The Measurement of Muscle Protein Synthesis in Broilers with a Flooding Dose Technique: Use of¹⁵N-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.

Effects of dietary energy levels on Pectoralis major mixed muscle protein turnover and body composition in two broiler lines housed in different grow‐out environments

“…Precursor‐product principle was utilized to calculate fractional synthesis rate (FSR) as given in elsewhere (Dänicke et al, 2001; Ekmay et al., 2013), which is given by the following equation:…”

“…Starting oven temperature was 100°C and was held for 0.65 min, the temperature was increased 30°C/min to 250°C, and held for 10 min. The mass Precursor-product principle was utilized to calculate fractional synthesis rate (FSR) as given in elsewhere (Dänicke et al, 2001;Ekmay et al, 2013) Degradation rate was measured using the following expression as follow (Rathmacher, 2000;Young & Munro, 1978):…”

In vivo collagen and mixed muscle protein turnover in 2 meat-type broiler strains in relation to woody breast myopathy

“…Precursor-product principle was used to calculate FSR as given elsewhere ( Danicke et al., 2001 ; Ekmay et al., 2013 ), which is given by the following equation: APE b = 15 N atom percent excess (relative to natural abundance) of phenylalanine in the protein; APE f = 15 N atom percent excess of free phenylalanine in tissues, assumed as the precursor pool; t = time [D]. …”

Effects of dietary amino acid levels and ambient temperature on mixed muscle protein turnover in Pectoralis major during finisher feeding period in two broiler lines

“…Starting oven temperature was 100°C and was held for 0.65 min; the temperature was increased 30°C/min to 250°C and held for 10 min. The mass spec- Precursor-product principle was utilized to calculate fractional synthesis rate (FSR) as given in elsewhere (Dänicke, Böttcher, Simon, & Jeroch, 2001;Ekmay, Salas, England, Cerrate, & Coon, 2013)…”