Effect of oligosaccharide additions on nitrogen-corrected true metabolizable energy of soy protein concentrate.

In order to determine TMEn response to individual saccharide moieties, five different sugar additions were made to a soy protein concentrate control that contained low levels of oligosaccharides. The sugar additions to the control were made to approximate the amounts of raffinose, stachyose, and sucrose found in soybean meal (SBM). All samples were precision-fed to adult Leghorn roosters to determine TMEn values. The control had a dry matter gross energy (GE) of 4,873 kcal/kg, CP of 73.1%, and TMEn value of 3,757 kcal/kg. Raffinose and stachyose significantly reduced TMEn values for the control. Sucrose did not exhibit this effect. In a second experiment, different levels of stachyose and raffinose were added separately to the control to develop a TMEn dose response curve for these alpha-galactosides of SBM. The TMEn of soy protein concentrate was found to be significantly decreased by stachyose and raffinose inclusion and to be dose dependent.