Effect of the Addition of Imbalanced Amino Acid Mixtures to a Low Protein Diet, on Weight Gains and Plasma Amino Acids of Chicks

The effect of sodium sulphate and methionine on the utilisation of non‐protein nitrogen by laying hens

“…No response to sodium sulphate was observed. The fact that food consumption was reduced with the diet containing 136-3 g protein/kg, although all diets had the same energy content, is in accord with the observations of Fisher and Saphiro (1961) and Hill and Olsen (1963). These authors suggested that the voluntary intake is depressed as a result of an inbalance in the amino acids.…”

A Chick Bioassay for Lysine

“…Furthermore, a diet containing a low level of C-l protein plus an amino acid mixture simulating C-l protein was found previously to give only slightly poorer growth than did a diet containing C-l protein alone at an equivalent contribution of Lamino acids (Hill and Olsen, 1963). How-ever, the assay, as outlined, lacks sufficient precision for general use as judged by the fiducial limits.…”

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

“…It has been theorized that when the low plasma level of a deficient amino acid is corrected, protein synthesis will continue until the second limiting amino acid will limit further protein synthesis, which will occur with a simultaneous decrease in the plasma free concentration for this amino acid (Hill et al, 1961;Hill and Olsen, 1963a). The effect of amino acid supplementation on the presence of other amino acids in blood plasma presents a further complication in the evaluation and correction of amino acid deficiencies.…”

“…Most of the depression in weight gains attributed to amino acid imbalance have been demonstrated with diets grossly deficient in an essential amino acid (Fisher and Shapiro, 1961;Hill and Olsen, 1963a;(chicks); (rats), Rmta and Harper, 1960;Sauberlich, 1961a) or by adding excess quantities of an amino acid to the diet (Sauberlich, 1961b (Becker, 1960). This depression in weight gains when lysine was added to soybean protein corresponds to the definition of "amino acid imbalance" stated by Harper (1958).…”

“…After fasting humans for 48 hours, a decreased concentration of lysine, threonine, methionine, arginine, and tryptophan occurred, while the plasma concentrations of leucine and valine increased (Charkey et al, 1955), indicating a species difference. Hill and Olsen (1963a) reported that in chicks fed a diet containing 15 percent isolated soybean protein and then deprived of feed for periods of 12 to 48 hours, a marked elevation in the concentrations of lysine and threonine was observed. Concentrations of glutamine, isoleucine, leucine, and valine were also elevated, but to a lesser extent, whereas concentra tions of arginine, histidine, phenylalanine, tryptophan, and tyrosine were depressed.…”