投喂鲍内脏多糖对罗非鱼肠道菌群结构的影响

利用PCR-DGGE和Illumina测序技术研究了罗非鱼(Oreochromisniloticus)肠道菌群结构及饲喂鲍内脏多糖后罗非鱼肠道菌群的动态变化。在罗非鱼肠道中检测到13个门的细菌,其中梭杆菌门(Fusobacteria,77.84%)为优势菌门,拟杆菌门(Bacteroidetes, 8.59%)、衣原体门(Chlamydiae, 6.18%)、变形菌门(Proteobacteria, 5.84%)和放线菌门(Actinobacteria, 1.20%)为次优势菌门,还检测到Saccharibacteria等8个菌门和一些未知类群。在属的水平上,优势菌属为鲸杆菌属(Cetobacterium)、Neochlamydia、邻单胞菌属(Plesiomonas)和不动杆菌属(Acinetobacter),分别占77.84%、5.796%、2.64%和1.13%,还有一个紫单胞菌科(Porphyromonadaceae)的未知属,占8.29%。此外还有分枝杆菌属(Mycobacterium)等6个菌属和一些未知属。投喂添加鲍多糖的饲料对罗非鱼肠道微生物的构成造成了明显影响,饲喂鲍多糖的处理组和饲喂普通饲料的对照组样品分别聚为两大类。投喂添加鲍多糖饲料后,放线菌门、Saccharibacteria、疣微菌门和TM6_Dependentiae的丰度显著下调;在属的水平上,邻单胞菌属、鲸杆菌属的丰度上调;Neochlamydia、不动杆菌属、分枝杆菌属、Alsobacter、Aquicella、假单胞菌属、气单胞菌属、Alpinimonas等属的丰度下调。其中分枝杆菌属、Alsobacter、Aquicella和邻单胞菌属的丰度与对照差异显著(P0.05)。在种水平上,一些潜在致病菌,如鲍曼不动杆菌(Acinetobabacterbaumannii)、龟分枝杆菌(Mycobacteriumabscessus)、Aeromonas sharmana、耐酪酸冢村菌(Tsukamurella tyrosinosolvens)、铜绿色假单胞菌(Pseudomonas aeruginosa)等的丰度下调,其中龟分枝杆菌和耐酪酸冢村菌与对照差异显著(P0.05),而鲸杆菌属等有益菌的丰度上调。本研究从肠道微生物的角度来研究鲍内脏多糖对宿主的影响,为海洋生物活性物质的功效评价提供了新思路,也为鲍内脏活性物质的开发利用、益生元的研制等奠定理论基础。

The influence of feeding CAVP on intestinal microbiota of tilapia (Oreochromis niloticus)

The nutrient content of abalone viscera is similar to that of muscle. It contains rich proteins and various biologically active substances. However, the abalone viscera are often abandoned when processing or during consumption of abalone. This is not only a great waste, but also causes pollution to the environment. In recent years, with the exploration and research of marine active substances, abalone viscera have also been studied and developed. Intestinal microorganisms are known as "external organs" of the host, they are directly involved in the host''s nutrition, immunity, metabolism, and so on. They play important roles in maintaining the health of the host. A few studies have reported the in vitro and in vivo antioxidant activity of abalone polysaccharides and polypeptides; however, the effects of abalone active substances on the intestinal microorganism have not been previously reported. In this paper, the intestinal microbiota of tilapia and the influence of feeding abalone visceral crude polysaccharide (CAVP) on the intestinal microbiota were studied by PCR-DGGE and Illumina MiSeq sequencing. A total of 13 bacterial phyla were detected in the intestines of tilapia:Fusobacteria (77.84%) was the dominant phylum, Bacteroidetes (8.59%), Chlamydiae (6.18%), Proteobacteria (5.84%), and Actinobacteria (1.20%) were the subdominant phyla. Saccharibacteria, Firmicutes, Planctomycetes, Verrucomicrobia, TM6_Dependentiae, Cyanobacteria, Spirochaetae, Acidobacteria, and some unknown groups were also detected. At the genus level, Cetobacterium (77.84%) was the dominant genus, Neochlamydia (5.80%), Plesiomonas (2.64%), and Acinetobacter (1.13%) were the subdominant genera. There was also an unknown genus of the family Porphyromonadaceae, accounting for 8.29%. In addition, Mycobacterium, Alsobacter, Aquicella, Pseudomonas, Aeromonas, Alpinimonas, and some unknown genera were also detected. The addition of CAVP diet had an obvious influence on the intestinal microbiota of tilapia because the CAVP-treated samples and the control samples without CAVP clustered separately. After feeding CAVP, the abundance of Actinobacteria, Saccharibacteria, Verrucomicrobia, and TM6_Dependentiae decreased significantly (P < 0.05). At the genus level, the abundance of Plesiomonas and Cetobacterium was up-regulated, whereas the Neochlamydia, Acinetobacter, Mycobacterium, Alsobacter, Aquicella, Pseudomonas, Aeromonas, and Alpinimonas decreased, of which the abundance of Mycobacterium, Alsobacter, Aquicella, and Plesiomonas decreased significantly compared with that of the control (P < 0.05). After feeding CAVP, the abundance of some pathogens, such as Mycobacterium abscessus, Acinetobabacter baumannii, Aeromonas sharmana, Tsukamurella tyrosinosolvens, and Pseudomonas aeruginosa decreased, in which the Mycobacterium abscessus and Tsukamurella tyrosinosolvens decreased significantly compared with that of the control (P < 0.05). On the other hand, the probiotic bacteria, such as Cetobacterium, increased. This study investigated the effects of CAVP on the host with regard to intestinal microbes; it provides insight into the efficient evaluation of marine active substances, and also lays a theoretical foundation for the development and utilization of bioactive substances and the development of prebiotics from abalone viscera. In addition, this study is of importance in recycling abalone viscera and reducing environmental pollution.