Pathological Changes in the Microstructure of longissimus lumborum Muscle from Five Breeds of Pigs

Agricultural University of Kraków, Department of Reproduction and Animal Anatomy, Mickiewicza 24/28, 30-059 Kraków, Poland.
Folia Biologica (Impact Factor: 0.88). 01/2012; 60(1-2):55-60. DOI: 10.3409/fb60_1-2.55-60
Source: PubMed


The aim of the study was to determine the extent of histopathological changes in m. longissimus lumborum of PL, PLW, Duroc, Pietrain, and Puławska pigs (N = 30 per breed) aged 210 days. Changes in fibre size (atrophy, hypertrophy - giant fibres), changes in fibre shape (angular fibres), degenerative lesions (necrosis with phagocytosis) and connective tissue hypertrophy were evaluated. The percentage of individual pathological changes in m. longissimus lumborum of the analysed pig breeds was relatively low. Significantly more normal fibres were found in the muscles of Puławska compared to Pietrain pigs. Muscle fibre atrophy was the most frequent and extensive histopathological change. The muscles of Puławska pigs had significantly fewer atrophic, giant and angular fibres, significantly less necrosis with phagocytosis, and less animals with connective tissue hypertrophy compared to the other pig breeds. On the other hand, Pietrain pigs were characterized by a greater number of animals with giant fibres and a significantly higher proportion of giant fibres compared to the other breeds. Also the diameter of giant fibres was the largest in Pietrain, intermediate in PL and PLW, and the smallest in Duroc and Pulawska pigs. Moreover, current findings indicate that giant fibres may arise from each muscle fibre type (I, IIA and IIB). It is concluded that selection of pigs for increased leanness contributes to the incidence of histopathological changes, which may decrease pork quality.

Download full-text


Available from: Dorota Wojtysiak
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Based on literature date and on their own experiences, the authors present the morphology, development and growth of the striated muscle, and the role of giant and splitting muscle fibers, and the mechanism of muscle splitting. The muscle develops from the myotom, the myoblasts become coherent myotubules, which then differentiate into muscle fibers. The longitudinal growth of the muscle fibers can take place through the elevation of the number of the sarcomeres or through their prolongation; however the exact mechanism of the morphological and structural changes in the skeletal muscle and myofibrils in the postnatal period is not clearly understood. Recent literature data suggests that postnatal growth of muscle can take place through the splitting of the giant muscle fibers. The presence and splitting of the giant muscle fibers seems to be related to the pathologic metabolism of the muscle, but their presence was detected also in normal muscles. The histological grading system, developed by the authors that provides an opportunity to define the stages (G1–G4) of split muscle fibers may be useful in the future also in the veterinary practice.
    Full-text · Article · Sep 2015 · Magyar Allatorvosok Lapja
  • [Show abstract] [Hide abstract]
    ABSTRACT: In pigs, an intense research have been performed in order to select genetic markers, which could be associated with important production traits and may be included in breeding program. The aim of the present study was to compare the whole gene expression profile of semimembranosus muscle from three pig breeds differing in muscularity, fatness traits and meat quality. The RNA-seq analysis was performed on 16 animals: Pietrain (5), Polish Landrace - PL (4) and Pulawska pigs (7). The transcriptome sequencing of muscle tissue (m. semimembranosus) was carried out on HiScanSQ System (Illumina) with 50 single-end cycles. The validation of obtained results and exact estimation of transcript abundance was performed by real-time PCR method. The present study showed the differential expression of 229 genes between Pulawska and PL pigs, and 87 between Pulawska and Pietrain (p≤0.05). The Pulawska breed was characterized by significantly higher expression of only 9 and 43 genes compared to Pietrain and PL pigs, respectively. Accordingly to functional annotation of DEGs, several novel genes were proposed which were involved with processes such as purine and pirymidine biosynthesis, cell cycle, protein transport and metabolism. These genes may be potentially responsible for muscle cell growth and development. On the other hand, the up-regulation of genes involved in immune processes, observed in native Pulawska pigs, may be related with a very good resistance to diseases of this breed. The different expression profile of selected genes may illustrate the effect of long-term selection to improve the meat content in carcasses conducted on pigs.
    No preview · Article · Oct 2015