scholarly journals Overcoming nature’s paradox in skeletal muscle to optimise animal production

2019 ◽  
Vol 59 (11) ◽  
pp. 1957
Author(s):  
Gordon S. Lynch ◽  
René Koopman
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibre ◽  
Oxidative Capacity ◽  
Animal Production ◽  
Food Sources ◽  
Muscle Size ◽  
Meat Production ◽  
Endurance Capacity ◽  
Muscle Fibre Size ◽  
Fibre Size

Nature’s paradox in skeletal muscle describes the seemingly mutually exclusive relationship between muscle fibre size and oxidative capacity. In mammals, there is a constraint on the size at which mitochondria-rich, high O2-dependent oxidative fibres can attain before they become anoxic or adapt to a glycolytic phenotype, being less reliant on O2. This implies that a muscle fibre can hypertrophy at the expense of its endurance capacity. Adaptations to activity (exercise) generally obey this relationship, with optimal muscle endurance generally being linked to an enhanced proportion of small, slow oxidative fibres and muscle strength (force and/or power) being linked to an enhanced proportion of large, fast glycolytic fibres. This relationship generally constrains not only the physiological limits of performance (e.g. speed and endurance), but also the capacity to manipulate muscle attributes such as fibre size and composition, with important relevance to the livestock and aquaculture industries for producing specific muscle traits such as (flesh) quality, texture and taste. Highly glycolytic (white) muscles have different traits than do highly oxidative (red) muscles and so the ability to manipulate muscle attributes to produce flesh with specific traits has important implications for optimising meat production and quality. Understanding the biological regulation of muscle size, and phenotype and the capacity to manipulate signalling pathways to produce specific attributes, has important implications for promoting ethically sustainable and profitable commercial livestock and aquaculture practices and for developing alternative food sources, including ‘laboratory meat’ or ‘clean meat’. This review describes the exciting potential of manipulating muscle attributes relevant to animal production, through traditional nutritional and pharmacological approaches and through viral-mediated strategies that could theoretically push the limits of muscle fibre growth, adaptation and plasticity.

scholarly journals Using AAV vectors expressing the β2-adrenoceptor or associated Gα proteins to modulate skeletal muscle mass and muscle fibre size

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Adam Hagg ◽  
Timothy D. Colgan ◽  
Rachel E. Thomson ◽  
Hongwei Qian ◽  
Gordon S. Lynch ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibre ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Fibre Size ◽  
Fibre Size

Skeletal muscle fibre size adaptation to an eight-week swimming programme

1980 ◽  
Vol 44 (2) ◽  
pp. 161-165 ◽  
Author(s):  
J. -M. Lavoie ◽  
A. W. Taylor ◽  
R. R. Montpetit
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibre ◽  
Skeletal Muscle Fibre ◽  
Muscle Fibre Size ◽  
Fibre Size

scholarly journals Myostatin is a key mediator between energy metabolism and endurance capacity of skeletal muscle

2014 ◽  
Vol 307 (4) ◽  
pp. R444-R454 ◽  
Author(s):  
Etienne Mouisel ◽  
Karima Relizani ◽  
Laurence Mille-Hamard ◽  
Raphaël Denis ◽  
Christophe Hourdé ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Energy Metabolism ◽  
Exercise Capacity ◽  
Fiber Type ◽  
Muscle Metabolism ◽  
Oxidative Capacity ◽  
Muscle Size ◽  
Endurance Capacity ◽  
Adult Mice ◽  
Exercise Induced

Myostatin (Mstn) participates in the regulation of skeletal muscle size and has emerged as a regulator of muscle metabolism. Here, we hypothesized that lack of myostatin profoundly depresses oxidative phosphorylation-dependent muscle function. Toward this end, we explored Mstn −/− mice as a model for the constitutive absence of myostatin and AAV-mediated overexpression of myostatin propeptide as a model of myostatin blockade in adult wild-type mice. We show that muscles from Mstn −/− mice, although larger and stronger, fatigue extremely rapidly. Myostatin deficiency shifts muscle from aerobic toward anaerobic energy metabolism, as evidenced by decreased mitochondrial respiration, reduced expression of PPAR transcriptional regulators, increased enolase activity, and exercise-induced lactic acidosis. As a consequence, constitutively reduced myostatin signaling diminishes exercise capacity, while the hypermuscular state of Mstn−/− mice increases oxygen consumption and the energy cost of running. We wondered whether these results are the mere consequence of the congenital fiber-type switch toward a glycolytic phenotype of constitutive Mstn −/− mice. Hence, we overexpressed myostatin propeptide in adult mice, which did not affect fiber-type distribution, while nonetheless causing increased muscle fatigability, diminished exercise capacity, and decreased Pparb/d and Pgc1a expression. In conclusion, our results suggest that myostatin endows skeletal muscle with high oxidative capacity and low fatigability, thus regulating the delicate balance between muscle mass, muscle force, energy metabolism, and endurance capacity.

scholarly journals The Hippo pathway effector YAP is a critical regulator of skeletal muscle fibre size

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
K. I. Watt ◽  
B. J. Turner ◽  
A. Hagg ◽  
X. Zhang ◽  
J. R. Davey ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibre ◽  
Hippo Pathway ◽  
Skeletal Muscle Fibre ◽  
Muscle Fibre Size ◽  
Fibre Size ◽  
The Hippo Pathway

Energy utilization and metabolism in spawning migrating Early Stuart sockeye salmon (Oncorhynchus nerka): the migratory paradox

2004 ◽  
Vol 61 (3) ◽  
pp. 452-465 ◽  
Author(s):  
Anders Kiessling ◽  
Kerstin Lindahl-Kiessling ◽  
Karl-Heinz Kiessling
Keyword(s):  
Muscle Fibre ◽  
Sockeye Salmon ◽  
White Muscle ◽  
Oncorhynchus Nerka ◽  
Oxidative Capacity ◽  
Energy Utilization ◽  
Muscle Fibre Size ◽  
Fibre Size ◽  
Energy Strategies ◽  
Rostral Part

Sockeye salmon (Oncorhynchus nerka) were followed during their 1400-km-long migration from cessation of feeding outside British Columbia, Canada, up the Fraser River to spawning. Enzymatic capacity (indicative of glycolysis, β-oxidation, and respiratory chain ATP formation), muscle fibre size distribution, body and muscle conformation, and gross chemical composition in different parts of red and white muscle were monitored to determine energy strategies throughout the migration. The mobilization of extramuscular lipid depots was also monitored. The most conspicuous change in white muscle, concomitant with a large decrease in protein content, was an ordered reduction in muscle fibre size and lipid depots with distance covered, resulting in an accumulation of fibres with a cross section between 2000 and 6000 µm2 and a maintained level of 4% intramuscular fat. A peak in oxidative capacity was noted in red muscle during the strenuous passage of Fraser Canyon. In white muscle, glycolytic capacity was maintained at least until passage of the Fraser Canyon. Enzymatic capacity was higher in the caudal than rostral part of the muscle. Differences were also found between lateral and dorsal parts of the white muscle, indicating significant differences in the timing and magnitude of enzymatic capacity of red and white muscle.

scholarly journals Resistance Training and Testosterone Levels in Male Patients with Chronic Kidney Disease Undergoing Dialysis

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Stig Molsted ◽  
Jesper L. Andersen ◽  
Inge Eidemak ◽  
Adrian P. Harrison ◽  
Niels Jørgensen
Keyword(s):  
Resistance Training ◽  
Muscle Fibre ◽  
Binding Protein ◽  
Muscle Fibres ◽  
Muscle Fibre Size ◽  
Testosterone Levels ◽  
Fibre Size ◽  
Igf Binding ◽  
Male Patients ◽  
Igf Binding Protein

Background.We investigated serum testosterone and insulin-like growth factor 1 (IGF-1) levels’ associations with muscle fibre size and resistance training in male dialysis patients.Methods.Male patients were included in a 16-week control period followed by 16 weeks of resistance training thrice weekly. Blood samples were obtained to analyse testosterone, luteinizing hormone (LH), IGF-1, and IGF-binding protein 3. Muscle fibres’ size was analysed in biopsies fromm. vastus lateralis.Results.The patients’ testosterone levels were within the normal range at baseline (n=20) (19.5 (8.2–52.1) nmol/L versus 17.6 (16.1–18.0), resp.) whereas LH levels were higher (13.0 (5.5–82.8) U/L versus 4.3 (3.3–4.6),P<0.001, resp.). IGF-1 and IGF-binding protein 3 levels were higher in the patients compared with reference values (203 (59–590) ng/mL versus 151 (128–276),P=0.014, and 5045 (3370–9370) ng/mL versus 3244 (3020–3983),P<0.001, resp.). All hormone levels and muscle fibre size (n=12) remained stable throughout the study. Age-adjusted IGF-1 was associated with type 1 and 2 fibre sizes (P<0.05).Conclusion.Patients’ total testosterone values were normal due to markedly increased LH values, which suggest a compensated primary insufficiency of the testosterone producing Leydig cell. Even though testosterone values were normal, resistance training was not associated with muscle hypertrophy. This trial is registered withISRCTN72099857.

The specificity of endurance training on muscular power and muscle fibre size

Ergonomics ◽  
1980 ◽  
Vol 23 (7) ◽  
pp. 667-678 ◽  
Author(s):  
STEFAN H. CONSTABLE ◽  
RICHARD L. COLLINS ◽  
GARY S. KRAHENBUHL
Keyword(s):  
Endurance Training ◽  
Muscle Fibre ◽  
Muscular Power ◽  
Muscle Fibre Size ◽  
Fibre Size

Influence of isaxonine on the target phenomenon, muscle fibre size and neuromuscular junction in the tenotomized and denervated gastrocnemius muscle of the rat

1986 ◽  
Vol 69 (3-4) ◽  
pp. 337-340 ◽  
Author(s):  
J. De Bleecker ◽  
W. De Coster ◽  
J. De Reuck ◽  
J. P. Blancquaert
Keyword(s):  
Neuromuscular Junction ◽  
Muscle Fibre ◽  
Gastrocnemius Muscle ◽  
Muscle Fibre Size ◽  
Fibre Size

Relation between body size and muscle fibre diameter in the newborn lamb

1956 ◽  
Vol 47 (4) ◽  
pp. 449-455 ◽  
Author(s):  
D. M. Joubert
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Muscle Fibre ◽  
Fibre Diameter ◽  
Rectus Femoris ◽  
Muscle Fibres ◽  
Muscle Fibre Size ◽  
Fibre Size ◽  
Ewe Lambs ◽  
Positive Correlations

1. An investigation is reported in which the relationship was examined between body size and muscle fibre size of nineteen newborn lambs and including twelve males and seven females. Body size was measured in terms of the dead body weight and that of the dressed carcass, while muscle fibre size was estimated on the basis of the mean crossdiameter of 150 fibres per lamb.2. It was shown that the dressing (or carcass) percentage tends to increase with an increase in body weight, from 42·26% at a body weight of 2000 g. to 49·04% at 7000 g.3. Of the 2850 cross-diameters recorded, the majority (33·8%) of the fibres measured between 8·0 and 9·6 μ, while individual fibres varied in size from 1·6 to 22·4 μ.4. Highly significant, positive correlations were shown to exist between both body (r = 0·996) and carcass (r = 0·946) weight, and mean muscle fibre diameter, indicating that differences in size between the lambs may be accounted for largely by corresponding variations in the size of individual muscle fibres.5. Of the three muscles sampled m. gastrocnemius had the largest mean fibre diameter (10·38μ), followed in decreasing order by m. rectus femoris (9·72 μ) and m. longissimus dorsi (9·09 μ). These inter-muscle differences were significant at the 1% level of probability.6. Ram lambs had significantly thicker muscle fibres (10·32 μ) than ewe lambs (8·72 μ), but also weighed the heavier and produced heavier dressed carcasses. Some evidence was produced, however, in support of the theory that at comparable weights males possess thinner individual, and therefore a greater number of fibres than females.

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