The effect of magnesium oxide supplementation on muscle glycogen metabolism before and after exercise and at slaughter in sheep

2001 ◽  
Vol 52 (7) ◽  
pp. 723 ◽  
Author(s):  
G. E. Gardner ◽  
R. H. Jacob ◽  
D. W. Pethick
Keyword(s):  
Magnesium Oxide ◽  
Muscle Glycogen ◽  
Glycogen Metabolism ◽  
Post Exercise ◽  
Exercise Regimen ◽  
Before And After ◽  
Series Of Experiments ◽  
Glycogen Repletion ◽  
Exercise Muscle ◽  
Muscle Biopsies

This study was a series of experiments designed to test the influence of supplemental magnesium oxide (MgO) on muscle glycogen concentration in sheep exposed to stress (exercise) and the commercial slaughter process, and to test the effectiveness of this supplement in the commercial scenario. In Expt 1, Merino wethers maintained on a mixed ration (metabolisable energy 11 MJ/kg and crude protein 16.3% in DM) were supplemented with MgO at the rate of 0%, 0.5%, or 1% of their ration for 10 days prior to a single bout of exercise and for 10 days prior to slaughter at a commercial abattoir. The exercise regimen consisted of 4 intervals of 15 min, with muscle biopsies taken by biopsy drill from the m. semimembranosis (SM) and m. semitendinosis (ST) pre-exercise and immediately post-exercise, and at 36 and 72 h post-exercise. Muscle biopsies were also taken 1 week prior to slaughter from the SM and ST, with further samples taken approximately 30 min post-slaughter. Ultimate pH (pHu) of the SM, ST, and m. longissimus dorsi (LD) was measured 48 h after slaughter. Sheep supplemented with MgO lost less muscle glycogen in the ST during exercise, and repleted more muscle glycogen in the SM during the post-exercise repletion phase, than unsupplemented sheep. The supplemented animals also had higher muscle glycogen concentrations in the ST at slaughter. In Expt 2, MgO was administered to Merino wether lambs for 4 days prior to slaughter in the form of a water-borne slurry at a rate equivalent to 1% of their ration. This treatment resulted in significantly reduced muscle glycogen concentrations in both the SM and ST at slaughter. In Expts 3–5, MgO was used as an ‘in-feed’ supplement in the commercial scenario. In each case, slaughter-weight Merino lambs were supplemented with MgO at the rate of 1% of their ration for 4 days prior to commercial slaughter. Positive responses were seen in 2 of the 3 experiments, with increased glycogen concentrations and a reduced pHu. The animals that demonstrated no response to MgO had the lowest pHu after slaughter, suggesting a minimal stress load, thus providing very little scope for an effect of the MgO supplement. We conclude that MgO can reduce the effects of exercise, leading to a subsequent reduction in glycogen loss, and an increase in the rate of glycogen repletion in skeletal muscle following exercise. The results support MgO supplementation as a viable option for reducing the stress associated with commercial slaughter.

The impact of nutrition on bovine muscle glycogen metabolism following exercise

2001 ◽  
Vol 52 (4) ◽  
pp. 461 ◽  
Author(s):  
G. E. Gardner ◽  
B. L. McIntyre ◽  
G. D. Tudor ◽  
D. W. Pethick
Keyword(s):  
Muscle Glycogen ◽  
Glycogen Metabolism ◽  
Minimal Impact ◽  
Glycogen Concentration ◽  
Exercise Regimen ◽  
Cereal Grain ◽  
Glycogen Repletion ◽  
Dietary Treatments ◽  
The Impact ◽  
Muscle Glycogen Concentration

The aims of this study were to develop a muscle biopsy technique which imposed minimal stress on cattle, enabling accurate monitoring of muscle glycogen concentration; to develop a method based on exercise, for controlled depletion of glycogen from muscle; and to utilise the model to determine the ability of cattle on hay and cereal grain diets to replete muscle glycogen. Expt 1 established the influence of repetitive muscle biopsies on muscle glycogen concentration. It consisted of 3 trials in which cattle received 4 serial biopsies every 36 h over a 108-h period. Repetitive biopsy had minimal impact on M. semimembranosus (SM) glycogen concentrations, although it did reduce concentration in the M. semitendinosus (ST), particularly when animals were penned individually. Expt 2 established an exercise regimen in which cattle were trotted at 9 km/h for five 15-min intervals, with 15 min rest between each interval, depleting muscle glycogen by approximately 50%. Expt 3 determined the repletion rates of muscle glycogen, by utilising the exercise/biopsy model. Cattle were allocated to 4 dietary treatments: hay, silage, hay–barley, and hay–maize. The metabolisable energy (ME) of these rations ranged from 8 to 11.3 MJ/kg. After the exercise regimen, glycogen concentration repleted in a linear fashion over 72 h in the SM of the animals fed maize, barley, and silage. In contrast, the ST of these animals was refractory to glycogen repletion over the same period. Both the SM and ST of the cattle on the hay diet showed no significant repletion following exercise. Repletion following exercise demonstrated a positive linear relationship with ME intake.

Regulation of muscle glycogen phosphorylase activity following short-term endurance training

1996 ◽  
Vol 270 (2) ◽  
pp. E328-E335 ◽  
Author(s):  
A. Chesley ◽  
G. J. Heigenhauser ◽  
L. L. Spriet
Keyword(s):  
Endurance Training ◽  
Muscle Glycogen ◽  
Glycogen Phosphorylase ◽  
Citrate Synthase ◽  
Phosphorylase Activity ◽  
Short Term ◽  
Mitochondrial Potential ◽  
Before And After ◽  
Glycogen Phosphorylase Activity ◽  
Muscle Biopsies

The purpose of this study was to examine the regulation (hormonal, substrate, and allosteric) of muscle glycogen phosphorylase (Phos) activity and glycogenolysis after short-term endurance training. Eight untrained males completed 6 days of cycle exercise (2 h/day) at 65% of maximal O2 uptake (Vo2max). Before and after training subjects cycled for 15 min at 80% of Vo2max, and muscle biopsies and blood samples were obtained at 0 and 30 s, 7.5 and 15 min, and 0, 5, 10, and 15 min of exercise. Vo2max was unchanged with training but citrate synthase (CS) activity increased by 20%. Muscle glycogenolysis was reduced by 42% during the 15-min exercise challenge following training (198.8 +/- 36.9 vs. 115.4 +/- 25.1 mmol/kg dry muscle), and plasma epinephrine was blunted at 15 min of exercise. The Phos a mole fraction was unaffected by training. Muscle phosphocreatine utilization and free Pi and AMP accumulations were reduced with training at 7.5 and 15 min of exercise. It is concluded that posttransformational control of Phos, exerted by reductions in substrate (free Pi) and allosteric modulator (free AMP) contents, is responsible for a blunted muscle glycogenolysis after 6 days of endurance training. The increase in CS activity suggests that the reduction of muscle glycogenolysis was due in part to an enhanced mitochondrial potential.

Muscle glycogen availability and temperature regulation in humans

1989 ◽  
Vol 66 (1) ◽  
pp. 72-78 ◽  
Author(s):  
L. Martineau ◽  
I. Jacobs
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Temperature Regulation ◽  
Vastus Lateralis ◽  
Water Immersion ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Exercise Regimen ◽  
Before And After ◽  
Muscle Groups

The effects of intramuscular glycogen availability on human temperature regulation were studied in eight seminude subjects immersed in 18 degrees C water for 90 min or until rectal temperature (Tre) decreased to 35.5 degrees C. Each subject was immersed three times over a 3-wk period. Each immersion followed 2.5 days of a specific dietary and/or exercise regimen designed to elicit low (L), normal (N), or high (H) glycogen levels in large skeletal muscle groups. Muscle glycogen concentration was determined in biopsies taken from the vastus lateralis muscle before and after each immersion. Intramuscular glycogen concentration before the immersion was significantly different among the L, N, and H trials (P less than 0.01), averaging 247 +/- 15, 406 +/- 23, and 548 +/- 42 (SE) mmol glucose units.kg dry muscle-1, respectively. The calculated metabolic heat production during the first 30 min of immersion was significantly lower during L compared with N or H (P less than 0.05). The rate at which Tre decreased was more rapid during the L immersion than either N or H (P less than 0.05), and the time during the immersion at which Tre first began to decrease also appeared sooner during L than N or H. The results suggest that low skeletal muscle glycogen levels are associated with more rapid body cooling during water immersion in humans. Higher than normal muscle glycogen levels, however, do not increase cold tolerance.

scholarly journals Low pre‐exercise muscle glycogen availability offsets the effect of post‐exercise cold water immersion in augmenting PGC‐1α gene expression

2019 ◽  
Vol 7 (11) ◽  
pp. e14082 ◽  
Author(s):  
Robert Allan ◽  
Adam P. Sharples ◽  
Matthew Cocks ◽  
Barry Drust ◽  
John Dutton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Muscle Glycogen ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Post Exercise ◽  
Exercise Muscle

scholarly journals Coffee Increases Post-Exercise Muscle Glycogen Recovery in Endurance Athletes: A Randomized Clinical Trial

Nutrients ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 3335
Author(s):  
Laís Monteiro Rodrigues Loureiro ◽  
Eugênio dos Santos dos Santos Neto ◽  
Guilherme Eckhardt Molina ◽  
Angélica Amorim Amato ◽  
Sandra Fernandes Arruda ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Randomized Clinical Trial ◽  
Muscle Glycogen ◽  
Glycogen Synthase ◽  
Double Blind ◽  
Post Exercise ◽  
Glycogen Resynthesis ◽  
Ergometer Exercise ◽  
Exercise Muscle ◽  
Insulinemic Response

Coffee is one of the most widely consumed beverages worldwide and caffeine is known to improve performance in physical exercise. Some substances in coffee have a positive effect on glucose metabolism and are promising for post-exercise muscle glycogen recovery. We investigated the effect of a coffee beverage after exhaustive exercise on muscle glycogen resynthesis, glycogen synthase activity and glycemic and insulinemic response in a double-blind, crossover, randomized clinical trial. Fourteen endurance-trained men performed an exhaustive cycle ergometer exercise to deplete muscle glycogen. The following morning, participants completed a second cycling protocol followed by a 4-h recovery, during which they received either test beverage (coffee + milk) or control (milk) and a breakfast meal, with a simple randomization. Blood samples and muscle biopsies were collected at the beginning and by the end of recovery. Eleven participants were included in data analysis (age: 39.0 ± 6.0 years; BMI: 24.0 ± 2.3 kg/m2; VO2max: 59.9 ± 8.3 mL·kg−1·min−1; PPO: 346 ± 39 W). The consumption of coffee + milk resulted in greater muscle glycogen recovery (102.56 ± 18.75 vs. 40.54 ± 18.74 mmol·kg dw−1; p = 0.01; d = 0.94) and greater glucose (p = 0.02; d = 0.83) and insulin (p = 0.03; d = 0.76) total area under the curve compared with control. The addition of coffee to a beverage with adequate amounts of carbohydrates increased muscle glycogen resynthesis and the glycemic and insulinemic response during the 4-h recovery after exhaustive cycling exercise.

Route of carbohydrate administration affects early post exercise muscle glycogen storage in horses

2006 ◽  
Vol 38 (S36) ◽  
pp. 590-595 ◽  
Author(s):  
R. J. GEOR ◽  
L. LARSEN ◽  
H. L. WATERFALL ◽  
L. STEWART-HUNT ◽  
L. J. McCUTCHEON
Keyword(s):  
Muscle Glycogen ◽  
Glycogen Storage ◽  
Post Exercise ◽  
Exercise Muscle

Postexercise muscle and liver glycogen metabolism in male and female rats

1987 ◽  
Vol 62 (3) ◽  
pp. 1250-1254 ◽  
Author(s):  
P. A. Ivey ◽  
G. A. Gaesser
Keyword(s):  
Sex Difference ◽  
Muscle Glycogen ◽  
Exercise Bout ◽  
Glycogen Metabolism ◽  
Liver Glycogen ◽  
Female Rats ◽  
Glycogen Depletion ◽  
Male And Female ◽  
Glycogen Repletion ◽  
Fast Twitch

Male and female Wistar rats were run for 5 min at 1.7 mph at a 17% grade to determine whether a sex difference exists in the rate of glycogen resynthesis during recovery in fast-twitch red muscle, fast-twitch white muscle, and liver. Rats were killed at one of three time points: immediately after the exercise bout, and at 1 or 4 h later. Males had significantly higher resting muscle glycogen levels (P less than 0.05). Exercise resulted in significant glycogen depletion in both sexes (P less than 0.01). Males utilized approximately 50% more glycogen during the exercise bout than females (P less than 0.05). During the food-restricted 4-h recovery period, muscle glycogen was repleted significantly during the 1st h (P less than 0.05). Liver glycogen was not depleted as a result of the exercise bout, but fell during the first h of recovery (P less than 0.05) and remained low during the subsequent 3 h. The greater glycogen utilization in red and white fast-twitch muscle during exercise by males could represent a true sex difference but could also be attributable in part to the males having performed more work as a result of 20% greater body mass. We conclude that no sex difference was observed in the rates of muscle glycogen repletion after exercise or in liver glycogen metabolism during and after exercise, and rapid postexercise muscle glycogen repletion occurred at a time of accelerated liver glycogen depletion.

scholarly journals Pre-Exercise High-Fat Diet for 3 Days Affects Post-Exercise Skeletal Muscle Glycogen Repletion

2017 ◽  
Vol 63 (5) ◽  
pp. 323-330 ◽  
Author(s):  
Yumiko TAKAHASHI ◽  
Yutaka MATSUNAGA ◽  
Yuki TAMURA ◽  
Shin TERADA ◽  
Hideo HATTA
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
High Fat Diet ◽  
High Fat ◽  
Post Exercise ◽  
Skeletal Muscle Glycogen ◽  
Glycogen Repletion

Influence of Post-Exercise Carbohydrate-Protein Ingestion on Muscle Glycogen Metabolism in Recovery and Subsequent Running Exercise

2016 ◽  
Vol 26 (6) ◽  
pp. 572-580 ◽  
Author(s):  
Abdullah F. Alghannam ◽  
Dawid Jedrzejewski ◽  
James Bilzon ◽  
Dylan Thompson ◽  
Kostas Tsintzas ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Glycogen Metabolism ◽  
Dry Mass ◽  
Treadmill Running ◽  
Time To Exhaustion ◽  
Short Term ◽  
Double Blind ◽  
Protein Ingestion ◽  
Double Blind Design ◽  
Muscle Biopsies

We examined whether carbohydrate-protein ingestion influences muscle glycogen metabolism during short-term recovery from exhaustive treadmill running and subsequent exercise. Six endurance-trained individuals underwent two trials in a randomized double-blind design, each involving an initial run-to-exhaustion at 70% VO2max (Run-1) followed by 4-h recovery (REC) and subsequent run-to-exhaustion at 70% VO2max (Run-2). Carbohydrate-protein (CHO-P; 0.8 g carbohydrate·kg body mass [BM-1]·h-1 plus 0.4 g protein·kg BM-1·h-1) or isocaloric carbohydrate (CHO; 1.2 g carbohydrate·kg BM-1·h-1) beverages were ingested at 30-min intervals during recovery. Muscle biopsies were taken upon cessation of Run-1, postrecovery and fatigue in Run-2. Time-to-exhaustion in Run-1 was similar with CHO and CHO-P (81 ± 17 and 84 ± 19 min, respectively). Muscle glycogen concentrations were similar between treatments after Run-1 (99 ± 3 mmol·kg dry mass [dm-1]). During REC, muscle glycogen concentrations increased to 252 ± 45 mmol·kg dm-1 in CHO and 266 ± 30 mmol·kg dm-1 in CHO-P (p = .44). Muscle glycogen degradation during Run-2 was similar between trials (3.3 ± 1.4 versus 3.5 ± 1.9 mmol·kg dm-1·min-1 in CHO and CHO-P, respectively) and no differences were observed at the respective points of exhaustion (93 ± 21 versus 100 ± 11 mmol·kg dm-1; CHO and CHO-P, respectively). Similarly, time-to-exhaustion was not different between treatments in Run-2 (51 ± 13 and 49 ± 15 min in CHO and CHO-P, respectively). Carbohydrate-protein ingestion equally accelerates muscle glycogen resynthesis during short-term recovery from exhaustive running as when 1.2 g carbohydrate·kg BM-1·h-1 are ingested. The addition of protein did not alter muscle glycogen utilization or time to fatigue during repeated exhaustive running.

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