Use of the mobile nylon bag technique for determination of apparent ileal digestibilities of crude protein and amino acids in feedstuffs for pigs.

Three digestibility experiments were conducted to evaluate the potential of determination of apparent ileal digestibilities (AID) of crude protein (CP) and amino acids (AA) by the mobile nylon bag technique (MNBT) using 21 feedstuffs and three mixed diets. In two conventional digestibility experiments (Exp. 1 and 2), AID were determined using in total 10 barrows (BW 35 kg) fitted with simple T-cannulas at the terminal ileum. For the MNBT studies, four pigs were fitted with a simple T-cannula at the proximal duodenum and a Post-Valve T-Caecum (PVTC) cannula at the terminal ileum. The MNBT studies included the feedstuffs ( n = 10) from Exp. 1 and 2 as well as 14 further feedstuffs and mixed diets in which AID coefficients had been determined in previous trials. For each feedstuff 60 nylon bags were used. In vitro digestion of the bags was carried out in pepsin-HCl solution with 450 IU pepsin/l at pH 2.0 and 37°C for 4 h. In the 28-day in vivo experiment, 15 nylon bags per pig and day were inserted through the duodenal cannula and collected through the PVTC cannula after passage through the small intestine. Coefficients of AID were calculated based on the disappearance of CP and AA from the nylon bags during the