title: The measurement of muscle protein synthesis in broilers with a flooding dose technique: use of 15N-labelled phenylalanine, GC-MS and GC-C-IRMS.
abstract: An experiment was carried out to measure fractional muscle protein synthesis rates (k(s)) in broilers with injection of a flooding dose of phenylalanine (1 ml/100 g body weight of 150 mM phenylalanine; 38 atom percent excess (APE) [15N]phenylalanine). K(s) was calculated from the [15N] enrichment in phenylalanine of tissue-free and protein-bound phenylalanine using both gas chromatography mass spectrometry (GC-MS) and gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) for measurements after a 10 min isotope incorporation period. The tertiary-butyldimethylsilyl (t-BDMS) derivatives of phenylalanine were used for gas chromatographic separation in both systems. GC-MS and GC-C-IRMS were calibrated for a range of 7 to 37 [15N]APE and 0 to 0.62 [15N]APE, respectively, and for sample sizes of 0.45 to 4.5 nmol phenylalanine and 7 to 40 nmol phenylalanine, respectively. Reproducibility of standards as a measure of precision varied from 0.06 to 0.29 [15N]APE and from 0.0004 to 0.0018 [15N]APE in GC-MS and GC-C-IRMS, respectively. K(s) was measured in the m. pectoralis major of broilers fed rye based diets (56%) which were provided either unsupplemented (-) or supplemented (+) with an enzyme preparation containing xylanase. K(s) in breast muscles was significantly increased from 21.8%/d to 23.9%/d due to enzyme supplementation. It can be concluded from the study that the measurement of protein synthesis in broilers with the flooding dose technique can be carried out by using [15N]phenylalanine, GC-MS and GC-C-IRMS.
authors.affiliation: Institute of Animal Nutrition and Planned Crop Storage, Agricultural Faculty, Martin-Luther-University Halle-Wittenberg, Germany. sven.daenicke@fal.de
authors.forename: S
authors.initials: S
authors.lastname: Dänicke
authors.forename: W
authors.initials: W
authors.lastname: Böttcher
authors.forename: O
authors.initials: O
authors.lastname: Simon
authors.forename: H
authors.initials: H
authors.lastname: Jeroch
mesh_terms: D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000502:physiology*; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry / Q000502:physiology*; D009587:Nitrogen Isotopes / Q000032:analysis; D010649:Phenylalanine / Q000378:metabolism; D014176:Protein Biosynthesis; D011506:Proteins / Q000032:analysis
chemical_list: D009587:Nitrogen Isotopes; D011506:Proteins; D010649:Phenylalanine