Sex differences in muscle topography and its relationship to muscularity in Double Muscled cattle

Shahin, Karima A.

doi:10.1016/0301-6226(94)00073-g

Cited by 3 publications

(2 citation statements)

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“…Evidence for a similar sexual dimorphism in fast muscle fibre recruitment patterns has been reported for the Argentine hake ( Merluccius hubbsi Marini) in which females also reach a larger body size than males (Calvo, 1989). In mammals, males are often larger than females and this sexual dimorphism is associated with greater muscle mass (Shahin, 1995). It has been suggested that this sexual dimorphism is attributable to differences in androgens (Bardin & Catterall, 1981), insulin‐like growth factor I (Liu et al , 2000), growth hormone (Udy et al , 1997) and the processed form of myostatin (McMahon et al , 2003).…”

Section: Discussionmentioning

confidence: 99%

Myotube production in fast myotomal muscle is switched‐off at shorter body lengths in male than female Atlantic halibutHippoglossus hippoglossus(L.) resulting in a lower final fibre number

Hagen

Vieira

Solberg

et al. 2008

Journal of Fish Biology

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A sampling method is described to determine accurately the number of fast myotomal muscle fibres (N F ) in a large flatfish species, the Atlantic halibut Hippoglossus hippoglossus. An unusual feature of the fast myotomal muscle is the presence of internalized strips of slow muscle fibres. In fish of 1Á5-3Á5 kg (n ¼ 24), the total cross-sectional area (A TC ) of fast muscle was 18% greater in the dorsal than ventral myotomal compartments (P < 0Á05), whereas there was no significant difference between left-and right-hand sides of the body. Due the bilateral asymmetry, muscle blocks (5 Â 5 Â 5 mm) were prepared to systematically sample each myotomal quadrant (dorsal, ventral, left-and right-side) and the diameters of 150 fast fibres measured per block. Smooth non-parametric probability functions were fitted to a minimum of 800 measurements of fibre diameter per quadrant (n ¼ 5). There were no significant differences in the distribution of muscle fibre diameters between myotomal compartments and therefore N F could be estimated from a single quadrant. The number of blocks required to estimate N F with a repeatability of AE2Á5% increased from six at 300 g body mass to 17 at 96Á5 kg, caused by variation within and between blocks. Gompertz curves were fitted to measurements of fibre number and fork length (L F ). The estimated final fibre number was 8Á96 Â 10 5 (7Á99-9Á94 Â 10 5 , 95% CI) for males and 1Á73 Â 10 6 (1Á56-1Á90 Â 10 6 , 95% CI) for female fish. The estimated L F for cessation of fibre recruitment in the fast muscle of female fish (1775 mm) was almost twice that in males (810 mm), reflecting their greater ultimate body size.

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