Comparative Evaluation of Immunological Protective Efficacy Among Various Marek's Disease Vaccines in Chickens
[Objective]To understand the immune protection effects of different commercial Marek's disease vaccines,and provide valuable data for Marek's disease prevention and control,this study analyzed the immune protection of 7 batches/varieties(A-D,F-H)of CV1988 or CVI988+HVT commercial vaccine.[Method]A total of 140 1-day-old SPF chickens were randomly divided into 9 groups,groups G01 to G07.G01 to G07(15 chickens/group)were immunized with Marek's disease vaccine A-D and F-H according to the manufacturer's recommended dose,respectively,while groups G08(challenge control group,15 chickens)and G09(blank control group,20 chickens)were not immunized.At 7 days of age,the chickens of groups G01 to G08 were intraperitoneally injected with Md5 strain(1 000 PFU/bird).All chickens were raised to 120 days of age.The protective effect of each vaccine was evaluated through the examination of virus plaque numbers,vaccine replication,weight differences post-challenge,clinical manifestations,and pathological changes.[Result]The virus plaque number of all 7 vaccine batches confirmed to national standard(2 000 PFU/feather),and the virus plaque number of vaccine F(6 467 PFU/feather)was the highest.The replication rate of vaccine F was faster than other vaccines.After challenged with Md5 strain,the weight of the challenge control group chickens were decreased,and the unvaccinated chickens challenged with Md5 had 93.3％(14/15)mortality,and 100％(15/15)MD lesions.Compared with blank control group,there was no significant difference in body weight in groups G01 to G07(P＞0.05).The mortality of vaccinated chickens in groups G01-G07 were 0/14,3/15,5/15,0/14,0/13,0/15 and 1/15,respectively.The MD lesion proportion of vaccinated chickens in groups G01-G07 were 5/14,8/15,7/15,5/14,3/13,3/15 and 5/15,respectively.The results of immune challenge protection test showed that 7 batches of Marek's disease vaccine had a certain protective effect on chickens,and the protection index of these vaccines were 45.7％-73.3％.[Conclusion]Different manufacturer's Marek's disease vaccine demonstrated comparable protective effect against Md5 strain of MDV.Furthermore,the bivalent vaccine exhibited higher protection(73.3％)compared to the monovalent vaccine.
Marek's diseasecommercial vaccinechallenge protection testprotection index
万方数据
维普
