Lamb myofibre characteristics are influenced by sire estimated breeding values and pastoral nutritional system

2006 ◽  
Vol 57 (6) ◽  
pp. 627 ◽  
Author(s):  
P. L. Greenwood ◽  
G. E. Gardner ◽  
R. S. Hegarty

The objective of this study was to establish the extent to which lamb myofibre characteristics at ~8 months of age were influenced by sire (n = 9) estimated breeding values (EBVs) and pasture-based nutritional systems (low and high quality and availability, LOW and HIGH) from birth to slaughter (n = 56). Immunostaining of myosin heavy chain isoforms in longissimus muscle fibres revealed that as the post-weaning eye muscle depth EBV (PEMD) increased, the percentage of type 2B/X myofibres increased and the percentage of type 2A myofibres decreased. The percentage of type 2B/X myofibres also increased with increasing PEMD in the semimembranosus muscle, but not in the semitendinosus muscle. Post-weaning fat depth (PFAT) EBV was negatively related with the percentage of type 2B/X myofibres in longissimus and semitendinosus muscles and with the relative area of more glycolytic to more oxidative fibre types, although there was an interaction with nutritional system in the semitendinosus muscle, with this ratio increasing with the PFAT EBV among the LOW nutrition lambs. Overall, post-weaning weight (PWWT) EBV had less effect on myofibre characteristics than PEMD and PFAT EBVs. Average cross-sectional area of myofibres was more affected by the LOW than HIGH nutritional system in longissimus muscle (–25%) compared with semitendinosus (–21%) and semimembranosus (–15%) muscles. LOW nutrition resulted in a significantly smaller cross-sectional area of all myofibre types in longissimus muscle and of types 2A, 2AB/X, and 2B/X in semimembranosus and semitendinosus muscles. Overall, the relative area of glycolytic myofibres increased and/or more oxidative myofibre types decreased in LOW compared with HIGH nutritional system lambs in longissimus and semimembranosus, but not in semitendinosus muscle. The results demonstrate significant influences of sire EBVs on myofibre characteristics of lambs, the extent of which depends upon muscle type and nutritional regimen. More specifically, they suggest continued selection for increased muscling and reduced fatness in lambs are associated with shifts in the proportions of myofibre types, with potential for adverse effects on eating quality. They also show that the direction and magnitude of the effects of chronic, moderate postnatal nutritional restriction at pasture on myofibre characteristics vary between muscles with different contractile, metabolic, and/or functional characteristics.


1963 ◽  
Vol 3 (10) ◽  
pp. 249
Author(s):  
RM Seebeck

Variations in the cross-sectional area of eye muscle of carcasses cut between the tenth and eleventh ribs were investigated, using 105 Hereford and 51 Angus steers aged 20 months. These cattle consisted of three groups, born in successive years. At constant carcass weight, statistically significant differences in eye muscle area were found between breeds and between years. Breed and year differences were also found in eye muscle area with width and depth of eye muscle constant, so that there are limitations to the estimation of eye muscle area from width and depth measurements. A nomograph is given for estimating eye muscle area from width and depth for Hereford and Angus cattle, when all animals are reared in the same year and environment. The use of eye muscle area as an indicator of weight of carcass muscle is discussed.



1960 ◽  
Vol 19 (3) ◽  
pp. 786-789 ◽  
Author(s):  
J. F. Price ◽  
A. M. Pearson ◽  
J. A. Emerson


2006 ◽  
Vol 57 (6) ◽  
pp. 651 ◽  
Author(s):  
P. L. Greenwood ◽  
G. E. Gardner ◽  
R. S. Hegarty

This study examined influences of sire (n = 9) estimated breeding values (EBVs), sire-group (Muscle, Growth, and Control), and nutrition (low and high quality and availability pasture) from birth to slaughter at ~8 months of age on indices of muscle cellularity and transcriptional and translational capacity in 56 castrate lambs. Effects of nutritional systems to 8 months of age were greater, overall, than those due to EBVs or sire-group. Amount of DNA increased with increasing EBV for post-weaning eye muscle depth (PEMD or Muscle EBV) in longissimus but not in semimembranosus and semitendinosus muscles, while Muscle EBV also had an inverse association with concentration of DNA. Protein to DNA and RNA to DNA were related positively to Muscle EBV, the associations being strongest for the semitendinosus muscle. Post-weaning weight (PWWT or Growth) EBV correlated positively with the RNA to DNA ratio and, among high but not low nutrition lambs, was inversely related to concentration of muscle DNA, whereas post-weaning fat depth (PFAT or Fat) EBV was correlated positively with RNA concentration. Overall, the magnitude of effects of sire-group was less than for sire EBVs, presumably due to differing selection pressures for muscling, fatness, and growth. High nutrition lambs had more protein to DNA than low nutrition lambs in the longissimus and semitendinosus muscles, but not in the semimembranosus muscle. In low compared with high nutrition lambs, concentration of DNA was greater in the longissimus and semitendinosus muscles. Total amount of DNA was reduced by more in low compared with high nutrition in the longissimus and semimembranosus than in the semitendinosus, and amount of protein was reduced by more in low compared with high nutrition in the longissimus than in the other two muscles. We conclude that genetic selection for eye muscle depth in sheep has differing effects on cellular characteristics of the longissimus, semimembranosus, and semitendinosus muscles, and has greater effects on muscle cellular characteristics than genetic selection for post-weaning weight or fat depth.



2003 ◽  
Vol 90 (2) ◽  
pp. 283-293 ◽  
Author(s):  
Kathryn L. Gatford ◽  
Jason E. Ekert ◽  
Karina Blackmore ◽  
Miles J. De Blasio ◽  
Jodie M. Boyce ◽  
...  

Maternal nutrition and growth hormone (GH) treatment during early- to mid-pregnancy can each alter the subsequent growth and differentiation of muscle in progeny. We have investigated the effects of varying maternal nutrition and maternal treatment with porcine (p) GH during the second quarter of pregnancy in gilts on semitendinosus muscle cross-sectional area and fibre composition of progeny, and relationships between maternal and progeny measures and progeny muscularity. Fifty-three Large White×Landrace gilts, pregnant to Large White×Duroc boars, were fed either 2·2 kg (about 35 % ad libitum intake) or 3·0 kg commercial ration (13·5 MJ digestible energy, 150 g crude protein (N×6·25)/kg DM)/d and injected with 0, 4 or 8 mg pGH/d from day 25 to 50 of pregnancy, then all were fed 2·2 kg/d for the remainder of pregnancy. The higher maternal feed allowance from day 25 to 50 of pregnancy increased the densities of total and secondary fibres and the secondary:primary fibre ratio in semitendinosus muscles of their female progeny at 61 d of age postnatally. The densities of secondary and total muscle fibres in semitendinosus muscles of progeny were predicted by maternal weight before treatment and maternal plasma insulin-like growth factor-II during treatment. Maternal pGH treatment from day 25 to day 50 of pregnancy did not alter fibre densities, but increased the cross-sectional area of the semitendinosus muscle; this may be partially explained by increased maternal plasma glucose. Thus, maternal nutrition and pGH treatment during the second quarter of pregnancy in pigs independently alter muscle characteristics in progeny.



2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 354-354
Author(s):  
Maslyn A Greene ◽  
Aliute Udoka ◽  
Rhonda Powell ◽  
Rooksana Noorai ◽  
Terri Bruce ◽  
...  

Abstract The objective of this study was to evaluate the miRNA transcriptome and muscle fiber characteristics of lambs from ewes consuming endophyte-infected tall fescue (E+) seed during two stages of gestation at two animal ages. Pregnant Suffolk ewes (yr 1 n = 36; yr 2 n = 60) were randomly assigned to one of two gestational treatments: E+ seed (1.77 mg/hd/d of ergovaline/ergovalinine) during mid- (gd 35 - 85; MID) or late-gestation (gd 86 – 133/parturition; LATE). Longissimus muscle samples (n = 3/E+ treatment/time) were collected from fetuses on gd 133 (FETAL; expt. 1) or from wethers after finishing to market weight (MKT; expt. 2) from ewes from MID and LATE E+ treatments. Data were analyzed as a 2 x 2 factorial with E+ treatment (MID or LATE), time (FETAL or MKT), and the two-way interaction in the model. Exposure to E+ fescue seed during LATE gestation reduced (P = 0.03) cross-sectional area of Type II muscle fibers at MKT but not at FETAL. Cross-sectional area of Type II muscle fibers were larger (P < 0.05) at MKT than FETAL. Animal age influenced miRNA expression with 120 miRNA differentially expressed. miRNA-22-3p and -29a were down regulated (P < 0.001; > -5 log fold change) with animal age; whereas miR-3958-3p, -410-3p, -299-5p and -487b-3p (P < 0.0001; > 3 log fold change) were up-regulated. Exposure to E+ during MID or LATE gestation did not alter miRNA expression. Muscle fiber hypertrophy increased from FETAL to MKT age altered the expression of miRNA in longissimus muscle.



2007 ◽  
Vol 47 (10) ◽  
pp. 1137 ◽  
Author(s):  
P. L. Greenwood ◽  
S. Harden ◽  
D. L. Hopkins

The objective of this study was to determine the extent to which sire breed (Merino, primarily a wool-producing breed, and Poll Dorset, primarily a meat-producing breed), gender (castrate and ewe), rearing type (single- or multiple-reared), age (4, 8, 14 and 22 months) and carcass weight influence ovine (n = 204) myofibre characteristics. In Merino-sired sheep, the relative area (% of total myofibre area) of type 2X myofibres was lower and of type 2A myofibres higher in the longissimus lumborum (longissimus) muscle than in Poll Dorset-sired sheep. Female sheep had a higher relative area of type 2X and a lower relative area of type 2A myofibres than castrate sheep in the longissimus muscle. The percentage of type 2A myofibres increased and of type 2X myofibres decreased in the longissimus between 4 and 22 months of age. Type 1 myofibres in the semitendinosus muscle were more prevalent and type 2X myofibres less prevalent in Merino than in Poll Dorset-sired sheep. The percentage of type 1 myofibres was lower in female than in castrate sheep. Age-related effects on semitendinosus myofibre characteristics varied with gender, sire breed and rearing type. Influences of rearing type on myofibre characteristics were evident in the semitendinosus muscle at younger ages, but did not persist to 22 months of age. The greatest increases in myofibre cross-sectional areas occurred between 8 and 14 months of age in the longissimus muscle, and between 14 and 22 months of age in the semitendinosus muscle. Carcass weight significantly influenced cross-sectional area of type 2A, 2AX and 2X myofibres in longissimus and semitendinosus muscles. It is concluded that influences of sire breed, gender, rearing type, age and carcass weight on ovine myofibre percentages varies between longissimus and semitendinosus muscles. Furthermore, the pattern of postnatal myofibre growth differs between these muscles.



1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.



Author(s):  
Antonio Cicchella ◽  
Monica Mannai ◽  
Jaan Ereline ◽  
Mati Paasuke ◽  
Helena Gapeyeva


2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.



Sign in / Sign up

Export Citation Format

Share Document