北疆地区阿勒泰断尾羔羊及杂交种的耐寒性能及体脂能量代谢研究

In winter cold wave sweeping cross many areas in Xinjiang, and had longer duration especially in northern region. Livestock were dead serious in the main pastoral areas, and caused great losses to animal husbandry. As a native species Altay sheep is formed by natural selection and is cold tolerance after the long-term closed cultivation in northern region of Xinjiang, which could withstand the persistent low-temperature environment. This project designated severed tail sheep, hybrid sheep compared with the Altay sheep for control, to detect the physiological and biochemical indexes, fat metabolism, and the effects of cold stress on gene expression in lipid synthesis and decomposition. Sympathetic nerve has a great influence on peripheral adipose tissue and energy metabolism in cold environment, so from ADRB3 signal pathway this paper discussed the interrelationship of downstream gene HSL and UCP. The immunohistochemical method was used to show the tyrosine hydroxylase and neuropeptide Y expressions. In last, we detected the properties of cold tolerance. The object is to analyze the adipose differentiation, energy metabolism pathway and the cold resistance ability in this three groups. Whether through cross breeding or tail reduce the fat deposition in the tail, fat redistribution is causing the decrease of anti-cold ability. This project aims to provide a theoretical basis for breeding cold tolerance sheep.

新疆冬季的寒潮与强降温频发，持续时间长，尤其北疆气候异常寒冷，主要牧区牲畜死亡严重。北疆地区经过长期封闭式自繁自育形成的优良土种抗寒品种阿勒泰大尾羊，能够抵御极端且持久的低温环境。本项目将阿勒泰羔羊进行断尾、与萨福克羊杂交种和正常组之间进行寒冷应激，拟通过检测脂肪代谢相关生理生化指标、体脂沉积、及与脂肪合成和分解相关基因的表达；另外寒冷环境下交感神经对外周脂肪组织以及能量代谢有很大影响，故从ADRB3的信号通路入手，研究下游的激素敏感脂酶和解偶联蛋白三者之间的关联，用免疫组织化学方法测定下丘脑和外周脂肪组织中酪氨酸羟化酶和神经肽Y的分布情况；最后对三组羔羊的抗寒性能进行测定。分析低温下杂交种和断尾羔羊的脂肪分化规律、能量代谢通路及对寒冷的抵抗能力，是否可以通过杂交育种或者断尾减少脂肪在尾部的大量沉积，但脂肪的重新分布是否导致其抗寒能力下降，研究结果将为新疆绵羊抗寒育种工作提供理论依据。

新疆冬季的寒潮与强降温频发，持续时间长，尤其北疆气候异常寒冷，主要牧区牲畜死亡严重。北疆地区经过长期封闭式自繁自育形成的优良土种抗寒品种阿勒泰大尾羊，能够抵御极端且持久的低温环境。本项目构建羔羊冷应激模型；ELISA测定血清中激素、血脂、IgG、皮质醇和抗氧化因子的含量；通过qPCR和Western Blot法测定羔羊不同组织中3种基因ADRB3、UCP1和HSL转录和翻译水平的变化；通过免疫组化方法检测TH和NPY的分布；用HE和甲苯胺蓝染色，观察羔羊小肠显微结构的变化及其杯状细胞、上皮淋巴细胞和肥大细胞的数量变化；应用qPCR法测定羔羊外周血白细胞和脾脏细胞因子mRNA的表达量变化，观察羔羊免疫功能。结果如下：三种羔羊血清中 TG、T-CHO、LDL和HDL浓度总体呈现上升趋势, 而LEP、GC和INS含量呈动态不规律变化。冷应激后羔羊血清中抗氧化因子SOD、MDA和GR含量先增加后减少，且高于常温组，GSH-PX的含量波动但呈下降趋势。冷应激后，阿勒泰羔羊颈部脂肪、肩胛间脂肪和腹股沟脂肪中FAS、LPL和SCDmRNA的表达量上升，PPARγmRNA在颈部脂肪和肩胛间脂肪中的表达量下降，在腹股沟脂肪中上升；杂交种羔羊LPLmRNA的表达量上升，SCD和PPARγmRNA在肩胛间脂肪和腹股沟脂肪中的表达量上升，在颈部脂肪中下降，FASmRNA在颈部脂肪和腹股沟脂肪中的表达量上升，在肩胛间脂肪中下降。冷应激后断尾羔羊FAS和LPLmRNA在腹股沟脂肪中呈上升趋势。SCD mRNA在颈部脂肪中呈下降趋势，肩胛间和腹股沟脂肪中上升。PPARγmRNA在颈部脂肪和腹股沟脂肪中上升，肩胛间脂肪中下降；冷刺激后羔羊各组织中ADRB3、UCP1和HSL的mRNA及蛋白表达呈动态变化，较常温组有所增加。冷应激后小肠的显微结构发生了相应变化，肠绒毛变短且变粗，炎性细胞增多，回肠内淋巴小结数量增多，小肠中杯状细胞和肥大细胞数量增多，上皮淋巴细胞数量减少；冷应激后外周血白细胞和脾脏中IL-1、IL-2、IL-4、Il-6、IL-10、IL-12、IFN-γ和IFN-β的mRNA表达量总体出现上升趋势，冷应激会造成杂交羔羊和断尾羔羊机体内出现炎症反应。研究结果将为新疆绵羊抗寒育种工作提供一定的理论依据。