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.

The lysine requirement of large-type turkey poults was studied in three experiments. For male poults to 4 weeks of age, diets containing 22% or 24% protein, and less than 1.50% lysine, did not support growth equivalent to that obtained when 28% protein diets were fed, or when the low-protein diets were supplemented to give a concentration of 1.50% or greater of lysine. It is concluded that the minimum lysine requirement in this period was 1.50% of a 28% protein diet or 5.3% of the protein. As a function of energy, the lysine requirement was at least 0.52% per megacalorie of metabolizable energy (M.E.) per kg. of diet.For male poults 4 to 8 weeks of age, the lysine requirement was 1.40% of a 26% protein diet or 5.4% of the protein. As a function of energy, the lysine requirement for this period was 0.46% per megacalorie of M.E. per kg. of diet.For male poults 8 to 12 weeks of age, diets containing less than 22% protein did not support maximum growth. For this stage of growth, the requirement was 22% protein with more than 5.09% of the protein as lysine, or 0.40% lysine per megacalorie of M.E. per kg. of diet.The lysine requirement was not a constant percentage of the protein over a range of protein concentrations in the diet within an age period, but did remain a constant percentage of the protein from 1 day to 8 weeks of age. In the 8-12 week period, lysine requirements were less (as a percentage of the protein) than at earlier stages of growth. ABSTRACTDiets composed mostly of low selenium corn and torula yeast were fed to laying hens to produce a selenium and/or vitamin E deficiency. The basal diet was also supplemented with 101. U. of vitamin E per kg., or 0.10 mg. /kg. selenite selenium, or a combination of vitamin E and selenium. Hens fed the basal diet decreased in egg production during the third month and for the remainder of the experiment, a decrease which was mostly corrected by vitamin E, and completely corrected by selenium. Fertility and hatchability of eggs were also low on the basal diet, and were also partly corrected by vitamin E, and completely corrected by selenium.The selenium content of lyophilized egg white and yolk is reported along with the selenium content of several tissues. Gross deficiency signs of the laying hen are also described.

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