Leucine, isoleucine and valine interactions in turkey poults

In four experiments, the interactions of leucine, isoleucine and valine in turkey poults were studied. The additon of 1.50% excess leucine to a 22% protein starter diet, marginal in isoleucine and valine, depressed growth. This growth depression was corrected by the addition of valine and isoleucine. The addition of the excess leucine caused a decrease in plasma valine and isileucine concentrations in experiments 3 and 4, and plasma valine concentration in experiment 1. The addition of valine caused a marked linear increase in plasma valine with little or no effect on plasma isoleucine. The addition of isoleucine to the diet caused an increase in plasma isoleucine. Plasma valine, however, was decreased by the addition of isoleucine to a high-leucine diet. It is concluded that interactions exist in turkey poults between leucine-valine, leucine-isoleucine and isoleucine-valine and that the growth reduction caused by added leucine can be partly alleviated by addition of valine or by valine plus isoleucine, but not be isoleucine alone.