Morphometrical and histochemical study of the cross striated skeletal muscles of pigs

Abstract

In this study morphological and histochemical parameters of the striated skeletal muscle of pigs of the Slovak large White breed was analyzed. New-born, one-day-old (1-day), three-day-old (3-day), eighteen-day-old (18-day), forty-eight-day-old (48-day), eighty-four-day-old (84-day), one-hundred-twenty-day-old (120-day), one-hundred-ninety-two-day-old (192-day) and finally onethousand-fifty-five-day-old pigs (1055-day) were used for this purpose. Samples from the three muscles m. triceps brachii (MTB), m. longissimus dorsi et lumborum (MLD) and m. rectus femoris (MRF) were. The samples were collected by necropsy, fixed in liquid nitrogen and sliced on a freezing microtome. All the samples were stained with hematoxylin-eosin, toluidine blue, oil red “0”, and succinate dehydrogenase (SDH) was used for differentiation of individual types of muscle fibres. Myogenesis is completed in the third day of the post-natal life of pigs. The creation of new muscle fibres is limited by the number of satellite cells which persist among muscle fibre populations. From birth up to eighteen days of post-natal growth, only red muscle fibres were detected, and white muscle fibres were manifested from the forty-eighth day (48-day) of post-natal growth. White muscle fibres were larger in diameter. The shape of muscle fibres changed with the growth in thickness from oval to angular shape. When pigs were growing, the proportion of interstitial connective tissue to muscle tissue remained in favour of muscle tissue. The results show the craniocaudal increase of muscle fibre thickness from MTB through MLD to MRF.