scholarly journals Effects of anabolic implants and ractopamine-HCl on muscle fiber morphometrics, collagen solubility, and tenderness of beef longissimus lumborum steaks

2017 ◽  
Vol 95 (3) ◽  
pp. 1219
Author(s):  
S. M. Ebarb ◽  
K. J. Phelps ◽  
J. S. Drouillard ◽  
K. R. Maddock-Carlin ◽  
M. A. Vaughn ◽  
...  
2017 ◽  
Vol 95 (3) ◽  
pp. 1219-1231 ◽  
Author(s):  
S. M. Ebarb ◽  
K. J. Phelps ◽  
J. S. Drouillard ◽  
K. R. Maddock-Carlin ◽  
M. A. Vaughn ◽  
...  

Author(s):  
MaryAnn J Matney ◽  
Morgan E Gravely ◽  
Travis G O’Quinn ◽  
James S Drouillard ◽  
Kelsey J Phelps-Ronningen ◽  
...  

Abstract The objective of this study was to determine effects of extended aging and intramuscular location on Warner-Bratzler shear force (WBSF), muscle fiber cross-sectional area (CSA), and protein degradation of semitendinosus (ST) and longissimus lumborum (LL) steaks. Left ST and LL were removed from 40 carcasses at 6 d postmortem. The ST was fabricated into 5 locations (LOC), with LOC 1 being most proximal and LOC 5 being most distal. The posterior LL was fabricated into 3 LOC, with LOC 1 being most anterior. Vacuum sealed ST steaks were aged 7, 14, 28, 56, or 112 d postmortem, while LL steaks were aged 7, 28, or 112 d postmortem at 2 ± 1°C. A steak from each LOC was assigned to WBSF or laboratory analyses. There were no Day of Aging (DOA) × LOC interactions for all dependent variables (P > 0.06). There were DOA effects for ST and LL WBSF values and degraded 38-kDa desmin (DES; P < 0.01). Day-7 ST-steak WBSF value was greater than all other days (P < 0.01) and d-14 steaks had greater WBSF value than remaining days (P < 0.05). Day-28 ST-steak WBSF values were greater than d-56 and -112 (P < 0.01), which did not differ (P = 0.53). In the LL, d-7 steaks had greater WBSF values than the other two timepoints (P < 0.01) and d-28 steaks had greater (P < 0.01) WBSF values than d-112 steaks. Degraded ST 38-kDa DES content was less on d 7 and 14 compared to all other days (P < 0.03), but did not differ (P = 0.79) from each other. Days 28 and 56 38-kDa DES content was less than d 112 (P < 0.01), but did not differ (P = 0.34) from each other. Degraded LL 38-kDa DES content was less on d 7 than d 28 and 112 (P < 0.02), which did not differ (P = 0.67). There were LOC effects for only ST WBSF and muscle fiber CSA (P < 0.05). Semitendinosus steak LOC 1 and 2 had greater WBSF values than all other locations (P < 0.01), but did not differ (P = 0.32) from each other. Semitendinosus steak LOC 3 and 5 had greater WBSF values than LOC 4 (P < 0.01), but did not differ (P = 0.85) from each other. The CSA of all ST fiber types were largest in LOC 1 compared to all other fiber types (P < 0.01). The CSA of all LOC 2 and 3 fiber types was greater than LOC 4 and 5 (P < 0.01), but were not different from each other (P > 0.81), and LOC 4 had greater CSA than LOC 5 (P < 0.01). Steak aging WBSF value improvements seemed proteolysis catalyzed, while the ST intramuscular tenderness gradient was more likely due to muscle fiber CSA.


2016 ◽  
Vol 94 (2) ◽  
pp. 869-881 ◽  
Author(s):  
S. M. Ebarb ◽  
J. S. Drouillard ◽  
K. R. Maddock-Carlin ◽  
K. J. Phelps ◽  
M. A. Vaughn ◽  
...  

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 309-309
Author(s):  
Nikole E Ineck ◽  
Kerry Rood ◽  
Jerrad F Legako ◽  
Shelby Quarnberg ◽  
Rachael Christensen

Abstract Cows nutritionally restricted during mid-gestation produce calves with differential fat and muscle deposition when compared to calves from non-restricted cows. However, little is currently known about effects these changes have on post-natal skeletal growth. We investigated whether calves from cows restricted in the second trimester had different expression of microRNA (miR), messengerRNA, and muscle fiber type when compared to calves from non-restricted dams. Cows were bred by the same sire, stratified by body weight (P = 0.80) and allocated to one of two treatments: maintenance (n = 16) or restricted (n = 18). Restricted cows received lower forage biomass (1662 kg/ha, dry matter (DM)) compared to maintenance (2309 kg/ha, DM). Restricted cows had mean BCS 1.55 lower (P = 0.001) than maintenance cows and weight difference of 188 kg (P = 0.024). After the second trimester, all cows and calves were treated similarly. Skeletal muscle biopsies were collected from calves at weaning, beginning of the feedlot, and harvest. Offspring from restricted cows expressed more (P < 0.05) miR-133a, -133b, -181d, -214, -424 and -486 in the biceps femoris (BF) at the beginning of the feedlot when compared to maintenance offspring. At harvest, offspring from restricted cows expressed more (P < 0.05) miR-133a and less (P < 0.01) miR-486 in the longissimus lumborum (LD) than offspring from maintenance cows. There was no change (P ≥ 0.27) in expression of Pax3, Pax7, Cdc25A, MamL1, Ezh2, and IGF-1R between offspring from the two treatment groups in the BF at the beginning of the feedlot or the LD at harvest. Expression was not different (P ≥ 0.14) in myosin heavy chain isoforms MHC-1, -2a, and -2x between offspring from maintenance and restricted in the BF at the beginning of the feedlot or the LD at harvest. These data provide novel insight into the molecular mechanism through which nutrient restriction in the second trimester alters fat and muscle deposition in the offspring.


Author(s):  
Joachim R. Sommer ◽  
Teresa High ◽  
Betty Scherer ◽  
Isaiah Taylor ◽  
Rashid Nassar

We have developed a model that allows the quick-freezing at known time intervals following electrical field stimulation of a single, intact frog skeletal muscle fiber isolated by sharp dissection. The preparation is used for studying high resolution morphology by freeze-substitution and freeze-fracture and for electron probe x-ray microanlysis of sudden calcium displacement from intracellular stores in freeze-dried cryosections, all in the same fiber. We now show the feasibility and instrumentation of new methodology for stimulating a single, intact skeletal muscle fiber at a point resulting in the propagation of an action potential, followed by quick-freezing with sub-millisecond temporal resolution after electrical stimulation, followed by multiple sampling of the frozen muscle fiber for freeze-substitution, freeze-fracture (not shown) and cryosectionmg. This model, at once serving as its own control and obviating consideration of variances between different fibers, frogs etc., is useful to investigate structural and topochemical alterations occurring in the wake of an action potential.


1971 ◽  
Vol 32 (1) ◽  
pp. 57-61 ◽  
Author(s):  
H. B. Hendricks ◽  
D. T. Lafferty ◽  
E. D. Aberle ◽  
M. D. Judge ◽  
J. C. Forrest

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