An isotope dilution model for partitioning phenylalanine uptake by the liver of lactating dairy cows

Crompton, L., Reynolds, C. ORCID: https://orcid.org/0000-0002-4152-1190, Mills, J. and France, J. (2011) An isotope dilution model for partitioning phenylalanine uptake by the liver of lactating dairy cows. In: Sauvant, D., van Milgen, J., Faverdin, P. and Friggens, N. (eds.) Modelling Nutrient Digestion and Utilization in Farm Animals. Wageningen Academic Publishers, Wageningen , pp. 218-225. ISBN 9789086861569 doi: 10.3920/978-90-8686-712-7_24

Abstract/Summary

An isotope dilution model for partitioning phenylalanine uptake by the liver of the lactating dairy cow was constructed and solved in the steady state. If assumptions are made, model solution permits calculation of the rate of phenylalanine uptake from portal vein and hepatic arterial blood supply, phenylalanine release into the hepatic vein, phenylalanine oxidation and synthesis, and degradation of hepatic constitutive and export proteins. The model requires the measurement of plasma fow rate through the liver in combination with phenylalanine concentrations and plateau isotopic enrichments in arterial, portal and hepatic plasma during a constant infusion of [1-13C]phenylalanine tracer. The model can be applied to other amino acids with similar metabolic fates and will provide a means for assessing the impact of hepatic metabolism on amino acid availability to peripheral tissues. This is of particular importance for the dairy cow when considering the requirements for milk protein synthesis and the negative environmental impact of excessive nitrogen excretion.

Item Type	Book or Report Section
URI	https://reading-clone.eprints-hosting.org/id/eprint/22167
Item Type	Book or Report Section
Refereed	Yes
Divisions	Life Sciences > School of Agriculture, Policy and Development > Department of Animal Sciences > Animal, Dairy and Food Chain Sciences (ADFCS)- DO NOT USE
Publisher	Wageningen Academic Publishers
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