Newcastle disease (ND) is one of the most important viral diseases in the world that causes considerable damages to the poultry industry. This study aimed to investigate the acute phase response in homologous interference between Newcastle disease vaccine virus and a virulent Newcastle disease virus (NDV) in chickens. The experimental chicks received live vaccine virus either before or after challenge with virulent NDV to determine the stronger immune system stimulation and higher acute phase response. A total of 250 day-old Cobb-500 commercial broiler chickens were divided randomly into 5 equal groups (n = 50), and the chicks in each group were treated as follows: Group 1 received live vaccine at 22 days of age. Group 2 was vaccinated 24 hours prior to the challenge with NDV at 23 days of age. Group 3 was challenged with NDV at 23 days of age and received live vaccine 24 hours later. Group 4 was the negative control. Group 5 was challenged with NDV at 23 days of age. Blood samples were collected at intervals of 3, 6, 12, 18, 24, 48, 72 hours, and on days 6 and 9 after first inoculation in all the groups; and measurements of haptoglobin, serum amyloid A, ovotransferrin, adenosine deaminase, serum proteins (total protein, albumin, globulins), and gangliosides (total sialic acid, lipid-bound sialic acid, and protein-bound sialic acid) were carried out according to standard procedures. The results showed that the challenge with NDV led to a significant increase in inflammatory factors and acute phase response, whereas vaccination caused a mild increase in these parameters. At 24 hours, group 3 (post-challenge vaccinated chicks) showed a stronger immune system stimulation and higher acute phase response than group 2 (pre-challenge vaccinated chicks). To summarize, the results of this study indicated that challenge with NDV could lead to a significant increase in the inflammatory factors and acute phase response, whereas vaccination alone could cause a mild increase in these parameters. The challenge with NDV followed by vaccination resulted in a stronger immune system stimulation and higher acute phase response than vaccination followed by the challenge with NDV. According to these findings, vaccination of the chicks with a live vaccine soon after natural infection with virulent NDV may help the chicks to overcome the sequelae of the disease.
Cite this article as: Ghaemmagham, M., Dadras, H., & Nazifi, S. (2021) Evaluation of Acute Phase Response in Viral Interference between Live Vaccine Virus and a Virulent Newcastle Disease Virus. Acta Veterinaria Eurasia, 47(2), 64-75.