Studies on the possibilities of improving the nutritive value of Swedish wheat bread. II. The effect of supplementation with lysine, threonine, methionine, valine and tryptophan.

Abstract

AbstractA basal diet containing wheat bread as the source of protein and carbohydrate, and sufficient quantities of vitamins, essential fatty acids and minerals was supplemented with combinations of lysine, threonine, methionine, valine and tryptophan and fed to male weanling rats. The addition of lysine and threonine to the basal diet improved the nutritive value of the bread protein considerably more than the addition of lysine alone, as measured by the growth rate and the gain in weight per g of nitrogen consumed. On a bread diet containing 2.0% nitrogen and fortified with 0.32% L‐lysine and 0.2% DL‐threonine, the rats gained 21.0 g per g of nitrogen consumed. The corresponding figures for rats given isonitrogenous diets in which spray dried skim milk or egg albumin supplied the protein were 20.1 and 22.4. No further improvement was obtained on addition of methionine, valine and tryptophan to bread diets supplemented with lysine and threonine.