This study determined dietary productive energy (PE) recommendations for broilers. Four experiments (E1 to E4) fed broilers a total of 60 pelleted diets within 1-56 d (4 experiments, 5 phases each, 3 treatments per phase) following Cobb 500 guidelines. They included replacements of soybean meal with cellulose (E1) or corn (E2) and inclusion levels of oil (E3) or total digestible amino acids (E4). One treatment consisted of a fully balanced diet in each experiment and feeding phase. A total of 9,600 birds were used (20 birds/pen, 8 pens –the experimental unit– per treatment, 3 treatments per feeding phase, 5 phases assessed, 4 experiments). In all feeding experiments and feeding phases, BW, BW gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were determined. Birds were scanned with Dual-Energy X-Ray Absorptiometry (DEXA) at the beginning and end of each feeding phase to determine the change in body composition and energy retention. Net energy (NE) for gain (NEg, kcal/kg) was calculated. Close to the end of each phase, birds from each treatment were placed in indirect calorimetry chambers to determine fasting heat production (FHP), and the NE for maintenance (NEm; kcal/kg) was calculated. PE (kcal/kg) was determined as NEg+NEm. A standard digestibility study was conducted to determine the N-corrected apparent metabolizable energy (AMEn). A database with 60 data rows was constructed, including all performance, body composition, and AMEn and PE measured values. The PE recommendation was defined as the PE value of the diet that maximized the response in each experiment and feeding phase. Data was analyzed using ANOVA and Tukey test. AMEn varied 2,468 – 3,061 kcal/kg, and PE 1,758 – 3,193 kcal/kg. Best response was observed in diets that contained mean 2,802, 2,829, 2,856, 2,887, and 2,826 AMEn kcal/kg in Starter, Grower, and Finisher 1, 2, and 3, respectively, while containing 2,884, 3,031, 2,914, 2,763, and 2,315 PE kcal/kg in the same phases. All values were adjusted to Cobb 500 AMEn recommendations, obtaining PE recommendations of 2,991, 3,163, 3,111, 2,967, and 2,579 PE kcal/kg for Starter, Grower, and Finisher 1, 2, and 3, respectively, following a quadratic trend (P<0.05). PE values showed a higher (P<0.05) correlation with FI and FCR than AMEn.

Martinez, D., N. Suesuttajit, C. Umberson and C. Coon. 2025. Dietary Productive Energy Recommendations for Broilers up to 56 Days of Age. 2025 International Poultry Scientific Forum, Abstract P387.