COMPARATIVE-ANALYSIS OF SATELLITE CELL PROPERTIES IN HEAVYWEIGHT AND LIGHTWEIGHT STRAINS OF TURKEY

The growth of muscle during postnatal development results partly from the proliferation of satellite cells and their fusion with muscle fibr es. We analysed the properties of satellite cells in a heavyweight (HW ) turkey strain characterized by high body weight and a fast growth ra te, and in a lightweight farm strain (LW) characterized by low body we ight and a slow growth rate. Satellite cell activation was then examin ed in stretched-overloaded anterior latissimus dorsi (ALD) muscle by w eighting one wing in young turkeys from both strains. As early as day 1 of stretching for HW and day 2 for LW, small embryonic-like fibres e xpressing ventricular cardiac myosin heavy chain (MHC) isoform were ob served. Following four days of stretching, the number of nascent fibre s had increased in both strains but was significantly greater in HW th an LW ALD muscle. The proliferation and differentiation capacities of satellite cells from HW and LW strains were investigated in culture. A s judged by in vitro measurements of H-3-thymidine incorporation and D NA content, satellite cells of HW turkey exhibited a greater prolifera tive capability than those of LW turkey. No differences in the tempora l appearance of muscle markers (desmin, MHC isoforms) were noted in be tween the two strains. These data confirm our in observations indicati ng vitro vivo that selection based on growth rate does not modify musc le fibre maturation. Our in and in observations suggest vivo vitro tha t variations in the postnatal muscle growth pattern between HW and LW strains may be related to a difference in the capacity of their satell ite cells to proliferate. (C) Chapman & Hall Ltd.