Immune response of genetically different Oreochromis fish species to Pseudomonce fluorescence vaccination [electronic resource].

Includes references.

This study have been designed to evaluate the effect of genetic variations on the degree of immune response of the three species (O. niloticus & O. auraus and their hybrid) to formalized whole culture of Ps. Fluorescence vaccine and variations in mortalities post challenge with virulent strains of Ps . fluorescence. Also to evaluate variations in the level of natural resistance among two Oreochromis fish species and their hybrid. Ps. fluorescence have been isolated from clinically infected fishes and fully identified. The incidence of Ps. fluorescence infections in diseased fish were studied in examined naturally infected tilapia fish species to choice the most virulent strains of Ps. fluorescence. Vaccination of the three species under experiment was done using formalized whole culture of Ps. fluorescence. Detection of mean antibody titers were done 0,14,21 and 35 days post vaccination for all vaccinated fish groups. Challenge test were done 35 days post vaccination (peak antibody titers) using the most virulent strain of Ps. fluorescence. Mortalities of all groups were recorded 15 days post challenge. The vaccine protecton efficacy of Ps. fluorescence killed vaccine have been evaiuated through detection of antibodies titers 7 days post challenge and mortality patterns 15 days post challenge in each Oreochromis species. The Results obtained showed that: Chromosomal analysis of the three Oreochromis species cleared that O. niloticus; O. auraus and their hybrid have the same chromosomal number. * level of antibody titers at day zero (one day before vaccination) cleared a superiority for O. niloticus in the level of natural resistance followed by O. aurausthen hybrid. * The antibody titers after vaccination showed significant differences in the level of immune response to vaccine with a significant superiority to O. niloticus followed by hybrid while O. auraus peak antibody titers. * Challenge test showed that O. niloticus recorded the highest survivability post challenge of vaccinated groups with virulent Ps. fluorescence followed by hybrid while O. auraus recorded the highest mortalities. * Antibody titers and mortalities not significantly vary between vaccinated groups of the three Oreochromis species, but significant differences have been reported between the vaccinated and non vaccinated groups of each species, so the vaccine reported a variable degrees of protection efficacy with superiority to O. niloticus followed by hybrid tilapia then O. auraus.

Summary in Arabic.

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