Two experiments were conducted to determine the AA and energy digestibility in 2 sources of enzyme-treated soybean meal (ESBM-1 and ESBM-2), in extruded soybean meal (SBM-EX), in soy protein concentrate (SPC), in conventional dehulled soybean meal (SBM-CV), in conventional 00-rapeseed expellers (RSE), and in a fermented co-product mixture (FCM) that contained rapeseed meal, wheat, soy molasses, and potato peel fed to pigs. In Exp. 1, the objectives were to determine the standardized ileal digestibility (SID) of CP and AA in ESBM-1, ESBM-2, SBM-EX, SPC, SBM-CV, RSE, and FCM fed to weanling pigs. Seven cornstarch-based diets were prepared using each of the protein sources as the sole source of CP and AA. A N-free diet was prepared to calculate basal endogenous losses of CP and AA and this diet was fed to 2 groups of pigs. The SID of Arg, His, Ile, Leu, Met, and Phe were greater (P < 0.05) in ESBM-1 than in SPC, and the SID of Lys was greater (P < 0.05) in SBM-CV than in ESBM-2. The SID of total indispensable AA was not different among the SBM products. The SID of total dispensable AA in ESBM-1 was only greater (P < 0.05) than in SPC. Therefore, the SID of total AA was greater (P < 0.05) in ESBM-1 than in SPC, but no other differences were observed among SBM products. The SID of most AA in RSE and the SID of all AA in FCM were less (P < 0.05) than in all the SBM products, but the SID of all AA in RSE was greater (P < 0.05) than in FCM. In Exp. 2, the objectives were to determine the digestibility of energy and the concentrations of DE and ME in ESBM-1, ESBM-2, SBM-EX, SPC, SBM-CV, RSE, and FCM. A corn-based diet consisting of 96.65% corn with vitamins and minerals was formulated. Seven additional diets containing corn and each of the experimental ingredients were also formulated. The ATTD of GE in corn was not different from SBM-CV, but was greater (P < 0.05) than in the other ingredients. The concentration of DE in ESBM-1, ESBM-2, SBM-EX, SPC, and SBM-CV was 4,272, 3,972, 4,432, 4,419, and 4,173 kcal/kg DM, respectively. The concentration of DE in RSE and FCM was 3,658 and 3,458 kcal/kg DM, respectively. The DE (DM basis) in corn (3,864 kcal/kg DM) was greater (P < 0.05) than in FCM, but less (P < 0.05) than in SBM-EX, SPC, ESBM-1, and SBM-CV. The DE (DM basis) in SBM-EX was greater (P < 0.05) than in SBM-CV, ESBM-2, RSE, and FCM, but not different from SPC and ESBM-1. The concentration of ME in ESBM-1, ESBM-2, SBM-EX, SPC, and SBM-CV was 4,158, 3,782, 4,240, 4,226, and 4,044 kcal/kg DM, respectively. The concentration of ME in RSE and FCM was 3,522 and 3,364 kcal/kg DM, respectively. The ME (DM basis) of ESBM-2 was less (P < 0.05) than in all other soybean products, but greater (P < 0.05) than in RSE and FCM. The ME (DM basis) of corn (3,780 kcal/kg DM) was less (P < 0.05) than in all soybean products except ESBM-2, but greater (P < 0.05) than in the rapeseed products. There was no difference in DE and ME (DM basis) between RSE and FCM, but the DE and ME for both ingredients were less (P < 0.05) than in all soybean products. In conclusion, although processing of soybean meal results in increased concentration of CP, processing may also reduce the digestibility of AA, which is likely due to heat damage during processing. There are, however, differences among processed soy products with some products having greater SID of AA, DE, and ME than others. Furthermore, the concentrations of DE and ME in all soybean products used in this experiment were greater than in rapeseed expellers and the fermented co-product mixture. Results also indicate that fermentation of a mixture of rapeseed meal, wheat, and relatively low quality co-products does not result in SID values that are similar to those of unfermented 00-rapeseed expellers or soybean products.
【 预 览 】
Amino acid digestibility and concentration of energy in processed soybean and rapeseed products fed to pigs