Skeletal muscle histochemistry of andalusian horses: a comparative study with other breeds

Abstract

The purpose of this study was to characterize the histochemical and morphometric profiles of the skeletal muscle in adult Andalusian horses, and compare it with those of Thoroughbred and Arabian horses. Muscle biopsies were taken from the Gluteus medius of 32 Andalusian horses (15 mares, 17 stallions), 24 Thoroughbred (17 mares, 7 stallions), and 15 Arabians (7 mares, 8 stallions), ranging from 5 to 24 years. Consistent sex differences in fibre type composition and fibre area were observed. A highly significant difference among breeds was also obtained, probably being related to the type of work for which the breeds have been selected. Results also imply that histochemical and morphometric properties of the skeletal muscle in Andalusians provide only a moderate endurance potential. However, since genetic factors are of importance, the endurance potential of a breed could be significantly increased by means of a correct genetic program.

El presente estudio trata de caracterizar los perfiles histoquímico y morfométrico del mús- culo esquelético en caballos Andaluces adultos, y compararlos con los de caballos Purasangre y Arabes. Se obtuvieron biopsias del músculo Gluteus medius de 32 caballos Andaluces (15 yeguas, 17 sementales), 24 Purasangre (17 yeguas, 7 sementales), y 15 Arabes (7 yeguas, 8 sementales), de 5 a 24 años de edad. Se observaron importantes diferencias en el porcentaje y tamaño de las fibras entre sexos y también entre razas, según el tipo de trabajo para el que cada raza ha sido específicamente seleccionada. Las propiedades histoquímicas y morfométricas del músculo esquelético en el caballo Andaluz sólo le proporcionan una capacidad de resistencia moderada. No obstante, dada la importancia de los factores genéticos, el potencial de resistencia de los caballos Andaluces podría modificarse significativamente mediante un adecuado programa genético.