多西环素对黄牛肠道微生物菌群多样性和功能预测的分析研究

Analysis and research on the diversity and function prediction of the intestinal microflora of cattle by doxycycline

为了研究多西环素对黄牛肠道微生物菌群结构和多样性的影响,试验随机选取3头健康黄牛,每天清晨饲喂后1小时,按体重灌服多西环素15 mg/kg,连续7 d,分别在灌药当天及灌药结束后的第2天清晨空腹采集直肠粪样。采用自身对照法,利用16S RNA测序技术提取样品中基因组DNA,分别对两次采集的粪便构建测序文库并进行Illumina MiSeq测序,进行生物信息学分析、样本复杂度分析和多样本比较分析,利用Tax4Fun程序进行功能注释和预测。结果表明:多西环素可降低黄牛肠道菌群的丰度和多样性,厚壁菌门相对丰度比灌服多西环素前有所增加,拟杆菌门相对丰度比灌服多西环素前有所减少。在门水平上,浮霉菌门和柔壁菌门丰度显著或极显著降低(P<0.05或P<0.01);属水平上拟杆菌属和产己酸菌属的丰度显著增加(P<0.05)。饲喂多西环素之后,在膜运转、复制与修复、辅酶因子和维生素代谢、新陈代谢、碳水化合物代谢、耐药性、传染病、内分秘系统等方面的功能基因代谢通路丰度上升。说明多西环素可以降低肠道微生物的相对丰度和多样性,改变代谢通路二级功能层的相对丰度。

In order to study the effect of doxycycline on the structure and diversity of the intestinal microflora of cattle, three healthy cattle were randomly selected in the experiment, and they were fed with doxycycline 15 mg/kg according to their body weights one hour after feeding every morning for seven consecutive days. Rectal feces samples were collected on an empty stomach in the early morning on the day of the administration and the second day after the end of the administration. Using self-control method, 16 S RNA sequencing technology was used to extract genomic DNA in samples;sequencing library construction and Illumina MiSeq sequencing were performed on the feces collected twice;bioinformatics analysis, sample complexity analysis and multi-sample comparative analysis were performed;Tax4 Fun program was used for function annotation and prediction. The results showed that doxycycline could reduce the abundance and diversity of the intestinal flora of cattle. The relative abundance of Firmicutes was higher than that before feeding doxycycline, and the relative abundance of Bacteroides was lower than that before feeding doxycycline. At the phylum level, the abundance of Planctomycetes and Tenericutes was significantly or extremely significantly reduced(P<0.05 or P<0.01);at the genus level, the abundance of Bacteroides and Caproiciproducens increased significantly(P<0.05). After feeding doxycycline, the functional gene abundance increased in metabolism pathways such as membrane transport, replication and repair, coenzyme factor and vitamin metabolism, metabolism, carbohydrate metabolism, drug resistance, infectious disease, endocrine system etc. The results suggested that doxycycline could reduce the relative abundance and diversity of intestinal microbes, and changing the relative abundance of secondary functional layers of metabolism pathways.