EFFECT OF THE RN- GENE ON ULTRASTRUCTURE AND PROTEIN-FRACTIONS IN PIGMUSCLE

The aim of the present experiment was to study the effect of the RN- g ene on ultrastructure of white fibres and the proportion of the differ ent protein fractions in Longissimus lumborum muscle of RN- pigs. The ultrastructure of muscle was observed in 4 RN- carrier pigs and 4 rn+r n+ homozygous pigs by mean of electron microscopy. Protein fractionati on and quantification were performed on muscle from a second group of 4 RN- and 4 rn+ pigs. No change in the proportions of the different pr otein compartments was observed. The abnormality of the glycolytic fib res of RN- pigs seems to be rather due to an increase of the glucid co ncentration in the sarcoplasm, perhaps secondarily to a modified osmol arity in the intracellular medium.