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Kerala Veterinary and Animal Sciences University, Wayanad

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Subject: Microbiology × Author: LINA KUNJAMMA MATHEWS × End date: 2023 × Start date: 2023 × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    ASSESSMENT OF IMMUNOGENIC POTENCY OF INACTIVATED VACCINE AGAINST RIEMERELLOSIS IN BREEDER DUCKS
    (COLLEGE OF VETERINARY AND ANIMALS SCIENCES MANNUTHY, THRISSUR , KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2023-02-09) LINA KUNJAMMA MATHEWS; Dr. Priya P. M.
    Riemerellosis or new duck disease, is an infectious disease in ducks caused by the bacterium Riemerella anatipestifer, which primarily causes an acute septicaemic infection in young ducklings. A subunit vaccine developed against the disease was compared to an inactivated vaccine in an earlier study, which proved the superiority of the latter in terms of efficacy. No studies have been carried out on maternally transferred antibodies (MTA) in ducklings born to the vaccinees. Hence, this study was undertaken. A total of 200 laying Kuttanad ducks of breeder stock maintained in the University Poultry and Duck Farm (UPDF), Mannuthy were grouped into two, comprising of 100 birds each, with T1 being the control group and T2, the treatment (vaccination) group. The oil-adjuvanted inactivated vaccine, prepared as per previously standardised protocol, was administered to T2group in two doses at weekly intervals. Blood samples, 20 each from T1 and T2, were collected on days 0, 14, 28, 56 and 90 post-immunisation (PI), whereas 10 eggs each from both the groups were collected on days 14, 28, 56 and 90 PI, to assess antibody titre in adult sera and egg yolk respectively, by ELISA. Fertile eggs collected between days 28 and 35 PI from each group were marked separately, incubated for hatching and the hatched-out day-old ducklings (n=24) from each group were selected randomly and reared. To evaluate MTA, blood was collected from six ducklings each from both the groups, on days 1, 3 and 10 to estimate antibody titre in the sera. The transfer of maternal antibodies was assessed by challenge studies upon inoculating 100 LD50 of RA1 subcutaneously to six ducklings each from both the groups on days 3 and 10. Statistical analysis of the ELISA titre of the adult duck sera revealed significant difference (p<0.001)between the titres of both the groups on all the days assessed except the 0th, confirming the potency of the vaccine in adult ducks. However, the assessment of MTA revealed some level of protective antibody in the ducklings in terms of mortality and gross pathological scoring, but not in levels detectable by ELISA.