Oxidation of essential amino acids by the ovine gastrointestinal tract
- 1 May 2003
- journal article
- research article
- Published by Cambridge University Press (CUP) in British Journal of Nutrition
- Vol. 89 (5) , 617-629
- https://doi.org/10.1079/bjn2003831
Abstract
It is not known if the ruminant animal gastrointestinal tract (GIT) can oxidise essential amino acids (AA) other than leucine. Therefore, the oxidation of four essential AA (leucine, lysine, methionine and phenylalanine), supplied systemically as labelled 1-13C forms, was monitored across the mesenteric-drained viscera (MDV; small intestine) and portal-drained viscera (PDV; total GIT), as part of a 4×4 Latin square design, in four wether sheep (35–45 kg) fed at 1·4 × maintenance. Oxidation was assessed primarily by appearance of13CO2,corrected for sequestration of [13C]bicarbonate. The GIT contributed 25 % (PPPP<0·001) between AA, e.g. phenylalanine (0·81), lysine (0·71), methionine (0·67), leucine (0·56), histidine (0·71), threonine (0·63) and tryptophan (0·48). These differences probably reflect incomplete re-absorption of endogenous secretions and, together with the varied oxidative losses measured, will alter the pattern of AA net supply to the rest of the animal.Keywords
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