Development of intrinsically labeled eggs and poultry meat for use in human metabolic research

Stephan van Vliet, Joseph W. Beals, Justin T. Parel, Christina D. Hanna, Pamela L. Utterback, Anna C. Dilger, Alexander V. Ulanov, Zhong Li, Scott A. Paluska, Daniel R. Moore, Carl M. Parsons, Nicholas A. Burd

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Background: Stable isotope amino acids are regularly used as tracers to examine whole-body and muscle protein metabolism in humans. To accurately assess in vivo dietary protein digestion and absorption kinetics, the amino acid tracer is required to be incorporated within the dietary protein food source (i.e., intrinsically labeled protein). Objective: We assessed the practicality of producing eggs and poultry meat intrinsically labeled with L-[5,5,5-2H3]leucine through noninvasive oral tracer administration. Methods: A specifically formulated diet containing 0.52% leucine was supplemented with 0.3% L-[5,5,5-2H3]leucine and subsequently fed to 3 laying hens (Lohmann LSLWhites) for 55 d. On day 55, the hens were slaughtered and their meat, bones, and organs were harvested to determine tissue labeling. In Expt. 1, 2 healthy youngmen [mean± SEM age: 22 6 1.5 y;mean ± SEM body mass index (BMI; in kg/m2): 23.7 6 0.5] ingested 18 g L-[5,5,5-2H3]leucine-labeled egg protein. In Expt. 2, 2 healthy young men (mean ± SEM age: 20.0 6 0.0 y; mean ± SEM BMI: 26.4 6 3.1) ingested 28 g L-[5,5,5-2H3]leucine-labeled poultry meat protein. Plasma samples (Expts. 1 and 2) andmuscle biopsies (Expt. 1) were collected before and after labeled-food ingestion. Results: High tracer labeling [> 20 mole percent excess (MPE)] in the eggs was obtained after 7 d and maintained throughout the feeding protocol (P < 0.05). Over a 55-d period, ;850 g egg protein (145 eggs)was produced, with amean ± SEMtracer enrichment of 22.060.8MPE.Mean6SEML-[5,5,5-2H3]leucine enrichment in themeat was 9.660.1MPE. In Expts. 1 and 2, the consumption of labeled eggs and poultry meat protein increased plasma L-[5,5,5-2H3]leucine enrichment, withmean ± SEM peak values of 6.7 6 0.1 MPE and 4.0 6 0.9 MPE, respectively. The mean ± SEM 5-h postprandial increase in myofibrillar L-[5,5,5-2H3]leucine enrichment after egg ingestion in healthy young men was 0.051 6 0.008 MPE (Expt. 1). Conclusion: We demonstrated the feasibility of producing intrinsically labeled eggs and poultry meat for use in human metabolic research.

Original languageEnglish
Pages (from-to)1428-1433
Number of pages6
JournalJournal of Nutrition
Issue number7
StatePublished - 2016


  • Muscle mass
  • Muscle protein synthesis
  • Nutrition
  • Protein digestion
  • Stable isotopes


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