Histochemical analysis of musculus vastus lateralis in pigs of different genotypes.

The histological and  histochemical structure of musculus vastus lateralis , thickness and frequency of different muscle fibre types were compared in pigs of various genotypes ( NN, Nn, nn  ). As found, pigs with genotypes  ( Nn and nn ) have a larger proportions of white muscle fibres ( 57,17 and 61,57 % ) as compared with the group of NN pigs (54,21 % ). On the other  hand, this  group  ( NN )  have  a  highest  relative  volume of  muscle fibres ( 91,15 % ) and lowest relative volume of intramuscular connective tissue   ( 8,85  % ).  The  lowest  relative  volume  of muscle  fibres (  86,50 % )  and  highest amount of  connective tissue ( 13,50 % ) was found in pigs of nn genotype. The thickness of muscle fibres in pigs ( Nn and nn ) has higher values than in the dominantly homozygotic ( NN ) pigs. The highest differences were measured in thickness of white and red fibres between recessive homozygotic ( nn ) and dominantly homozygotic ( NN) pigs.