title: Effects of muscle fiber type on glycolytic potential and meat quality traits in different Tibetan pig muscles and their association with glycolysis-related gene expression.
abstract: The myosin heavy chain (MyHC) composition, glycolytic potential, mitochondrial content, and gene expression related to energy metabolism were analyzed in eight muscles from Tibetan pigs, to study how meat quality develops in different muscle tissues. The muscles were classified into three clusters, based on MyHC composition: masseter, trapezius, and latissimus dorsi as 'slow-oxidative-type'; psoas major and semimembranosus as 'intermediate-type'; and longissimus dorsi, obliquus externus abdominis, and semitendinosus as 'fast-glycolytic-type'. The 'slow-oxidative-type' muscles had the highest MyHC I and MyHC IIA content (P < 0.01); 'intermediate-type' muscles, the highest MyHC IIx content (P < 0.01); and 'fast-glycolytic-type' muscles, the highest MyHC IIb content (P < 0.01). The pH values measured in 'slow-oxidative-type' muscles were higher than those in the other clusters were; however, the color of 'fast-glycolytic-type' muscles was palest (P < 0.01). Mitochondrial content increased in the order: fast-glycolytic-type < intermediate-type < slow-oxidative-type. In the 'slow-oxidative-type' muscles, the expression levels of genes related to ATP synthesis were higher, but were lower for those related to glycogen synthesis and glycolysis. Mitochondrial content was significantly positively correlated with MyHC I content, but negatively correlated with MyHC IIb content. MyHC I and mitochondrial content were both negatively correlated with glycolytic potential. Overall, muscles used frequently in exercise had a higher proportion of type I fibers. 'Slow-oxidative-type' muscles, rich in type I fibers with higher mitochondrial and lower glycogen and glucose contents, had a higher ATP synthesis efficiency and lower glycolytic capacity, which contributed to their superior meat quality.
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: L Y
authors.initials: LY
authors.lastname: Shen
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: J
authors.initials: J
authors.lastname: Luo
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: H G
authors.initials: HG
authors.lastname: Lei
authors.affiliation: College of Life Science, Sichuan Agricultural University, Chengdu, China.
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Jiang
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: L
authors.initials: L
authors.lastname: Bai
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: M Z
authors.initials: MZ
authors.lastname: Li
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: G Q
authors.initials: GQ
authors.lastname: Tang
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: X W
authors.initials: XW
authors.lastname: Li
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: S H
authors.initials: SH
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
authors.forename: L
authors.initials: L
authors.lastname: Zhu
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004734:Energy Metabolism / Q000235:genetics; D005786:Gene Expression Regulation; D006003:Glycogen / Q000378:metabolism; D006019:Glycolysis / Q000235:genetics*; D008460:Meat; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000096:biosynthesis* / Q000235:genetics; D024501:Nonmuscle Myosin Type IIB / Q000096:biosynthesis* / Q000235:genetics; D013552:Swine
chemical_list: D000255:Adenosine Triphosphate; D006003:Glycogen; D024501:Nonmuscle Myosin Type IIB; C103815:nonmuscle myosin type IIB heavy chain; D018995:Myosin Heavy Chains