AMINO-ACID AND ENERGY-REQUIREMENTS OF BROILER BREEDER HENS

Three trials, involving 1000 broiler breeder hens each, were conducted under rather uniform conditions in order to test the applicability of two models for calculating the amino acid requirements of broiler breeders, and to evaluate their energy requirements. The birds fed diets based on Model A (which assumes that all of the egg white and shell membrane proteins are synthesized during albumen formation and secretion at the expense of tissue proteins) produced at a rate greater than the planned target, whereas Model B (which assumes that only ovoglycoproteins and shell membranes are thus produced) supported a production close to the anticipated performance. This indicates the validity of Model B, developed for egg layers, to predict the requirements of the most limiting amino also for broiler breeder hens. The resulting practical diets contained considerably lower protein levels than customary. According to Model B, minimal amino acid requirements for broiler breeder hens producing a daily egg mass of 52.7 g. having a body weight of 3.5 kg and gaining weight at a rate of 4 g/day, calculated to be as follows (g/hen/day): methionine, .57; sulfur amino acids, .83; lysine, .76; arginine, 1.11; threonine, .72; valine, .92; isoleucine, .85; leucine, 1.25; tryptophane, .19; histidine,