| Autor: |
Nolles JA; Human and Animal Physiology Group, Wageningen University, Wageningen, The Netherlands. jelmer.nolles@wur.nl, Verreijen AM, Koopmanschap RE, Verstegen MW, Schreurs VV |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of animal physiology and animal nutrition [J Anim Physiol Anim Nutr (Berl)] 2009 Aug; Vol. 93 (4), pp. 431-8. |
| DOI: |
10.1111/j.1439-0396.2008.00820.x |
| Abstrakt: |
Postprandial oxidation of dietary free amino acids or egg white protein was studied using the [13CO2] breath test in rats, as well as in humans. Thirty-eight male rats were assigned to four dietary test groups. Two diets only differed in their protein fraction. Diet I contained 21% egg white protein. For the breath test egg white protein, intrinsically labelled with [1-13C]-leucine, was used as a substrate. Diet II contained the same amino acids as diet I, though not as egg white protein but in free form. Free [1-13C]-leucine was used to label this diet. In addition, two 1:1 mixtures of both diets were used. During the breath test either the free amino acid or the protein fraction was labelled as in diets I or II. The animals were breath-tested following short-term (day 5) and long-term adaptation (day 20) to their experimental diet. For all diets, including the mixed diets, postprandial oxidative losses on day 5 were significantly higher for the free leucine compared with the protein-derived leucine. Differences between free and protein-derived leucine oxidation had, however, largely disappeared on day 20. The human subjects were breath-tested without any adaptation period to the diets. The oxidative losses of free leucine were also higher than those of protein-derived leucine. None of the studies showed any indication for an interaction between the oxidation of protein-derived amino acids and free amino acids. It is concluded that free and protein-derived amino acids in the diet are mainly metabolized independently. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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