Abstract:

【Objective】 The purpose of the test was to investigate the effect of muscovy duck infected by muscovy duck reovirus on humoral immunity. 【Method】 Sixty healthy ducks at 5-day-old of age were randomly divided into two groups . The experimental group was injected 0.2ml muscovy duck reovirus (one penent of TCID50, TCID50=10-3.7558) on leg, and the controll group was injected normal saline at the same quantity. The quantity of plasma cells in bursa fabricius and the spleen was tested by the histochemical test method. The level of avian influenza antibodies in serum was tested by the method of indirect hemagglutination, also the content change of IL-2 and IL-6 in the serum was tested by the testing method of radiation immunization. 【Result】 Results showed that the quantity of plasma cells in bursa of fabricius and spleen in the experiment group was less than the controll group, had different degrees of decrease respectively during the time after attack test by using reovirus, especially after 15 day of infection the antibody of experiment group was the lowest (P＜0.01). The ability of antibody-producing decreased too. The avian influence antibody of experiment group was very significantly less than the controll group (P＜0.01), especially after 15 day of infection the antibody of experiment group was the lowest. But they all increased at 15 days after attack test .The content of IL-2 and IL-6 in the serum of experiment group ducks decreased on the first stage of the test ,but they all increased on the later stage compared with the former. However the content of IL-2 and IL-6 in the serum of experiment group ducks was lower than the control group (P＜0.01). 【Conclusion】 Ducks at five day old of age are infected by muscovy duck reovirus, plasma cells in immune organs (bursa of fabricius and spleen) are damaged and the ability of antibody forming decrease. The immunity function of ducks decrease because the virus decreased the content of immunity molecular (IL-2, IL-6) in serum. Therefore it is an effective way to enhance the humoral immunity of duck to control muscovy duck reovirus.

Key words: muscovy duck reovirus, humoral immunity, plasma cell, IL-2, IL-6