The Influence of L-Lysine Supplementation of 12, 14 and 16 Percent Protein Corn-Soybean Oil Meal Diets upon Nitrogen Balance of Growing Swine

Abstract

A 12.1% crude protein diet was inadequate to support satisfactory nitrogen retention by growing pigs, due in part to inadequate total nitrogen intake. This diet should have been adequate in tryptophan, methionine and lysine, after supplementation. This diet contained less isoleucine than has been reported to be required by growing pigs. Nitrogen retention values ranging from 0.96 to 1.23 gm of nitrogen retained per unit of metabolic size resulted when a 14.2% protein corn-soybean oil meal diet containing 0.137 to 0.157, 0.62 to 0.84 and 0.63% of tryptophan, lysine and isoleucine, respectively, was fed to growing pigs. The use of higher levels of lysine in conjunction with a 12.1% crude protein diet appeared to contribute toward a decrease in nitrogen retention of growing pigs, perhaps because lysine was not in the correct proportion to other essential amino acids in the diet. Supplementation of higher protein diets with additional lysine when these diets apparently contained adequate amounts of all other essential amino acids did not significantly influence nitrogen balance of growing pigs.