Effects of Soybean Meal Sources and Level on Growth Performance of Weanling Pigs

Abstract

Three experiments were conducted to compare the effects of increasing solvent-extracted soybean meal (SBM) or extruded-expelled SBM (EESOY) in diets for early weaned pigs. Pigs were fed a control diet (no SBM) or diets containing 20% or 40% SBM or EESOY. In Exp. 1, diets were formulated with calculated values for SBM and EESOY. In Exp. 1, from d 0 to 14, no differences were observed in ADG or ADFI (P>0.05), but gain-to-feed ratio (G:F) decreased (linear, P<0.03) with increases of either source. We speculated that the differences in performance resulted from the low protein content (lysine) of the EESOY compared with SBM (43.6% vs 46.5%). In Exp. 2, SBM nutrient values were analyzed prior to the experiment and used in diet formulation. From d 0 to 14, increasing SBM decreased (linear, P<0.02) ADFI and G:F. Increasing EESOY decreased ADG, ADFI, and G:F (linear, P<0.01). The EESOY from both experiments had trypsin inhibitor (TI) values >8 mg TI/g, suggesting under processing, whereas SBM only contained <2 mg TI/g. In Exp. 3, EESOY and SBM were analyzed for TI and CP; then, these values were used in diet formulation. From d 0 to 14, increasing EESOY decreased (linear, P<0.01) ADG and ADFI and improved (linear, P<0.01) G:F. Increasing SBM decreased ADFI, but improved G:F (linear, P<0.02). No differences (P>0.05) were found between SBM sources. These results suggest that when processed properly, EESOY has similar nutritional value as SBM in nursery pig diets.