Multivariate analysis of muscle fiber characteristics, intramuscular fat content and fatty acid composition in porcine longissimus thoracis muscle

Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to investigate the relationship between muscle fiber characteristics, intramuscular fat (IMF) content and fatty acid composition in the porcine longissimus thoracis muscle. The cluster with the highest IMF content had the highest saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and muscle fiber characteristics of type I (P<0.05). The polyunsaturated fatty acid (PUFA) showed positive correlations with the cross-sectional area and relative area of type IIB and the relative number of fiber type IIA in the HCA and PCA results. Therefore, porcine muscle with a high density, relative area and cross-sectional area of type I was found to have a high content of IMF, SFAs and MUFAs, whereas in the case of a large cross-sectional area and relative area of type IIB, the proportion of PUFAs increased. These findings lead to a better understand of different fatty acid compositions in skeletal muscles which have different metabolic and contractile properties.