Efficacy of Oil based Newcastle Disease (Mukteswar Strain) Vaccine against Prevailing Virulent Virus Strain of Poultry in Pakistan

Newcastle disease at present is one of the leading viral threat to commercial as well as backyard poultry inflicting heavy mortality and economic losses in Pakistan. Efficacy of Oil-based inactivated Newcastle disease (ND) vaccine was determined against the prevailing velogenic strain. Freeze dried seed virus after reconstitution in PBS was passaged in to 9 days embryonated chicken eggs for allanto-amniotic fluid. Vaccine was prepared by mixing one part of inactivated antigen with three parts of the montanide oil. The vaccine was evaluated for its safety, stability and immunogenicity both in vitro as well as in vivo conditions. One hundred and twenty five day old broilers birds were divided in 5 equal groups i.e., A to E. The birds of different groups were vaccinated with experimentally prepared vaccine alone and in combination with live ND virus (Mukteswar) at different age by using different dose rates and routes of administration. The anti-NDV antibody titer of all groups was determined on day 14, 21, 28, 35 and 42 post-vaccination. All the birds were challenged with velogenic field strain. The challenged survivor birds were bled on 42nd day of age to ascertain vaccinal response. 100% protection was observed in group B birds (challenged intramuscularly with experimental vaccine along with live Mukteswar strain vaccine through intra-ocular route) which suggested that simultaneous use of both live and killed oil-based vaccines at day 7^th of age will be helpful in prevention against disease out breaks. In A, C and D groups 90 % protection was attained due to experimental prepared vaccine. Hence, oil-base ND vaccine containing Mukteswar strain gave remarkable protective antibody titers to resist the field virus to produce the clinical disease. Therefore, from the findings of present study it can be concluded that oil based vaccine can instigate better immunity in early age in broiler chicks.