Comprehensive gene expression analyses between broiler and layer chick skeletal muscle myoblasts
Tomohide Takaya.
Institute for Biomedical Sciences, Faculty of Agriculture, Graduate School of Science and Technology, Shinshu University, Nagano, Japan.
2018 International Symposium on Animal Science and Technology (Ina, Japan), 2018/08/09 (Invited lecture).
Abstract
In association with an increase of world population, the total amount of meat consumption has been increasing in this half century. To improve efficiency of meat production, broiler chickens with well-developed muscle have been established by selective breeding. Skeletal muscle tissue is composed of numerous myofibers that are multinuclear contractile cells. During muscle development and growth, myofibers are formed by fusions of myogenic progenitor cells, called myoblasts. Remarkably, broiler myofibers grow 2-3 times faster than those of layer chickens. Understanding the charecteristics of broiler myoblasts is thus critically important for breed improvement and establishment of genetic markers.
To address this issue, primary-cultured myoblasts from chick embryos were utilized. Undifferentiated and growing myoblasts were maintained in growth medium (defined as day 0) then induced myotube formation in differentiation medium (day 1 and 2). EdU assay indicated that broiler myoblasts rapidly proliferate rather than layer myoblasts at day 0. Immunostaining for myosin heavy chain, a terminal differentiation marker for skeletal muscle, clearly visualized that broiler myoblasts promptly form myotubes during days 1-2 compared with layer myoblasts. It demonstrates that these characteristics of broiler myoblasts contribute to make well-developed muscle tissues in broiler chickens.
Recently, we comprehensively analyzed the genes expressed in broiler and layer myoblasts at days 0-2 by RNA-sequencing. Some gene clusters were identified, which are differentially expressed between broiler and layer chickens. These clusters are expected to involve the essential factors required for active cell properties of broiler myoblasts.