Comparative studies of skeletal muscle (m. longissimus dorsi) ultrastructure in swine breeds with different degrees of resistance to stress. Comparison between Duroc and Pietrain
Johannsen, U.; Menger, S.; von Lengerken, G.
Archiv für Experimentelle Veterinarmedizin 36(3): 357-374
1982
ISSN/ISBN: 0003-9055 PMID: 7138209 Document Number: 196649
Five Duroc and five Pietrain pigs underwent biopsy of the longissimus dorsi muscle while at rest and after a period of exercise and electrical stunning. Electron microscopy revealed poor mitochondrial white or intermediary fibres in both breeds. Duroc pigs had a higher concentration of lipid droplets in high density mitochondrial red muscle fibres. Type A mitochondrial pattern (high density compact matrix) was commoner than type B (looser matrix) in the Duroc, and was less widespread in the Pietrain. Degenerative mitochondrial changes were rare in both breeds. After stress mitochondrial character showed a higher rate of changes. The difference in response to stress in the two breeds is attributed to variations in the quantitative ratio of red and white or intermediary fibres and in the frequency distributions of type A and B mitochondria.