Lysine Requirements of Starting and Growing Turkeys

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.