Exploration of potential links between the gut microbiota and the behavior of Kryptolebias marmoratus

Details

Supervisors

Silvestre, Frédéric

Faculty

Faculté des sciences

Degree label

Master [120] en biologie des organismes et écologie, à finalité approfondie

Abstract

Kryptolebias marmoratus is a self-fertilizing fish. For this reason, some populations are highly isogenic. This unique capacity among vertebrates makes of K. marmoratus an excellent model organism for epigenetic studies. Particularly because, despite high isogeneity, great phenotypic plasticity is observed, including in their behavior. Many studies have underlined correlations in epigenome variability, indicating that epigenetic mechanisms compensate for the lack of genetic diversity. Gut microbiota could be an additional source of phenotypic diversity in this species. It has already been demonstrated on numerous occasions that its structure can impact host behavior, in both mammals and fish. In this study, fish from the population at Emerson Preserve Point in Florida were used. It is known to be the most isogenic population. This allows to minimize genetic impacts. Additionally, to minimize environmental influence, fish were raised in a shared environment. Once they reached the age of 60 days post hatching, the fish’s bold personality was assessed with a shelter test. The results were compared with measures taken on fish reared separately for another study. No impact of the rearing method under laboratory conditions was demonstrated on fish behavior. Despite the lack of significant differences evaluated between fish reared in the same environment, different levels of boldness were observed. These differences do not correlate with gut microbiota variations summarized using alpha and beta diversity indexes. The gut microbiome was sequenced using Rapid sequencing – 16S Barcoding Kit 24 V14 (SQK- 16S114.24) to amplify and sequence the V1-V9 region with the Nanopore MinION™ to increase accuracy. According to the diversity indexes analysed, variations in gut microbiota communities are particularly marked when the composition and the abundance are considered. Finally, the core microbiota of domesticated K. marmoratus is also established, and variations in its structure are also observed. This is a preliminary exploration of the gut microbiota composition in this species, and a first step in studying gut microbiota in a fish where the epigenome is known to introduce phenotypic plasticity, although it does not explain the totality of the diversity.