Apparent metabolizable energy value of meat and bone meal for White Pekin ducks

Apparent metabolizable energy and AME(n) values of 12 samples of meat and bone meal (MBM) were determined using 288 ducks with an average weight of 3.4 kg. Diets were formulated for each of the 12 MBM samples by substituting 0, 5, or 10% MBM in a basal cornsoybean meal diet; corn and soybean meal were adjusted at the same ratio to account for the substitution. Each diet was fed to 8 ducks in individual cages in a metabolism assay that employed a 4-d acclimation period followed by 3 d of excreta collection. The gross energy (GE), CP, crude fat (CF), ash, Ca, and P contents of the MBM samples, on a per kilogram of 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. The AME and AME(n) values of the MBM samples were calculated from the slope of the regression of MBM contribution (in kcal) to AME and AME(n), intake, respectively, against the amount (in kg) of MBM in diet. The AME or AME(n) of the 12 MBM samples ranged from 1,781 to 3,916 kcal/kg of DM or 1,772 to 3,662 kcal/kg of DM, respectively. The variation in AME was described by the regression equation AME = -7,272 + 5.000 GE (kcal/kg) - 19.43 CP (g/kg) - 29.51 CF (g/kg) - 297.17 P (g/kg) + 106.09 Ca (g/kg) + 17.03 ash (g/kg), with R-2 = 0.552 and SD = 753. The corresponding equation for AMEn was = -7,389 + 4.584 GE (kcal/kg) - 16.74 CP (g/kg) - 25.11 CF (g/kg) - 218.24 P (g/kg) + 97.29 Ca (g/kg) + 7.95 ash (g/kg), with R-2 = 0.598 and SD = 586. The results reveal that variation in each of the chemical components of MBM alone is not the sole determinant of AME or AMEn value of MBM, but that the interactions among these components influence energy utilization in MBM for ducks.