An association between genotypes at the porcine loci <i>MSTN (GDF8)</i> and <i>CAST</i> and microstructural characteristics of <i>m. longissimus lumborum</i>: a preliminary study

Abstract

An association between genotypes at the porcine loci MSTN (GDF8) and CAST and microstructural characteristics of m. longissimus lumborum : a preliminary study AbstractThe aim of the study was to evaluate the association between the microstructure characteristics of longissimus lumborum (LL) muscle and the genotype at porcine loci MSTN and CAST. The study was carried out on 132 unrelated pigs -93 crosses of Pietrain and (Polish Large White x Polish Landrace) and 39 Stamboek castrated males. Crosses Pi x (PLW x PL), with an equal proportion of castrated males (n=46) and females (n=47), were of genotype CC or CT at the locus RYR1, whereas Stamboek pigs were of genotype CC at this locus. The diameters of slow-twitch oxidative (STO), fast-twitch oxidative (FTO) and fast-twitch glycolytic (FTG) fibers, their per cent share in a bundle and number of fibers per 1 mm 2 were determined. Moreover, the analyses covered the frequency of occurrence of pathological fibers, including giant and angular fibers. The parameters examined, characterising the microstructure of LL muscle, were not found to be related to the presence of the C→T polymorphism in exon 3 of the MSTN gene, identified by enzyme TaqI. However, it was shown that the diameters of the STO, FTO and FTG fibres in the LL muscle were significantly smallest in the Stamboek pigs with genotype FF at locus CAST compared to both the remaining genotypes. Among the crosses Pi x (PLW x PL) this genotype was not observed. The content of FTG fibres in a bundle proved to be related to the CAST genotype in Stamboek pigs. The frequency of pathological fibres in the LL muscle was the lowest in pigs with genotype EE at the locus CAST, but only in the case of the crosses Pi x (PLW x PL) was this relation statistically significant. The studies should be continued to determine whether such relations occur in other pig breeds. The frequency of pathological fibres affects meat quality and thus the polymorphism of the CAST gene could be of importance in selection.

Histological structure of the musculus longissimus lumborum et thoracis in pigs with the same ryanodine receptor genotype (CC) in relation to carcass indicators

“…Ruusunen et al (2004) reported a higher white muscle fibre diameter (85.86 µm), but a lower intermediate and red muscle fibre diameter in MLLT (61.28 µm and 59.17 µm, respectively). Most thin red and most thick white muscle fibres were also reported by Kiessling et al (1982), Uhrín et al (1986b), Klosowska and Fiedler (2003) and Klosowska et al (2005). Concerning the above-mentioned results it is necessary to emphasize that different pig breeds and sampling methods were used.…”

Comparison of microstructural traits of <i>Musculus longissimus lumborum</i> in wild boars, domestic pigs and wild boar/domestic pig hybrids

“…The latest investigations showed that total number of fibres in pig muscles is fixed genetically in prenatal and earlier neonatal period. Postnatal muscle mass depends on increase of muscle fibres length and thickness (ASHTON et al, 2005;KLOSOWSKA et al, 2005;LEFAUCHEUR and ECOLAN, 2005;REHFELDT, 2005;REHFELDT and KUHN, 2006). The profile of muscle fibres is determined not only by genes and their polymorphism, but by many environmental factors.…”

Meat quality and ultrastructure of muscle tissue from fatteners of Wild Boar, Pulawska and its crossbreed Pulawska × (Hamshire × Wild Boar)

“…A lack of degenerative changes was most likely to rise from a fact that glycolysis process proceeded properly and meat acidity increased gradually. Numerous authors (BIEREDER et al 1999, BOGUCKA and KAPELANSKI 2004, FEDDERN et al 1995, KLOSOWSKA and FIEDLER 2003, KLOSOWSKA et al 2005, SOSNICKI 1996, WOJTYSIAK and MIGDAL 2007 found that in pigs of reduced adaptive abilities to the changed environmental conditions, wavy arrangement of myofibrils was observed as well as giant muscle fibres that did not show cross striation at the longitudinal cross-section. Besides, the authors confirmed the presence of muscle fibres with granular or follicular degeneration of sarcoplasma, the changes in a cell nucleus shape and location, the atrophy and disappearance of glycogen granules and mitochondrial cristae as well as mitochondrial swelling.…”