Resumen de Diferencias en composición química y relaciones con la calidad de la proteína de las harinas de soja según origen

Pilar García Rebollar, Tomás M. Rodríguez Serrano, J.D. Berrocoso, L. Camara, R. Lázaro, G.G. Mateos

• This research studied the chemical composition and correlations between chemical analyses and protein quality of SBM of 3 different origins (USA, n=168; BRA, n=139, and ARG, n=147). Samples were collected during a 6-yr period and analyzed for major chemical components including amino acids, sugars and protein quality. On as fed bases (88% DM), SBM from USA had more CP (47.3 vs. 45.4 vs. 46.6 %; P<0.001) and less NDF (7.8 vs. 9.2 vs. 10.5%; P<0.001) than SBM from ARG and BRA. Sucrose and stachyose contents were higher for the USA than for the BRA meal, with ARG meal being intermediate (P<0.001). The CP content was negatively related with sucrose (-0.70; P < 0.001) for USA and with NDF (-0.46 and -0.46, P < 0.001) for ARG and BRA meals. Also, P content was positively related with CP content (+0.60, P<0.001 for USA, and +0.26 and +0.32, P<0.01 for ARG and BRA meals). The PDI and KOH solubility were higher for USA than for ARG or BRA SBM (P<0,001) and they were positively related (P<0.001) with trypsin inhibitor activity. In addition, SBM from USA had more lys, met + cys, thr, and trp than SBM from BRA and ARG (P < 0.001). Lysine content per unit of CP was negatively related with CP content for USA (-0.47, P<0.001), positively (+0.21, P< 0.001) for BRA SBM, but no relationship (P>0.10) was found for ARG SBM. It is concluded that the nutritive value and the relationship among chemical components and protein quality of the meals varied widely among origins. Thus, the origin of the beans should be considered in the evaluation of the nutritive value of commercial soybean meals for formulation of feeds for non ruminant animals.