母猪日粮中添加肌醇对仔猪骨骼肌发育的影响及其机制

胚胎期和出生后早期的骨骼肌发育对猪的生长性能和生产效率意义重大。申请人前期研究发现，Ca2+信号在猪骨骼肌成肌-成脂分化中发挥重要作用。肌浆网Ca2+通道1,4,5-三磷酸肌醇受体1（IP3R1）的敲除提高了胞质Ca2+浓度，增强了成肌细胞分化能力，降低了小鼠骨骼肌重量。肌醇参与三磷酸肌醇的合成，是潜在的Ca2+信号营养调节剂，但是对猪骨骼肌发育的影响未见报道。本项目从肌醇-IP3R1-Ca2+信号-骨骼肌发育出发，以肌纤维生成和类型转化为落脚点，通过母猪妊娠期、泌乳期以及仔猪保育期日粮中添加肌醇，研究肌醇对猪胚胎期肌纤维生成和出生后肌纤维类型转化的影响；基于IP3R1沉默的猪成肌前体细胞，从细胞分化和能量代谢角度揭示IP3R1介导的Ca2+信号在肌醇调节猪骨骼肌发育中的作用。研究结果将通过靶向调控IP3R1-Ca2+信号，为改善猪骨骼肌发育、提高猪肉生产效率提供理论依据和营养手段。

Development of skeletal muscle during embryonic and early postnatal periods is of great significance to growth performance and meat production efficiency of pigs. Our previous studies have evidenced the important role of intracellular Ca2+ signaling in myogenesis and adipogenesis of porcine skeletal muscle. Furthermore, knockout of sarcoplasmic reticulum Ca2+ channel 1,4,5-inositol triphosphate receptor 1 (IP3R1) increased the cytoplasmic Ca2+ concentration, enhanced the myogenic differentiation of myoblasts, and reduced the weight of mouse skeletal muscle. Inositol is involved in the synthesis of inositol triphosphate and therefore, is a potential nutrition regulator of Ca2+ signal. However, its effect on the skeletal muscle development of pigs has not been reported. This project starts from the thought of inositol-IP3R1-Ca2+ signal-skeletal muscle development, and uses muscle fiber generation and fiber-type transition as a foothold. Effects of inositol on muscle fiber generation in embryonic period and muscle fiber-type transition in early postnatal period will be studied through the supplementation of inositol to gestational and lactating diets of sows and to nursery diets of piglets. What’s more, IP3R1 will be silenced in myogenic precursors derived from the skeletal muscle of pigs, and the role of IP3R1-mediated Ca2+ signaling in the regulation of porcine skeletal muscle development by inositol will be revealed from the perspective of cell differentiation and metabolism. Overall, this study will provide scientific evidence and nutritional strategies for improving skeletal muscle development and meat production efficiency of pigs through targeting IP3R1-Ca2+ signal axis.