Quantification of circulating peptides and assessment of peptide uptake across the gastrointestinal tract of sheep

F R Backwell, Rui Miguel Reis, David Wilson, Laura Leanne Bruce, Vivien Buchan, C MacRae

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Gastrointestinal absorption of peptides was examined in sheep fed a forage-based diet. Peptide concentrations were determined in arterial, portal, and mesenteric blood and plasma by quantification of amino acid concentrations before and after acid hydrolysis of samples that had been first deproteinized then subjected to Sephadex G-15 gel-filtration to remove residual protein. In contrast to other studies of ruminants, peptide concentrations for individual amino acids were lower than for the corresponding free amino acids with peptide (expressed as a proportion of total nonprotein amino acid) representing not more than .25 to .3 of total amino acid. Peptide concentrations in arterial, mesenteric, and portal blood and plasma were similar, indicating that on this diet there was no net uptake of peptides from the small intestine (mesenteric-drained viscera, MDV) or the whole tract (portal-drained viscera, PDV). Increasing the intake of alfalfa pellets from 800 to 1,200 g/d, while increasing the absorption and net flux across the MDV and PDV of free amino acids, had no effect on peptide absorption. Preparation of blood and plasma samples for peptide analysis with methods used in studies in which substantial peptide absorption has been reported indicated no net MDV or PDV flux of peptide. Such conflicting data on the extent of gastrointestinal peptide flux are discussed in the context of methodological differences and the importance of diet and physiological state of the animal.
Original languageEnglish
Pages (from-to)3315-22
Number of pages8
JournalJournal of Animal Science
Volume75
Issue number12
Publication statusPublished - 1 Dec 1997

Fingerprint

gastrointestinal system
Gastrointestinal Tract
Sheep
peptides
uptake mechanisms
sheep
Viscera
Peptides
animal organs
Amino Acids
Diet
free amino acids
amino acids
blood
diet
nonprotein amino acids
Medicago sativa
intestinal absorption
Ruminants
acid hydrolysis

Keywords

  • Amino Acids
  • Animals
  • Chromatography, Gel
  • Digestive System Physiological Phenomena
  • Glutamic Acid
  • Glutamine
  • Intestinal Absorption
  • Male
  • Peptides
  • Sheep
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Cite this

Backwell, F. R., Reis, R. M., Wilson, D., Bruce, L. L., Buchan, V., & MacRae, C. (1997). Quantification of circulating peptides and assessment of peptide uptake across the gastrointestinal tract of sheep. Journal of Animal Science, 75(12), 3315-22.

Quantification of circulating peptides and assessment of peptide uptake across the gastrointestinal tract of sheep. / Backwell, F R; Reis, Rui Miguel; Wilson, David; Bruce, Laura Leanne; Buchan, Vivien; MacRae, C.

In: Journal of Animal Science, Vol. 75, No. 12, 01.12.1997, p. 3315-22.

Research output: Contribution to journalArticle

Backwell, FR, Reis, RM, Wilson, D, Bruce, LL, Buchan, V & MacRae, C 1997, 'Quantification of circulating peptides and assessment of peptide uptake across the gastrointestinal tract of sheep', Journal of Animal Science, vol. 75, no. 12, pp. 3315-22.
Backwell, F R ; Reis, Rui Miguel ; Wilson, David ; Bruce, Laura Leanne ; Buchan, Vivien ; MacRae, C. / Quantification of circulating peptides and assessment of peptide uptake across the gastrointestinal tract of sheep. In: Journal of Animal Science. 1997 ; Vol. 75, No. 12. pp. 3315-22.
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