Abstract
Fish oil (FO) supplementation potentiates muscle protein synthesis (MPS) in response to a hyperaminoacidemic–hyperinsulinemic infusion. Whether FO supplementation potentiates MPS in response to protein ingestion or when protein ingestion is combined with resistance exercise (RE) remains unknown. In a randomized, parallel group design, 20 healthy males were randomized to receive 5 g/day of either FO or coconut oil control (CO) for 8 weeks. After supplementation, participants performed a bout of unilateral RE followed by ingestion of 30 g of whey protein. Skeletal muscle biopsies were obtained before and after supplementation for assessment of muscle lipid composition and relevant protein kinase activities. Infusion of l‐[ring‐13C6] phenylalanine was used to measure basal myofibrillar MPS at rest (REST), in a nonexercised leg following protein ingestion (FED) and following RE and protein ingestion (FEDEX). MPS was significantly elevated above REST during FEDEX in both the FO and CO groups, but there was no effect of supplementation. There was a significant increase in MPS in both groups above REST during FED but no effect of supplementation. Supplementation significantly decreased panPKB activity at REST in the FO group but not the CO group. There was a significant increase from REST at post‐RE for PKB and AMPK α2 activity in the CO group but not in the FO group. In FEDEX, there was a significant increase in p70S6K1 activity from REST at 3 h in the CO group only. These data highlight that 8 weeks of FO supplementation alters kinase signaling activity in response to RE plus protein ingestion without influencing MPS.
Highlights
Muscle protein synthesis (MPS) is an important metabolic determinant of human skeletal muscle mass (Glynn et al 2010; McGlory and Phillips 2014)
The increase in plasma concentrations of essential amino acids (EAAs) and leucine in the Fish oil (FO) group were significantly higher than the CO group at 15 min postexercise and protein feeding (P < 0.05; Fig. 2B–C), but the plasma concentration of leucine was significantly lower in the FO group compared to the CO group at 75 min postexercise and protein feeding (P < 0.05; Fig. 2C)
The novel finding from the present study is that despite a twofold increase in the n-3 polyunsaturated fatty acid (PUFA) composition of skeletal muscle, FO supplementation did not significantly enhance rates of myofibrillar MPS at REST nor in either FED or feeding and resistance exercise (FEDEX) condition compared to CO
Summary
Muscle protein synthesis (MPS) is an important metabolic determinant of human skeletal muscle mass (Glynn et al 2010; McGlory and Phillips 2014). The anabolic influence of protein ingestion and resistance exercise on skeletal muscle has led to studies examining the influence of the type (Tang et al 2009) and dose (Witard et al 2014) of protein on rates of MPS. These studies have shown that in young male adults the consumption of ~0.25 g/kg of high-quality protein results in the saturation of both a 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
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