The Lysine Requirement of Weanling Swine at Two Levels of Dietary Protein

Abstract

Weanling pigs weighing about 30 lb. were individually fed semi-purified diets containing either 12.8 or 21.7% protein to determine the response to varied levels of lysine. The source of protein was sesame seed meal supplemented with L-histidine. Supplementary lysine was added as L-lysine monohydrochloride. The rate of gain at the two levels of protein was similar, but the lysine requirement varied with the level of protein fed. At 12.8%. protein the pig required 0.71% lysine in the diet or 5.55% of the dietary protein; and, at 21.7% protein the lysine need was 0.95% of the diet or 4.38% of the dietary protein. Assuming a linear relationship between dietary protein and lysine need, expressed as a percentage of the protein, the need within the protein range studied may be expressed by the equation, Y=7.23−0.131χ, where Y is the lysine need and χ is the percent of dietary protein. Expressed as a percent of the total digestible nutrients, the lysine required in the low- and high-protein diets was 0.86 and 1.19%, respectively.