Draft Genome Sequence of Vibrio sp. Strain V1B Isolated from the Gut Microflora of the Scallop Argopecten purpuratus

The influence of diet on the microbiota of live-feed rotifers (Brachionus plicatilis) used in commercial fish larviculture

Live-feed is indispensable to commercial fish larviculture. However, high bacterial loads in rotifers could pose a biosecurity risk. While this may be true, live-feed associated bacteria could also be beneficial to fish larvae through improved feed utilization or pathogen inhibition following host microbiota modification. The study objective was to elucidate the largely unexplored microbiota of rotifers propagated on five different diets through bacterial community profiling by 16S rRNA gene amplicon sequencing. Investigated rotifer samples had a median observed alpha-diversity of 338 ± 87 bacterial species. Alpha- and Gamma-Proteobacteria dominated the rotifer microbiota followed by members of classes Flavobacteriia, Cytophagia, Mollicutes, Phycisphaerae and Bacteroidia. Different diets significantly altered the bacterial communities associated with rotifers according to PERMANOVA test results and beta dispersion calculations. A common core rotifer microbiome included 31 bacterial species present in relative abundances over 0.01%. We discuss the functional role of some microbiome members. Our data suggested the presence of several known fish pathogens in stock rotifers. However, we found no evidence for increased loads of these presumptive taxa in propagated live-feed rotifers during this field trial.

Draft Genome Sequence of a New Vibrio Strain with the Potential To Produce Bacteriocin-Like Inhibitory Substances, Isolated from the Gut Microflora of Scallop (Argopecten purpuratus)

A new Vibrio strain, V7A, was isolated from the intestinal tract of the Peruvian scallop (Argopecten purpuratus). Strain V7A clusters within the Mediterranei clade of the genus Vibrio and has the potential to produce bacteriocin-like inhibitory substances (BLIS). Here, we report the draft genome sequence of Vibrio mediterranei strain V7A.