Influence of the origin of the beans on the chemical composition and nutritive value of commercial soybean meals

Abstract

Commercial samples of soybean meal (SBM) from USA (n=180), Brazil (BRA; n=165) and Argentina (ARG; n=170) were collected from 2007 to 2015 to study the effects of the origin of the beans on chemical composition, crude protein (CP) quality and nutritive value of the meals. Samples were collected at the country of origin or at the arrival of vessels from these countries to Europe. On a dry matter (DM) basis, USA and BRA meals had more CP than ARG meals (532, 532 and 517g/kg, respectively; P<0.001). On a CP basis, Lys content was higher (6.17, 6.07 and 6.11% CP; P<0.001) in USA than in BRA meals, with ARG meals being intermediate. USA meals had more sucrose (84, 64 and 78g/kg) and stachyose (64, 53 and 57g/kg) but less neutral detergent fibre (90, 118 and 102g/kg) and raffinose (11, 16 and 14g/kg) than BRA and ARG meals (P<0.001). Ether extract was highest for the BRA meals (P<0.05). Mineral content depended on SBM origin, with BRA meals having more Fe but less Ca, P and K than USA and ARG meals (P<0.001). The AMEn for poultry and net energy for pigs, estimated from published equations, were higher (P<0.001) for the USA meals than for the South American meals. Protein quality indicators varied also with SBM origin. Urease activity was lowest for ARG meals, but the differences were of little practical interest. Protein dispersibility index, KOH protein solubility and trypsin inhibitor activity were higher (P<0.001) for the USA meals than for the BRA and ARG meals. Heat damage indicator, a variable that measures indirectly the incidence of Maillard reactions, was lowest in the USA meals (P<0.001). The correlations among chemical analyses, protein quality indicators and nutritive value traits were numerous and depended on the origin of the beans. The correlation between CP (g/kg DM) and Lys (% CP) contents was negative (P<0.001) for the USA SBM, positive (P<0.001) for the BRA SBM and not significant (P>0.10) for the ARG SBM. In summary, chemical composition, protein quality and nutritive value of the SBM varied widely with the origin of the beans. At equal CP content, USA meals had less fibre, more sucrose and Lys and better protein quality than South American meals. Consequently, nutritionists should consider the country of origin of the beans when preparing matrices for evaluating the nutritive value of commercial SBM.