title: Bioavailability of different dietary supplemental methionine sources in animals.
abstract: 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.
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhang
authors.forename: Eric A
authors.initials: EA
authors.lastname: Wong
authors.affiliation: Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, 3200 Litton-Reaves Hall (0306), Blacksburg, VA 24061, egilbert@vt.edu.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Gilbert
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001682:Biological Availability; D001692:Biological Transport; D002417:Cattle / Q000378:metabolism; D002645:Chickens / Q000378:metabolism; D019587:Dietary Supplements; D053858:Metabolic Networks and Pathways; D008715:Methionine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*; D013552:Swine / Q000378:metabolism; D014422:Turkeys / Q000378:metabolism
chemical_list: D000975:Antioxidants; C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D008715:Methionine