Metagenomic analysis of the gut microflora in Anguilla japonica, Anguilla marmorata and Anguilla bicolor pacifica
Date Issued
2015
Date
2015
Author(s)
Chang, Fang-Chi
Abstract
The Japanese eel is an important aquaculture species in east Asia. In the past 3 decades, glass eel abundances have been declining significantly, so the culture of other eel species becomes more and more popular during recent several years. There are 19 species and subspecies freshwater eels known worldwide and are widely distributed in the world. Among them, 6 species, Anguilla japonica, A. marmorata, A. bicolor pacifica, A. luzonensis (A. huangi), A. interioris and A. celebesensis are reported from Taiwan. Currently, A. japonica, A. marmorata and A. bicolor pacifica are commercially important cultured eel species in Taiwan. In large-scale production facilities, where fishes are exposed to stressful conditions, problems related to diseases and deterioration of environmental conditions can result in serious economic losses. Prevention and control of diseases in the aquaculture traditionally use synthetic chemicals and antibiotics, while the use of antimicrobial agents produces potential hazards to public health, including accumulation of residues in the environment, generation of drug-resistance bacteria and immunosuppression of host etc. In the past decades, new alternative approaches gradually use probiotics to substitute the chemotherapy. The commonly used probiotics in fish culture practices belong to genus Clostridium, Bacillus, Enteroccus, Lactobacillus, Shewanella, Leuconostoc, Lactococcus, Carnobacterium, Aeromonas, Pseudomonas and several other species. However, the ability of these probiotics to colonize in gut mucosa of freshwater eels has been little studied. The intestinal tract harbors a complex, stable and dynamic collection of microorganisms that produces digestive enzymes and nutrients as well as prevents pathogens and plays an important role in the maintenance of normal gut function. Therefore, several studies evaluate the microflora isolated from many aquaculture species to select bacteria with potential to become probiotics. In this study, we used remarkable advance of Next-generation sequencing technology (Illumina Mi-Seq) to analysis the intestinal microbiota of wild A. japonica, A. marmorata, A. bicolor pacifica and cultured sick A. japonica. The feeding experiment proved that the common and dominant bacterial genera found in intestine of wild eels have high efficiency to colonize in gut of cultured eels. This study found that microbial community of intestinal mucus varied with the environments and the eel species. Interestingly, there were some dominant bacterial genera shared in the gut of freshwater eels from different rivers and eel farm such as Clostridium, Cetobacterium, Plesiomonas, Serratia, Shewanella, Bradyrhizobium, Acinetobacter and Bacteroides. This research provides a baseline for use of probiotics and future probiotic studies.
Subjects
Anguillid eel
NGS
16S rRNA metagenomics
intestinal microflora
probiotics
SDGs
Type
thesis
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