Oral infection
At the end of the feeding trial, fifteen fish/groups were fasted for 24 h. They were fed on an infected diet once/day for the three successive days. Signs of disease and their mortality were monitored for 15 days post challenge. Throughout this period, the fish were fed on the basal diet to apparent satiation once/day.
Statistical analysis
The data obtained were statistically assessed by the analysis of variance (ANOVA, through the general linear model procedure of the SPSS14.0 software). The values were expressed as means ± standard error. Duncan’s multiple range tests were used to test the significance of the difference between means by considering the differences significant at p < 0.05.