QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Leterme, P. Articles by Huisman, J. Search for Related Content PubMed PubMed Citation Articles by Leterme, P. Articles by Huisman, J.

The Use of ¹⁵N-Labeled Dietary Proteins for Determining True Ileal Amino Acid Digestibilities Is Limited by Their Rapid Recycling in the Endogenous Secretions of Pigs^1,2,

Pascal Leterme³, André Théwis, Etienne François^*, Piet Van Leeuwen, Bernard Wathelet and Joop Huisman

Faculté Universitaire des Sciences Agronomiques, Zootechnie, B-5030 Gembloux, Belgium ^* CRA Station de Chimie et Physique Agricoles, B-5030 Gembloux, Belgium TNO-ILOB, 6700 AA Wageningen, The Netherlands Faculté Universitaire des Sciences Agronomiques, Chimie Organique et Biologique, B-5030 Gembloux, Belgium

We assessed the use of ¹⁵N-labeled dietary proteins as a possible tool for the determination of the true ileal amino acid (AA) digestibility in pigs. The first experiment was designed to study the dietary N excretion pattern at the ileum subsequent to the ingestion of a single ¹⁵N-labeled meal. In a second experiment, we compared ileal endogenous AA outputs and true AA digestibility estimates obtained in pigs ingesting ¹⁵N-labeled dietary proteins in a single meal vs. intravenous infusion of [¹⁵N]leucine for 10 d during the ingestion of a pea-based diet and a protein-free starch diet. The proportion of endogenous N found in the ileal digesta differed when the label was delivered orally (50%) vs. intravenously (72%) and changed with time. As a consequence, the true ileal AA digestibilities measured with labeled diets were lower. A third experiment demonstrated that this was due to the rapid recycling of labeled dietary N in endogenous moieties, because ¹⁵N was found in blood within 10 min of consuming the labeled meal, within 50 min of consumption in pancreatic enzymes, 90 min in bile and 4 h in ileal mucins. We conclude that the use of ¹⁵N-labeled meals for determination of true ileal AA digestibilities is limited by the fast recycling of dietary N in endogenous secretions following a single ¹⁵N-labeled meal. The accuracy of results will depend on meaningful estimates of AA flow during a limited period and accurate estimates of ¹⁵N in AA.

KEY WORDS: • pigs • amino acid • ileal digestibility • endogenous • ¹⁵N

¹ Reported in part at the following symposia: Leterme, P., Théwis, A., Genot, L., François, E. and Wathelet, B. (1993) Determination of the true ileal digestibility of amino acids in pigs by means of ¹⁵N-labeled diets. First Int. Symposium on Nitrogen Flow in Pig Production and Environmental Consequences, Wageningen (The Netherlands), June 8–11; Leterme, P., van Leeuwen, P., Théwis, A., Huisman, J. & François, E. (1994) Determination of the true ileal digestibility of pea amino acids by means of ¹⁵N-labeled diets or animals. VIth Int. Symp. on Digestive Physiology in Pigs, Bad Doberan (Germany), October 4–6; and Leterme, P., Monmart, T., Théwis, A. & François, E. (1995) Rate of recycling of the dietary nitrogen in the digestive secretions in pigs. VIIth Symposium on Protein Metabolism and Nutrition. Santarém (Portugal), May 24–27.

² Supported by the ‘Institut pour l'Encouragement de la Recherche dans l'Industrie et l'Agriculture’ (IRSIA), Brussels (contract no. 5586A), the National Funds for Scientific Research (FNRS), Brussels (contract FRFC no. 2.4552.92) and the TNO-ILOB, Wageningen. The stay of PL in Wageningen was supported by a EU short-term training grant (GT920155).

³ The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 USC section 1734 solely to indicate this fact.

Manuscript received 7 December 1995. Revision accepted 21 May 1996.

This article has been cited by other articles:

				A. Deglaire, P. J. Moughan, C. Bos, K. Petzke, S. M. Rutherfurd, and D. Tome A Casein Hydrolysate Does Not Enhance Gut Endogenous Protein Flows Compared with Intact Casein When Fed to Growing Rats J. Nutr., March 1, 2008; 138(3): 556 - 561. [Abstract] [Full Text] [PDF]

				C. Bos, B. Stoll, H. Fouillet, C. Gaudichon, X. Guan, M. A. Grusak, P. J. Reeds, D. Tome, and D. G. Burrin Intestinal lysine metabolism is driven by the enteral availability of dietary lysine in piglets fed a bolus meal Am J Physiol Endocrinol Metab, December 1, 2003; 285(6): E1246 - E1257. [Abstract] [Full Text] [PDF]