Skeletal muscle fibres as factors for pork quality

• Published in: Livestock production science Vol. 60; no. 2-3; pp. 255 - 269
• Main Authors: Karlsson, Anders H., Klont, Ronald E., Fernandez, Xavier
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-07-1999; Elsevier
• Subjects: Agricultural sciences; CALIDAD; CARNE DE CERDO; CERDO; FIBRAS MUSCULARES; FIBRE MUSCULAIRE; ID Lelystad, Institute for Animal Science and Health; ID-Lelystad, Instituut voor Dierhouderij en Diergezondheid; Life Sciences; Meat; Muscle fibre; MUSCLE FIBRES; Pig; PORCIN; PORK; Pork quality; QUALITE; QUALITY; SWINE; VIANDE PORCINE; Muscle fibre; Pork quality; Meat; Pig
• ISSN: 0301-6226; 1872-6070
• DOI: 10.1016/S0301-6226(99)00098-6

Interaction between muscle fibres, perimortem energy metabolism and different environmental factors determine postmortem transformation from muscle to meat. Muscle fibres are not static structures, but easily adapt to altered functional demands, hormonal signals, and changes in neural input. Their dynamic nature makes it difficult to categorise them into distinct units. It must be realised that some properties may change without affecting others or without changing histochemical appearance of a given fibre such as species specificity, developmental or adaptive processes or pathological conditions, and that transient fibre types exist. Therefore, a distinction between specific types must strictly refer to the method that has been used for the typing. Theoretically, there will be at least as many fibre types as there are motor units in a muscle, and within a muscle a fibre type may show a continuum of structural and functional properties which overlap with other fibre types. Histochemical and biochemical properties of a muscle, such as fibre type composition, fibre area, oxidative and glycolytic capacities, and glycogen and lipid contents, are factors that have been found to influence meat quality. An important factor for post-mortem changes and meat quality is the metabolic response that takes place in the different fibre types pre-slaughter. Selection for leaner pigs and for a higher proportion of large muscle fibres, especially of type IIB, can result in poor capillarisation and consequently an insufficient delivery of oxygen and substrates and elimination of end products, such as CO2 and lactate, and thereby a reduced pork quality. In the future, fibre types in pig muscle will probably be investigated with more advanced and sensitive techniques, which makes it is possible to look at adaptations in different contractile, sarcoplasmic proteins as well as other muscle proteins that are of importance for cell differentiation and muscle cell metabolism. Furthermore, single fibre dissection and quantitative biochemical analyses may increase the knowledge about metabolic and contractile properties of the muscle fibre. The literature indicates possibilities to include muscle fibre characteristics in breeding schemes for improved meat quality, while preserving optimal production traits. In order to use muscle fibre characteristics in a beneficial way for future breeding programmes, further investigations are needed to better understand the physiological mechanisms. Selection experiments based on biochemical and histochemical characteristics determined in biopsies or otherwise and study of the correlated selection responses, may possibly provide better tools to study these relationships.