Early Protein Restriction of the Broiler Chicken and Carcass Quality upon Later Marketing

Abstract

Commercial source day-old chicks were reared sexes separate in floor pens and fed corn soybean meal rations (3100 kcal ME/kg) during the first 2 weeks that contained crude protein at, above, and below the estimated requirement (24, 26, and 22%, respectively). Common feeds, respective of sex, were offered through the subsequent 2 to 5 weeks of age and finishing period.Performance at 2 weeks was comparable with birds fed the 26 and 24% protein rations, but body weight and feed conversion was reduced with those offered the 22% level. Differences attributable to starting protein were not detected in either sex after the subsequent growing period at 5 weeks or finishing by 45 days with the male and 54 with female.Apparent carcass yield and grades for conformation, fleshing, and finish were not influenced by marginal dietary protein changes during the starting period, regardless of sex and age marketed. Presumably, extensive body size changes subsequent to deprivation permitted a complete compensatory adjustment.