Overview of the gut microflora in wild-caught fish at the Lebanese shore -

Abstract

Microflora refers to the collection of live microscopic organisms that flourish inside the organs of living creatures including fishes. Bacteria living on the inner intestinal walls play an important role in digesting food, absorbing nutrients and defending the host from outer pathogens. All living organisms including fish interact with and are affected by bacteria. However, the gut flora of wild fish remains poorly characterized. The aim of this work is to provide an overview of the bacteria colonizing the gut of wild-caught fish. After isolation of cultivable bacteria, 16s ribosomal DNA sequencing was performed for identification purposes. R program was then used to compare sequences corresponding to bacteria from 15 different fish species divided into three categories based on their habitat, diet and origin. The potential pathogenicity of some bacteria was also investigated using the model organisms Danio rerio and Drosophila melanogaster. Serratia and Aeromonas salmonicida were lethal to Drosophila while all Danio rerio fish didn't show any distress symptoms when exposed to these bacteria. This study paves the way to a more complete project including the identification of the uncultivable bacteria that reside in the gut, the examination of several specimens per fish species and the extension of the analysis to a larger number of fish species.