Muscle growth, cell number, type and morphometry in single and twin fetal lambs during mid to late gestation

Abstract

Muscle growth, myofibre number, type and morphometry were studied in large hindlimb muscles of single and twin fetal lambs during mid to late gestation. Placental insufficiency, evident by lower total placentome weight and number per fetus, resulted in reduced fetal weights from 100 to 140 days gestation in twins compared with singletons (at 140 days: 5016 108 g v. 5750 246 g, respectively; P<0.05). However, competition between littermates did not consistently reduce muscle mass (15–22%) until 140 days gestation. Apparent myofibre number increased with age, indicating that the full complement of myofibres in some large hindlimb muscles may be achieved during early postnatal life. Litter size did not impact on apparent myofibre number in the semitendinosus, plantaris or gastrocnemius muscles. However, a transient effect on myofibre number in the adductor femoris muscle was observed from 80–120 days gestation. The phenotypic maturation of myofibres was unaffected by increasing litter size. Smaller muscle mass in twins was associated with smaller myofibre cross-sectional area in the semitendinosus, adductor femoris and gastrocnemius muscles at 140 days gestation. A similar trend was observed for the plantaris muscle. These results indicate that while competition between littermates for nutrients in late gestation can impact on both fetal and muscle mass, the fetus has the capacity to buffer against the effects of restricted nutrient supply on myofibre hyperplasia and phenotypic maturation, but myofibre hypertrophy is compromised.

Molecular cloning, structural analysis, and tissue expression of the TNNT3 gene in Guizhou black goat

“…5), which is similar to the results of McCoard et al (2001). Four TNNT isoforms have been found in ten different muscle groups in bovine (Muroya et al, 2003c).…”

The effect of maternal nutrient restriction during late gestation on muscle, bone and meat parameters in five month old lambs

“…Accumulation of myonuclei in foetal ovine skeletal muscle is nutritionally mediated (Greenwood et al, 1999;McCoard et al, 2000), being relating to IGF-1 and -II stimulating both proliferation and differentiation of myoblasts and satellite cells in both a time and concentration-dependent manner Fahey et al, 2005b). Indeed in another species, namely the pig, a reduction in plasma IGF-1 caused by undernutrition compared with adequately fed animals, has been associated with a dramatic alteration in fibre type proportions of m. Longissimus dorsi, m. Soleus and m. Rhomboideus .…”

Advances in research on the prenatal development of skeletal muscle in animals in relation to the quality of muscle-based food. I. Regulation of myogenesis and environmental impact

“…Previously, Greenwood et al (1999 and did not observe differences in myofibre number, but decreased muscle weights, muscular DNA, RNA and protein contents and cell cycle activity at low foetal or birth weight. Similarly McCoard et al (2000) found no differences in myofibre number comparing single and twin lamb foetuses. Moloney and Drennan (2006) studied the effects of birth weight on growth and carcass quality in Charolais cattle and found heavier carcasses that tended to be leaner from high birth weight (54.1 kg) compared with low birth weight (41.4 kg) calves, whereas meat quality characteristics remained unaffected.…”