Comparisons of different myosin heavy chain types, AMPK, and PGC-1α gene expression in the longissimus dorsi muscles in Bama Xiang and Landrace pigs

Abstract

ABSTRACT. Bama Xiang and Landrace pigs are the local fatty and lean breeds, respectively, in China. We compared differences in carcass traits, meat quality traits, and myosin heavy chain (MyHC) types in the longissimus dorsi muscles between Bama Xiang and Landrace pigs. This was done in pigs of the same age, using real-time PCR, to investigate the relationship between MyHC fiber types and carcass characteristics, meat quality traits, and the key factors regulating muscle fiber type. Bama Xiang pigs exhibited smaller size and slower growth than Landrace pigs (P < 0.01). We found that the superior meat quality, especially the high intramuscular fat (IMF) content in Bama Xiang pig, was related to elevated type I oxidative muscle fiber content (P < 0.01). In contrast, Landrace pig muscle had a higher glycolytic type IIb muscle fiber content (P < 0.01). MyHC I gene expression was significantly positively correlated with backfat thickness and IMF content (P < 0.01). MyHC IIb was significantly negatively correlated with IMF content (P < 0.05), and positively correlated with carcass yield (P < 0.05). AMP-activated protein kinase and peroxisome proliferatoractivated receptor-g coactivator-1a are suggested to be the two key factors regulating muscle fiber type in pigs. Our results indicate that muscle fiber composition is one of the key differences leading to the differences of meat quality between Bama Xiang and Landrace pigs. These results may provide a theoretical basis for further studies of the molecular mechanism underlying the excellent meat quality of the Bama Xiang pig.

Expression of Myosin Heavy Chain and Some Energy Metabolism-Related Genes in the Longissimus Dorsi Muscle of Krškopolje Pigs: Effect of the Production System

“…On the basis of an increased oxidative potential of LD in organic pigs, differences were also expected in the expression of some key genes involved in myofiber energy metabolism, as physical activity could be considered one of the most potent physiological stimuli promoting oxidative metabolism in skeletal muscles (45) because of the potential association with meat quality and, in particular, intramuscular fat (IMF) content (46)(47)(48)(49). Therefore, the expression of selected energy metabolismrelated genes involved in carbohydrate and lipid metabolism pathways was addressed in the present study.…”

Age-Dependent Expression of MyHC Isoforms and Lipid Metabolism-Related Genes in the Longissimus Dorsi Muscle of Wild and Domestic Pigs

“…In this comparative study, we evaluated age-dependent changes in relative mRNA expression of MyHCs and selected lipid metabolism-related genes in the longissimus dorsi of WPs and DPs. The relative abundance of MyHC transcripts and the relationships among them have previously been studied in diverse pig breeds [3,8,12,13,20,24,25,26,27]. However, only a subset of these studies has explored temporal/developmental changes in MyHC expression [8,12,25,28].…”

“…The relative abundance of MyHC transcripts and the relationships among them have previously been studied in diverse pig breeds [3,8,12,13,20,24,25,26,27]. However, only a subset of these studies has explored temporal/developmental changes in MyHC expression [8,12,25,28]. Most of these studies compared commercial and indigenous pig breeds [12,13,20,26], and to date, studies involving WPs used only enzyme-immunohistochemical approaches to classify myofiber types [1,4,11,29].…”

“…In the pig, the oxidative myofiber types that express MyHC-I, -IIa, and -IIx are also associated with desirable meat quality properties, such as the water-holding capacity, pH, and tenderness (reviewed by Listrat et al [10]). The ratio of preferentially oxidative myofiber types is higher in wild pigs (WPs) and some indigenous pig breeds than in the highly selected modern domestic pig (DP) breeds [11,12,13]. A recent comparative study of young pigs of the Iberian and conventional breeds showed that under identical nutrition and management conditions, the Iberian pigs had a higher intramuscular fat content and oxidative metabolism in the longissiumus dorsi muscle [14].…”

“…In vitro evidence suggests that this gene also plays a role in myoblast differentiation [16]. Additionally, other lipid metabolism-related genes, especially those involved in lipogenesis (e.g., peroxisome proliferator-activated receptor gamma, PPARγ ), fatty acid uptake (e.g., lipoprotein lipase, LPL ), and fatty acid oxidation (carnitine palmitoyltransferase-1B, CTP-1B ), have attracted research interest in pig muscle tissues because of their potential association with meat quality [12,13,17].…”