Evaluation of Acute Phase Response in Viral Interference between Live Vaccine Virus and a Virulent Newcastle Disease Virus

Özet

Newcastle disease (ND) is one of the most important viral diseasesin the world that causes considerable damages to thepoultry industry. This study aimed to investigate the acute phaseresponse in homologous interference between Newcastledisease vaccine virus and a virulent Newcastle disease virus(NDV) in chickens. The experimental chicks received live vaccinevirus either before or after challenge with virulent NDV todetermine the stronger immune system stimulation and higheracute phase response. A total of 250 day-old Cobb-500 commercialbroiler chickens were divided randomly into 5 equalgroups (n = 50), and the chicks in each group were treated asfollows: Group 1 received live vaccine at 22 days of age. Group2 was vaccinated 24 hours prior to the challenge with NDV at23 days of age. Group 3 was challenged with NDV at 23 days ofage and received live vaccine 24 hours later. Group 4 was thenegative control. Group 5 was challenged with NDV at 23 daysof 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 allthe groups; and measurements of haptoglobin, serum amyloidA, ovotransferrin, adenosine deaminase, serum proteins (totalprotein, albumin, globulins), and gangliosides (total sialic acid,lipid-bound sialic acid, and protein-bound sialic acid) were carriedout according to standard procedures. The results showedthat the challenge with NDV led to a significant increase in inflammatoryfactors and acute phase response, whereas vaccinationcaused a mild increase in these parameters. At 24 hours,group 3 (post-challenge vaccinated chicks) showed a strongerimmune system stimulation and higher acute phase responsethan group 2 (pre-challenge vaccinated chicks). To summarize,the results of this study indicated that challenge with NDVcould lead to a significant increase in the inflammatory factorsand acute phase response, whereas vaccination alone couldcause a mild increase in these parameters. The challenge withNDV followed by vaccination resulted in a stronger immunesystem stimulation and higher acute phase response than vaccinationfollowed by the challenge with NDV. According to thesefindings, vaccination of the chicks with a live vaccine soonafter natural infection with virulent NDV may help the chicks toovercome the sequelae of the disease.