Patterns of succinate dehydrogenase activity in a leg muscle of the domestic duck during postnatal development
Transverse sections of iliotibialis cranialis from male Muscovy ducks were reacted for histochemical demonstration of myofibrillar adenosine triphosphatase (ATPase) and for succinate dehydrogenase (SDH) activities. The distribution of SDH activity within muscle fibers was measured with a microscope photometer and a computer-controlled scanning stage. From 1 to 10 weeks after hatching, the average SDH activity across muscle fiber areas decreased. All fiber types exhibited a decline of SDH activity in their central axis. However, fibers with strong ATPase and weak SDH concurrently developed stronger SDH activity in their subsarcolemmal zone. Thus, centripetal radial gradients of SDH activity within fibers became more negative as muscle fibers grew in cross-sectional area.