|Dozier iii, William|
Submitted to: Journal of Applied Poultry Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/25/2006
Publication Date: 2/25/2007
Citation: Dozier III, W.A., Corzo, A., Kidd, M.T., Branton, S.L. 2007. Dietary apparent metabolizable energy and amino acid density effects on growth and carcass traits of heavy broilers. Journal of Applied Poultry Research. 16:192-205. Interpretive Summary: Feed cost represents 65% of the total live production cost for broiler chickens that supports an industry that produces 8 billion birds annually. Large percentage of the cost of the diet is energy and protein/amino acid contributing ingredients. Research is sparse on the interactive effects of dietary energy and amino acids on performance of broilers grown to heavy weights. This study examined responses of broilers fed diets varying in metabolizable energy and amino acids on performance and carcass yields from 42 to 56 days of age. Results indicated that decreasing dietary metabolizable energy from 3,240 to 3,140 kcal/kg resulted in 7 points poorer feed conversion, but increased total breast meat yield by 0.7 percentage points. Increasing amino acid density by 10% also increased total breast meat yield by 0.5 percentage points.
Technical Abstract: Two experiments (Exp) were conducted to evaluate the interactive effects of dietary AME and amino acid (AA) density (total basis) on broiler chickens from 42 to 56 d of age. In Exp 1, diets were formulated to contain low AME (3,140 kcal/kg) and moderate AME (3,240 kcal/kg) in combination with moderate AA (16.2% CP, 0.88% Lys, and 0.75% TSAA) and high AA (18.0% CP, 0.98% Lys, and 0.83% TSAA). Dietary treatments in Exp 2 were diets formulated to contain moderate AME (3,220 kcal/kg) and high AME (3,310 kcal/kg) combined with moderate and high AA concentrations used in Exp 1. In general, dietary AME and AA did not interact to influence growth and meat yield responses. Broilers provided the low AME diet in Exp 1 consumed more feed and had poorer feed conversion, but had higher total breast meat yield than birds fed the moderate AME diet. In Exp 2, broilers fed the high AME diet from 42 to 56 d had increased BW gain, decreased feed consumption, and improved feed conversion. Feeding the high AA diets in both Exp decreased feed consumption, improved feed conversion, and increased total breast meat yield. Establishing nutritional programs for heavy broilers late in development between 2.5 and 3.6 kg nutritionists may need to consider increasing AA density to optimize breast meat yield. Increasing the AME content of the diet improves nutrient utilization, but not breast meat yield.