Growth and Performance of Broiler Chicks During the Starter and Grower Phases in Phase-Feeding

An experiment was conducted to evaluate the efficacy of a nutrition program referred to as “phase-feeding” (PF) over the first 6 weeks posthatching. Diets were formulated using amino acid recommendations from the National Research Council (NRC) (1994) or from linear regression equations generated from best estimates of lysine (Lys), sulfur amino acid (SAA), and threonine (Thr) requirements. Regression equations were used to predict weekly Lys, SAA, and Thr requirements for use in a PF regimen that involved lowering amino acid levels following each respective week of the experiment, resulting in six diets fed over the 6-week period. Over the entire experiment (0 to 6 weeks), birds fed a PF regimen throughout had an increased (P \u3c 0.05) weight gain, feed intake, and weight gain per unit of digestible Thr intake relative to birds fed NRC requirements throughout. No differences (P \u3c 0.05) in carcass yield or abdominal fat percentage were noted. These data suggest that PF during the first 6 weeks of age can support growth and carcass yield comparable to diets formulated using NRC requirements. Dietary cost analysis indicates that substantial economic benefits may result from the use of PF during the starter and grower periods

Phase-feeding affects crude protein intake, excretion, and retention of broilers from 21 to 63 days

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 \u3c 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 \u3c 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