Route of tracer administration does not affect ileal endogenous nitrogen recovery measured with the 15N-Isotope dilution technique in pigs fed rapidly digestible diets

C.A. Steendam, M.W.A. Verstegen, S. Tamminga, H. Boer, M. van 't End, B. Verstappen, W.R. Caine, G.H. Visser

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)


The 15N-isotope dilution technique (15N-IDT), with either pulse-dose oral administration or continuous i.v. administration of [15N]-L-leucine (carotid artery), both at 5 mg/(kg body weight · d), was used to measure ileal (postvalve T-cecum cannula) endogenous nitrogen recovery (ENR) in pigs (9 ± 0.6 kg). Diets were cornstarch, enzyme-hydrolyzed casein with no (control) or high (4%) content of quebracho extract (Schinopsis spp.) rich in condensed tannins. Blood was sampled from a catheter in the external jugular vein. Mean plasma 15N-enrichment at d 8-10 was higher (P = 0.0009) after i.v. than after oral administration [0.0356 vs. 0.0379 atom% excess (APE)]. Plasma 15N-enrichment for i.v. infused pigs was 0.01117 APE higher (P <0.0001) and for orally dosed pigs 0.0081 APE lower (P <0.0001) at 11 h postprandial compared with 1 h postprandial. Apparent ileal N digestibility was higher (P <0.0001) for the control (85.5%) than for the quebracho diet (69.5%). ENR was calculated from the ratio of 15N-enrichment of plasma and digesta. The ENR for the quebracho diet was 300% higher than for the control diet (6.03 vs. 1.94 g/kg dry matter intake, P <0.001). The real N digestibility (92.2 ± 0.4%) was equal for both diets (P = 0.1030) and both tracer methods (P = 0.9730). We concluded that oral administration of [15N]leucine provides reasonable estimates of ENR in pigs fed semipurified diets with high or low content of tannins; however, one must be careful in extrapolating this conclusion to studies with other protein sources or feeding frequencies
Original languageEnglish
Pages (from-to)3068-3075
JournalThe Journal of Nutrition
Issue number11
Publication statusPublished - Nov 2004



  • amino-acid flows
  • kg liveweight pig
  • protein-free
  • ileal digesta
  • distal ileum
  • growing pigs
  • excretion
  • infusion
  • leucine
  • losses

Cite this