Amino Acid Availability and Energy Values of Soybean Meals

Two experiments were conducted using five sources of soybean meal (SBM) that included hexane extracted SBM produced from high-protein soybeans (SBM-HP) and from conventional soybeans (SBM), and mechanically expelled meal produced from high-protein soybeans (ESBM-HP), low-oligosaccharides soybeans (ESBM-LO), and conventional soybeans (ESBM). The standardized ileal digestibility (SID) of crude protein and amino acids in the five sources of SBM were measured in the first experiment. Five diets that each contained one source of SBM as the only AA-containing ingredient and a N-free diet were formulated. Twelve growing barrows (initial BW: 67.7 kg) were allotted to a replicated 6 × 6 Latin square design with six periods and six diets. Each period lasted seven days and ileal digesta were collected on day six and seven. With the exception of tryptophan, no differences in SID values between meals extracted from high protein or conventional soybeans were observed. The expelled SBM-HP and ESBM-LO had greater (P <= 0.05) ileal digestibility values for histidine, isoleucine, lysine, threonine and valine compared to the expelled conventional ESBM. The SID for all indispensable amino acids in the expelled ESBM-HP was greater (P <= 0.05) compared to the extracted SBM-HP and for the conventional SBM. The ideal digestibilities for arginine, isoleucine, leucine, phenylalanine and tryptophan were greater (P <= 0.05) in the expelled meal compared to the extracted meal.

The second experiment was designed to measure metabolize energy (ME) in the five SBM using 48 growing barrows (initial BW: 38.6 kg) that were placed in metabolism cages and randomly allotted to six diets with eight replicates per diet. A corn-based diet and five diets based on a mixture of corn and each source of SBM were formulated. Urine and feces were collected during a five-day collection period, and values for ME in each source of SBM were calculated using the difference procedure. Results showed that ME in the extracted SBM-HP was greater (P <= 0.05) than in the extracted conventional SBM (4,074 vs. 3,672 kcal/kg DM). The ME in the expelled SBM-HP was also greater (P <= 0.05) than in the expelled conventional SBM and in the SBM-LO (4,059 vs. 3,620 and 3,721 kcal/kg DM). The researchers concluded that SBM processed from high protein soybeans has greater feeding (energy) value than conventional SBM.

Baker, K.M. and H.H. Stein. 2008. High-protein and low-oligosaccharide varieties of soybeans fed to growing pigs. J. Anim. Sci. 86:179/J. Dairy Sci. 91:179 (Abstract 208).