title: Heritability of percentage of fast myosin heavy chains in skeletal muscles and relationship with performance.
abstract: The purpose of this study was to determine the percentage of fast myosin heavy chains (fast MHCs = MHC 2A + 2B) in 2 propelling muscles to estimate the heritability and to identify any relationship with performance. The gluteus medius and the biceps femoris muscles were biopsied in 100 related French Anglo-Arabian horses. The percentages of slow and fast myosin heavy chains were measured using an ELISA technique. The heritability (s.e.) of the fast MHCs percentage was estimated at 13% (0.1) using a restricted maximum likelihood resolution of a mixed animal model. There were significant (P < 0.05) correlations between the performance level and the fast MHCs percentage of the gluteus medius and biceps femoris muscles: 0.47 and 0.34 respectively. An analysis of variance revealed a significant (P < 0.05) effect of performance level in gallop racing and show jumping on the fast MHCs percentage of the gluteus medius muscle. The good performers in gallop racing (75.5 > 69.6% fast MHCs) and show jumping (74.1 > 67.8% fast MHCs) had a higher percentage of fast MHCs in the gluteus medius than poor performers (P < 0.05). This muscular analysis could be one of the interesting physiological traits to measure for early selection of gallop racing and show jumping horses.
authors.affiliation: INRA, Station de Génétique Quantitative et Appliquée, Groupe Cheval, Jouy-en-Josas, France.
authors.forename: E
authors.initials: E
authors.lastname: Barrey
authors.forename: J P
authors.initials: JP
authors.lastname: Valette
authors.forename: M
authors.initials: M
authors.lastname: Jouglin
authors.forename: C
authors.initials: C
authors.lastname: Blouin
authors.forename: B
authors.initials: B
authors.lastname: Langlois
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001706:Biopsy; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D006736:Horses / Q000235:genetics* / Q000502:physiology; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000235:genetics* / Q000502:physiology
chemical_list: D018995:Myosin Heavy Chains