A histological study of post mortem changes in the skeletal muscle of the fowl (Gallus domesticus). II. The cytoarchitecture.

Changes in the histology of skeletal muscle at an ultrastructural level have been studied in the pectoralis thoracica and iliotibialis muscles of the fowl (Gallus domesticus). The carcasses were stored at 40 degrees C and samples removed at various times post mortem. The Z discs and I bands degenerate rapidly (less than 4 hours) but the thick filaments of the A band are remarkably resistant to change (greater than 24 hours). The sarcolemma, mitochondria, glycogen content, sarcotubular system and myonuclei also show marked changes in less than 4 hours. Myelin figures and autophagic vacuoles are among other features seen in post mortem tissue. There are more degenerate mitochondria and vesicular remnants of the sarcotubular system in the iliotibialis than in the pectoralis muscle, but this reflects a differing concentration of these organelles in vivo. No other consistent difference in the post mortem histology of these muscles has been observed.