Comparison of survival by day (left panel) and cumulative mortality (right panel) between naïve and vaccinated rag1^−/− mutant zebrafish fed antibiotic feed in Trial 3.

<p>Asterisk indicates a significantly lower mortality rate in vaccinated rag1^−/− mutant zebrafish when compared to naïve rag1^−/− mutant zebrafish. Fish were vaccinated with RE33® an attenuated strain of <i>E. ictaluri</i> and 4 weeks later challenged by a secondary injection of virulent <i>E. ictaluri</i>. Ten days after the vaccination, fish received feed supplemented with oxolinic acid for 7 days. DPI = days post secondary exposure. Error bars indicate standard error of the mean, SEM, between tanks (n = 16).