Fiber-type proportions and diameters in the longissimus muscle of beef heifers undergoing catch-up (compensatory) growth

1991 ◽  
Vol 71 (4) ◽  
pp. 1031-1035 ◽  
Author(s):  
E. Yambayamba ◽  
M. A. Price
Keyword(s):  
Muscle Fiber ◽  
Compensatory Growth ◽  
Fiber Type ◽  
Feed Restriction ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Longissimus Muscle ◽  
Slaughter Weight ◽  
Ad Libitum ◽  
Ad Libitum Feeding

Fifty-three Hereford crossbred heifers (211 ± 28(mean ± SD) kg, 197 ± 13 d of age at day 1) were used to study the effects of mild, chronic feed restriction followed by refeeding on some longissimus muscle fiber characteristics. Five animals were slaughtered on day 1 for analysis of initial muscle fiber characteristics. The remaining 48 animals were randomly penned in groups of 6 and assigned to treatments as follows: three pens to ad libitum feeding; three pens to 2 mo of feed restriction followed by refeeding, and two pens to 4 mo of feed restriction followed by refeeding. Animals in one ad libitum and one restricted pen were slaughtered after 2 mo and those in one pen from each treatment after 4 mo, and the remainder at the final slaughter weight of about 410 kg. Two months of feed restriction had no effect on the proportions of longissimus muscle fiber-types, "red" (βR), "white" (αW), and "intermediate" (αR), but fiber diameters were smaller (P < 0.05) in the restricted than in the ad-libitum-fed animals. Four months of feed restriction was associated with a relatively higher (P < 0.05) proportion of βR fibers and lower (P < 0.05) proportion of αW fibers than ad libitum feeding. Muscle fiber diameters were larger (P < 0.05) in the ad-libitum-fed than in the restricted heifers. No significant feeding treatment differences were found in fiber-type proportions or fiber diameters at the final slaughter weight. Key words: Heifers, feed restriction, realimentation, muscle fibers, fiber-type, compensatory growth

Growth performance and carcass composition in beef heifers undergoing catch-up (compensatory) growth

1991 ◽  
Vol 71 (4) ◽  
pp. 1021-1029 ◽  
Author(s):  
E. Yambayamba ◽  
M. A. Price
Keyword(s):  
Compensatory Growth ◽  
Live Weight ◽  
Carcass Composition ◽  
Feed Restriction ◽  
Beef Heifers ◽  
Slaughter Weight ◽  
Permanent Effect ◽  
Catch Up ◽  
Ad Libitum ◽  
Ad Libitum Feeding

Fifty-three Hereford crossbred heifers (211 ± 28 (mean ± SD) kg; 197 ± 13 d of age at day 1) were used to study catch-up growth and its effects on carcass composition. Five heifers were slaughtered on day 1; the remaining 48 were randomly penned in groups of six and assigned to treatments as follows: three pens to ad libitum feeding (target gain > 1.0 kg d−1); three pens to 2 mo of feed restriction (target gain 0.5 kg d−1); followed by realimentation; and two pens to 4 mo of feed restriction (target gain: 2 mo at 0.5 kg d−1 and 2 mo at 0.0 kg d−1) followed by realimentation. Animals from one pen were slaughtered from each treatment after 2 mo, after 4 mo, and at a final slaughter weight of about 410 kg. During the final period (4 mo to slaughter), growth rate was greater (P < 0.05) in the 4-mo than in the 2-mo restricted–realimented animals or the ad-libitum-fed animals (1.91 vs. 1.18 vs. 1.02 kg d−1), respectively. Feed restriction for 2 mo had no significant effect on the composition of the three-rib cut, but 4 mo of feed restriction was associated with significantly lower and higher (P < 0.05) proportions of fat and bone, respectively, in the three-rib cut. Muscle proportion was not affected by treatment. At the final slaughter weight, no significant differences were found among treatments in the tissue proportions of the three-rib cut. It is concluded that 2 or 4 mo of feed restriction, starting at 6 mo of age, has no permanent effect on a heifer's live weight or body composition. Key words: Heifers, feed restriction, realimentation, compensatory growth, carcass composition

Blood flow to different skeletal muscle fiber types during contraction

1983 ◽  
Vol 245 (2) ◽  
pp. H265-H275 ◽  
Author(s):  
B. G. Mackie ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Oxidative Capacity ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Blood Flows ◽  
Fast Twitch

Blood flow to fast-twitch red (FTR), fast-twitch white (FTW), and slow-twitch red (STR) muscle fiber sections of the gastrocnemius-plantaris-soleus muscle group was determined using 15 +/- 3-microns microspheres during in situ stimulation in pentobarbital-anesthetized rats. Steady-state blood flows were assessed during the 10th min of contraction using twitch (0.1, 0.5, 1, 3, and 5 Hz) and tetanic (7.5, 15, 30, 60, and 120/min) stimulation conditions. In addition, an earlier blood flow determination was begun at 3 min (twitch series) or at 30 s (tetanic series) of stimulation. Blood flow was highest in the FTR (220-240 ml X min-1 X 100 g-1), intermediate in the STR (140), and lowest in the FTW (70-80) section during tetanic contraction conditions estimated to coincide with the peak aerobic function of each fiber type. These blood flows are fairly proportional to the differences in oxidative capacity among fiber types. Further, their absolute values are similar to those predicted from the relationship between blood flow and oxidative capacity found by others for dog and cat muscles. During low-frequency contraction conditions, initial blood flow to the FTR and STR sections were excessively high and not dependent on contraction frequency. However, blood flows subsequently decreased to values in keeping with the relative energy demands. In contrast, FTW muscle did not exhibit this time-dependent relative hyperemia. Thus, besides the obvious quantitative differences between skeletal muscle fiber types, there are qualitative differences in blood flow response during contractions. Our findings establish that, based on fiber type composition, a heterogeneity in blood flow distribution can occur within a whole muscle during contraction.

Human Skeletal Muscle Fiber Types: Delineation, Development, and Distribution

1997 ◽  
Vol 22 (4) ◽  
pp. 307-327 ◽  
Author(s):  
Robert S. Staron
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Key Words Aging ◽  
Fiber Number ◽  
Human Limb

This brief review attempts to summarize a number of studies on the delineation, development, and distribution of human skeletal muscle fiber types. A total of seven fiber types can be identified in human limb and trunk musculature based on the pH stability/ability of myofibrillar adenosine triphosphatase (mATPase). For most human muscles, mATPase-based fiber types correlate with the myosin heavy chain (MHC) content. Thus, each histochemically identified fiber has a specific MHC profile. Although this categorization is useful, it must be realized that muscle fibers are highly adaptable and that innumerable fiber type transients exist. Also, some muscles contain specific MHC isoforms and/or combinations that do not permit routine mATPase-based fiber typing. Although the major populations of fast and slow are, for the most part, established shortly after birth, subtle alterations take place throughout life. These changes appear to relate to alterations in activity and/or hormonal levels, and perhaps later in life, total fiber number. Because large variations in fiber type distribution can be found within a muscle and between individuals, interpretation of data gathered from human muscle is often difficult. Key words: aging, myosin heavy chains, myogenesis, myofibrillar adenosine triphosphate

Carnitine metabolism in human muscle fiber types during submaximal dynamic exercise

1996 ◽  
Vol 80 (3) ◽  
pp. 1061-1064 ◽  
Author(s):  
D. Constantin-Teodosiu ◽  
S. Howell ◽  
P. L. Greenhaff
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Group Formation ◽  
Free Carnitine ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Carnitine Metabolism ◽  
Type I Fibers

The effect of prolonged exhaustive exercise on free carnitine and acetylcarnitine concentrations in mixed-fiber skeletal muscle and in type I and II muscle fibers was investigated in humans. Needle biopsy samples were obtained from the vastus lateralis of six subjects immediately after exhaustive one-legged cycling at approximately 75% of maximal O2 uptake from both the exercised and nonexercised (control) legs. In the resting (control) leg, there was no difference in the free carnitine concentration between type I and II fibers (20.36 +/- 1.25 and 20.51 +/- 1.16 mmol/kg dry muscle, respectively) despite the greater potential for fat oxidation in type I fibers. However, the acetylcarnitine concentration was slightly greater in type I fibers (P < 0.01). During exercise, acetylcarnitine accumulation occurred in both muscle fiber types, but accumulation was greatest in type I fibers (P < 0.005). Correspondingly, the concentration of free carnitine was significantly lower in type I fibers at the end of exercise (P < 0.001). The sum of free carnitine and acetylcarnitine concentrations in type I and II fibers at rest was similar and was unchanged by exercise. In conclusion, the findings of the present study support the suggestion that carnitine buffers excess acetyl group formation during exercise and that this occurs in both type I and II fibers. However, the greater accumulation of acetylcarnitine in type I fibers during prolonged exercise probably reflects the greater mitochondrial content of this fiber type.

Effect of sex and exogenous porcine somatotropin on longissimus muscle fiber characteristics of growing pigs.

1990 ◽  
Vol 68 (4) ◽  
pp. 1176-1181 ◽  
Author(s):  
M. B. Solomon ◽  
R. G. Campbell ◽  
N. C. Steele
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Live Weight ◽  
Growing Pigs ◽  
Fiber Types ◽  
Longissimus Muscle ◽  
Meat Tenderness ◽  
Giant Fiber ◽  
Porcine Somatotropin ◽  
Dose Levels

Abstract Thirty-seven pigs with an initial live weight of 60 kg were used to investigate the effects of daily exogenous porcine somatotropin (pST) administration at two dose levels (0 and 100 µg·kg−1·d−1) for a 31-d period on muscle fiber characteristics and meat tenderness of boars, gilts and barrows. Excipient boars and gilts had more αW and fewer αR fibers than did those receiving pST. The percentage of muscle fiber type for barrows was not affected by pST treatment. The administration of pST resulted in an increase in muscle fiber size for all three fiber types in all three sexes, but these changes were of greater magnitude in barrows (31.8%) and gilts (27.8%) than in boars (9.3%). Somatotropin negated the intrinsic sex effect differences in fiber area of the pigs. There was no difference in tenderness among excipient boars, barrows and gilts; however, with the inclusion of pST, shear force decreased in boars and gilts and increased in barrows. A high proportion of the pST-treated pigs contained giant fibers in the longissimus muscle. Furthermore, a small proportion of the pST-treated pigs exhibited pale, soft, exudative muscle. Whether the giant fiber anomalies occurred through increased muscle activity or from fibers undergoing degenerative changes was not determined.

Metabolic variation among alpha-motoneurons innervating different muscle-fiber types. I. Oxidative enzyme activity

1984 ◽  
Vol 51 (3) ◽  
pp. 529-537 ◽  
Author(s):  
D. W. Sickles ◽  
T. G. Oblak
Keyword(s):  
Optical Density ◽  
Muscle Fiber ◽  
Enzyme Activities ◽  
Tibialis Anterior ◽  
Fiber Type ◽  
Ventral Horn ◽  
Oxidative Enzyme ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Fast Twitch

We have examined the oxidative metabolism of rat alpha-motoneurons innervating muscles composed predominantly of one muscle-fiber type. Intramuscular injections of horseradish peroxidase (HRP) into the tensor fasciae latae (TFL) (approximately 94% fast-twitch glycolytic fibers, FG), tibialis anterior (TA) (approximately 66% fast-twitch oxidative-glycolytic, FOG; 32% FG), and soleus (SOL) (approximately 84% slow-twitch oxidative, SO) muscles permitted identification of motoneurons innervating these muscles. gamma-Motoneurons (less than 25-micron average soma diameter) were eliminated from the sampling. The alpha-motoneurons innervating the TFL were considered as FG, those innervating the tibialis anterior as FOG, and those of the soleus as SO. Alternate 5-micron serial cryostat sections were processed for HRP and nicotinamide adenine dinucleotide-diapharase (NADH-D) (oxidative enzyme) activities. Controls were included to assure reliability of reaction product quantitation. Motoneuron pools of each muscle were characterized by their shape and location within the ventral horn. Cells identified on HRP sections as innervating each of the muscles were located on sections processed for NADH-D activity. The optical density of motoneurons in sections processed for NADH-D activity was measured with a Zeiss Zonax MPM 03 microdensitometer. The mean relative NADH-D activities (optical density) of alpha-motoneurons innervating the TFL (FG), TA (FOG), and SOL(SO) muscles were 0.261, 0.305, and 0.447, respectively. Although some overlap in distribution of enzyme activities was observed, statistical analysis indicated significant differences between the NADH-D activities of each type of alpha-motoneuron. This is the first report of any metabolic difference in alpha-motoneurons belonging to different motor-unit types.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle fiber types and size in trained and untrained muscles of elite athletes

1985 ◽  
Vol 59 (6) ◽  
pp. 1716-1720 ◽  
Author(s):  
P. A. Tesch ◽  
J. Karlsson
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Deltoid Muscle ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Relative Distribution ◽  
Long Distance ◽  
Tissue Samples ◽  
Greco Roman

Tissue samples were obtained from vastus lateralis and deltoid muscles of physical education students (n = 12), Greco-Roman wrestlers (n = 8), flat-water kayakers (n = 9), middle- and long-distance runners (n = 9), and olympic weight and power lifters (n = 7). Histochemical stainings for myofibrillar adenosinetriphosphatase and NADH-tetrazolium reductase were applied to assess the relative distribution of fast-twitch and slow-twitch (ST) muscle fiber types and fiber size. The %ST was not different in the vastus (mean SD 48 +/- 14) and deltoid (56 +/- 13) muscles. The %ST was higher (P less than 0.001), however, in the deltoid compared with vastus muscle of kayakers. This pattern was reversed in runners (P less than 0.001). The %ST of the vastus was higher (P less than 0.001) in runners than in any of the other groups. The %ST of the deltoid muscle was higher in kayakers than in students, runners (P less than 0.001), and lifters (P less than 0.05). The mean fiber area and the area of ST fibers were greater (P less than 0.01) in the vastus than the deltoid muscle. Our data show a difference in fiber type distribution between the trained and nontrained muscles of endurance athletes. This pattern may reflect the adaptive response to long-term endurance training.

Comparisons of longissimus muscle metabolic enzymes and muscle fiber types in Korean and western pig breeds

Meat Science ◽  
2008 ◽  
Vol 78 (4) ◽  
pp. 455-460 ◽  
Author(s):  
Nam-Kuk Kim ◽  
Jong-Hyun Lim ◽  
Min-Jin Song ◽  
Oun-Hyun Kim ◽  
Beom-Young Park ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Metabolic Enzymes ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Longissimus Muscle ◽  
Pig Breeds

Inducible isoform of HSP70 is constitutively expressed in a muscle fiber type specific pattern

1991 ◽  
Vol 261 (5) ◽  
pp. C774-C779 ◽  
Author(s):  
M. Locke ◽  
E. G. Noble ◽  
B. G. Atkinson
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Constitutive Expression ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Nylon Membrane ◽  
White Gastrocnemius

The most prominent group of stress or heat-shock proteins (HSPs) has an Mr of approximately 70,000 and is collectively referred to as the HSP70 family. The extent of stress inducibility and subcellular location of the various HSP70 isoforms differ, but all appear to be involved with ATP-dependent stabilization or solubilization of proteins. One isoform, termed the inducible isoform of HSP70 (HSP72i), is normally absent in unstressed cells. In a previous study, we detected a protein corresponding in Mr and pI to HSP72i in unstressed rat muscle. Therefore, it was of interest to determine if this expression in unstressed muscle cells is general or confined to specific muscle fiber types. To answer this question we have employed various rat hindlimb muscles that differ in fiber type proportion from predominantly type I (soleus) to predominantly type IIB (white gastrocnemius). Proteins from muscle homogenates were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted to a nylon membrane, probed with a monoclonal antibody for HSP72i, and visualized using an alkaline phosphatase-conjugated secondary antibody. Immunoblot analyses demonstrate the constitutive expression of HSP72i in rat muscles comprised primarily of type I muscle fibers (soleus), but not in muscles comprised primarily of type IIB fibers (white gastrocnemius). In muscles of mixed fiber type, HSP72i content is roughly proportional to the percentage of type I fibers. These results substantiate that unstressed rat muscles express the inducible HSP72 isoform and demonstrate that its constitutive expression is proportional to the type I muscle fiber composition.

Muscle Fiber Types, Characteristics and Meat Quality

2013 ◽  
Vol 634-638 ◽  
pp. 1263-1267
Author(s):  
Lin Su ◽  
Hui Li ◽  
Xue Xin ◽  
Yan Duan ◽  
Xiao Qing Hua ◽  
...  
Keyword(s):  
Meat Quality ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Influence Factors ◽  
Muscle Fiber Type ◽  
Basic Unit ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Type Conversion ◽  
Fiber Type Distribution

Muscle fiber is the basic unit of muscle tissue, this paper summarized the types of muscle fiber of animals, the influence factors of muscle fiber type distribution and the muscle fiber type conversion in the process of growth constantly. Discuss the important effect of muscle fiber type on meat quality.

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