AAB Archives Animal Breeding AAB Arch. Anim. Breed. 2363-9822 FBN Dummerstorf Göttingen, Germany 10.5194/aab-48-50-2005 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 Kłosowska D. 1 Kurył J. 2 Elminowska-Wenda G. 1 Kapelański W. 3 Walasik K. 1 Pierzchała M. 2 Cieślak D. 2 Bogucka J. 1 Department of Animal Histology, University of Technology and Agriculture, Mazowiecka 28, 85-084 Bydgoszcz, Poland Institute of Genetics and Animal Breeding, Polish Academy of Siences, Jastrzebiec, 05-552 Wolka Kosowska, Poland Department of Pig Breeding, University of Technology and Agriculture, Mazowiecka 28, 85-084 Bydgoszcz, Poland 10 10 2005 48 1 50 59 Copyright: © 2005 D. Kłosowska et al. 2005 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://aab.copernicus.org/articles/48/50/2005/aab-48-50-2005.html The full text article is available as a PDF file from https://aab.copernicus.org/articles/48/50/2005/aab-48-50-2005.pdf

The aim of the study was to evaluate the association between the microstructure characteristics of <i>longissimus lumborum (LL)</i> muscle and the genotype at porcine loci <i>MSTN</i> and <i>CAST</i>. 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 <i>RYR1</i>, whereas Stamboek pigs were of genotype <i>CC</i> 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<sup>2</sup> 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 <i>LL</i> muscle, were not found to be related to the presence of the C→T polymorphism in exon 3 of the <i>MSTN</i> gene, identified by enzyme <i>Taq</i>I. However, it was shown that the diameters of the STO, FTO and FTG fibres in the <i>LL</i> muscle were significantly smallest in the Stamboek pigs with genotype FF at locus <i>CAST</i> 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 <i>CAST</i> genotype in Stamboek pigs. The frequency of pathological fibres in the LL muscle was the lowest in pigs with genotype EE at the locus <i>CAST</i>, 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 <i>CAST</i> gene could be of importance in selection.