冷季补饲对欧拉型藏羊瘤胃发酵及其瘤胃微生物区系的调控

There are more variety breeds in Tibet sheep, but the classification is so confusion and the morphology is more different. Euler Tibetan sheep live in the northeast Qinghai-Tibet plateau above 3500m.It’s the landscape sheep and main breeds of the area. It’s also one of the scare large sheep breeds. The mutton is very delicious and the nutritional value is high. And it is purely natural, green, pollution-free and security. Consumer likes it very much. But the shape of Euler Tibetan sheep are different from the others. There are no reports about the difference of ruminal structure and digestive fuction between Euler Tibetan sheep and other Tibetan sheep. The study on mechanism of its ruminal structure and digestive fuction is still blank. So, in this study Euler Tibetan sheep will be selected as the research object. Different quantity of concentrate supplementary feeding will be designed for experimental treatment.Through a hay period (cold season) supplementary feeding test, histomorphometric of rumen; Ruminal fermentation parameters ;Rumen microbial enzyme activity；Number and diversity of rumen microorganisms；Weight and body measurements will be tested. Comparative analysis will be used to clear the relationship between body weight and body measurements and rumen fermentation parameters, rumen microbes ,and the effect of concentrate supplementary feeding amount on Euler Tibetan sheep rumen fermentation regulation mechanism and production performance in cold season. It has important significance to know rumen environment improvement and improve the domestic ruminant production performance under the condition of supplementary feeding in cold season of Tibetan sheep of Qinghai-Tibet Plateau region.

藏系绵羊种类繁多，分类混乱，形态差异较大。欧拉型藏羊生存在3500m以上的青藏高原东北部，是高原景观羊种和当家畜种，也是国内少有的大型羊种，羊肉品质好、营养价值高，属纯天然、绿色、无污染、安全畜产品，倍受消费者青睐。其外形与其他藏系绵羊差异较大，但其瘤胃组织结构及其微生态环境与其他藏系绵羊有无差异尚未见报道。营养水平对其瘤胃组织结构和消化功能的作用机制研究依然空白。因此，本研究拟以欧拉型藏羊为研究对象，以不同精料补饲量为试验处理，通过1个枯草期（冷季）补饲试验，测定瘤胃组织形态结构；瘤胃发酵参数；瘤胃微生物酶活；瘤胃微生物数量和多样性；体重、体尺指标。对比分析体重、体尺指标与瘤胃发酵参数和瘤胃微生物之间的关系，明确冷季精料补饲量对欧拉型藏羊瘤胃发酵调控的机制及其对生产性能的影响。这一研究对认识冷季补饲条件下藏羊瘤胃内环境改善,探索提高青藏高原地区家养反刍动物生产性能有重要意义。

冷季欧拉型藏羊通过放牧摄入的营养物质满足不了其营养需要，导致体重下降，需要对其补饲一定量的饲草料，以保证动物良好的生存状态和更高的生产性能。本项目研究了冷季补饲状态下欧拉型藏羊生产性能、屠宰性能、瘤胃组织形态结构、瘤胃发酵参数、瘤胃微生物酶活和瘤胃微生物数量及多样性等的变化，试验结果表明：1）冷季补饲精饲料可显著提高欧拉型藏羊日增重，维护机体健康，提高屠宰性能，增加经济效益（P<0.05）。2）冷季补饲精饲料可降低瘤胃乙酸的百分比，提高其它VFAs的百分比，调控发酵类型，提高微生物酶活性和细菌的绝对数量（P<0.05）；补饲0.30kg精料时微生物酶活性和细菌、真菌及原虫绝对数量均下降。3）冷季补饲精饲料，瘤胃细菌的丰富度、多样性和PD_whole_tree指数提高，古生菌和厌氧真菌的降低。补饲0.20kg精料时，细菌的多样性及原虫的丰富度、多样性和PD_whole_tree指数均最高，细菌丰富度最低。4）补饲精料显著下调Bacteroidetes、Prevotella-1和拟杆菌门/厚（硬）壁菌门（B/F）的值，显著上调Firmicutes和Euryarchaeota相对丰度（P<0.05）。补饲0.20kg精料，Byssochlamys、Orpinomyces、Neocallimastix、Polyplastron、Diplodinium和Isotricha相对丰度最高。5）补饲精料显著下调细菌的Metabolism功能和Genetic Information Processing功能（P<0.05）；显著上调Environmental Information ProcessingCellular Processes功能（P<0.05），古生菌与细菌的功能相反；补饲精料显著提高Saprotroph-Symbiotroph营养型真菌数量，显著降低Pathotroph-Saprotroph营养型和Pathotroph营养型真菌数量（P<0.05）。综上，在本试验条件下，补饲0.20kg精饲料更有利于改善藏羊瘤胃内环境，调控瘤胃微生物菌群结构和功能，改善动物机体健康，提高藏系绵羊的综合经济效益。本研究对认识冷季补饲对藏羊瘤胃内环境改善，探索提高青藏高原地区家养反刍动物生产性能有重要的实践意义。