RELATIONSHIPS BETWEEN MICROSTRUCTURE OF M USCLE-TISSUE AND STRESS SENSIBILITY IN LANDRACE PIGS

Muscle fibre structure, fibre nuclei accumulation and distribution of capillaries were determined in biopsy samples of longissimus muscle fr om 51 halothane negative and 39 halothane positive Landrace pigs at 19 0+/-10 days of age. Meat quality traits were determined after slaughte r from the same muscle. Differences in microstructure between the grou ps reflected insufficient physiological capacity in the halothane posi tive animals. In this group a higher diameter of all three fibre types (differences 17%; 15%; 5%) and a higher percentage of white, glycolyt ic fibre type (5%) were found. The number of nuclei and the number of capillaries per muscle area unit were decreased (26%; 12%) and more fi bres from the histopathological type of angular fibres were counted. T hese changes of microstructure in muscle of halothane positive pigs ca n be interpreted as suboptimal physiological conditions with respect o xygen supply and cellular protein synthesis capacity in fibres. They r elate to functional alterations of the whole musculature and to meat q uality.