PSVI-29 Effect of pig weight and exogenous enzyme supplementation on ileal endogenous amino acid losses and standardized ileal amino acid digestibility of soybean meal produced from Kentucky-grown soybeans

Abstract There is increasing interest in using locally sourced soybeans and soybean meal. Ileal amino acid digestibility (IAAD) of soybean meal from Kentucky-grown soybeans was evaluated in 25- and 50-kg cannulated pigs. The experiment used sixteen pigs in a randomized complete block design consisting of four treatments with 4 pigs per treatment. This was repeated in time resulting in eight replicates per treatment for both body weight (BW)groups. After cannulation at about 20 kg BW, all pigs were allowed to recover from the surgery and were fed a corn-SBM-based diet that met all nutrient and energy requirements. The experimental diets consisted of two nitrogen-free diets [NFD] with or without exogenous enzyme supplementation (phytase and a combination of phytase and carbohydrase enzymes) and two semi-purified diets containing soybean meal from Kentucky-grown soybeans as the only source of protein with or without exogenous enzyme supplementation. Each diet was fed for 7 consecutive d with 10-h ileal digesta collection on d 6 and 7. The same diets were fed to the same set of pigs at about 50 kg BW. Data were analyzed as a factorial arrangement of treatments (BW x diet) for ileal endogenous amino acid losses (IEAAL), apparent IAAD and standardized IAAD (SIAAD). Data from the NFD were used to determine the SIAAD from the AIAAD values. Exogenous enzyme supplementation increased (P < 0.05) IEAAL except for Gly and Pro while samples collected during phase 2 had greater (P < 0.05) IEAAL (10 amino acids). Pig BW did not influence IEAAL. Enzyme supplementation did not increase AIAAD except for Arg, Ala, Gly, N, and total AA while apparent ileal N, Met, Thr, and Val digestibility was greater (P < 0.05) in 50 kg pigs. Interactions between BW and diets showed that 50 kg pigs fed the SBM diet containing enzyme supplementation had greater (P < 0.05) N, Arg, and total AA digestibility compared with 50 kg pigs without enzyme supplementation. Digestibility of Val and Asp was greater (P < 0.05) in samples collected during phase 2. After correction for basal IEAAL, 50 kg pigs had greater (P < 0.05) SIAAD values for 12 of the AA analyzed while exogenous enzyme supplementation resulted in greater (P < 0.05) SIAAD for 9 of the AA analyzed. The SIAAD values for four AA (His, Phe, Val, and Asp) were greater (P < 0.05) for samples collected in phase 2. Results from this study showed that exogenous enzyme supplementation increased IEAAL and that IAAD of SBM produced from Kentucky-cultivated soybeans was high and that exogenous enzyme supplementation improved the SIAAD values of several amino acids. The IAAD values of SBM produced from soybeans cultivated in KY was high and are similar to values reported in the literature.