A model for experimental infections with Vibrio (Listonella) anguillarum in first feeding turbot (Scophthalmus maximus L.) larvae under hatchery conditions

Abstract

Vibriosis is one of the main causes of mortality in all stages of fish. In larvae, further improvements on the control and knowledge of bacterial diseases require the development of models for experimental infections. A reproducible model for in vivo infections of first feeding turbot (Scophthalmus maximus) larvae with the pathogen Vibrio (Listonella) anguillarum is described. Experimental challenges were carried out under hatchery conditions considering different ways of delivery of V. (Listonella) anguillarum strain 90-11-287 serotype O1 to turbot larvae: via rotifers (orally) and via water of the larval rearing tanks (bath). The effect of the supernatant of the bacteria culture was also considered and discussed. The model proposed is based on the incorporation of the bacteria into previously enriched rotifers and the delivery to the larvae during the rotifer feeding period. The effect of infections was already evident 24-72 h after the first challenged day. Final mortalities (day 8-14) in infected larvae were 56-72% with respect to unchallenged larvae. Mortalities achieved by applying the protocol of infection are reliable, reproducible and adequate for experimental purposes. The model of infection via rotifers proposed in this study is a useful tool for experimental purposes in the larval rearing of marine fish.

Immunohistochemistry of Atlantic cod larvae Gadus morhua experimentally challenged with Vibrio anguillarum

“…Supernatant from Vibrio anguillarum leads to mortality in turbot Scophthalmus maximus larvae (Planas et al 2005(Planas et al , 2006. Supernatants of bacterial cultures include extracellular products (ECP) produced by the bacteria.…”

“…There are no obvious explanations for this result. The washing procedure prior to challenge may have stressed the bacteria, resulting in a temporary loss of virulence (Planas et al 2005). Chemotactic motility mediated by the polar flagellum is essential for virulence of V. anguillarum (Milton et al 1996, O'Toole et al 1996, Ormonde et al 2000.…”

Screening and characterisation of potentially pathogenic bacteria associated with Atlantic codGadus morhualarvae: bath challenge trials using a multidish system

“…Our results suggest that a route of entry other than bath-challenge alone is required or, alternatively, that a combination of both bath and oral exposure is needed. Experiments that deliver challenges via live feed have been performed on turbot Scophthalmus maximus larvae (Grisez et al 1996, Planas et al 2005 but to the best of our knowledge no such experiments have been performed on cod larvae. Another explanation for the lack of pathogenicity is the possibility of quorum sensing.…”

Calcareous assemblages of the southeastern Mediterranean low-tide estuaries — Seasonal dynamics and paleo-environmental implications

“…The occurrence of potentially pathogenic strains from the family Vibrionaceae is highly correlated with temperature, leading to increased virulence and the occurrence of emerging agents in warmer waters (Thompson et al, 2004;Vezzulli et al, 2010). Beside Vibrio splendidus, we detected other strains of potential pathogens of fish (Listonella anguillarum), crustaceans (V. penaeicida) and bivalves (Vibrio tapetis), which were associated with mass mortality events in some cases (Allam et al, 2002;Aguirre-Guzman et al, 2003;Planas et al, 2005;Pernet et al, 2012). Optimal growth temperature is not known for most of the bacterial species here, but vibriosis in fish tends to occur at water temperatures above 15°C (Frans et al, 2011).…”