HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Interpretive Summary 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 Lobley, G. E. Articles by Vázquez-Añón, M. Search for Related Content PubMed PubMed Citation Articles by Lobley, G. E. Articles by Vázquez-Añón, M.

Absorption and Digestive Tract Metabolism of 2-Hydroxy-4-Methylthiobutanoic Acid in Lambs

G. E. Lobley^*,1, T. J. Wester^*,2, G. Holtrop, J. J. Dibner, D. S. Parker and M. Vázquez-Añón

^* Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK
Biomathematics and Statistics Scotland, Rowett Research Institute, Bucksburn, Aberdeen, AB21 9SB, UK
Novus International, St. Louis, MO

¹ Corresponding author: g.lobley{at}rowett.ac.uk

Anabolic availability of the hydroxyl methionine analog, 2-hydroxy-4-methylthiobutanoic acid (HMTBA), given as oral doses to lambs, was quantified both directly as appearance in the portal vein and as synthesis to Met by digestive tract tissues. Eight lambs, prepared with vascular catheters in the mesenteric and portal veins plus the aorta, received twice daily for 7 d either 0.46 g or 2 g of HMTBA. On d 7, [1-¹³C]HMTBA was supplied as 1 oral dose while [methyl-²H₃]Met was infused into the jugular vein. Peak absorption as HMTBA occurred 70 to 90 min after the oral dose. All digestive tract tissues converted HMTBA to Met, equivalent to 24% of the Met provided by the diet for the larger HMTBA dose. Overall, total availability of HMBTA averaged 17.9% of the dose (range 10.6 to 27.9%), with 12.5% (range 7 to 22%) as absorbed HMBTA and the remainder as Met synthesized by digestive tract tissues. Release of ¹³CO₂ into the portal vein accounted for another 23% of the dose. In all digestive tract tissues, the D-isomer was present in a smaller proportion than in the dose. In terms of whole-body kinetics, HMTBA loss from the plasma followed first-order kinetics, with a mean biological half-life of 76 min. Using this value, a simple model was devised to estimate HMTBA absorption based on peripheral plasma samples. When compared with direct measures of absorption, the model gave a slope of 0.81 (R² = 0.68) and offers a practical means to test HMTBA availability to animals.

Key Words: 2-hydroxy-4-methylthiobutanoic acid • digestive tract • lambs • absorption

This article has been cited by other articles:

				H. Lapierre, M. Vazquez-Anon, D. Parker, P. Dubreuil, and G. E. Lobley Short Communication: Absorption of 2-Hydroxy-4-Methylthiobutanoate in Dairy Cows J Dairy Sci, June 1, 2007; 90(6): 2937 - 2940. [Abstract] [Full Text] [PDF]