Arginine-Lysine Antagonism in the Chick and Its Relationship to Dietary Cations

Abstract

Broiler-strain chicks were reared to four weeks of age with semipurified diets based on protein from casein (30%), soybean (26%) or sesame meal (30%). A total of at least 2.4% arginine was required for maximal growth with the casein diet. When arginine was suboptimal, growth was stimulated by extra glycine, glutamic acid, leucine and creatine but not by ammonium acetate or citrate. Lysine depressed growth severely and this effect was largely counteracted in a competitive manner by arginine. In the presence of excess lysine, extra glycine and glutamic acid had no stimulating effect. Soybean protein supplemented with methionine supported a maximal growth rate, but addition of lysine depressed growth and produced gross symptoms of arginine deficiency. This effect was counteracted by a combination of arginine, glycine and potassium acetate. Potassium acetate supplementation of the casein diet produced a marked stimulation of growth rate with or without added lysine, but had no effect when added to the basal soybean protein diet. When added to a sesame meal diet deficient in lysine, potassium acetate appeared to depress growth. Excess arginine also depressed growth when lysine was limiting and potassium acetate was included, but not when lysine was adequate. The results suggest a metabolic antagonism between arginine and lysine.