Determination and Prediction of the Energy Content and Amino Acid Digestibility of Enzymolytic Soybean Meal for Growing Pigs

This study investigated the nutritional value of enzymolytic soybean meal (ESBM) in growing pigs through two experiments. Experiment 1 evaluated the digestible energy (DE) and metabolizable energy (ME) values using twenty-two crossbred pigs (Duroc × Landrace × Yorkshire; initial BW 36.47 ± 0.63 kg) in a replicated 11 × 3 incomplete Latin square design. The dietary treatments comprised a corn-based diet and ten test diets formulated by substituting 30% corn with ESBM. Experiment 2 evaluated standardized ileal digestibility (SID) of amino acid (AA) through a 10 × 6 incomplete Latin square design involving ten pigs (Duroc × Landrace × Yorkshire; initial BW: 21.30 ± 1.38 kg) fitted with T-cannulas. All experimental diets contained 40% ESBM as the sole source of AA and 0.2% titanium dioxide as an indigestible marker. The results revealed variations in the chemical composition of ESBM samples, with coefficients of variation (CV) exceeding 9% for all analyzed components except for gross energy (GE), which had a CV of 4.65%. The mean DE and ME were 16.46 MJ/kg DM (13.82 to 19.13 MJ/kg DM) and 15.73 MJ/kg DM (12.79 to 18.77 MJ/kg DM), respectively. The best-fit prediction equations for DE and ME were as follows: DE (MJ/kg DM) = −26.31 + (2.74 × GE) − (0.17 × CP) (R2 = 0.76, p < 0.01) and ME (MJ/kg DM) = −28.45 + (2.85 × GE) − (0.19 × CP) (R2 = 0.70, p = 0.01). The mean SID of Lys, Met, Thr, Trp, Val, and total AA were 81.72% (71.19 to 95.64%), 81.36% (45.59 to 95.76%), 76.19% (59.67 to 90.40%), 50.61% (15.40 to 74.13%), 81.23% (69.39 to 92.99%), and 84.29% (67.36 to 96.56%), respectively. In this study, ESBM5 exhibited higher energy content and AA digestibility, whereas ESBM8 demonstrated the lowest nutritional value. The ash content exhibited the strongest negative correlation with DE (r = −0.75; p < 0.05) and ME (r = −0.76; p < 0.05), while Trp showed the strongest positive correlation with the SID of AA. The chemical composition of ESBM can be effectively used to predict DE, ME, and SID of AA in growing pigs.