Effects of Dietary Energy and Amino Acid Density During Finisher and Withdrawal Phases on Live Performance and Carcass Characteristics of Cobb MV x 700 Broilers

Meeting dietary energy needs of broilers accounts for the largest proportion of feed costs, and energy has long been identified as a driver of feed intake (FI) in poultry. Dietary energy content can also influence responses of broilers to dietary amino acids (AA). Therefore, 2 experiments (Exp) were conducted to determine the effects of energy density in the finisher (29-36 d) and withdrawal (37-46 d) diets on Cobb MV x 700 broiler performance and processing characteristics. Treatments in Exp 1 were a factorial arrangement of sex and energy density [low (LE), medium (ME), and high energy (HE)], whereas treatments in Exp 2 were a factorial arrangement of energy (LE, ME, and HE) and AA density [medium AA (MAA) or high AA (HAA)]. In Exp 1, no energy or energy x sex interactions were observed on overall (29-46 d) live performance or processing measurements of broilers. In Exp 2, energy density had no effect on overall live performance or carcass composition. Birds fed MAA diets had higher FI and body weight gain than birds fed the HAA diets during the overall experimental period. Processed part weights and yields were unaffected by AA density, except for pectoralis minor yields, which were higher for birds fed HAA than for those fed MAA diets. These data indicated that changes in 29-46 d energy density of the magnitude used in this study did not influence responses of Cobb MV x 700 broilers to varying AA levels.