349 Preliminary analysis of large dose nicotinamide riboside supplementation effect on barrow muscle performance weakness.

Abstract When dosed daily at up to 45 mg/kg body weight for 10 d, a previous study reported nicotinamide riboside (NR) delayed muscle fatigue onset through a slower muscle fiber recruitment pattern. Because of the success of this dosing program, this study aimed to determine if feeding a larger NR dose for a longer period improved pig muscle weakness and performance by delaying the onset of fatigue. Barrows (N=41) were stratified by weight and randomly assigned to one of two treatments (TRT): a conventional swine finishing diet containing 0 (CON) or 150 (NR+) mg/kg body weight NR daily. Supplementation was administered during the last 14-feeding d, after which pigs were subjected to a performance test by being briskly walk around a 270 m course. Performance data included speed, time, and distance until subjective fatigue was achieved. Prior to testing, surface electromyography (sEMG) sensors were affixed to tensor fascia latae (TFL), bicep femoris (BF), and semitendinosus (ST) to measure median power frequency (MdPF) and root mean square (RMS) as indicators of action potential velocity and muscle fiber recruitment or frequency and amplitude assessment in the time domain, respectively. Raw sEMG data were processed for each electrical burst representing muscle contraction, normalized to the first 30 s of each barrow’s trail, and normalized data were averaged into five periods during the performance test. There were no TRT effects for laps around the course, distance, exhaustion time, and speed (P≥0.67). There were no interactions, TRT, or Period main effects for MdPF (P≥0.29). There was a Muscle main effect where TFL had greater normalized MdPF than BF and ST muscles (P≤0.01), which did not differ (P=0.56) from each other. There were no TRT × Muscle × Period or TRT × Muscle interactions for normalized RMS (P≥0.23), but there tended to be a TRT × Period interaction (P=0.07). Across all muscles, CON barrow normalized RMS was greater than NR+ normalized RMS during period 1 (P=0.01), while there were no differences during periods 2 and 3 (P≥0.12). During periods 4 and 5, NR+ barrows had greater normalized RMS (P≤0.04) than CON barrows. Even though NR did not improve barrow performance testing measures, possibly due to behavioral matters, sEMG data indicated NR+ had more active muscle fibers during fatigue periods, indicating large dose NR may increase muscle strength and muscle fiber resistance to fatigue.