本文選題：牦牛 + 細(xì)菌��； 參考：《蘭州大學(xué)》2016年博士論文

【摘要】：青藏高原被稱為世界“第三極”,擁有全球海拔最高、面積最大和唯一被四季放牧利用的高寒草地。獨(dú)特的高寒生態(tài)環(huán)境(高海拔、寒冷、缺氧、紫外線強(qiáng)、牧草季節(jié)供應(yīng)嚴(yán)重失衡),使得生存于此的牦牛種群在協(xié)同進(jìn)化過(guò)程中產(chǎn)生了一系列特殊的適應(yīng)機(jī)制。近年來(lái)的研究發(fā)現(xiàn),與黃牛相比,牦牛在消化器官組織結(jié)構(gòu)、牧食行為、氮素利用效率、甲烷排放、瘤胃甲烷菌菌群結(jié)構(gòu)、季節(jié)間能量分配等方面均優(yōu)于黃牛;并從牦牛全基因組測(cè)序中找到了適應(yīng)高寒營(yíng)養(yǎng)脅迫的相關(guān)功能基因。為此我們推斷,長(zhǎng)期的極端環(huán)境與營(yíng)養(yǎng)脅迫,使細(xì)菌/甲烷菌在牦牛瘤胃和不同腸道部位中分別形成了特殊的時(shí)間動(dòng)態(tài)和空間分布模式,以幫助宿主提高能量利用效率和有效應(yīng)對(duì)每年長(zhǎng)達(dá)8個(gè)月的冷季營(yíng)養(yǎng)匱乏。本試驗(yàn)以牦牛為研究對(duì)象,主要利用通用引物515F/806R通過(guò)16S二代高通量測(cè)序,分析了細(xì)菌/甲烷菌在瘤胃中的定植過(guò)程(3、14、60、180、365和730天)、季節(jié)動(dòng)態(tài)(春、夏、冬)和不同腸道部位(19個(gè)部位)的空間分布,擬尋找牦牛腸道微生態(tài)系統(tǒng)中有助于宿主適應(yīng)高寒嚴(yán)酷生態(tài)系統(tǒng)的特殊微生物群落,為進(jìn)一步通過(guò)調(diào)控腸道微生態(tài)系統(tǒng)提高牦牛生產(chǎn)性能和實(shí)現(xiàn)藏區(qū)畜牧業(yè)的可持續(xù)發(fā)展提供理論基礎(chǔ)和技術(shù)支撐。本研究得到的主要結(jié)果如下:1.牦牛瘤胃細(xì)菌/甲烷菌定植過(guò)程中豐度指數(shù)Chao1的增加分為三個(gè)梯度,3和14天為第一階段,60、180和365天為第二階段,730天為第三階段;多樣性指數(shù)Shannon在3、14天低于其它年齡組(P0.05),其它年齡組之間沒(méi)有差異(P0.05)。2.牦牛瘤胃細(xì)菌定植過(guò)程中優(yōu)勢(shì)門水平的細(xì)菌是厚壁菌門(Firmicutes),擬桿菌門(Bacteroidetes)和變形菌門(Proteobacteria)三大類,約占85%。其中厚壁菌門(Firmicutes)所占的比例最高,在不同年齡組之間維持在約50%;擬桿菌門(Bacteroidetes)從3天的23%增加到了730天的43%;變形菌門(Proteobacteria)從3天的17%降低到了730天的2.3%。以上兩種菌門的增加/降低都呈現(xiàn)出幼齡段(3、14天)、發(fā)育段(60、180天)和成年段(365、730天)階梯式的變化。3.牦牛瘤胃甲烷菌—廣古菌門從3天的0.3%增加到60天最高的2%,隨后在成年組(365、730天)維持在約1.3%。4.瘤胃微生物定植過(guò)程中的途徑主要是通過(guò)母畜唾液,將從母畜瘤胃中反芻帶到口腔的瘤胃微生物轉(zhuǎn)移到幼齡反芻動(dòng)物的瘤胃中。5.牦牛瘤胃細(xì)菌/甲烷菌季節(jié)變化過(guò)程中的豐度指數(shù)Chao1從大到小的順序是春夏秋,多樣性指數(shù)Shannon與豐度指數(shù)呈現(xiàn)相同的趨勢(shì),但是春夏兩季之間多樣性更加接近。同一季節(jié)組內(nèi)相似性春季最低,夏季最高。6.不同季節(jié)間以厚壁菌門(Firmicutes)和擬桿菌門(Bacteroidetes)為優(yōu)勢(shì)菌,在春、夏、冬三個(gè)季節(jié)所占的比例分別為75%、80%和77%。其中擬桿菌門的組成比例在春季最低約45%,在夏冬兩季基本相同約為54%;而厚壁菌門在春夏冬三個(gè)季節(jié)的比例分別是30、26、23%。7.在冷季(春冬兩季),由于牦牛采食牧草中的纖維含量增高,瘤胃微生物中分解纖維的菌屬高于暖季(夏季),而夏季中降解植物次級(jí)代謝產(chǎn)物和利用可溶性糖、氨基酸的菌屬高于冷季。春季中的纖維降解菌屬的種類和比例高于冬季。牦牛瘤胃甲烷菌的比例在冬季最低,而春夏兩季的比例基本相同。8.在相同的低氮日糧下,牦牛和黃牛不同腸道部位的細(xì)菌/古菌Alpha和Beta多樣性沒(méi)有差異。細(xì)菌/甲烷菌在不同腸道部位的豐度指數(shù)(Chao1)和多樣性指數(shù)(Shannon),都是在前腸道內(nèi)容物和大腸最高,前腸道壁次之,小腸中最低。不同腸道部位同一樣品組內(nèi)微生物多樣性在小腸部位最低,其次是大腸,前腸道(內(nèi)容物和腸道壁)中相似性最高。9.忽略不同的腸道部位,在門水平的優(yōu)勢(shì)細(xì)菌是厚壁菌門(Firmicutes)和擬桿菌門(Bacteroidetes),在前腸道和小腸約占75%,而大腸中的占比高達(dá)90%。厚壁菌門(Firmicutes)在小腸和大腸中的比例高于前腸道,而擬桿菌門(Bacteroidetes)在前腸道部位高于小腸和大腸。甲烷菌的比例在小腸高于腸道其它部位。Cyanobacteria菌門在牦牛不同腸道部位的比例高于黃牛。10.在前腸道壁分布的優(yōu)勢(shì)菌屬主要參與氧氣、尿素和揮發(fā)性脂肪酸的吸收利用;前腸道部位內(nèi)容物中比例較高的菌屬主要負(fù)責(zé)來(lái)自日糧中的纖維素、植物次級(jí)代謝產(chǎn)物、淀粉和糖類的降解與利用;小腸中具有優(yōu)勢(shì)的菌屬很少,主要是參與維生素的合成和黏素的降解;大腸主要負(fù)責(zé)吸收和利用一些沒(méi)有被前腸道部位消化吸收的糖類、次級(jí)代謝產(chǎn)物和鹽類。PICRUSt功能分析顯示牦牛腸道微生態(tài)中比黃牛存在更多未知的菌群。與KEGG數(shù)據(jù)庫(kù)比對(duì),牦牛高于黃牛的基因家族的數(shù)量要多于黃牛高于牦牛的數(shù)量,其中能量?jī)?chǔ)存、脂質(zhì)代謝和聚糖合成和代謝的三大基因家族在牦牛要高于黃牛,這些基因家族的差異,可能會(huì)幫助牦牛提高能量利用效率。本試驗(yàn)首次全面分析了細(xì)菌/甲烷菌在放牧牦牛瘤胃中的時(shí)間動(dòng)態(tài)和不同腸道部位的空間分布。同時(shí),利用PICRUSt對(duì)細(xì)菌/甲烷菌的基因功能進(jìn)行了全面預(yù)測(cè),為青藏高原極端環(huán)境條件下的牦牛腸道微生物如何應(yīng)對(duì)嚴(yán)酷的環(huán)境脅迫提供了重要的科學(xué)依據(jù)和理論支撐。
[Abstract]:The Qinghai Tibet Plateau is known as the "third pole" of the world. It has the highest altitudes, the largest area and the only cold grassland used by the four seasons. The unique Alpine ecological environment (high altitude, cold, anoxia, ultraviolet light, and the seasonal supply of herbage is out of balance), which makes a series of yak populations living in the process of co evolution. In recent years, studies have found that yaks are superior to yellow cattle in the structure of the digestive organs, grazing behavior, nitrogen use efficiency, methane emission, rumen methanogens group structure, and interseasonal energy distribution, compared with yellow cattle, and the related functions adapted to alpine nutrition stress are found in the whole gene group of yak. For this reason, we infer that long-term extreme environment and nutritional stress make bacteria / methanogens in the rumen and different intestinal parts of the yak, respectively, to form a special time dynamic and spatial distribution pattern to help the host improve the efficiency of energy utilization and to respond effectively to the cold season nutrition shortage for up to 8 months. The main purpose of this study is to analyze the spatial distribution of bacterial / methanogens in the rumen of the rumen (3,14,60180365 and 730 days), seasonal dynamics (spring, summer, winter) and different intestinal sites (19 parts) by high throughput sequencing of the 16S two generation by the universal primer 515F/806R, which is intended to help the host adapt to the adaptation of the host to Gao Hanyan. The special microbial community of the cool ecosystem provides the theoretical basis and technical support for further regulating the production performance of the yaks and realizing the sustainable development of the Tibetan animal husbandry by regulating the intestinal microflora system. The main results of this study are as follows: 1. the increase of the abundance index Chao1 in the rumen bacteria / methane bacteria colonization process of the yak is divided into two parts. The three gradient, 3 and 14 days were the first, the 60180 and 365 days were second, the 730 day was third; the diversity index Shannon was lower than the other age groups (P0.05), and there was no difference between the other age groups (P0.05) the bacteria of the dominant gate level in the rumen bacterial colonization of.2. yak were Firmicutes, Bacter Oidetes) and deformable bacteria gate (Proteobacteria) were the three major categories, accounting for about 85%., which accounted for the highest proportion of the Firmicutes, maintained about 50% in different age groups, and the bacteriobacteria (Bacteroidetes) increased from 23% in 3 days to 43% in 730 days; the Proteus gate (Proteobacteria) decreased from 17% to two bacteria of 730 days from 3 days. The increase / decrease of the door showed a young age (3,14 days), the development segment (60180 days) and the adult segment (365730 days) of the step change of the.3. yak rumen methanogens - the palaeo - palaebacterium gate increased from 0.3% to the highest 60 days in the 3 day, and the pathway in the adult group (365730 days) to maintain in the about 1.3%.4. rumen microbial colonization was mainly through the mother. The abundance index of the.5. yak in the rumen of the rumen of the ruminant from the rumen of the animal to the rumen of the rumen to the rumen of the young ruminant is the same in the order of spring and summer autumn, the diversity index Shannon and the abundance index are the same, but between the two seasons of spring and summer. In the same season, the similarity in the same season is the lowest in spring, and the highest.6. in summer is Firmicutes and Bacteroidetes. In spring, summer and winter, the proportion of the three seasons is 75%, 80% and 77%., and the proportion of the phyllillas is about 45% in spring, and in the two seasons of summer and winter. The same agreement was 54%, while the proportion of the three seasons in the spring and summer winter was 30,26,23%.7. in the cold season (in the spring and winter two seasons). The fiber content in the rumen microbes was higher than that in the warm season (in summer), and the secondary metabolites of plants and the use of soluble sugar and amino acids in summer were higher than those in the warm season (in summer). The species and proportion of fiber degrading bacteria in spring are higher than that in winter. The proportion of yak rumen methanogens is the lowest in winter, and the proportion of the two seasons in spring and summer is basically the same as.8. in the same low nitrogen diet. There is no difference in the diversity of bacteria / Alpha and Beta in the different intestinal parts of yak and yellow cattle. Bacteria / methanogens are different The abundance index (Chao1) and diversity index (Shannon) of the intestinal tract were the highest in the anterior intestine and the large intestine. The anterior intestinal wall was the second and the lowest in the small intestine. The microbial diversity in the same sample group was the lowest in the small intestine, followed by the large intestine, and the highest similarity in the anterior intestine (content and intestinal wall) was ignored by.9.. In the intestinal tract, the dominant bacteria at the portal level are Firmicutes and Bacteroidetes, in the anterior intestine and the small intestine about 75%, while the proportion of the large intestine in the large intestine is higher than that in the small intestine and large intestine (Firmicutes) in the small intestine and the large intestine than in the anterior intestine, and the bacteribacillus gate (Bacteroidetes) is higher in the anterior intestine than in the small intestine and the large intestine (Bacteroidetes). The proportion of methanogens in the small intestine is higher than that of.Cyanobacteria bacteria in the other parts of the intestines. The proportion of.10. in the yak is higher than that of the yellow cattle. The dominant bacteria in the anterior intestinal tract are mainly involved in the absorption and utilization of oxygen, urea and volatile fatty acids; the bacteria with higher proportion in the contents of the anterior intestine are mainly responsible for the diet. The degradation and utilization of cellulose, secondary metabolites of plants, starch and carbohydrates; the dominant bacteria in the small intestine are rare, mainly involved in the synthesis of vitamins and the degradation of the amyloid; the large intestine is mainly responsible for absorption and utilization of some sugars that are not digested and absorbed by the anterior intestine. Secondary metabolites and salt.PICRUSt functions are analyzed. Compared with the KEGG database, the number of yaks higher than the yellow cattle is more than the number of yak, and the three big gene families of energy storage, lipid metabolism and glycan synthesis and metabolism in Yak cattle are higher than the yellow cattle, and the difference of these gene families can be found. It can help yak to improve the efficiency of energy utilization. The time dynamics and spatial distribution of bacteria / methanogens in the rumen of Grazing Yaks were analyzed for the first time. At the same time, the genetic function of bacteria / methanogens was comprehensively predicted by PICRUSt for the Yak's intestinal microbiology under the extreme environment of the Qinghai Tibet Plateau. How to deal with severe environmental coercion provides important scientific basis and theoretical support.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：S823.85
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本文編號(hào)：2026201