Clinical trial of killed ND vaccines used in broiler industry

Background: Given the high importance of Newcastle disease and its global scope, the existence of a targeted vaccination program against the disease that can protect the herd has always presented producers around the world with serious challenges. In the meantime, given the key role of the injected killed vaccine and the high diversity of killed Newcastle vaccines available on the market (in terms of price, whether the vaccine is imported or local, etc.), the existence of a comparison to examine different vaccines can be a major step in developing the best vaccination program. Methods: One of the well-known ways to determine the performance of the vaccine is to measure the serum antibody titer of the vaccinated chicken. Among the various methods available for measuring the serum antibody titer, the HI (hemagglutination inhibition) method is often be chosen. This method is based on the ability of the pathogen (bacteria or virus) to agglutinate (coagulate) red blood cells. The vaccines used in this trial were named as four vaccines A, B, C, D to avoid possible bias and conflict of interest. Blood sampling was performed on days ۱ (only to ensure maternal antibodies), ۱۰, ۲۰, ۳۰, ۴۰, and ۴۸ of the experimental and control groups. (Day ۱: ۱۲ samples and subsequent days each ۱۳۰ samples). A total of ۶۶۲ samples were sent to the laboratory after the end of sampling and analyzed. Results: The results showed that the performance of the tested vaccines on day ۳۰ was significantly different. Also, in a quantitative comparison, one of the experimental groups had a much more favorable performance. Conclusion: Therefore, it is appropriate for each producer to choose the appropriate vaccine for their farm, considering the contamination of the area, the farm's history, and the advice of a veterinarian.

کلیدواژه ها:

Broiler ، Newcastle disease ، hemagglutination inhibition ، vaccination