The Effects of Energy and Amino Acid Levels on Performance and Carcass Quality of Male and Female Broilers Grown Separately

Abstract

Studies were conducted to evaluate the response of male and female broiler chickens to diets containing different levels of energy and amino acids. Two energy series were compared: 3,080, 3,135, and 3,190 kcal of ME/kg (“low”) and 3,190, 3,245, and 3,300 kcal of ME/kg (“high”) in pelleted starter, grower, and finisher diets. Diets provided a minimum of 85, 90, 95, 100, 105, and 110% of suggested amino acid recommendations for the broiler male except for Met and TSAA, which were kept at 105%. Modifications were made in feeding periods, recognizing the differences in rate of gain and marketing ages of the two sexes. Feeding periods were 0 to 21, 21 to 42, and 42 to 56 days for males and 0 to 18, 18 to 35, and 35 to 49 days for females. Four floor pen trials utilizing 9,600 male and 9,600 female broilers were conducted. Birds were processed to determine dressing percentage and abdominal fat pad weights.Energy content of the diets had no significant (P>.05) effect on body weight or feed efficiency for male or female broilers. Carcass dressing percentage of females, but not males, was significantly (P<.05) increased on the high energy series. Abdominal fat pad was not influenced by energy for either sex. For both sexes, increasing dietary amino acid levels resulted in significant (P≤.05) linear improvements in live weights and feed utilization and a reduction in abdominal fat pad weight. There were no treatment by sex interactions for any of the parameters, indicating that both sexes responded to changes in energy and amino acid levels in a similar manner. Therefore, the results of this study do not support feeding nutritionally different diets to male versus female broilers when feeding periods are adjusted by sex.