Ileal Digestibility of Amino Acids in Conventional and Low-Kunitz Soybean Products Fed to Weanling Pigs

Abstract

An experiment was conducted to determine the standardized ileal digestibility (SID) of amino acids (AA) in four sources of full-fat soybeans (FFSB) and in one source of soybean meal (SBM). The FFSB had different concentrations of trypsin inhibitor units (TIU) and included two sources of conventional FFSB, and two sources of a soybean variety that was selected for a reduced concentration of the Kunitz trypsin inhibitor. The conventional FFSB was either low temperature-processed (LT-FFSB-CV; 37.7% CP, 35.4 TIU/mg) or high temperature-processed (HT-FFSB-CV; 40.5% CP, 4.4 TIU/mg). The low-Kunitz FFSB was also either low temperature-processed (LT-FFSB-LK; 36.2% CP, 23.5 TIU/mg) or high temperature-processed HT-FFSB-LK; (38.2% CP, 4.0 TIU/mg). The SBM contained 47.5% CP and 3.20 TIU/mg. Twelve weanling barrows (initial BW: ) were fitted with a T-cannula in the distal ileum. Pigs were allotted to a replicated Latin square design with six diets and six periods per square. Five diets were prepared using each of the soybean sources as the only source of AA in the diet. An N-free diet was also included in the experiment to measure basal endogenous losses of AA. The two low temperature-processed FFSB had lower (p