Combined use of 16S ribosomal DNA and automated ribosomal intergenic spacer analysis to study the bacterial community in catfish ponds

Abstract

To apply culture-independent techniques to explore the bacterial community composition in catfish pond water. 16S rDNA libraries were constructed and sequenced from 15 pond water samples. Automated ribosomal intergenic spacer analysis (ARISA) was used to fingerprint each bacterial community. A broad diversity in bacterial species composition was found by 16S rDNA analysis. Alphaproteobacteria was the most represented class in all ponds, followed by Gammaproteobacteria and Gram-positive high G + C content bacteria. Uniqueness of bacterial communities from each individual pond was confirmed by ARISA. Catfish pathogens were detected sporadically. Bacterial communities in a catfish aquaculture setting can vary from pond to pond at one given point. No correlation could be made between bacteria composition and fish strain or between bacterial profile and the presence of catfish pathogens in a particular pond. This is the first report showing the composition of bacterial communities in catfish ponds. Fish health specialists and catfish aquaculture managers should be aware of the wide differences in bacterial communities between ponds and include this variable in fish husbandry practices.