A model was developed to simulate the basal metabolism, deposition of protein in carcass and feathers, and carcass fat deposition. The model assumes the existence of a pool of readily available nutrients in the animal, simulating metabolism based on the flow of nutrients to and from this pool. Nutrients are originated from feed intake or tissue catabolism, and may be used for maintenance, feather and carcass protein deposition and carcass fat deposition. The simulation process is dynamic, with maintenance and tissue turnover occurring simultaneously. In case energy is insufficient for maintenance, lean and fat tissues are catabolized, and their energy is added to the pool. Nitrogen (N) is also required for maintenance and lean tissue growth. In case of N deficiency, this nutrient is obtained from muscle catabolism. Feather and lean tissue growth is dependent on genetic background and on the largest nutritional limitation (nitrogen or energy) in the nutrient pool. The amount of fat tissue stored depends on the energy available in the pool, being greater when there is excess energy. The effect of sex and different genotypes is expressed through changes in the parameters. The model is able to simulate deposition of protein and fat in the carcass and protein in the feathers.
lean tissue; fat tissue; maintenance; catabolism; feathers; metabolism; tissue deposition
