Institute of Animal Breeding & Genetics, Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China.
J Appl Physiol (1985). 2011 Dec;111(6):1789-97. doi: 10.1152/japplphysiol.00551.2011. Epub 2011 Sep 1.
In ovo administration of IGF-1 to poultry eggs has effective roles on post hatching muscle development. However, the secondary muscle development stages at the late embryo development stage are important for muscle fiber formation and differentiation. To investigate the roles of in ovo administration of IGF-1 on duck secondary muscle development, we injected rhIGF-1 into duck eggs in hatching at day 12. After administration on days 18, 21, 24, and 27 in hatching (E18d, E21d, E24d, and E27d, respectively), muscle samples were isolated, and the muscle tissue weight, muscle fiber parameters, and myoblast proliferation rate in leg and breast muscle were analyzed. Additionally, the expression levels of the transcription factors MyoG and MRF4 were detected using qPCR. Results show that embryo body weight and muscle fiber parameters, including muscle fiber diameter (MFD) and the number of myofibers per unit area, are upregulated in IGF-1-treated groups. Moreover, the transcription factors MyoG and MRF4 are expressed at higher levels in the experimental groups compared with the control groups. These results suggest that in ovo administration of IGF-1 to poultry eggs can mediate the expression of MyoG and MRF4, induce myoblast proliferation, and finally influence muscle development during the secondary muscle development stages.
在鸡胚中注射 IGF-1 对孵化后肌肉发育有积极作用。然而，胚胎发育后期的次级肌肉发育阶段对于肌肉纤维的形成和分化非常重要。为了研究在鸡胚中注射 IGF-1 对鸭次级肌肉发育的作用，我们在孵化第 12 天向鸭蛋中注射 rhIGF-1。在孵化后第 18、21、24 和 27 天（E18d、E21d、E24d 和 E27d）进行注射后，分离肌肉样本，分析腿部和胸部肌肉的肌肉组织重量、肌肉纤维参数和成肌细胞增殖率。此外，还使用 qPCR 检测转录因子 MyoG 和 MRF4 的表达水平。结果表明，IGF-1 处理组的胚胎体重和肌肉纤维参数（包括肌纤维直径（MFD）和单位面积肌纤维数量）均升高。此外，实验组中转录因子 MyoG 和 MRF4 的表达水平高于对照组。这些结果表明，在鸡胚中注射 IGF-1 可以调节 MyoG 和 MRF4 的表达，诱导成肌细胞增殖，最终影响次级肌肉发育阶段的肌肉发育。
