滩羊妊娠期日粮亮氨酸水平对子代骨骼肌蛋白质合成的调控机制

Skeletal muscle mass and myofiber type are known to affect meat quality. Leucine can induce skeletal muscle protein synthesis, and maternal nutrition during gestation have long-time effects on skeletal muscle growth and development in offspring. But the regulatory mechanism of dietary leucine level during gestation on the skeletal muscle protein synthesis and myofiber type of offspring at different growth stages was not been studied. In the present study, Ningxia Tan sheep will be used as animal model, the effect of dietary leucine levels during gestation on the growth performance, carcass characteristic, meat quality, blood parameters, and protein turnover of offspring at different growth stages will be determined, and the molecular association between dietary leucine levels and muscle growth and myofiber type will be further exploreed by quantitative PCR, Western blot and proteomic analyses. In addition, in vitro cell culture test will used to further study mechanism regulating skeletal muscle protein synthesis. The research results will enrich the theory of maternal impact on offspring growth and development, so called "developmental programming", which will provide scientific foundation for improving carcass composition and meat quality of Tan sheep.

骨骼肌含量和肌纤维类型与肉质密切相关而受到广泛关注。研究表明，亮氨酸可促进骨骼肌蛋白质合成，而妊娠期母体营养状况对子代骨骼肌生长发育会产生持续性影响。然而，妊娠期日粮亮氨酸水平对出生后子代不同生长阶段骨骼肌蛋白质合成及肌纤维类型的调控机制目前仍不清楚。本项目以宁夏滩羊为动物模型，通过动物试验确定妊娠期日粮亮氨酸水平对子代羔羊和育成羊生长性能、胴体组成、肉质、血液指标及蛋白质周转的影响；同时采集不同处理组子代的背最长肌和半腱肌作为样品，利用Real-time PCR和Western blot分析对子代羔羊和育成羊肌纤维类型的影响；运用蛋白组学揭示妊娠期日粮亮氨酸水平调控子代不同生长阶段骨骼肌蛋白质合成的关键蛋白；最后，采用体外细胞培养试验进一步验证关键蛋白调控骨骼肌蛋白质合成的机制。研究结果将理论上丰富妊娠期母体营养调控子代生长发育的相关理论，实践上能够为改善滩羊胴体组成和肉质提供科学依据。

亮氨酸可促进骨骼肌蛋白质合成，而妊娠期母体营养状况对子代骨骼肌生长发育会产生持续性影响。滩羊是宁夏地区优良地方品种，目前滩羊胴体瘦肉率和肉质下降，成为制约滩羊产业发展的主要因素，而骨骼肌蛋白质合成及肌纤维类型与肉质密切相关。针对妊娠期日粮亮氨酸水平对出生后子代骨骼肌蛋白质合成及肌纤维类型的调控机制仍不明晰现状。本课题以宁夏滩羊为动物模型，首先确定了妊娠期滩羊日粮适宜亮氨酸添加水平，通过检测和分析，我们发现，妊娠期添加适宜亮氨酸能够显著提高母羊繁殖性能和生产性能，对新生子代滩羊生产性能起到积极调控作用。滩羊妊娠期添加适宜亮氨酸能够显著提高子代不同生长阶段（10 kg和35 kg）骨骼肌蛋白质合成；提高了与肉质正相关的肌纤维类型比例；蛋白质组学和体外细胞培养实验结果，进一步揭示了妊娠期亮氨酸对子代骨骼肌蛋白质沉积和肌纤维类型组成的调控机理。本课题研究结果丰富了妊娠期母体营养对子代肉质及生产调控的相关理论。