Myofibre types in eight skeletal muscles from the eastern grey kangaroo (Macropus giganteus)

Abstract

A selection of muscles from male Eastern Grey kangaroos was assessed for myofibre type. Myofibres were classified as slow-oxidative (type I), fast-oxidative-glycolytic (type IIA), fast-glycolytic (type IIB) and intermediate types (IIC and IIAB) based on staining with monoclonal antibodies specific to myosin heavy chain isoforms. Classification using these antibodies was validated with myofibrillar adenosine triphosphatase, nicotinamide adenosine dehydrogenase, and alpha glycerophosphate dehydrogenase staining. The most abundant myofibre type in the muscles studied was type IIB-fastglycolytic, with the exception of M. psaos minor. Staining characteristics for myofibres were similar to other mammalian species apart from type IIA, which did not react with the type II (fast) antibody used in this study.