| In recent years,the infectious diseases with spleen necrosis,which are caused by the new type of duck reovirus(NDRV)infection,are widely popular in many provinces in China.The disease will hinder the growth and development of ducklings and greatly reduce the feed return rate.NDRV infection can cause damage to the spleen and other immune organs of ducks,resulting in immunosuppression and increased susceptibility to other pathogens.It can infect all kinds of ducklings,and the smaller the age,the higher the incidence rate and mortality rate.In this study,we used chicken embryo hepatocytes to amplify the new type of duck reovirus sdyc strain in laboratory to obtain a large number of cell virus solution,prepare inactivated vaccine,immunize the egg chickens to prepare a new type of duck reovirus yolk antibody,which provides a strong guarantee for the prevention and control of the new type of duck reovirus.The new strain of duck reovirus sdyc was inoculated with chicken embryo hepatocytes.After 36 hours of virus infection,the cytoviral fluid was collected,and the supernatant was centrifuged to be used as the antigen solution for inactivated vaccine.The virulence titer and purity of the amplified virus solution were tested,which was in line with the requirements of vaccine preparation.At 37 ?,0.2 % formaldehyde solution inactivated virus solution for 24 h,and the inactivated virus solution and Tween-80 were mixed in 94:6 ratio to prepare the vaccine water phase.Two and three oil emulsion vaccines were added to sterile operation to make inactivated oil emulsion vaccine.The safety,dosage form,physical properties and storage conditions of the vaccine were tested,which was in accordance with the preparation standard.The egg yolk samples were collected every week after 4 times of immunization for ELISA antibody titer test.The results showed that the antibody level of the eggs reached the highest level in the third week after four immunization,and then the antibody level gradually decreased.After four times of immunization,egg yolk antibody was prepared after egg yolk separation,primary inactivation,acidizing extraction,secondary inactivation,primary filtration,bacteria removal filtration,ultrafiltration concentration,three inactivation and bacteria removal filtration.The physical properties,p H value,safety and antibody titer of yolk antibody were tested,which was in accordance with the production standard of antibody.The results showed that the level of antibody increased rapidly after the antibody was injected,the level of antibody reached the highest value in the third day,and then decreased slowly.The antibody titer of the serum was still positive on the 21 th day after the injection of 1 m L yolk antibody.The duration of the antibody protection completely covered the whole susceptible period of the duckling,which could greatly reduce the infection rate of the new type of duck reovirus to the ducklings.The healthy ducklings were artificially infected with the new type of duck reovirus,and the virus was discharged on the same day after the attack.The clinical manifestations were slow,prone to lying,piling up and diet decreased.The spleen necrosis and liver bleeding were obvious in the duckling.After the onset of the disease,the number of virus-free ducklings decreased until the sick ducklings no longer expel the virus,the mental state was obviously improved,the intake and drinking water volume returned to normal,and the liver and spleen symptoms of the ducks after the antibody injection were slightly.The results show that the new type of duck reovirus yolk antibody is simple in production process,low in cost,safe,effective in protection and high cure rate.It can be used to prevent and treat the new type of duck reovirus infection with spleen necrosis as the main symptom,make up for the serious economic loss caused by the disease,prevent and prevent the new type of duck reovirus infection and The treatment is of great value. |
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