Bacterial contributions to total and endogenous recoveries of nitrogen and amino acids in ileal digests of newly weaned piglets fed protease-treated soybean meal

The bacterial contributions to total and endogenous recoveries of nitrogen (N) and amino acids in ileal digesta of newly weaned piglets were determined. Twelve piglets were fed maize starch-based diets with soybean meal, which was untreated (SBM), incubated (1:2 w/v in distilled water adjusted to pH 4.5, for 16 h at 50 degrees C; CI-SBM), sprayed with protease (1 mi kg(-1) of soybean meal; PS-SBM) and incubated with protease (1 ml kg(-1) of soybean meal; PI-SBM). Ileal digesta were collected from the piglets on days 6 to 7 and then on days 15 to 16 after weaning. Bacterial N contributions were similar (P > 0.05); 17.1, 16.4, 14.6 and 21.0 g/100 g of total N in ileal digesta of piglets fed SBM, CI-SBM, PS-SBM and PI-SBM, respectively. Bacterial contributions of arginine, isoleucine, leucine, phenylalanine, valine and serine were higher (P < 0.05) in ileal digesta of piglets fed PI-SBM. Contributions to endogenous recoveries of N and amino acids were similar (P > 0.05) between diets. The bacterial contributions of N and all amino acids were lower (P < 0.05) on days 6 to 7 than on days 15 to 16 after weaning. Bacterial contribution to the endogenous recovery of most of the amino acids was lower (P < 0.05) on days 6 to 7 than on days 15 to 16 after weaning. In conclusion, the bacterial contributions of N and amino acids in ileal digesta of piglets increases after weaning. (C) 1999 Elsevier Science B.V. All rights reserved.