Newcastle disease vaccination program in broilers using a Apathogenic heat-resistant vaccine

The Newcastle disease (ND) is among the most common and deadly poultry diseases worldwide. Thermostable Newcastle disease virus (NDV) vaccines have been used widely to protect village chickens against Newcastle disease, due to their decreased dependence on cold chain for transport and storage. The Newcastle Disease V۴ Heat-Resistant (NDV۴HR) vaccine is an Apathogenic heat-resistant live vaccine that can induce immunity in chickens. A total of ۶۰ one-day-old Arain local hybrid broilers divided into three groups of ۲۰. Group A had the usual vaccination program in broiler flocks (۷ Days old: B۱ type by eye drop+ ND Killed vaccine by IM; ۱۸ and ۲۸ days old: Lasota strain orally), group B did not receive any vaccine, and Group C received orally the NDV۴HR vaccine six times from the first day to the ۳۵th day of rearing. All groups were nasally challenged with acute Newcastle virus (genotype VIId) on the ۳۵th rearing day. Regarding HI serum antibody titer of the birds after the challenge, group B had the highest (۷.۱۲ ± ۱.۰۵), and Group C (۶.۳۷ ± ۱.۳۱) had a higher titer than Group A (۶ ± ۱.۲۲). After the challenge with the Newcastle virus, the necropsy findings and clinical symptoms of the disease were almost similar in groups A and C. Group B showed the most signs with higher casualties than other groups. Regarding weight gain, Group C had the most weight at the end of the study (۲۲۰۴ ± ۱۰۶). On the second day after the challenge, groups A and B had virus shedding through the trachea and cloaca; however, group B shed the virus only through the trachea. Furthermore, on the ۷th day after the challenge, group A shed the virus through the cloaca, and group B through the trachea and the cloaca. At the same time, there was no virus shedding in group C. This study showed that V۴HR vaccine provokes an antibody response that protects the birds against virulent virus challenge.

کلیدواژه ها:

Broiler Chickens ، Heat-resistant vaccine ، NDV۴ ، Newcastle disease