Effect of ractopamine-hydrochloride and trenbolone acetate on longissimus muscle fiber area, diameter, and satellite cell numbers in cull beef cows1

2007 ◽  
Vol 85 (8) ◽  
pp. 1893-1901 ◽  
Author(s):  
J. M. Gonzalez ◽  
J. N. Carter ◽  
D. D. Johnson ◽  
S. E. Ouellette ◽  
S. E. Johnson
Keyword(s):  
Satellite Cell ◽  
Muscle Fiber ◽  
Longissimus Muscle ◽  
Trenbolone Acetate ◽  
Cell Numbers ◽  
Fiber Area ◽  
Ractopamine Hydrochloride

Mechanical load-dependent regulation of satellite cell and fiber size in rat soleus muscle

2006 ◽  
Vol 290 (4) ◽  
pp. C981-C989 ◽  
Author(s):  
X. D. Wang ◽  
F. Kawano ◽  
Y. Matsuoka ◽  
K. Fukunaga ◽  
M. Terada ◽  
...  
Keyword(s):  
Satellite Cell ◽  
Muscle Fiber ◽  
Satellite Cells ◽  
Central Region ◽  
Sarcomere Length ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fiber Properties ◽  
Rat Soleus Muscle ◽  
The Mean

The effects of mechanical unloading and reloading on the properties of rat soleus muscle fibers were investigated in male Wistar Hannover rats. Satellite cells in the fibers of control rats were distributed evenly throughout the fiber length. After 16 days of hindlimb unloading, the number of satellite cells in the central, but not the proximal or distal, region of the fiber was decreased. The number of satellite cells in the central region gradually increased during the 16-day period of reloading. The mean sarcomere length in the central region of the fibers was passively shortened during unloading due to the plantarflexed position at the ankle joint: sarcomere length was maintained at <2.1 μm, which is a critical length for tension development. Myonuclear number and domain size, fiber cross-sectional area, and the total number of mitotically active and quiescent satellite cells of whole muscle fibers were lower than control fibers after 16 days of unloading. These values then returned to control values after 16 days of reloading. These results suggest that satellite cells play an important role in the regulation of muscle fiber properties. The data also indicate that the satellite cell-related regulation of muscle fiber properties is dependent on the level of mechanical loading, which, in turn, is influenced by the mean sarcomere length. However, it is still unclear why the region-specific responses, which were obvious in satellite cells, were not induced in myonuclear number and fiber cross-sectional area.

scholarly journals Ractopamine Hydrochloride and Estradiol + Trenbolone Acetate Implants Alter Myogenic mRNA, <i>β</i>-Adrenergic Receptors, and Blood Metabolites

2020 ◽  
Vol 10 (03) ◽  
pp. 447-467
Author(s):  
T. L. Harris ◽  
Z. K. Smith ◽  
F. R. B. Ribeiro ◽  
M. A. Jennings ◽  
G. J. Vogel ◽  
...  
Keyword(s):  
Adrenergic Receptors ◽  
Blood Metabolites ◽  
Trenbolone Acetate ◽  
Ractopamine Hydrochloride

scholarly journals Effects of steroidal implants on feedlot performance, carcass characteristics, and serum and meat estradiol-17β concentrations of Holstein steers

2019 ◽  
Vol 4 (1) ◽  
pp. 206-213 ◽  
Author(s):  
Pedro Henrique Vilela Carvalho ◽  
George A Perry ◽  
Tara L Felix
Keyword(s):  
Feed Efficiency ◽  
Animal Health ◽  
Average Daily Gain ◽  
Carcass Characteristics ◽  
Feed Ratio ◽  
Longissimus Muscle ◽  
Feedlot Performance ◽  
Trenbolone Acetate ◽  
Daily Gain ◽  
Estradiol 17Β

Abstract The objectives of the study were to determine the effect of steroidal implants on growth performance, carcass characteristics, and estradiol-17β (E2) concentrations in the blood and longissimus muscle of Holstein steers fed a grain-based diet. Seventy Holstein steers (average initial BW = 275 ± 6.4 kg, 10 to 12 mo of age) were assigned to treatments: (i) implanted with 80 mg of trenbolone acetate (TBA) and 16 mg of E2 (Component TE-IS with Tylan; Elanco Animal Health, Greenfield, IN) at the start of the trial (day 0), and reimplanted with 120 mg of TBA and 24 mg of E2 (Component TE-S with Tylan; Elanco Animal Health) on day 84 of the experiment; or (ii) no implant. Implanted Holstein steers were heavier (P ≤ 0.01) than nonimplanted Holstein steers in the middle (day 84) and at the end of the experiment (day 186). Implanting Holstein steers increased (P &lt; 0.01) average daily gain (ADG) and dry matter intake (DMI) without affecting gain-to-feed ratio compared with nonimplanted animals. Carcasses from implanted Holstein steers had greater (P &lt; 0.01) hot carcass weight (HCW) and longissimus muscle (LM) area than carcasses from nonimplanted steers. Implanting did not affect (P ≥ 0.21) other carcass characteristics. There was an increase (P = 0.03) of 1.3 pg of E2/g of muscle in implanted Holstein steers compared with that from nonimplanted Holstein steers. There was an implant × day interaction (P &lt; 0.01) in serum E2 concentrations. Serum E2 concentrations were not altered in nonimplanted Holstein steers, whereas E2 concentration increased (P &lt; 0.01) after steers were implanted, regardless of implant characteristics. Serum E2 peaked at 28 days after the first implant and then rapidly declined after day 56. In summary, steroidal implants administered on days 0 and 84 increased DMI, ADG, HCW, and LM area in Holstein steers compared with nonimplanted steers due to increased serum E2 concentrations. However, these changes did not improve feed efficiency or other carcass characteristics.

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