Characterization of fibers from gluteus medius muscle in horses by histochemical and immunohistochemical methods.

Biopsies were taken at a depth of 4cm from the Gluteus medius muscle of 16 horses. The animals were 6 years old and had not been trained during 3 mont hs before the study. The samples were analized by mATPase miofibrillar tech nique to determine the fibrillar composition by NADH-TR technique to determ ine the oxidative capacity of the fibres and immunohistochemistry to determ ine the fibre type. The histochemical study revealed an average fibrillar composition of 14, 39 , 30 and 17 % for fibres typed I. IIA, IIX oxidative and IIX no oxidative a nd the inmunohistochemistry study showed 16, 35, 29 y 20% for fibres type I , IIA, IIX and IIA-IIX. The statistical analyses showed a good relationship between the histochemic al and inmunohistochemical method in the determination of fiber types, The immunohistochemical method allows a good identification of the fiber in adult horses.