The relationship between muscle characteristics and meat quality remains controversial, likely because the existence of neuromuscular compartments (NMCs) is often overlooked. The aim was to determine in the NMCs the fibre types and its percentages, absolute areas (AA) and relative areas (RA) to quantify the heterogeneity of the muscle. The left biceps femoris (BF) muscles were removed from the carcasses of ten pigs of commercial breeds, preserving the primary branches of the caudal gluteal and sciatic nerves for identifying the NMCs. Muscle samples were obtained from the centre of the NMCs to identify the fibre types. Myosin heavy chains were determined by myofibrillar adenosine triphosphatase (mATPase) reaction and by using monoclonal antibodies. The pig biceps femoris muscle contains four NMCs grouped by RA values in oxidative (BR3-BR4) and glycolytic (BR1, BR2) compartments. The RAs of these NMCs varied significantly for fibre types I and IIB (pâ¤0.05). The RA accurately typifies NMCs, and the relationship between their values enables efficient study of compartmentalisation by studying only capillaries after the primary branches of the nerve were identified. Our results highlight the complexity of muscle structure and the importance of its consideration when assessing muscle, sampling and muscle processing for meat production.
Anatomy, muscle fibre, neuromuscular compartment.