Skeletal muscle characteristics in 2 year-old race-trained thoroughbred horses

Dean Alan Sewell, R.C. Harris, D.J. Marlin

    Research output: Contribution to journalArticle

    Abstract

    Skeletal muscle samples were obtained by needle biopsy from two depths of the m. gluteus medius of 50, young race-trained thoroughbred racehorses. Histochemical and biochemical characteristics of the muscle samples were analysed. Fibres were classified as type I, type IIa or type IIb on the basis of the pH dependent lability of the myosin ATPase reaction. The activities of citrate synthase (CS) and glycogen phosphorylase (Phos) were determined. Muscle fibre composition varied markedly between deep and superficial muscle samples and this was reflected in differences in the activities of citrate synthase (CS) and phosphorylase (Phos). CS activity was greater in samples taken from a depth of 90 mm (deep) than those taken from a depth of 40 mm (superficial: 122 +/- 19 compared with 88 +/- 16 mu mol/g dry muscle/min at 25 degrees C). Phos activity was greater in superficial samples (137 +/- 20) compared with deep samples (117 +/- 21). Regression analysis was used to estimate the enzyme activities in the different fibre types. No significant correlations were observed between histochemical and biochemical measures and subsequent racing performance.

    Original languageEnglish
    Pages (from-to)87-96
    Number of pages10
    JournalComparative Biochemistry and Physiology
    Volume108
    Issue number1
    DOIs
    Publication statusPublished - May 1994

    Keywords

    • EQUINE SKELETAL MUSCLE
    • MUSCLE FIBERS
    • GLUTEAL MUSCLE
    • CITRATE SYNTHASE
    • GLYCOGEN-PHOSPHORYLASE
    • EXERCISE
    • MIDDLE GLUTEAL MUSCLE
    • FIBER TYPES
    • ENZYME-ACTIVITIES
    • CARNOSINE CONTENT
    • MEDIUS
    • SAMPLES
    • FEMORIS
    • XENOPUS
    • SIZE

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