Food First Approach to Stimulate Muscle Protein Synthesis in Healthy Adults

On both infusion trials, participants will report to the laboratory at 0700 h after an
overnight fast. Upon arrival to the lab, the participant will fill out a questionnaire and a
baseline breath sample will be collected to determine 13CO2 enrichment by isotope ratio mass
spectrometry. A Teflon catheter will be inserted into the antecubital vein for a baseline
blood sample (t=-210) and then participants will receive priming doses of NaH13CO2 (2.35
µmol·kg-1), L-[1-13C]leucine (7.6 µmol·kg-1), and L-[ring-2H5]phenylalanine (2.0 µmol·kg-1).
Subsequently, a continuous intravenous solution of L-[1-13C]leucine (0.10 µmol·kg-1·min-1)
and L-[ring-2H5]phenylalanine (0.05 µmol·kg-1·min-1) will be initiated (t=-210) and
maintained over the infusion trials. A second Teflon catheter will be inserted into a heated
dorsal vein for repeated arterialized blood sampling and remained patent by a 0.9% saline
drip. Breath samples and arterialized blood samples will be collected every 30 to 60 minutes
during the postabsorptive and postprandial states. In the post-absorptive state of infusion
trial 1, muscle biopsies will be collected at t=-150 and -30 min of infusion to determine
basal-state myofibrillar protein synthesis rates, relative skeletal muscle amino acid
transporter content, and anabolic-related signaling. In the subsequent cross-over trial only
1 muscle biopsy will be collected at t=-30 for Western blot analysis and postabsorptive
myofibrillar protein-bound tracer enrichment. After collection of the resting muscle biopsy
at t=-30 for both trials, the participants will perform resistance exercise that consists of
4 sets of 10-12 repetitions or to muscular failure at 65-70% of 1-RM for both leg press and
leg extension exercise.

Immediately after the completion of the exercise bout, participants will ingest either 3.5 oz
of Salmon fillet or a matched isolated amino acid and fat mixture (t=0). Completion of the
meal will mark the start of the postprandial stage and additional muscle biopsies will be
collected at t=120 and t=300.

Inclusion Criteria:

- Age 20-35 years

- Recreationally-active adults: ≥ 30 min of physical activity at moderate intensity ≥ 3
times per week

- English fluency

Exclusion Criteria:

- Smoking

- Known allergies to fish consumption

- Vegans

- Diagnosed GI tract diseases

- Arthritic conditions

- A history of neuromuscular problems

- Diagnosed cognitive impairments

- Recent (1 year) participation in amino acid tracer studies

- Predisposition to hypertrophic scarring or keloid formation

- Individuals on any medications known to affect protein metabolism (i.e.
corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne
medications).

- High blood pressure (Systolic > 140 mm HG; Diastolic > 90 mm HG)

- Alcohol consumption >10 drinks per week

- Metabolic disorders (e.g., Metabolic Syndrome, diabetes, thyroid diseases)

- Consumption of thyroid, androgenic or other medications known to affect endocrine
function

- Consumption of ergogenic-leves of dietary supplements that may affect muscle mass
(e.g., creatine, HMB), insulin-like substances, or anabolic/catabolic pro-hormones
(e.g., DHEA) within 6 weeks prior to participation

- Currently pregnant

- A suboptimal diet quality score as assessed by ASA24 dietary records

- Asthma

- Hypogonadism

- Cardiovascular disease, arrhythmias