Nutritional evaluation of soybean meals varying in oligosaccharide content

Three conventional soybean meals (CSBM) and five low-oligosaccharide soybean meals (LOSBM) were evaluated. Meals were prepared by solvent-extracting flakes from generic soybean lines and soybean lines genetically modified to contain varying oligosaccharide content. The mean raffinose, stachyose, and galactinol levels in the CSBM were 0.58, 3.23, and 0%, respectively. The mean (range) raffinose, stachyose, and galactinol levels in the LOSBM were 0.08 (0.03 to 0.17%), 0.42 (0.04 to 1.08%), and 0.104 (0 to 0.24%), respectively. The crude fiber, fat, and ash contents of all SBM were similar, whereas the CP and sucrose contents of the LOSBM were slightly higher than the CSBM. The effect of SBM type on digesta passage rate, dry matter digestibility, and TME_N was assessed in conventional and cecectomized roosters using a precision-fed rooster assay (8 × 2 factorial design). Quantitative collection of excreta for 4, 8, 12, 16, 20, 24, and 48 h postfeeding indicated little or no effect of SBM type on digesta passage rate. The dry matter digestibility and TME_N values for the SBM were lower for cecectomized roosters compared with conventional roosters (P < 0.05), and there was no significant SBM × bird type interaction. The mean TME_N values (kcal/kg DM) for the CSBM and LOSBM were 2,739 and 2,931, respectively, which was a difference of 7% (P < 0.05). The two LOSBM with the lowest total raffinose, stachyose, and galactinol levels (0.07% and 0.25%) had average TME_N values that were 9.8% (P < 0.05) higher than their respective genetic controls. Digestibilities of raffinose and stachyose were much higher (P < 0.05) in conventional roosters than in cecectomized roosters. The results of this study indicated that the TME_N of LOSBM was higher than that of CSBM.