Loading...
Substantial differences between organ and muscle specific tracer incorporation rates in a lactating dairy cow
Burd, N Hamer, Henrike M. Pennings, Bart Pellikaan, Wilbert F. Senden, Joan M. Gijsen, Annemie P. Van Loon, Luc
Burd, N
Hamer, Henrike M.
Pennings, Bart
Pellikaan, Wilbert F.
Senden, Joan M.
Gijsen, Annemie P.
Van Loon, Luc
Abstract
We aimed to produce intrinsically L-[1-13C]phenylalanine labeled milk and beef for subsequent use in human nutrition research. The collection of the various organ tissues after slaughter allowed for us to gain insight into the dynamics of tissue protein turnover in vivo in a lactating dairy cow. One lactating dairy cow received a constant infusion of L-[1-13C]phenylalanine (450 µmol/min) for 96 h. Plasma and milk were collected prior to, during, and after the stable isotope infusion. Twenty-four hours after cessation of the infusion the cow was slaughtered. The meat and samples of the various organ tissues (liver, heart, lung, udder, kidney, rumen, small intestine, and colon) were collected and stored. Approximately 210 kg of intrinsically labeled beef (bone and fat free) with an average L-[1-13C]phenylalanine enrichment of 1.8±0.1 mole percent excess (MPE) was obtained. The various organ tissues differed substantially in L-[1-13C]phenylalanine enrichments in the tissue protein bound pool, the highest enrichment levels were achieved in the kidney (11.7 MPE) and the lowest enrichment levels in the skeletal muscle tissue protein of the cow (between 1.5–2.4 MPE). The estimated protein synthesis rates of the various organ tissues should be regarded as underestimates, particularly for the organs with the higher turnover rates and high secretory activity, due to the lengthened (96 h) measurement period necessary for the production of the intrinsically labeled beef. Our data demonstrates that there are relatively small differences in L-[1-13C]phenylalanine enrichments between the various meat cuts, but substantial higher enrichment values are observed in the various organ tissues. We conclude that protein turnover rates of various organs are much higher when compared to skeletal muscle protein turnover rates in large lactating ruminants.
Keywords
Date
2013
Type
Journal article
Journal
PLoS ONE
Book
Volume
8
Issue
6
Page Range
1-10
Article Number
ACU Department
Centre for Exercise and Nutrition
Faculty of Health Sciences
Faculty of Health Sciences
Collections
Relation URI
Source URL
Event URL
Open Access Status
Open access
License
File Access
Open
Notes
[http://creativecommons.org/licenses/by/4.0/]
This work is licensed under a [http://creativecommons.org/licenses/by/4.0/] Creative Commons Attribution 4.0 International License.