健康和患病卵形鲳鲹肠道菌群结构的差异

为研究病害发生后卵形鲳鲹肠道菌群结构的差异及其与养殖环境的关系,分析不同样品中的菌群组成和细菌多样性。实验采用Illumina HiSeq高通量测序技术和生物信息学分析手段,分别构建了健康鱼水样、患病鱼水样、健康鱼肠道、患病鱼肠道和饵料颗粒5个样品中菌群的16S rRNA基因测序文库。研究表明,与健康鱼肠道细菌组成相比,患病鱼肠道中螺旋体门相对丰度显著升高,厚壁菌门和拟杆菌门相对丰度显著降低;患病后肠道中的细菌种类仅为健康鱼肠道细菌种类总数的54.94%;健康卵形鲳鲹肠道菌群中有73.46%的可操作分类单元(OTUs)与水体样品中OTUs一致,有70.58%与饲料样品一致,而患病后分别只有17.98%和38.95%的OTUs与水体和饲料样品一致。健康卵形鲳鲹肠道中黑海弧菌的相对丰度为17.19%,患病后该菌的相对丰度大幅提高,达到78.90%;健康鱼肠道中鳆发光杆菌占比54.53%,患病鱼肠道中不含鳆发光杆菌。健康和患病鱼肠道菌群种类组成类似,但存在一定差异,病害的发生会导致肠道细菌多样性显著降低。健康鱼肠道菌群与养殖环境和颗粒饲料中菌群组成关系密切,而患病后鱼肠道细菌多样性受环境中菌群的影响较小。黑海弧菌在患病鱼肠道中的大量增殖可能是引起其患病的重要原因。

Variance analysis of intestinal bacterial community between healthy and diseased Trachinotus ovatus

In order to investigate the difference of the intestinal community structure and its relationship with environmental factors in response to disease, the intestines of healthy and diseased Trachinotus ovatus were used to analyze the bacterial community composition and diversity as well as the culture waters and pellet feed. The five samples were studied by using Illumina HiSeq high-throughput sequencing and biological information analysis method. Compared with the intestinal microflora of the healthy pompano, the relative abundances of Spirochaetes significantly increased in the diseased pompano, whereas, the Firmicutes and Bacteroidetes exhibited an opposite pattern. The bacteria species in diseased pompano intestine only accounted for 54.94% in healthy pompano. There was 73.46% of the OTUs in the healthy ovate intestine, the same as that in the culture waters, and 70.58% in the feed, while the percentage dropped to 17.98% and 38.95% in the diseased pompano. Notably, the disease pompano had a higher relative abundance of Vibrio ponticus than healthy pompano being 78.90% and 17.19%, respectively. In addition, the relative abundance of Photobacterium leiognathi in healthy pompano was 54.53%, but absent in diseased pompano. The intestinal bacterial composition was relatively stable but there were still some difference between healthy and diseased pompano. After the occurrence of disease, the bacterial diversity declined markedly. The culture water and feed had a close correlation with the healthy pompano intestine but low influence on diseased pompano in bacterial species composition.