禽网状内皮组织增生症病毒和A亚群禽白血病病毒共感染对疫苗免疫鸡生长性能和免疫器官的影响

Effects of Co-infection of Avian Reticuloendotheliosis Virus and Subgroup A Avian Leukosis Virus on the Growth Performance and Immune Organs of Vaccine Immunized Chickens

关键词:  REV  ALV-A  共感染  生长性能  免疫器官

Key words:  REV  ALV-A  co-infection  growth properties  immune organs

摘要:

禽为分析不同免疫状态下禽网状内皮组织增生症病毒(reticuloendotheliosis virus, REV)和A亚群禽白血病病毒(avian leukosis virus, ALV-A)共感染对鸡生长性能及免疫器官的影响，通过对 1日龄和 10日龄常规疫苗免疫鸡群、1日龄灭活疫苗免疫鸡群、1日龄活疫苗免疫鸡群进行REV与ALV-A单感染或共感染，于不同日龄称重，采集免疫器官，对生长性能、免疫器官比重进行比较和分析。结果显示，1日龄鸡单感染或共感染REV和ALV-A均会引起发病、死亡及体重下降，REV、ALV-A单感染组及共感染组平均病死率依次为27.6%、11.6%及31.9%，表明，疫苗免疫刺激增强了REV与ALV-A感染的致病性。10日龄鸡REV、ALV-A单感染及共感染于81日内病死率分别为13.3%、6.7%及20%，低于1日龄感染各相应组，体重下降程度也低于 1日龄感染鸡，表明鸡的日龄越高对REV、ALV-A感染的抵抗力越强。活疫苗与灭活疫苗免疫的比较显示，两种疫苗免疫应激均能引起鸡体重下降明显，且活疫苗免疫对体重的抑制作用更明显。REV单感染和共感染对生长发育的抑制作用高于ALV-A单感染，尤其是共感染对鸡体重的抑制作用最明显。对免疫器官比重的影响方面，1日龄感染时，共感染组胸腺比重显著降低，10日龄感染影响不显著，表明鸡日龄越大对病毒感染的抵抗力越强；常规免疫可引起法氏囊比重下降，但对法氏囊的影响是可恢复的，而REV单感染和共感染会加重常规免疫对法氏囊的损伤，且损伤更持久或不可恢复；ALV-A单感染对法氏囊的损伤影响不明显；单感染和共感染对脾脏比重的影响均不显著。本研究为深入研究REV和ALV-A单感染或者共感染诱导鸡群发生免疫抑制机制积累了重要的实验数据。

Abstract:

In order to analyze the effects of co-infection of reticuloendotheliosis virus (REV) and subgroup A avian leukosis virus (ALV-A) on growth performance and immune organs in different immune states，this study conducted single infection or co-infection of REV and ALV-A on 1-day-old and 10-day-old vaccine immunized chickens, 1-day-old inactivated vaccine immunized chickens and 1-day-old live vaccine immunized chickens. The chickens were weighed and immune organs were collected at different ages. The body weight and the proportion of immune organs were compared and analyzed. The results showed that single infection or co-infection with REV and ALV-A in 1-day-old chickens could cause morbidity, death and weight loss The average mortality of REV, ALV-A single infection group and co-infection group were 27.6%, 11.6% and 31.9%.It showed that vaccine immune stimulation enhanced the pathogenicity of REV and ALV-A infection. The mortality of co-infection, REV single infection and ALV-A single infection in 10-day-old chickens within 81 days were 20%, 13.3% and 6.7% respectively, which was lower than that in 1-day-old chickens, and the degree of weight loss was also lower than that in 1-day-old infected chickens, it showed that the older the age of chickens, the greater the resistance to virus infection. The comparison between live vaccine and inactivated vaccine showed that both of them could cause significant weight loss, and the inhibitory effect of live vaccine on weight was more obvious. The inhibitory effect of REV single infection and co-infection on growth and development was higher than that of ALV-A single infection, especially the co-infection had the most obvious inhibitory effect on chicken body weight. In terms of the effect on the proportion of immune organs, the proportion of thymus in the co-infection group decreased significantly at 1 day of age, but not at 10 days of age, indicating that the older the chicken is, the greater the resistance to virus infection. Routine immunization could reduce the proportion of bursa of Fabricius, but the effect on bursa of Fabricius could be recovered. Single infection and co-infection of REV would aggravate the damage of bursa of Fabricius in routine immunization state, and the damage was more lasting or unrecoverable; ALV-A single infection had no obvious effect on the injury of bursa of Fabricius; Single infection and co- infection had no significant effect on the proportion of spleen. This study provides important experimental data for further study on the immunosuppressive mechanism of chicken flocks induced by single or co-infection of REV and ALV-A.