Effect of metabolizable energy levels and conditioning temperatures on broiler performance, processing yield, footpad lesions, and nutrient digestibility from 1 to 42 d of age

This study evaluated the main effects and interactions of 2 ME levels and 3 conditioning temperatures on broiler performance, processing yield, footpad lesions, tibia ash, and nutrient digestibility from 1 to 42 d of age. A total of 1,350 d-old YPM x Ross 708 male broilers were randomly distributed in 54 floor pens and assigned to 6 treatments (9 replicates/treatment). Diets were formulated to contain 2 ME levels (standard energy [SE] and -130 kcal/kg reduced energy [RE]) in all feeding phases. Basal diets for each ME level were manufactured using 3 conditioning temperatures (80, 84, and 88°C). Feed intake (FI), BW, and FCR were determined at 14, 28, 35, and 42 d of age. On d 42, ileal digesta (5 birds/pen) was collected for nutrient digestibility analysis and broilers were processed on d 43. Data were analyzed as a 2 × 3 factorial arrangement using the GLIMMIX procedure of SAS and means separated using Tukey's test. Broilers fed SE had improved FCR (P < 0.05) compared to broilers fed RE in every evaluated period. Performance parameters from 15 to 42 d and processing yields were unaffected (P > 0.05) by conditioning temperatures. Apparent ileal digestibility (AID) of fat and energy was higher (P < 0.05) in broilers fed SE compared to broilers fed RE. Broilers fed diets conditioned to 88°C had lower (P < 0.05) AID of Ca and P compared to broilers fed diets conditioned to 80 and 84°C. Overall, most performance parameters were unaffected by conditioning temperatures, but broilers fed SE diets had improved performance and AID of fat and energy compared to broilers fed RE diets.