Prediction equations for the energy values of soybean meal for pigs at the growing phase with ex-post validation1 Equações de predição dos valores energéticos do farelo de soja para suínos em crescimento com validação ex post

The aim of this study was to determine and validate prediction equations for digestible (DE) and metabolizable energy (ME) of soybean meal for growing pigs. The prediction equations were developed using data from chemical composition, digestibility and metabolizability of soybean meal samples (n = 25) evaluated in essays at Embrapa Suínos e Aves. The equations were estimated through regression analysis, using the REG procedure of SAS and adjusted R2 was the criterion of choice to select the best models. Two equations were estimated for DE and two for ME. To validate the equations, one experiment with two essays was performed to determine the values of DE and ME of five samples of soybean meal. In each essay, 24 growing pigs with an initial weight of 54.20 ± 1.28 kg at first and 54.60 ± 2.26 kg at second essay, were sorted in a complete randomized block design with 6 treatments (1 reference diet and 5 test diets) and 4 replicates. Considering the lowest prediction error (ep), the equations to predict the DE and ME of soybean meal were: DE = 48153 – 1586.1(PB) + 744.5(EE) + 363.6(FB) 1398.3(MM) + 15.5(PB2) – 170.8(EE2) – 29.3(FB2) + 5.4(FDA2) – 2.5(FDN2) + 90.6(MM2) – 8.2(EEFDA) + 33(EEFDN), with R2 = 0.88 and ep = 2.32 and ME = 12692 – 2397.7(MM) – 56.8(EE2) + 164.9(MM2) – 102.2(EEFB) – 12.25(EEFDA) + 67.6(EEFDN) + 5.5(PBFB) – 2.9(PBFDN) with R2 = 0.65 and ep = 1.69. Based on the chemical composition data and correlations, it was possible to establish prediction equations for the values of digestible and metabolizable energy of soybean meal for pigs, being necessary validation for greater accuracy of the models.