The Amino Acid Requirement of Laying Hens: 5. Amino Acid Balance in Low Protein Diets

Abstract

IT WAS recently demonstrated that the levels of essential amino acids found to be minimal for egg production with diets composed of free amino acids were also minimal when supplied from intact feed ingredient protein (Johnson and Fisher, 1959). To supply such minimal amino levels, less than 12% dietary protein was required. However, although egg production was maintained on such low protein diets, egg weight and body weight were significantly inferior when compared to standard (15% protein) laying rations.In order to investigate the nature of the limiting factors involved in egg size and body weight on the low protein diet, supplementation with poor quality protein was studied. If the diet were merely inadequate in nitrogen (non-essential amino acids) the supplements would be expected to improve performance. A deficiency of a specific essential amino acid would not be corrected by a source of nitrogen unless it provided a sufficient excess…