1. The cost of the conversion of L-methionine precursors in mammals and birds
- Author
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J. van Milgen, Ruth Ferrer, Raquel Martín-Venegas, Yves Mercier, A. Toscan, D.I. Batonon-Alavo, Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'Elevage [Rennes] (PEGASE), AGROCAMPUS OUEST-Institut National de la Recherche Agronomique (INRA), Adisseo France SAS, FRA, Departament de Fisiologia, Universitat de Barcelona (UB), Adisseo Brazil, Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
- Subjects
stoechiométrie ,030309 nutrition & dietetics ,métabolisme énergétique ,[SDV]Life Sciences [q-bio] ,7. Clean energy ,03 medical and health sciences ,chemistry.chemical_compound ,biochemical analysis ,oiseau ,efficience ,mammals ,conversion ,0303 health sciences ,Methionine ,énergie nette ,0402 animal and dairy science ,méthionine ,analyse biochimique ,mammifère ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,stoichiometry ,acide aminé ,Biochemistry ,chemistry ,amino acid - Abstract
To fulfil the requirements for methionine, animal diets are widely supplemented with synthetic methionine sources such as L-methionine (L-Met), DL-methionine (DL-Met), and DL-2-hydroxy-4-(methylthio)-butanoic acid (DL-OH-Met). The objective of this study is to calculate the energy cost of the different conversion steps leading to L-Met and to propose energy equivalence values for DL-Met and DL-OH-Met, relative to that of L-Met. The conversion of DL-OH-Met to L-Met involves a nitrogen-sparing effect, because excess nitrogen can be used for the transformation of DL-OH-Met to L-Met, rather than being excreted as urea or uric acid Consequently, the ME-to-GE ratio of DL-OH-Met is 109% in mammals and 114% in birds, compared to the value of DL-Met. Because of differences in metabolism and the formation of hydrogen peroxide in the conversion to L-Met, the NE-to-ME ratios are 96% for DL-Met and 100% for DL-OH-Met in both mammals and birds. The conversion of DL-OH-Met to L-Met is therefore energetically less costly than the conversion of DL-Met. The stoichiometric approach presented here only considers the biochemical conversion steps, without considering the cost of transport and further transformation steps.
- Published
- 2019