Effects of whey protein hydrolysate ingestion on post-exercise muscle protein synthesis compared with intact whey protein in rats

• Published in: Nutrition & metabolism 2019-12, Vol.16 (1), p.90-90, Article 90
• Main Authors: Nakayama, Kyosuke, Tagawa, Ryoichi, Saito, Yuri, Sanbongi, Chiaki
• Format: Article
• Language: English
• Subjects: Amino acids; Aminoacidemia; Animals; Body weight; Chromatography; Food science; FSR; Insulin; Kinases; Laboratories; Leucine; Milk proteins; mTOR signaling; Muscle protein anabolism; Phosphorylation; Physical training; Protein binding; Protein biosynthesis; Protein hydrolysates; Protein sources; Protein synthesis; Proteins; Rapamycin; Swimming; TOR protein; Variance analysis; Whey protein
• ISSN: 1743-7075; 1743-7075
• DOI: 10.1186/s12986-019-0417-9

It is well known that ingestion of protein sources can stimulate muscle protein synthesis (MPS). The intake of whey protein is highly effective especially for accelerating MPS. Whey protein hydrolysate (WPH) can raise postprandial plasma concentration of amino acids, which impact stimulation of MPS more rapidly and highly than intact whey protein. However, it is unclear which is more effective for stimulating MPS, WPH or intact whey protein. The aim of the present study was to compare the effects of the WPH and whey protein on MPS in rats after exercise. Rats were first subjected to a 2 h. swimming protocol. After this, in experiment 1, we evaluated time-dependent changes in the fractional synthetic rate (FSR) of the triceps muscle in Male Sprague-Dawley rats after ingestion of intact whey protein (30, 60, 90 or 120 min after ingestion). Then in experiment 2, at the time point that the results of Experiment 1 revealed postprandial FSR was highest (60 min after ingestion), we measured the FSR after ingestion of the WPH or whey protein at two different doses (0.5 or 2.0 g protein/kg body weight), or with deionized water (control), again after exercise. Plasma components and mammalian target of rapamycin (mTOR) signaling were also measured. In experiment 1, postprandial FSR was highest 60 min after whey protein was administered. In experiment 2, the FSR 60 min after ingestion of the WPH was higher than that of whey protein (significant treatment main effect). Moreover, at a lower dose, only the WPH ingestion caused greater MPS and phosphorylated 4E-binding protein 1 (4E-BP1) levels compared with the control group. These results indicate that ingestion of the WPH was associated with greater post-exercise MPS compared with intact whey protein, especially at lower doses.