The Protein Requirement of the Growing Chick Determined with Amino Acid Mixtures

The nitrogen requirement of chicks was determined using crystalline amino acid diets. For optimum efficiency of feed utilization the requirement was found to be approximately 4.0% nitrogen. It was observed, however, that a lower nitrogen level (3.2%) resulted in equally good growth and nitrogen retention, but lower feed utilization. Chicks were able to gain satisfactorily on this low nitrogen diet by voluntarily eating more of the ration. This has the effect of increasing the absolute intake of dietary amino acids.