University of Arkansas, Fayetteville Division of Agriculture


An experiment was conducted to assess effects of phase-feeding (PF) on crude protein (CP) intake, excretion, and retention of broilers. Six birds were housed individually and were fed diets formulated using recommendations from National Research Council (NRC) or linear regression equations. Two PF treatments were prepared: standard (PF) and low (PF10), in which predicted lysine, sulfur amino acids, and threonine recommendations were reduced by 10%. For PF and PF10, two diets (high-nutrient and low-nutrient density) were blended in variable quantities to produce rations matching predicted amino acid requirements over two intervals. Birds were fed a single NRC grower and finisher diet or a series of PF and PF10 diets that were switched every other day. With the exception of weight gain, which was lower for PF than for birds fed the NRC and PF10 diets, no differences in growth performance were observed. Both PF diets reduced CP intake numerically from 21-43 d and 21-63 d, and significantly from 43-63 d (P < 0.055). Retention of CP was not impacted by diet although there was a tendency toward increased CP retention in birds fed the PF10 diet from 43-63 d (P = 0.071). Excretion of CP during the finisher period was reduced (P < 0.05) for birds fed PF and PF10 diets, and total CP excretion was numerically reduced (4.0% and 8.6%, respectively). These data indicate that in addition to economic benefits, PF may result in environmental benefits.