Effects of Low and High Soybean Meal Inclusion on Growth Performance and Carcass Characteristics of Grow-finish Pigs

Abstract An increased demand for renewable biofuels is driving increases in soybean crush capacity and the potential for higher SBM levels in swine diets. Relatively few studies have evaluated high and low levels of SBM use for production economics and important sustainability assessments. The objective of this experiment was to evaluate low (5-15%) and high SBM levels (20-37%) with or without increased standardized ileal digestible (SID) lysine in diets on growth performance and carcass characteristics in a commercial facility. A total of 1,106 mixed-sex pigs (DNA 600 × 241; 12.7 ± 0.26 kg) were used in a 111-d study. Pigs were placed in 44 pens at the South Dakota State University commercial wean-to-finish research facility to investigate the effects of low or high SBM inclusion with increased levels of SID lysine. Pens were stocked with 25 ± 1 pigs, with approximately equal distribution of barrows and gilts. The lmer function of R was used as a randomized complete block design with pen serving as the experimental unit, and the statistical model considered fixed effects of dietary treatment. Dietary treatments were randomly allotted to pens within block by body weight (BW) and location. On d 56, pigs weighed on average 55.5kg and were reallotted to one of four treatments: low SBM, low SBM increased SID Lys, high SBM, high SBM increased SID Lys. Pigs previously fed low or high SBM were divided at phase transition and continued the same or increased SID lysine. Pigs fed the high SBM had increased ADG and G:F (P 0.01) compared to those fed the low SBM diets. Decreased BW in the low SBM with no increased SID lysine was observed at d 28 after the treatment split and continued to market (P 0.05). However, when increasing SID lysine during the late growing period, pigs previously fed the low SBM treatment gained faster than pigs continuing to be fed the low SBM treatment (P 0.01). In conclusion, increasing SID lysine in low SBM diets improved ADG and ADFI (P ≤ 0.05) from d56 to market. No differences were observed for total removals. High SBM diets in this study increased BW, ADG, and G:F compared to low SBM diets.