Induction of mild enterocolitis in zebrafish Danio rerio via ingestion of Vibrio anguillarum serovar O1

Vibrio anguillarum is the etiological agent of a fatal hemorrhagic disease known as vibriosis that affects a wide range of fish species, causing severe economic losses. Several investigations have been carried out to elucidate the virulence mechanisms of this pathogen and to develop rapid detection techniques and effective disease-prevention strategies. The aim of our study was to evaluate the most effective way to induce mild enteritis in a fish model, in order to allow further applications. The experiments were carried out using 2 methods of administration of V. anguillarum serotype O1 to adult zebrafish Danio rerio: via intraperitoneal injection and via ingestion of infected Artemia nauplii. The results showed that the intraperitoneal administration often caused massive fish death due to severe systemic involvement. In our experiments, the effect of intraperitoneal infection was evident 48 h post infection, with cumulative mortality within 7 d post infection with severe histopathological changes in kidney hematopoietic tissue and in the intestine. In contrast, oral infection via Artemia did not show systemic involvement and only a moderate degree of inflammatory influx of the mucosa, a partial recovery at 12 d post infection, and no mortality. For these reasons, oral infection with live food appears to be the most effective method to induce mild enteritis with a local inflammatory response.