Comparative analysis of microbial community structure between healthy and Aeromonas veronii-infected Yangtze finless porpoise

Zhigang Liu,Yaping Wang,Chao Wu,Nuo Wang,Daoping Yu,Zhongkai Li,Aoyun Li,Aifang Zheng,Mudassar Iqbal,Mengmeng Zhao

doi:10.1186/s12934-020-01383-4

Abstract

BackgroundThe gut microbiota is a complex ecosystem, which is essential for the metabolism, health and immunity of host. Many diseases have been shown to be closely related to the alteration of intestinal flora. Aeromonas veronii as a conditioned pathogen can cause disease in Yangtze finless porpoise through intestinal infections. However, it is not clear whether the disease caused by Aeromonas veronii is related to changes of intestinal flora. In the current study, the diversity and composition of gut microbiota in the healthy and Aeromonas veronii-infected Yangtze finless porpoise were evaluated by high-throughput sequencing to further investigate the potential association between intestinal flora alteration and pathogen invasion.ResultsA total of 127,3276 high-quality sequences were achieved and 2465 operational taxonomic units (OTUs) were in common among all samples. The results of alpha diversity showed that there was no obvious difference in richness and diversity between healthy and Aeromonas veronii-infected Yangtze finless porpoise. Firmicutes, Bacteroidetes and Proteobacteria were the most dominant phyla in all samples. In addition, the healthy Yangtze finless porpoise exhibited higher abundance of Firmicutes and Fusobacteria than Aeromonas veronii-infected Yangtze finless porpoise, while, the level of Proteobacteria was decreased. At the genus level, Paeniclostridium and Paraclostridium were the predominant bacteria genera in the CK (healthy Yangtze finless porpoise) group. In the DIS (Aeromonas veronii-infected Yangtze finless porpoise) group, Lactobacillus and unidentified_Enterobacteriaceae were the dominant bacteria genera and the proportion of Paeniclostridium, Paraclostridium, Terrisporobacter, Cetobacterium, Candidatus Arthromitus, Terrabacter and Dechloromonas were reduced.ConclusionsIn conclusion, our results showed that Aeromonas veronii infection can alter the gut microbiota of the Yangtze finless porpoise by affecting the number of harmful bacteria and beneficial bacteria.

Highlights

The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) is a rare species that mainly lives in the Yangtze River basin, Dongting lake and Poyang lake in China
Sequences analyses It is well known that a number of erroneous or questionable sequences can be produced during the high throughput sequencing
The results of rarefaction curves (Chao1 curve and Shannon curve) and rank abundance curve suggested that the total number of sequences, depth, abundance and evenness meet the requirement for sequencing and analysis (Figs. 1, 2)

Summary

Introduction

The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) is a rare species that mainly lives in the Yangtze River basin, Dongting lake and Poyang lake in China. The number of Yangtze finless porpoise is gradually declining and less than 2000 are remaining [1, 2]. The Yangtze finless porpoise has been listed as an endangered species by the International Union for Conservation of Nature (IUCN) since 2013. Aeromonas veronii as a conditioned pathogen can cause disease in Yangtze finless porpoise through intestinal infections. It is not clear whether the disease caused by Aeromonas veronii is related to changes of intestinal flora. The diversity and composition of gut microbiota in the healthy and Aeromonas veronii-infected Yangtze finless porpoise were evaluated by high-throughput sequencing to further investigate the potential association between intestinal flora alteration and pathogen invasion

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Conclusion