VacciMonitor (Feb 2023)
Preparation and evaluation of formalized bivalent Newcastle and Salmonella poultry vaccine
Abstract
This study was conducted to prepare and evaluate the potency of different inactivated vaccine formulations that protect chickens against Salmonella Enteritidis and Newcastle disease virus using Montanide as adjuvant. Protection and the humoral immune response of prepared vaccines against Salmonella Enteritidis and Newcastle disease virus was evaluated and compared to imported vaccine. In this study, different formulae of Salmonella Enteritidis and Newcastle disease vaccines were prepared and compared with the imported one by measuring the antibody titer against Newcastle disease virus by hemagglutination inhibition test and the antibody titer against Salmonella Enteritidis using Enzyme Linked Immunosorbent Assay. On the other hand, the protection percentages against Newcastle disease and Salmonella Enteritidis were recorded to determine the best effective formula. The highest hemagglutination inhibition antibody level against NDV at first week was recorded for the prepared combined Newcastle disease and Salmonella Enteritidis vaccine (4.2 log2) followed by the prepared monovalent Newcastle disease (3.4 log2); the lowest antibody level (3.1 log2) was obtained with the imported vaccine. A gradual increase was observed in all groups to 7.1 log2, 6.8 log2 and 6.4 log2 at fourth week post vaccination, respectively. The antibody titer against Salmonella Enteritidis was 552 for the prepared combined Salmonella Enteritidis and Newcastle disease, followed by the prepared monovalent Salmonella Enteritidis (477) at first week post vaccination; the antibody titer obtained for the imported vaccine was 477. There was a gradual increase to 1456, 1406 and 1130 at fourth week post vaccination, respectively. Prepared combined vaccines gave the highest protection percentage, followed by prepared monovalent types and finally imported vaccines. Vaccination by the prepared combined Salmonella Enteritidis and Newcastle disease vaccine may be a way to increase the resistance of birds to Salmonella and Newcastle and to decrease the shedding rate.
