protein diets on free amino acids in plasma of young men: Effect of wheat gluten diet.

“…Unpublished data from our laboratory, however, showed that the concentration of free lysine in the plasma and tissues did not decrease in adult rats fed diets containing different levels of wheat gluten for four weeks. Furthermore, in starving chicks (8,9) and sheep (10) and protein-deprived men (11) the plasma lysine concentration remains normal or increases. Moreover, EDWARDS et al (12) showed that plasma free lysine was not affected significantly by supplying a wheat gluten diet to human adults.…”

“…This may be explained by the following considerations. l) A normal or rather increased concentration of plasma lysine was demonstrated in starving chick (8,9) and sheep (10) and protein-deprived men (11), in which tissue breakdown was increased. In subjects on gluten diets, tissue proteins may be catabolized to compensate for the poor amino acid composition of the gluten, as indicated by BANKS et al (22).…”

Diet and Feeding Interval Effects on Serum Amino Acid Concentrations of Growing Swine

“…Serum histidine levels showed no significant changes during the first 12 hr of refeeding; however, aftet 24 hr of shortinterval refeeding the serum histidine concentration was increased relative to earlier For personal use only. Mitchell et al 1964), the protein fed (Clark et al 1963;Richardson et al 1965), and the duration of fasting (Hill and Olsen 1963 Mitchell et al (1968) showed that a broken-line response curve in serum amino acid concentrations could be used to assess the amino acid requirements of pigs fed a diet for 12 days, with the requirement level suggested to be at a dietary concentration producing the break point in the SAA curve. When the diet was fed for only 1 day a linear SAA response curve to dietary SAA concentration was obtained, from which no estimate of requirement could be made.…”

Relationship of blood plasma free amino acids and ingested protein in swine

“…The former effect might be explained by the continuation of the fasting effect as amino acids have been observed to decrease in concentration with time in chicks upon fasting (Gray et al, 1960;Hill and Olsen, 1963b). However, two hours after ingesting a protein meal, the digestive processes are operating at a high intensity.…”

“…By this method, the amino acid(s) deficient in a protein could be easily calculated and in order of limitation. Hill and Olsen (1963b) used a modification of the method proposed by Longnecker and Hause (1959). These authors calculated plasma amino acid ratios by relating the plasma amino acid concentration, corrected for the concentration obtained when a nonprotein diet was fed, to the chick's amino acid requirement.…”