Open Access
Bioavailability of different dietary supplemental methionine sources in animals
Shuai Zhang1,Eric A. Wong1,Elizabeth R. Gilbert1,*
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA
DOI: 10.2741/E744 Volume 7 Issue 3, pp.478-490
Published: 01 June 2015
(This article belongs to the Special Issue Amino acids in nutrition, health, and disease)
*Corresponding Author(s):  
Elizabeth R. Gilbert

Dietary methionine is indispensable for animal maintenance, growth and development. L-methionine (L-Met), and its synthetic forms DL-methionine (DL-Met) and 2-hydroxy-4 (methylthio) butanoic acid (HMTBA) are common supplemental methionine sources in animal diets. There are different characteristics for cellular absorption, transport, metabolism and bio-efficiency between these three dietary methionine sources. Moreover, there are differences in their utilization among various species such as chickens, pigs and ruminants. As a methionine precursor, HMTBA is efficacious in the promotion of growth in animals. It is absorbed mainly by monocarboxylate transporter 1 (MCT1), coupled with the activity of the Na+/H+ exchanger (NHE3), while DL-Met uptake occurs via multiple carrier-mediated systems. Liver, kidney and small intestine can metabolize D-Met and HMTBA to L-Met through oxidation and transamination. In ruminants, the non-hepatic tissues act as major sites of HMTBA conversion, which are different from that in chickens and pigs. HMTBA also has additional benefits in anti-oxidation. Understanding the characteristics of uptake and metabolism of different methionine sources will greatly benefit the industry and bioscience research.

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Shuai Zhang, Eric A. Wong, Elizabeth R. Gilbert. Bioavailability of different dietary supplemental methionine sources in animals. Frontiers in Bioscience-Elite. 2015. 7(3); 478-490.