Effect on performance, carcass composition, yield, and financial return of dietary energy and lysine levels in starter and finisher diets fed to broilers

• Published in: Poultry science Vol. 72; no. 5; pp. 806 - 815
• Main Authors: HOLSHEIMER, J.P., RUESINK, E.W.
• Format: Journal Article
• Language: English
• Published: 01.05.1993
• Subjects: analisis economico; analyse economique; benefice; broiler chickens; carcass composition; composicion de la canal; composition de la carcasse; desempeno; diet; dieta; economic analysis; efficacite alimentaire; eficiencia de conversion del pienso; energy metabolism; feed conversion efficiency; gain de poids; ganancia de peso; ganancias; lisina; lysine; metabolisme energetique; metabolismo energetico; pollo de engorde; poulet de chair; profit; regime alimentaire; rendement; rendimiento; weight gain; yields
• ISSN: 0032-5791; 1525-3171
• DOI: 10.3382/ps.0720806

Dietary regimens affect performance, yields, and financial return. Preference for certain dietary regimens depends on whether aiming for either best performance, highest yields, or greatest return, or a combination of two or more of the variables. This was studied in an experiment in which in a factorial arrangement of treatments, Ross male broiler chicks were fed six different starter diets from 0 to 14 days: Diet 1 with 3,250 kcal ME/kg and 1.15% Lys; Diet 2 with 3,000 kcal ME/kg and 1.06% Lys; Diet 3 with 2,750 kcal ME/kg and 0.97% Lys. The energy:Lys ratios in these diets were the same. Diets 4 to 6 had the same composition as Diets 1 to 3, respectively, but Lys was increased by 0.15, 0.14, and 0.13%, respectively. Three finisher diets with 3,250 kcal ME/kg were fed from 15 to 49 days, with Lys levels of 1.10, 1.20, and 1.30%. In all diets Lys was the first-limiting amino acid. Maximum gain and minimum feed:gain ratios were obtained using a starter diet with either 3,250 kcal ME/kg and 1.15% Lys or 3,000 kcal ME/kg and 1.06% Lys, in combination with the finisher diet with an increased Lys content of 1.30% (P < 0.05). Deposition of carcass protein up to 7 wk of age was highest in the groups fed 1.20 and 1.30% Lys in the finisher period (P < 0.05), irrespective of the diets fed in the starter period. Deposition of fat was not different among the dietary treatments. The dietary treatments had effect on yield response. Financial calculations show that the diets resulting in best performance and yields did not result in greatest financial return.