Amino acid digestibility in conventional, high-protein, or low-oligosaccharide varieties of full-fat soybeans and in soybean meal by weanling pigs

An experiment was conducted to measure the digestibility of crude protein (CP) and amino acids (AA) by weanling pigs in full-fat soybeans (FFSB) produced from conventional (FFSB-CV), high-protein (FFSB-HP), or low-oligosaccharide (FFSB-LO) varieties of soybeans. A source of soybean meal (SBM) that was produced from a conventional variety of soybeans was also used in the experiment. Cornstarch-based diets containing FFSB-CV, FFSB-HP, FFSB-LO, or SBM as the sole source of AA were formulated. A nitrogen-free diet was used to determine basal ileal endogenous losses of AA. The coefficient of ileal standardized digestibility (CISD) of AA in the four ingredients was measured using 10 barrows (initial body weight: 10.1 ± 1.82 kg) that were equipped with a T-cannula in the distal ileum. The CISD of leucine, lysine, and phenylalanine in FFSB-CV was greater (P<0.05) than in SBM, but the CISD of AA in FFSB-HP and FFSB-LO were not different (P>0.05) from the CISD of AA in SBM. With the exception of methionine, tryptophan, and cysteine, no differences in CISD of AA among the three sources of FFSB were observed (P>0.05). It is concluded that the CISD of most AA in FFSB-HP and FFSB-LO are not different from the CISD of AA in FFSB-CV or in SBM, but FFSB-CV has a greater CISD of leucine, lysine, and phenylalanine than SBM if fed to weanling pigs.