There is growing debate about increasing the net energy (NE) value of soybean meal (SBM) in swine formula. To aid in precise formulation using lysine (Lys) and phosphorus (P) to NE ratios as constraints, this trial aims to project standardized ileal digestible (SID) Lys and standardized total tract digestible (STTD) P to NE ratios utilizing different SBM NE. The Lys curves with different SBM NE was obtained by reanalyzing a meta-analysis (Orlando et al., 2021) previously conducted to determine the SID Lys ratio for 11–150 kg PIC pigs. This analysis included data from 29 trials dating from 2013 to 2020 utilizing 48,338 pigs with sire lines from PIC 337 and dam lines from PIC Camborough. A new STTD P to NE ratio curve was generated by modifying SBM NE from Vier et al. (2019 a,b), in which STTD P to NE ratios was calculated in 2 nursery and 1 growing-finishing trials with a total of 4,350 PIC pigs from 11 to 130 kg. The SID Lys or STTD P levels reported in each trial were used with NE systems that employed SBM NE ranging from 78% to 100% of corn NE, alongside the NE of other ingredients based on NRC (2012). Models were developed on mixed gender. For Lys curve analysis, treatment mean within each trial (n = 288) was considered as experimental unit and trial as a random effect. The SID Lys to calorie recommendations are based on the average of the requirement estimates for average daily gain (ADG) and gain to feed ratio (G:F). At these levels, approximately 100% of maximum ADG and 99.4% of maximum G:F are achieved. After determining the requirement estimates within each growth phases, a quadratic equation of Lys to calorie ratios was fit with the SBM NE ranging from 78% to 100% of corn NE. The equations are described as: g of SID Lys:Mcal of NE = 0.0000327185 × (weight, kg × 2.204622)² – 0.0214484253 × (weight, kg × 2.204622) + 6.0773690201 – (SBM to Corn NE ratio, % – 78%) × 100 × [0.0000002086 × (weight, kg × 2.204622)² – 0.0001219031 × (weight, kg × 2.204622) + 0.0212453295]. Regarding P curve, the requirement estimates are expected to achieve 100% of maximum ADG and G:F. The quadratic equation of STTD P to calorie ratio was fit as: 0.000047 × weight, kg² – 0.014391 × weight, kg + 2.027515 – (SBM to Corn NE ratio, % – 78%) × 100 × (0.00000043 × weight, kg2 – 0.000106 × weight, kg + 0.007598). These data provide the estimated SID Lys and STTD P requirements for maximal growth performance for PIC pigs from 11- to 150-kg based when using different SBM NE in feed formulation.

Guo, J., C. Vier, J. Montoro, N. Lu, R. Navales, S. Dritz, W. Cast and W. Orlando. 2025. Determining the standardized ileal digestible lysine and standardized total tract digestible phosphorus requirements of growing-finishing pigs utilizing different soybean meal net energy. 2025 American Society of Animal Science Midwest Section meeting, Abstract 180.