The effect of maternal undernutrition on muscle fibre type in the newborn lamb

2003 ◽  
Vol 2003 ◽  
pp. 60-60
Author(s):  
A.J. Fahey ◽  
J.M. Brameld ◽  
T. Parr ◽  
P.J. Buttery
Keyword(s):  
Muscle Fibre ◽  
Meat Quality ◽  
Fibre Type ◽  
Muscle Development ◽  
Nutrient Supply ◽  
Muscle Fibre Type ◽  
Growth Potential ◽  
Muscle Fibres ◽  
General Hypothesis ◽  
Maternal Undernutrition

Muscle fibre type can influence meat quality (Maltinet al1997). Muscle fibre formation occurs during gestation and in the sheep the total number of fibres in a muscle is essentially fixed at birth. (Ashmereet al1972). Postnatal growth of muscle is entirely due to elongation and widening of the existing muscle fibres. Therefore the gestational period is important in the long-term growth potential of the animal. By investigating changes in muscle fibre type, the aim of this study was to test the general hypothesis that the poor carcass quality sometimes seen in ruminant animals may be due to poor nutrition at strategic time points during the animal’s development. As agricultural practices continue to become more extensive, variation in the nutrient supply to the animal is becoming more common. Therefore it is important to understand the effect of any changes in nutrient supply to the mother, during gestation on the subsequent muscle development of the fetus and ultimately the effects on meat quality.

scholarly journals Post-synaptic morphology of mouse neuromuscular junctions is linked to muscle fibre type

2020 ◽  
Author(s):  
Aleksandra M. Mech ◽  
Anna-Leigh Brown ◽  
Giampietro Schiavo ◽  
James N. Sleigh
Keyword(s):  
Motor Neuron ◽  
Muscle Fibre ◽  
Fibre Type ◽  
Neuromuscular Junctions ◽  
Fibre Diameter ◽  
Neuromuscular Diseases ◽  
Neuronal Morphology ◽  
Muscle Fibre Type ◽  
Muscle Membrane ◽  
Muscle Fibres

AbstractThe neuromuscular junction (NMJ) is the highly specialised peripheral synapse formed between lower motor neuron terminals and muscle fibres. Post-synaptic acetylcholine receptors (AChRs), which are found in high density in the muscle membrane, bind to acetylcholine released into the synaptic cleft of the NMJ, ultimately facilitating the conversion of motor action potentials to muscle contractions. NMJs have been studied for many years as a general model for synapse formation, development and function, and are known to be early sites of pathological changes in many neuromuscular diseases. However, information is limited on the diversity of NMJs in different muscles, whether muscle fibre type impacts NMJ morphology and growth, and the relevance of these parameters to neuropathology. Here, this crucial gap was addressed using a robust and standardised semi-automated workflow called NMJ-morph to quantify features of pre- and post-synaptic NMJ architecture in an unbiased manner. Five wholemount muscles from wild-type mice were dissected and compared at immature (post-natal day, P7) and early adult (P31-32) timepoints. Post-synaptic AChR morphology was found to be more variable between muscles than that of the motor neuron terminal and there were greater differences in the developing NMJ than at the mature synapse. Post-synaptic architecture, but not neuronal morphology or post-natal synapse growth, correlates with fibre type and is largely independent of muscle fibre diameter. Counter to previous observations, this study indicates that smaller NMJs tend to innervate muscles with higher proportions of fast twitch fibres and that NMJ growth rate is not conserved across all muscles. Furthermore, healthy pre- and post-synaptic NMJ morphological parameters were collected for five anatomically and functionally distinct mouse muscles, generating reference data that will be useful for the future assessment of neuromuscular disease models.Graphical Abstract

Form and classification of motor endings in mammalian muscle spindles

1985 ◽  
Vol 225 (1239) ◽  
pp. 195-212 ◽  
Keyword(s):  
Muscle Fibre ◽  
Fibre Type ◽  
Muscle Spindles ◽  
Muscle Fibre Type ◽  
Motor Axon ◽  
Muscle Fibres ◽  
Intrafusal Muscle ◽  
Axon Terminals ◽  
Hindlimb Muscle

The presynaptic features of 234 motor endings supplied to cat hindlimb muscle spindles have been studied in teased, silver preparations, and the postsynaptic features of a further 27 endings have been studied in serial, 1 μm thick, transverse sections. In the presynaptic study motor endings received by the three types of intrafusal muscle fibre were compared with the endings supplied to spindles by the various functional categories of motor axon. Three forms of motor ending were found that had significantly different presynaptic features. These forms correspond closely to those previously identified in the literature as p 1 (β), p 2 (dynamic γ) and trail (static γ). The results of the postsynaptic study showed that the degree of indentation of the intrafusal muscle fibres by motor axon terminals increases with greater distance from the primary ending, irrespective of muscle-fibre type. We conclude that the postsynaptic form of intrafusal motor endings is determined by distance from primary ending and muscle-fibre type. It is not determined by type of motor axon, and cannot be correlated with presynaptic form so as to produce a unified classification of intrafusal motor endings.

scholarly journals Effects of Dietary Energy Sources on Post Mortem Glycolysis, Meat Quality and Muscle Fibre Type Transformation of Finishing Pigs

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0131958 ◽  
Author(s):  
Yanjiao Li ◽  
Jiaolong Li ◽  
Lin Zhang ◽  
Changning Yu ◽  
Meng Lin ◽  
...  
Keyword(s):  
Muscle Fibre ◽  
Meat Quality ◽  
Fibre Type ◽  
Muscle Fibre Type ◽  
Energy Sources ◽  
Dietary Energy ◽  
Finishing Pigs ◽  
Post Mortem ◽  
Type Transformation

Meat quality and muscle fibre type characteristics of Southdown Rams from high and low backfat selection lines

Meat Science ◽  
1993 ◽  
Vol 33 (1) ◽  
pp. 97-109 ◽  
Author(s):  
I.T. Kadim ◽  
R.W. Purchas ◽  
A.S. Davies ◽  
A.L. Rae ◽  
R.A. Barton
Keyword(s):  
Muscle Fibre ◽  
Meat Quality ◽  
Fibre Type ◽  
Muscle Fibre Type

scholarly journals PL-016 Endurance training, muscle fibre type composition and the maximal capacity for fat oxidation

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Chris Shaw ◽  
Courtney Swinton ◽  
Maria Gabriela Morales Scholz ◽  
Tasman Erftemeyer ◽  
Andrew Aldous ◽  
...  
Keyword(s):  
Muscle Fibre ◽  
Fibre Type ◽  
Fat Oxidation ◽  
Muscle Fibre Type ◽  
Muscle Fibres ◽  
Type I ◽  
Maximal Rate ◽  
Fibre Type Composition ◽  
Type Composition ◽  
Whole Muscle

Objective A greater capacity for fat oxidation in endurance trained athletes is linked to greater utilisation of intramuscular lipid (IMCL). IMCL breakdown occurs only in type I muscle fibres yet little is known about the fibre type specific abundance of lipid regulatory proteins. We explored the impact of endurance training on the maximal rate fat oxidation, muscle fibre type and muscle fibre type specific abundance of proteins regulating IMCL metabolism. Methods Endurance trained (n=7, 28 ± 3 years, VO2max62.6 ± 1.6 ml·min-1·kg-1) and untrained (n=8, 25 ± 1 years, VO2max44.9 ± 1.9 ml·min-1·kg-1) males performed an incremental exercise test to determine maximal fat oxidation rate. Muscle fibre type composition and fibre type-specific IMCL content was assessed with immunofluorescence microscopy and protein abundance was analysed with immunoblotting on pooled single muscle fibres and whole muscle. Results Endurance trained individuals displayed a higher peak fat oxidation rate (0.49 ± 0.05 vs. 0.20 ± 0.03 g·min-1, P<0.05), which correlated with type I fibre percentage (R = 0.83, P < 0.01) and VO2max (R = 0.78, P < 0.01). Type I muscle fibres from endurance trained individuals had a greater abundance of ATGL. In whole muscle, the endurance trained group had greater abundance of PLIN2, PLIN5 and ATGL compared to the untrained group (P < 0.05). Furthermore, autophagy flux measured as LC3-II/I ratio was higher in type I muscle fibres and LC3-II/I, lysosomal markers (LAMP2) and chaperone-mediated autophagy markers (LAMP2A) were all higher in whole muscle of endurance trained individuals (P < 0.05). Conclusions These results demonstrate that the maximal rate of fat oxidation is related to the proportion of type I muscle fibres. Furthermore, IMCL storage and the abundance of key proteins regulating lipid metabolism is fibre type specific and greater in endurance trained individuals. Muscle fibre type composition should be considered when investigating the regulation of IMCL utilisation and markers of autophagy.

scholarly journals Malleability of the motor system: a comparative approach

1985 ◽  
Vol 115 (1) ◽  
pp. 375-391 ◽  
Author(s):  
G. Goldspink
Keyword(s):  
Muscle Fibre ◽  
Power Output ◽  
Fibre Type ◽  
Motor Units ◽  
Intrinsic Rate ◽  
Muscle Fibre Type ◽  
Comparative Approach ◽  
Muscle Fibres ◽  
Cross Sectional ◽  
Type Transformation

The various ways in which the power output of muscles can be changed are described. As a result of exercise and growth, force production is increased by an increase in the cross-sectional area of the fibres. This is associated with changes in the rate of synthesis and degradation of muscle proteins which lead to build up of the myofibrils. These then split longitudinally when they reach a critical size. This process is repeated so that the number of myofibrils increases very considerably. Also, during growth, the displacement is increased by increasing the length of the muscles. To do this more sarcomeres are produced in series along the length of the fibres. This is induced by stretch which also encourages fibre growth in girth as well as in length. Yet another way of changing the power output of a muscle is to change the types of muscle fibres (motor units) within the muscle. Fibre type transformation has been fibres (motor units) within the muscle. Fibre type transformation has been shown to occur with cross innervation and stimulation but it does not usually occur with exercise training. It has been possible, however, to change the fibre type proportions in young animals. Also, by combining stretch with stimulation, it has been possible for instance to make the fast glycolytic fibres add on fast oxidative type sarcomeres or even slow oxidation type sarcomeres. Interestingly, fibre transformation also occurs in some species of fish during acclimation to low temperatures in that the specific myofibrillar ATPase activity is increased. This means that the reduction in power output due to decreased temperature is to some extent compensated for by an increase in the intrinsic rate of shortening. EMG studies of fish swimming at different temperatures have shown that the acclimated fish can swim faster and can derive more aerobic sustainable power as a result of this change.

Distributions of nerve and muscle fibre types in locust jumping muscle

1978 ◽  
Vol 73 (1) ◽  
pp. 205-233 ◽  
Author(s):  
G. Hoyle
Keyword(s):  
Muscle Fibre ◽  
Fibre Type ◽  
Muscle Fibre Type ◽  
Interference Microscopy ◽  
Muscle Fibre Types ◽  
Muscle Fibres ◽  
Relaxation Rates ◽  
Mechanical Responses ◽  
Slow Type ◽  
Slow Muscle Fibres

Muscle fibres of the locust extensor tibiae (jumping muscle) were examined by interference microscopy and by electron microscopy. The electrical responses of single fibres and the mechanical responses of bundles or selected regions to the nerve fibres were examined. Four axons innervate the muscle: fast (FETi), slow (SETi), common inhibitor (CI) and dorsal unpaired median (DUMETi). Their distributions were examined by combined electrophysiological tracing and EM sectioning. The mean diameter of muscle fibres in different regions varies from 40 to 140 micrometer and is related to the local leg thickness rather than muscle fibre type. The fine structure of a fibre is related to its innervation. Fibres innervated by FETi but not SETi are of fast type ultrastructurally. Fibres innervated by SETi but not by FETi are of slow type ultrastructurally. Fibres innervated by both axons are generally intermediate between the extremes though more nearly of fast type than slow. Distal slow muscle fibres have much slower relaxation rates than do proximal ones. The most proximal bundles are of mixed muscle fibre type. There is an abrupt transition from a mixed population to homogeneous fast type, in the muscle units immediately distal to the most proximal bundles. This transition is associated with the presence of DUMETi terminals on some of the fibres distal to the transition point. There are no SETi endings on these same fibres. Fibres innervated by both SETi and FETi are scattered throughout the leg, but are commonest in the dorsal bundles. The percentage of these increases progressively passing distally. The most distal muscle fibres are innervated by SETi but not by FETi. It is concluded that different regions of the muscle will play different roles functionally since they are differentially sensitive to the pattern of SETi discharge.

Effects of p.C430S polymorphism in the PPARGC1A gene on muscle fibre type composition and meat quality in Yorkshire pigs

2010 ◽  
Vol 41 (6) ◽  
pp. 642-645 ◽  
Author(s):  
J. M. Kim ◽  
K. T. Lee ◽  
K. S. Lim ◽  
E. W. Park ◽  
Y. S. Lee ◽  
...  
Keyword(s):  
Muscle Fibre ◽  
Meat Quality ◽  
Fibre Type ◽  
Muscle Fibre Type ◽  
Fibre Type Composition ◽  
Type Composition ◽  
Yorkshire Pigs
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