Absence of changes in fiber type with aging in avian muscles.

The anterior latissimus dorsi of the pigeon, a slow tonic muscle, and biventer cervicis, a mixed muscle, of two age groups (1-2 years old versus 6-8 years old) were compared with respected to percentages of fiber types and activities of adenosine triphosphatase (ATPase) and succinic dehydrogenase (SDH), as estimated histochemically, to determine whether these became altered with old age. These parameters did not change between the young and old birds for either type of muscle.