Responses of broiler chickens to the nutrient recommendations of NRC (1994) and the Ross broiler management manual

Summary Background: broiler producers arbitrarily use feeding standards, potentially compromising bird performance and economic efficiency. Objectives: to compare two feeding standards (NRC, 1994 vs. Ross 308 strain catalogue) on productive performance, carcass traits, nutrient consumption and digestibility in Ross 308 strain of broiler chickens. Methods: a total of 300 one-day old straight-run broilers were assigned to two feeding programs with five replicates and 30 birds in each. Diets were formulated to meet nutrient requirement recommendation by NRC (1994) and fed during 1-21 and 22-42 days of age, while the diet formulated following Ross 308 strain catalogue recommendation was fed in three periods: 1-10, 11-24 and 25-42 days of age. Fecal digestibility of nutrients was determined after feeding diets containing 0.3% Cr2O3 as an external marker. At the end of the experimental period, two birds (one male and one female) from each replicate were slaughtered to determine carcass traits. Results: within 1-21 d, the Ross recommended diet increased feed intake and improved feed conversion ratio (p<0.05). Over the whole experimental period, the performance parameters were not significantly affected by the dietary treatments. Chickens on the Ross 308 recommended diet consumed more total sulfur containing amino acids per Kg of weight gain during the whole experimental period (p