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

## TL;DR

This study evaluates the energy content and amino acid digestibility of enzymolytic soybean meal (ESBM) in growing pigs, finding significant variation among samples and developing prediction equations for nutritional values.

## Contribution

The study provides new prediction equations for energy and amino acid digestibility in ESBM, based on its chemical composition.

## Key findings

- Significant variation in energy content and amino acid digestibility was observed among ten ESBM samples.
- Regression equations were developed to predict digestible and metabolizable energy based on chemical composition.
- Ash content showed the strongest negative correlation with energy values, while tryptophan correlated positively with amino acid digestibility.

## Abstract

Enzymolytic soybean meal (ESBM) is commonly incorporated into swine diets as a high-quality protein supplement. Nevertheless, considerable variability in chemical composition exists among ESBM samples from different manufacturers, primarily due to differences in soybean meal sources and enzymatic processing technologies. Moreover, limited data have been reported on the nutritional value of ESBM from different sources for growing pigs. Therefore, this study selected ten ESBM samples produced by representative enterprises from eight provinces in China. We systematically compared their chemical composition, energy content, and amino acid digestibility in growing pigs. Results revealed significant variation in digestible energy, metabolizable energy, and amino acid digestibility among the ESBM samples, and regression equations were established based on chemical composition. This study provides valuable references for the precise application of ESBM in pig diet formulations.

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.