Effects of genetic selection and processing of soybeans and soybean meal on nutritional quality

Five experiments were conducted to study the effects of genetic selection and processing of soybeans and soybean meal on nutritional quality when fed to pigs. The objectives of Exp. 1 and 2 were to determine standardized ileal digestibility (SID) of AA, and the DE and ME in de-hulled conventional full fat soybeans (FFSB-CV), high-protein full fat soybeans (FFSB-HP), and low-oligosaccharide full fat soybeans (FFSB-LO). Results indicate that the SID of most AA in FFSB-LO is similar to values in FFSB-CV, but greater (P < 0.05) than values in FFSB-HP. This may have been due to heat damage in FFSB-HP, which resulted in reduced AA digestibility due to Maillard reaction. Results also indicate that there were no significant differences in DE and ME among the 3 sources of FFSB. The objectives of Exp. 3 and 4 were to determine SID of AA, and the DE and ME in expeller soybean meals (ESBM) produced from conventional soybeans (ESBM-CV) and soybeans with low (ESBM-LT) or ultra-low (ESBM-ULT) concentrations of trypsin inhibitor soybeans. Results indicate that the SID of all AA was greater (P < 0.05) in SBM than in all the ESBM, therefore, it is not possible to use these low-trypsin inhibitor beans in diets fed to pigs without heat treatment with only 7 to 12 units of trypsin inhibitors. The results also indicate that the concentration of trypsin inhibitors does not seem to affect energy concentration in the meals. The objective of Exp. 5 was to determine SID of AA in 4 sources of fermented soybean meal (FSBM). The results indicate that there are differences among commercial sources of FSBM in the SID of most AA. Relatively low SID of most AA in some sources of FSBM is most likely due to overheating during production of these ingredients, resulting in Maillard reactions and subsequent destruction of Lys and reduction in AA digestibility