天然草原牧草代谢能水平、脂肪及脂肪酸组成季节变化是绵羊（Aries ovis）脂肪代谢、沉积特性的环境胁迫力。牧草代谢能水平是绵羊采食、脂肪代谢，特异性组织脂肪沉积的重要信号，是绵羊适应性的重要遗传性状。牧草代谢能水平的高低决定绵羊采食量，同时，牧草代谢能水平与脂肪含量协同调控机体糖平衡和脂肪代谢。本项目拟以北方草原为环境背景，以短脂尾、长脂尾、短瘦尾、长瘦尾、肥臀羊等北方主要绵羊品种为研究对象，通过瘤胃瘘管测定结合近红外技术研究牧草代谢能的季节变异；应用气相色谱技术研究牧草和绵羊体脂脂肪酸组成变异的关系。通过调控饲粮的代谢能水平和脂肪含量，模拟北方草原牧草季节性动态变化，采用生化、生理学，近红外及气相色谱技术相结合,研究不同尾脂绵羊的脂肪沉积和部位特异性；揭示牧草不同代谢能水平对绵羊采食调控、脂肪细胞发育的传导机理。研究成果将为绵羊能量高效利用途径及人类糖尿病、肥胖症的防治提供基础参考。

The grass of the natural pasture differs in its metabolic enrery and the fat content in addition to fatty acids profile . Development of adipose tissue and lipid metabolism of sheep(Aries ovis) are closely associated with adaptive evolution under the environmental stresses of ME alteration of the grasses of the pasture. The alteration of ME in grasses of the pasture is the transforming signal of adipocyte developemnt and fat metabolism which are the form of fitness of sheep through evolution process. The content of ME in the grasses determines intake of the sheep and it also cooperates with fat and fatty acids invlving into the energy balance and Glucose homeostasis process. This research proposal will be based on the different environment in the natural pastures of western China, and it selected 5 types of sheep breeds as animal models with different anatomical position of the fat depots, which includes the breeds with short-fat tail,long-fat tail, short-fatless tail,long-fatless tail and fat buttocks. The technology of animal model- NIR(Near Infrared Spectroscopy) testing system will be applied to study and to simulate the natural alteration of ME in grasses of the different pastures. The gas chromatography technology will be applied to study the fat content and fatty acids profile of the grasses and also sheep depotes. This research proposal was designed phased ME rations for the different sheep breeds to understand that how the adipocytes development and the fat depotes proceeding can be altered through the ME levels of feeds,and how the energy balance and glucos homaostasis of sheep body responses to the different levels of ME of the rations, especially in the extrem scenarios regarding nature pasture condition over the year. In addition, the regulation of fat deposition,the morphological characteristics of the adipocytes and regulation of the signal transduction pathway at different anatomic locations of the different sheep breeds with specific tail features will be thoroughly studied regarding the engergy intake and fat intake by the sheep.The results expected from the proposed research project will be to clarify the effects of ME levels of the rations on the regulation of adipocytokines (e.g.,leptin, adiponectin and resistin) and the effect of adipocytokine level of the plasma on glucose homaestasis and energy balance machanism. Results of the research also expected to elucidate the tissue-specific depot mechanisms of the sheep breeds and its adipocytes development under environmental stress such as energy alteration.To understand the complexity of lipid metabolism with alteration of feed energy supply addressed above will provide useful references in addressing issues of human obesity and diabetes and it will also provide new concept of the efficiency use of energy feeds so that the grains will be saved for important sector of society. It is cosistant with overall policy of grain security.