SOME BIOPHYSICAL AND BIOCHEMICAL TRAITS IN ANTEMORTEM AND POSTMORTEM SKELETAL-MUSCLE OF PIGS WITH DIFFERENT RN PHENOTYPE

RN phenotype of Pen Ar Lan pigs was identified by determining the glyc olytic potential (GP) in muscle biopsies at 70-80 kg liveweight. Exper iment involved 6 rn(+) homozygous (m(+)) and 6 RN-carriers (RN-). Prot ein soluble in phosphate buffer (0.1 M, pH 7) was determined in muscle biopsy samples and post mortem muscle (longissimus lumborum). pH, WHC (assessed by a centrifugation technique) and R value (ATP/IMP) were e stimated in biopsy samples after 1 hour of incubation at 39 degrees C and in post mortem muscle (24 h). Citrate synthetase (CS) activity was estimated in longissimus lumborum muscle after slaughter. Muscle from RN-carriers contained higher GP (P < 0.01), less soluble protein (P < 0.01) and slightly less WHC (P < 0.05) in biopsied samples. Higher GP (P < 0.01), less soluble protein (P < 0.01) and higher CS activity (P < 0.05) were found in RN-carriers post mortem. Significant correlatio ns were found between GP and soluble protein in biopsied (r = -0.63) a nd between GP and CS activity (r = 0.73) in post mortem muscle samples . The results confirm the values of the muscle biopsy on live animals and post mortem to predict the RN phenotype in pigs.