Sex-related gut microbiota in three geographically separated Norway lobster (Nephrops norvegicus) populations

Abstract

Despite the ecological and economic interest of the Norway lobster (Nephrops norvegicus), its gut microbiota remains largely understudied. The current study aimed at investigating the gut bacterial microbiota in three geographically separated N. norvegicus populations from the Mediterranean and the North Sea and detecting any potential sex-related microbiota differences, by high-throughput sequencing of the V3-V4 16S rRNA gene diversity of the gut tissue. From the Greek population, egg-bearing females were also caught. A total of 2,385 operational taxonomic units (OTUs) were identified and between 417 and 1290 occurred in each population/sex group. The dominant OTUs belonged to the Fusobacteriia and Bacteroidia (Sweden), Bacilli and Gammaproteobacteria (Italy) and Spirochaetia and Bacilli (Greece) bacterial classes. In the eggs, the Actinobacteria, Alphaproteobacteria and Gammproteobacteria prevailed. Four OTUs related to the Oceanispirochaeta, Kordiimonas, Desulfovibrio, Carboxylicivirga genera and one unafilliated OTU were positively correlated (p values between 0.001 and 0.04) to body size indicating their potential role in the animals nutrition and growth. No statistically significant differences were found between males-females in each of the three populations. However, statistically significant differences between populations for each sex, were found for all females (p values between 0.008 and 0.032) and for the males between the most distant populations, i.e. Italy-Sweden (p=0.021) and Greece-Sweden (p=0.015). The eggs microbiota was statistically different from both the adult females (p=0.027) and males (p=0.046) gut microbiota. Overall, this study showed that N. norvegicus gut microbiota are differentiated between geographically distant populations and that sex-related differences are not significant.