Prediction equations were obtained for the apparent metabolizable energy (EMAn) values of energetic feedstuffs used in broiler chicken diets by meta-analysis. A bibliographical review of the studies carried out in Brazil was performed to collect information concerning energy values and chemical composition (CP, EE, MM, CF, NDF, and ADF) of feedstuffs. The effects of gender (male, female and mixed), age (1st and 2nd week, 3rd and 4th week, 5th and 6th week, and older 6th weeks or indefinite), and the metabolism assay methodology (excrete total collection or forced fed + excrete total collection) were also considered, constituting a factorial scheme (3x4x2). The stepwise procedure was used to study the association among equation variables by their importance, and Proc Reg (SAS) was used to fit the multiple linear regression model. The equations which best estimated the EAMn of the energetic feedstuffs were AME = 4,371.18 - 26.48CP + 30.65EE - 126.93MM - 52.26CF - 25.14NDF + 24.40FDA (R²=0.81) and AME = 4,205.23 + 30.58EE - 130.35MM - 58.29CF - 28.31NDF + 16.71NDA (R²=0.81). NDF and ADF variables were important in the equations, influencing the feedstuffs energetic values.
broiler; metabolizable energy; NDF; ADF