Chemical composition, amino acid digestibility, and apparent metabolizable energy of soybean meals of different origins in broilers

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The physicochemical characteristics, protein quality, apparent and standardized (SID) ileal digestibility of CP and amino acids, and AMEn content of soybean meal (SBM) were determined in 27 samples from Argentina (ARG), Brazil (BRA), and USA in 21-d-old broilers. On an 88% DM basis, CP was higher for the BRA and USA meals than for the ARG meals (46.6 and 46.2 vs. 45.1%; P < 0.001) whereas sucrose (7.26 and 7.93 vs. 6.08%) and stachyose (5.41 and 4.96 vs. 4.01%) contents were higher ( P < 0.001) for the USA and ARG meals than for the BRA meals. Also, per unit of protein, the USA meals had more Lys (6.18 vs. 5.99 vs. 6.10%; P < 0.001) and Met + Cys (2.78 vs. 2.68 vs. 2.74%; P < 0.01) than the BRA meals, with the ARG meals being intermediate. Urease activity, protein dispersibility index, KOH protein solubility, and trypsin inhibitor activity values were higher ( P < 0.05) for the USA meals than for the ARG and BRA meals. From 0 to 14 d of age, all the birds were fed a common commercial diet followed by their respective experimental diets (53% of an N-free diet and 47% of the SBM tested) for 7 days. The SID of Lys (88.7 vs. 86.9 and 87.5%) and the AMEn content (2,331 vs. 2,255 vs. 2,282 kcal/kg) were higher ( P < 0.05) for the USA meals than for the BRA meals, with the ARG meals being intermediate. Also, in this period, broilers fed the USA SBM grew faster (42.7 vs. 38.7 and 39.1 g/d; P < 0.001) and had better feed conversion ratio (1.74 vs. 1.89 and 1.88 g/g; P < 0.001) than broilers fed the ARG or the BRA SBM. In summary, the nutritional value of commercial SBM varied with the country of origin of the soybeans. Consequently, soybean origin should be taken into consideration to estimate with greater accuracy the protein quality and nutritional value of commercial soybean meals.