Novel Two-Slope Equations to Predict Amino Acid Concentrations Using Crude Protein Concentration in Soybean Meal

Amino acid (AA)-to-crude protein (CP) ratios in soybean meal (SBM) may be different for different sources of SBM depending on the presence of additional hulls. Therefore, this study was conducted to develop novel two-slope equations to predict the concentrations of AAs in SBM using CP as an independent variable. Regression analyses were performed with each AA in SBM as the dependent variable and the CP as the independent variable. Among all AAs, the predicted Lys in SBM (% dry matter (DM)) was: Lys = 3.19 − 0.026 × (51.88 − CP) where CP < 51.88% DM and Lys = 3.19 + 0.072 × (CP − 51.88) where CP > 51.88% DM with R2 = 0.51 and p < 0.001. In conclusion, the novel equations provided reasonable estimates of the AA concentrations from different ranges of CP in SBM.