奶牛乳房炎与肠道菌群的关联研究

发布时间：2019-04-29 07:31

【摘要】：乳房炎是奶牛养殖场中的高发病,经抗生素治愈后极易复发。疾病的反复发作导致奶牛的产奶量持续下降,乳头坏死,进而被淘汰。乳房炎也是哺乳期妇女常患的疾病,传统的抗生素治疗损伤新生儿的神经系统。在乳房炎的治疗方法中,抗生素因其大量的负面作用使得其已不适合在乳房炎治疗中滥用,应加快开发新的且有效的抗生素替代物用以治疗或预防乳房炎。益生菌在多种疾病的预防与治疗中都有成功的应用实例。因此,益生菌在乳房炎的治疗与预防中是否真的有效是一个有趣的研究方向。益生菌主要于宿主的肠道中发挥其关键作用,因此肠道菌群与乳房炎发病是否有关联,是益生菌能否应用于乳房炎的治疗中需要解答的首个问题。在本论文中,以健康奶牛与患乳房炎奶牛为对象,对健康奶牛与乳房炎奶牛的肠道菌群中常见的菌属与菌种进行定量研究,相关性分析结果发现在两组奶牛之间,以L.buchneri为首的乳杆菌种对两组差异的贡献度最大,达到27.32%,其次为L.sake,达到9.64%。选定哺乳期无菌小鼠为动物模型,将乳房炎奶牛粪便与健康奶牛粪便分别移植入无菌小鼠体内,同时选取一组移植乳房炎奶牛粪便的小鼠进行益生菌干预。通过菌群移植,对哺乳期小鼠的乳腺组织以及身体其它各项免疫指标进行监控,探究移植健康奶牛粪便小鼠组与移植乳房炎奶牛粪便小鼠组以及移植乳房炎奶牛粪便同时进行益生菌干预组小鼠的乳腺组织是否发生炎症以及炎症程度如何。实验结果发现,移植乳房炎奶牛粪便的小鼠在菌群移植25天检测时发现明显的乳腺组织炎症反应,而移植健康奶牛粪便的小鼠没有明显的炎症,进行益生菌干预的小鼠组炎症较弱。在组织病理学检验之后,采集三组小鼠粪便样品与两组奶牛粪便样品一同进行了宏基因组测序以及16S rRNA基因全长测序。结果发现,奶牛肠道菌群移植入小鼠体内之后,其结构发生改变,但是在移植健康组奶牛粪便的小鼠组中,肠道菌群的结构改变较小,更倾向于健康组奶牛的肠道菌群结构；移植乳房炎奶牛粪便的两组小鼠,其中一组进行益生菌干预的小鼠组,两组小鼠的肠道菌群结构区分度较小,但与乳房炎奶牛的肠道菌群结构改变较大。同时在健康组奶牛与移植其粪便的小鼠组肠道菌群中产乙酸、丁酸以及琥珀酸的菌属丰度较高。16S rRNA基因全长测序发现在移植健康奶牛粪便的小鼠中Lactobacillus的含量较高。从宏基因组测序的结果与16S rRNA基因全长测序结果发现,患乳房炎奶牛与健康奶牛的肠道菌群结构与功能都存在差异,且将奶牛肠道菌群移植入无菌小鼠之后,这种菌群结构与功能之上的差异同时被放大形成鲜明的对比。实验结果表明健康的肠道菌群结构对于保持奶牛的健康状态有直接的影响,益生菌可调节奶牛的肠道菌群,对于维持奶牛健康,预防和缓解乳房炎有不可忽视的潜能。
[Abstract]:Mastitis is a high incidence in dairy cattle farms and easy to recur after being cured by antibiotics. The recurrence of the disease led to a continuous decline in milk production, nipple necrosis, and thus elimination of milk production in cows. Mastitis is also a common disease among lactating women. Traditional antibiotics treat neonatal nervous system damage. In the treatment of mastitis, because of its negative effects, antibiotics are no longer suitable for abuse in mastitis treatment. It is necessary to speed up the development of new and effective antibiotic substitutes for the treatment or prevention of mastitis. Probiotics have been successfully applied in the prevention and treatment of many diseases. Therefore, whether probiotics is really effective in the treatment and prevention of mastitis is an interesting research direction. Probiotics play a key role in the host intestine, so whether the intestinal flora is associated with mastitis is the first question whether probiotics can be used in the treatment of mastitis. In this paper, healthy cows and cows with mastitis were used to quantitatively study the common bacteria and bacteria in the intestinal microflora of healthy cows and mastitis cows. The results of correlation analysis showed that between the two groups of cows, the results of correlation analysis showed that there was no significant difference between the two groups of cows. The difference between the two groups was the largest by L.buchneri, with 27.32%, followed by L.sake, which reached 9.64%. Lactating aseptic mice were selected as animal models. Mastitis cow feces and healthy cow feces were transplanted into aseptic mice, and a group of mice transplanted mastitis cow feces were selected for probiotics intervention. Through microflora transplantation, breast tissue and other immune indexes of lactating mice were monitored. To investigate whether the mammary tissue of the mice transplanted with healthy cow feces and the mice transplanted with mastitis cow feces and the mice treated with probiotics at the same time had inflammation and the degree of inflammation. The results showed that mice transplanted with mastitis cow feces showed significant inflammation in breast tissue during 25 days of microflora transplantation, but no significant inflammation was found in mice transplanted with cow feces from healthy cows. The inflammation of mice treated with probiotics was weaker than that of mice treated with probiotics. After histopathological examination, three groups of mice fecal samples and two groups of cow fecal samples were collected and sequenced for metagenomic sequencing and 16s rRNA gene full-length sequencing. The results showed that the structure of intestinal flora was changed after it was transplanted into mice, but in the group of mice transplanted with cow feces, the structure change of intestinal flora was smaller, and it was more inclined to the structure of intestinal flora of cow in healthy group. Two groups of mice transplanted mastitis cow feces, one group of mice treated with probiotics, the intestinal microflora structure of the two groups of mice was smaller, but with mastitis cow intestinal flora structure change is greater. At the same time, the abundance of bacteria producing acetic acid, butyric acid and succinic acid was higher in the intestinal flora of healthy cows and mice transplanted with their feces. The full-length sequencing of 16s rRNA gene showed that the content of Lactobacillus in the feces of transplanted healthy cows was higher. From the results of macro-genome sequencing and full-length 16s rRNA gene sequencing, it was found that there were differences in the structure and function of intestinal flora between cows with mastitis and healthy cows, and the intestinal flora of dairy cows was transplanted into aseptic mice. The differences in the structure and function of this flora are also magnified to form a sharp contrast. The results showed that the structure of healthy intestinal flora had a direct effect on maintaining the healthy state of dairy cows. Probiotics could regulate the intestinal microflora of dairy cows, which could not be ignored to maintain the health of dairy cows, prevent and relieve mastitis.
【学位授予单位】：内蒙古农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S858.23

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