The effect of time off feed prior to slaughter on muscle glycogen metabolism and rate of pH decline in three different muscles of stimulated and non-stimulated sheep carcasses

2006 ◽  
Vol 57 (11) ◽  
pp. 1229 ◽  
Author(s):  
B. L. Daly ◽  
G. E. Gardner ◽  
D. M. Ferguson ◽  
J. M. Thompson
Keyword(s):  
Muscle Glycogen ◽  
Carcass Characteristics ◽  
Glycogen Metabolism ◽  
Glycogen Concentration ◽  
Ph Values ◽  
Access To Water ◽  
And Control ◽  
Muscle Glycogen Concentration ◽  
Sheep Muscle ◽  
Measuring Ph

The aim of this study was to determine the effect of time off feed (TOF) prior to slaughter on muscle glycogen metabolism and rate of pH decline in sheep muscle. All animals were maintained on a roughage diet for 6 weeks and were then subjected to either 0, 2, or 4 days TOF with access to water, prior to slaughter. Glycogen concentrations were determined post-slaughter for 3 different muscles, M. longissimus thoracis et lumborum (LTL), M. semimembranosus (SM), and M. semitendinosus (ST), as well as measuring pH declines for all animals in each of the 3 muscles under both electrically stimulated and control conditions. Ultimate pH values (pHu) were determined 48 h post-slaughter. Both the 2-day and 4-day TOF groups lost liveweight during their curfew period, whereas the control (0-day) group gained weight. TOF had no effect on post-slaughter carcass characteristics, muscle glycogen concentrations, pHu, or rate of pH decline. Increased muscle glycogen concentrations resulted in faster rates of pH decline. This response was curvilinear, plateauing at a glycogen concentration of about 56 mmol/kg muscle. Muscle glycogen concentration also affected the response of pH decline to electrical stimulation, interacting with muscle and pre-stimulation pH. Low muscle glycogen levels limited delta pH only in the SM and ST and only in muscles of lower pre-stimulation pH.

Diet and Muscle Glycogen Concentration in Relation to Physical Performance in Swedish Elite Ice Hockey Players

1996 ◽  
Vol 6 (3) ◽  
pp. 272-284 ◽  
Author(s):  
Christian Åkermark ◽  
Ira Jacobs ◽  
Margareta Rasmusson ◽  
Jan Karlsson
Keyword(s):  
Physical Performance ◽  
Muscle Fiber ◽  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
Glycogen Metabolism ◽  
Ice Hockey ◽  
Vastus Lateralis Muscle ◽  
Fiber Distribution ◽  
Glycogen Concentration ◽  
Muscle Glycogen Concentration

The effects of carbohydrate (CHO) loading on physical characteristics including muscle fiber distribution, muscle glycogen concentration, and physical performance were studied in two top Swedish ice hockey teams. Players were randomly allocated to two groups: those consuming a CHO-enriched diet (CHO group) and those consuming a mixed diet (controls). Biopsies from the vastus lateralis muscle were taken three times: after Game 1, before Game 2, and after Game 2. Muscle fiber distribution averaged 50 ± 2% slow twitch fibers (mean ± 1SEM).Muscle glycogen concentrations (measured in mmol glucose units · kg−1wet muscle) were as follows: after Game 1, 43 ± 4 (ail players); before Game 2,99 ± 7 (CHO group) and 81 ± 7 (controls); and after Game 2, 46 ± 6 (CHO group) and 44 ± 5 (controls). Distance skated, number of shifts skated, amount of time skated within shifts, and skating speed improved with CHO loading. It was concluded that individual differences in performance could be related to muscle glycogen metabolism.

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.

Role of glycogen concentration and epinephrine on glucose uptake in rat epitrochlearis muscle

1997 ◽  
Vol 272 (4) ◽  
pp. E649-E655 ◽  
Author(s):  
J. Jensen ◽  
R. Aslesen ◽  
J. L. Ivy ◽  
O. Brors
Keyword(s):  
Glucose Uptake ◽  
Muscle Glycogen ◽  
Similar Treatment ◽  
Glycogen Concentration ◽  
Spearman's Rho ◽  
Spearman’S Rho ◽  
Tracer Amount ◽  
Muscle Glycogen Concentration ◽  
Basal Glucose Uptake

The effects of diet-manipulated variations in muscle glycogen concentration and epinephrine on glucose uptake were studied in epitrochlearis muscles from Wistar rats. Both basal and insulin-stimulated glucose uptake [measured with a tracer amount of 2-[1,2-3H(N)]deoxy-D-glucose] inversely correlated with initial glycogen concentration (glycogen concentration vs. basal glucose uptake: Spearman's rho = -0.76, n = 84, P < 0.000001; glycogen concentration vs. insulin-stimulated glucose uptake: Spearman's rho = -0.67, n = 44, P < 0.00001). Two fasting-refeeding procedures were used that resulted in differences in muscle glycogen concentrations, although with similar treatment for the last 48 h before the experiment. In the rats with the lower glycogen concentration, basal as well as insulin-stimulated glucose uptake was elevated. The muscle glycogen concentration had no effect on epinephrine-stimulated glycogenolysis. Epinephrine, however, was found to reduce basal glucose uptake in all groups. These results suggest that 1) the glycogen concentration participates in the regulation of both basal and insulin-stimulated glucose uptake in skeletal muscle, 2) the magnitude of epinephrine-stimulated glycogen breakdown is independent of the glycogen concentration, and 3) epinephrine inhibits basal glucose uptake at all glycogen concentrations.

Muscle glycogen concentrations in commercial consignments of Australian lamb measured on farm and post-slaughter after three different lairage periods

2005 ◽  
Vol 45 (5) ◽  
pp. 543 ◽  
Author(s):  
R. H. Jacob ◽  
D. W. Pethick ◽  
H. M. Chapman
Keyword(s):  
Western Australia ◽  
Muscle Glycogen ◽  
Glycogen Concentration ◽  
Age Class ◽  
Muscle Types ◽  
Carry Over ◽  
On Farm ◽  
Muscle Glycogen Concentration

The aim of this study was to gain an understanding of the distribution of glycogen concentrations and ultimate pH (pHu) in 2 different muscle types for lambs slaughtered under commercial conditions in Western Australia, and to compare muscle glycogen concentrations in lambs on farm and after slaughter. The study included 13 different consignments of prime lambs from a range of commercial scenarios. In each consignment, muscle glycogen concentration was measured in a group of lambs on farm and subsequently after slaughter in 3 different lairage groups. The lairage groups were: slaughter on arrival (no lairage), slaughter after 1 day, and slaughter after 2 days in lairage. Biopsies of M. semimembranosus and the M. semitendinosus were taken from live lambs on farm just before farm curfew before transport and from carcasses immediately after slaughter. There was a significant effect of consignment on muscle glycogen concentration. Muscle glycogen concentrations on farm were lower than 1 g/100 g in 4 consignments for the M. semimembranosus and 11 consignments for the M. semitendinosus. The cause of the differences between consignments was unclear as nutrition, genotype and age class were confounded between consignments. Glycogen concentrations were lower and meat pHu higher for sucker lamb compared with carry-over lamb consignments. However, lambs finished on grain-based feedlot rations had higher muscle glycogen concentrations than lambs finished on pasture and sucker lambs when finished on pastures only. Sucker lambs were only crossbred while carry-over lambs included crossbred and Merino genotypes. When data from different consignments were pooled and the effect of consignment was considered, there were no differences between muscle glycogen concentration measured on farm and muscle glycogen concentration measured after slaughter. However, there were differences between sample times within individual consignments. Glycogen concentration at slaughter was different from glycogen concentration on farm in more consignments for M. semitendinosus than M. semimembranosus, suggesting a difference between consignments for the effect caused by stress. Typically, the M. semimembranosus glycogen concentration at slaughter was lower than on farm in consignments consisting of Merino genotypes that had high muscle glycogen concentrations on farm. In the consignments in which lairage time had an effect on muscle glycogen concentration, the differences were small. In some consignments a difference occurred between lairage times for pHu without any difference occurring for muscle glycogen concentration.

Carbohydrate feedings and exercise performance: effect of initial muscle glycogen concentration

1993 ◽  
Vol 74 (6) ◽  
pp. 2998-3005 ◽  
Author(s):  
J. J. Widrick ◽  
D. L. Costill ◽  
W. J. Fink ◽  
M. S. Hickey ◽  
G. K. McConell ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Exercise Performance ◽  
Power Output ◽  
Time Trial ◽  
Serum Glucose ◽  
O2 Consumption ◽  
Performance Effect ◽  
Glycogen Concentration ◽  
Performance Times ◽  
Muscle Glycogen Concentration

To determine whether the ergogenic benefits of carbohydrate (CHO) feedings are affected by preexercise muscle glycogen levels, eight cyclists performed four self-paced time trials on an isokinetic ergometer over a simulated distance of 70 km. Trials were performed under the following preexercise muscle glycogen and beverage conditions: 1) high glycogen (180.2 +/- 9.7 mmol/kg wet wt) with a CHO beverage (HG-CHO), 2) high glycogen (170.2 +/- 10.4 mmol/kg wet wt) with a non-CHO beverage (HG-NCHO), 3) low glycogen (99.8 +/- 6.0 mmol/kg wet wt) with a CHO beverage (LG-CHO), and 4) low glycogen (109.7 +/- 5.3 mmol/kg wet wt) with a non-CHO beverage (LG-NCHO). The CHO drink (ingested at the onset of exercise and every 10 km thereafter) provided 116 +/- 6 g CHO/trial and prevented the decline in serum glucose observed during both NCHO trials. Performance times ranged from 117.93 +/- 1.44 (HG-CHO) to 122.91 +/- 2.46 min (LG-NCHO). No intertrial differences (P > 0.05) were observed for O2 consumption (75% of maximal O2 consumption), power output (237 W), or self-selected pace (8.44 min/5 km) during the initial 71–79% of exercise. Over the final 14% of the time trial, power output and pace (231 W and 8.62 min/5 km) were similar for the HG-CHO, HG-NCHO, and LG-CHO conditions, but both variables were significantly lower during the LG-NCHO trial (198 W and 9.67 min/5 km, P < 0.05 vs. all other trials).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Mechanism linking glycogen concentration and glycogenolytic rate in perfused contracting rat skeletal muscle

1992 ◽  
Vol 284 (3) ◽  
pp. 777-780 ◽  
Author(s):  
P Hespel ◽  
E A Richter
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Rat Skeletal Muscle ◽  
Phosphorylase Activity ◽  
Tension Development ◽  
Glycogen Concentration ◽  
The Difference ◽  
Resting Muscle ◽  
Muscle Glycogen Concentration ◽  
Glycogen Breakdown

The influence of differences in glycogen concentration on glycogen breakdown and on phosphorylase activity was investigated in perfused contracting rat skeletal muscle. The rats were preconditioned by a combination of swimming exercise and diet (carbohydrate-free or carbohydrate-rich) in order to obtain four sub-groups of rats with varying resting muscle glycogen concentrations (range 10-60 mumol/g wet wt.). Pre-contraction muscle glycogen concentration was closely positively correlated with glycogen breakdown over 15 min of intermittent short tetanic contractions (r = 0.75; P less than 0.001; n = 56) at the same tension development and oxygen uptake. Additional studies in supercompensated and glycogen-depleted hindquarters during electrical stimulation for 20 s or 2 min revealed that the difference in glycogenolytic rate was found at the beginning rather than at the end of the contraction period. Phosphorylase alpha activity was approximately twice as high (P less than 0.001) in supercompensated muscles as in glycogen-depleted muscles after 20 s as well as after 2 min of contractions. It is concluded that glycogen concentration is an important determinant of phosphorylase activity in contracting skeletal muscle, and probably via this mechanism a regulator of glycogenolytic rate during muscle contraction.

Transgenic mice overexpressing GLUT-1 protein in muscle exhibit increased muscle glycogenesis after exercise

2000 ◽  
Vol 278 (4) ◽  
pp. E588-E592 ◽  
Author(s):  
Jian-Ming Ren ◽  
Nicole Barucci ◽  
Bess A. Marshall ◽  
Polly Hansen ◽  
Mike M. Mueckler ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Muscle Glycogen ◽  
Glycogen Synthase ◽  
Progressive Increase ◽  
Second Phase ◽  
Glycogen Accumulation ◽  
Glut 1 ◽  
Glycogen Concentration ◽  
High Level ◽  
Muscle Glycogen Concentration

The purpose of the present study was to determine the rates of muscle glycogenolysis and glycogenesis during and after exercise in GLUT-1 transgenic mice and their age-matched littermates. Male transgenic mice (TG) expressing a high level of human GLUT-1 and their nontransgenic (NT) littermates underwent 3 h of swimming. Glycogen concentration was determined in gastrocnemius and extensor digitorum longus (EDL) muscles before exercise and at 0, 5, and 24 h postexercise, during which food (chow) and 10% glucose solution (as drinking water) were provided. Exercise resulted in ∼90% reduction in muscle glycogen in both NT (from 11.2 ± 1.4 to 2.1 ± 1.3 μmol/g) and TG (from 99.3 ± 4.7 to 11.8 ± 4.3 μmol/g) in gastrocnemius muscle. During recovery from exercise, the glycogen concentration increased to 38.2 ± 7.3 (5 h postexercise) and 40.5 ± 2.8 μmol/g (24 h postexercise) in NT mice. In TG mice, however, the increase in muscle glycogen concentration during recovery was greater (to 57.5 ± 7.4 and 152.1 ± 15.7 μmol/g at 5 and 24 h postexercise, respectively). Similar results were obtained from EDL muscle. The rate of 2-deoxyglucose uptake measured in isolated EDL muscles was 7- to 10-fold higher in TG mice at rest and at 0 and 5 h postexercise. There was no difference in muscle glycogen synthase activation measured in gastrocnemius muscles between NT and TG mice immediately after exercise. These results demonstrate that the rate of muscle glycogen accumulation postexercise exhibits two phases in TG: 1) an early phase (0–5 h), with rapid glycogen accumulation similar to that of NT mice, and 2) a progressive increase in muscle glycogen concentration, which differs from that of NT mice, during the second phase (5–24 h). Our data suggest that the high level of steady-state muscle glycogen in TG mice is due to the increase in muscle glucose transport activity.

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