Metabolizable energy value of meat and bone meal for pigs

Metabolizable energy and N-corrected ME (MEn) values of 12 samples of meat and bone meal (MBM) were determined using 288 barrows with an average BW of 35 +/- 3.1 kg. For each of 12 MBM samples, diets were formulated by substituting 0, 50, or 100 g/kg MBM (as-fed basis) in a basal 170 g of CP/kg corn-soybean meal diet; corn and soybean meal were adjusted at the same ratio to account for the substitution. Each diet was fed to eight barrows in individual metabolism crates in metabolism studies that used a 5-d acclimation, which was followed by a 5-d period of total, but separate, collection of feces and urine. The GE, CP, crude fat (CF), ash, Ca, and P contents of the MBM samples, per kilogram (DM basis), ranged from 3,493 to 4,732 kcal, 496.7 to 619.1 g, 91.1 to 151.2 g, 200.3 to 381.9 g, 54.3 to 145.8 g, and 25.6 to 61.7 g, respectively. For each of the 12 MBM samples, MBM intake and MBM contribution to ME and MEn increased linearly (P < 0.05) with increasing level of MBM in the diets. The ME and MEn content of each of the MBM samples was calculated from the slope of the regression of MBM contribution (in kilocalories) to ME and MEn intake, respectively, against quantity (in kilograms) of MBM intake. The ME and MEn of the 12 MBM samples ranged from 1,569 to 3,308 kcal/kg DM and 1,474 to 3,361 kcal/kg DM, respectively. The variation in ME was described by the regression equation: ME = 6,982 + 0.283 GE (kcal/kg) - 6.26 CP (g/kg) - 3.75 CF (g/kg) + 129.47 P (g/kg) - 54.91 Ca (g/kg) - 6.57 ash (g/kg), with an R2 of 0.612 and SD of 376. For MEn, the corresponding equation was: MEn = 3,937 + 1.089 GE (kcal/kg) - 8.74 CP (g/kg) + 3.58 CF (g/kg) + 60.89 P (g/kg) - 15.92 Ca (g/kg) - 9.57 ash (g/kg), with an R2 of 0.811 and SD of 314. Simpler regression equations describing variation in ME or MEn were 9,254 - 7.41 CP (g/kg) - 9.41 ash (g/kg), with R2 of 0.504 and SD of 278; or 12,504 - 10.71 CP (g/kg) - 13.44 ash (g/kg), with R2 of 0.723 and SD of 249. Pearson correlation analysis indicated that the variations in ME and MEn of the MBM samples were not related to any of the major chemical components. The results indicated that variation in each of the chemical components of MBM alone is not the sole determinant of ME or MEn content of MBM, but that the interactions among these components influence energy use in MBM for pigs.