RESUMEN
The influence of broiler age on the apparent metabolizable energy (AME) and nitrogen-corrected AME (AMEn) of meat and bone meal (MBM) was investigated. A corn-soy basal diet and an experimental diet wherein 300 g/kg of the basal diet was replaced (w/w) with MBM were developed. The diets, in pellet form, were fed to six replicate cages across six age groups, namely d 1 to 7, 8 to 14, 15 to 21, 22 to 28, 29 to 35 or 36 to 42 d post-hatch. Birds were fed either a starter diet from d 1-21 or a finisher diet from d 22-35. Basal and experimental diets were introduced on d 1, 8, 15, 22, 29 and 36 with 10 (d 1-7), 8 (d 8-14) and 6 (d 15-42) birds per replicate. Total collection of excreta was carried out during the last 4 d of each age period. A linear decrease (p < 0.001) in the retention of dry matter and nitrogen was observed with advancing age. The AMEn of MBM showed a linear increase (p < 0.05), rising from 12.56 MJ/kg during d 1-7 to 13.90 MJ/kg during d 29-35, followed by a decline to 13.41 MJ/kg during d 36-42. The current findings showed that the energy utilization of MBM increased with the advancing age of broilers. Age-dependent AMEn values of MBM may need to be considered when MBM is included in feed formulations.
RESUMEN
Grain legumes are fair sources of protein, amino acids and energy, and can be used as a replacement for soybean meal in poultry feed formulations as the soybean meal becomes short in supply and costly. However, a concern associated with the use of grain legumes in poultry feeding is the presence of antinutritional factors. The effective processing and utilisation of these grain legumes in poultry feeding are well documented. The current review focuses on four selected grain legumes (lupins [Lupinus albus and Lupinus angustifolius], field peas [Phaseolus vulgaris], faba beans [Vicia faba] and chickpeas [Cicer arietinum]) and their nutrient content, the presence of antinutritional factors, processing methods and feeding value, including updated data based on recent research findings.
RESUMEN
Standardized ileal digestibility coefficients (SIDC) of nitrogen (N) and amino acids (AA) in two protein sources (soybean meal [SBM] and canola meal [CM]) were investigated at six broiler ages (d 7, 14, 21, 28, 35, and 42). Two assay diets were formulated to contain either SBM (413 g/kg) or CM (553 g/kg) as the sole dietary AA source. Titanium dioxide (5 g/kg) was added as an indigestible marker. A total of 696 male broilers at 1 d old were allotted to 12 replicate cages per age group. Each assay diet was offered to birds for 4 d prior to the ileal digesta collection on d 7 (14 birds/cage), 14 (12 birds/cage), 21 (10 birds/cage), 28 (8 birds/cage), 35 (8 birds/cage) and 42 (6 birds/cage), respectively. The apparent digestibility coefficients were standardized using age-specific basal endogenous AA flows. In the SBM group, though the SIDC of N tended to be influenced (quadratic; P = 0.075) by age, no linear or quadratic response of age effect was observed on the average SIDC of indispensable (IAA) and total AA (TAA). An age effect (quadratic; P < 0.05) was observed on the average SIDC of dispensable AA (DAA) in SBM with the highest value recorded at d 7, followed by a decrease from d 14 to 28, which increased beyond d 35. The SIDC of some individual AA (Arg, Thr, Trp, Cys, Pro) were affected (P < 0.05 or P < 0.001) in a quadratic manner by age. In the CM, the SIDC of N, average SIDC of IAA, DAA and TAA were influenced (quadratic; P < 0.05 or P < 0.001) by age. The SIDC of N and average SIDC of DAA and TAA were higher from d 7 to 14, declined at d 21, and then increased beyond d 28. The average SIDC of IAA was low between d 7 and 28 and increased thereafter. The SIDC of individual AA were affected (linear or quadratic; P < 0.05 or P < 0.001) by different magnitudes by age. The age influence on the SIDC AA was variable, depending on the protein source and AA. The results demonstrate that age-specific SIDC AA data might need consideration in broiler feed formulations.