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Relationships among muscle fiber type composition, fiber diameter and MRF gene expression in different skeletal muscles of naturally grazing Wuzhumuqin sheep during postnatal development
Author(s) -
Siqin Qimuge,
Nishiumi Tadayuki,
Yamada Takahisa,
Wang Shuiqing,
Liu Wenjun,
Wu Rihan,
Borjigin Gerelt
Publication year - 2017
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1111/asj.12848
Subject(s) - biceps , fiber type , muscle fibre , fiber , anatomy , longissimus dorsi , skeletal muscle , gene expression , biology , composition (language) , chemistry , endocrinology , gene , zoology , biochemistry , organic chemistry , linguistics , philosophy
The aim of this study was to determine the relationships among muscle fiber‐type composition, fiber diameter, and myogenic regulatory factor ( MRF) gene expression in different skeletal muscles during development in naturally grazing Wuzhumuqin sheep. Three major muscles (i.e. the Longissimus dorsi ( LD ), Biceps femoris ( BF ) and Triceps brachii ( TB )) were obtained from 20 Wuzhumuqin sheep and 20 castrated rams at each of the following ages: 1, 3, 6, 9, 12 and 18 months. Muscle fiber‐type composition and fiber diameter were measured using histochemistry and morphological analysis, and MRF gene expression levels were determined using real‐time PCR . In the LD muscle, changes in the proportion of each of different types of fiber (I, IIA and IIB ) were relatively small. In the BF muscle, a higher proportion of type I and a 6.19‐fold lower proportion of type IIA fibers were observed ( P < 0.05). In addition, the compositions of type I and IIA fibers continuously changed in the TB muscle ( P < 0.05). Moreover, muscle diameter gradually increased throughout development ( P < 0.05). Almost no significant difference was found in MRF gene expression patterns, which appeared to be relatively stable. These results suggest that changes in fiber‐type composition and increases in fiber size may be mutually interacting processes during muscle development.