Preparation Of Chicken Coccidia Egg Yolk Antibody And Its Application

Chicken coccidiosis is a widespread parasitic disease caused by one or more Eimeria species in the genus Eimeria that seriously harms the chicken industry.In recent years,with the intensification and scale-up of chicken breeding,higher requirements have been put forward for the prevention and control of chicken coccidiosis.For a long time,chemical drugs have been the main means of preventing and treating chicken coccidiosis.Due to the frequent use of drugs,coccidiosis resistance has increased,and chemical drug residues have also caused great harm to public health.In addition,the development and application of coccidiosis vaccines have been initially applied in production,but there are still some problems such as strong virulence and insufficient immune protection.Therefore,the use of vaccines has certain limitations.Therefore,searching for safe and efficient control of chicken coccidiosis has become one of the research hotspots in this field.Egg yolk antibodies have high specificity and no side effects,and their role in practice in the prevention and treatment of various diseases has been confirmed.It can be seen that the prevention and control of coccidiosis through anti-coccidial yolk antibodies can become a new way to prevent and control the disease.In this study,four types of coccidia live egg sacs were used to immunize laying hens to prepare their yolk antibodies,which were used as feed additives to feed chicks infected with coccidia to investigate the effect of yolk antibodies in the actual treatment of coccidiosis.Provide reference for prevention and treatment of the disease.1 Preparation and identification of anticoccidial tetravalent IgYThe purified oocysts of tender,giant,pile and precocious Eimeria were mixed in the same proportion.After ultrasonication,they were mixed with adjuvant as an immunogen,and 180-day-old laying hens were intramuscularly immunized.It was1×105/piece,immunized once every 10 days and immunized 5 times.Eggs were taken every 10 days after laying to separate the yolk,and the yolk antibody was extracted by water dilution method with saturated ammonium sulfate method.Purity determination of purified IgY by SDS-PAGE SDS-PAGE analysis showed that the purified egg yolk antibody consisted of a heavy chain of about 66 KDa and a light chain of about 40 KDa,and the purity was up to 95%.2 Establish an indirect ELISA method to analyze the increase and decrease of antibody after immunizationThe oocysts of Tender,Heap,Giant and Precocious Coccidia were sonicated and the antigen concentration was adjusted to 0.74mg/m L.By optimizing the reaction conditions,the optimal conditions for the indirect ELISA method were screened;analysis.At the same time,the established method is used to evaluate the growth and decline of antibodies after immunization.The results showed that the optimal dilution of the antigen was 1:400,and the specific test showed that the yolk antibody could specifically recognize the coccidia antigen.And the method has good sensitivity and reproducibility;after 3 immunizations,the antibody level in the yolk starts to rise gradually,and reaches the peak on the 60th day,the highest titer reaches 1:25600,and maintains a high level for a long time3 Evaluation of the effect of IgY on chicken coccidiosis15-day-old white feather broilers were randomly divided into 9 groups,namely white control group,red control group,negative yolk powder control group,drug addition group and yolk powder addition group???,each group had 15 birds.Egg yolk antibody was added to the feed from 15 days old for 6 days,the drug addition group received 0.25g/piece for 4 days;when the chickens were 16 days old,all groups except the white control group were infested with infection Coccidia oocysts1×10~4/piece.Calculate the relative weight gain rate,the number of oocysts,cecum disease and anticoccidial index respectively,and comprehensively evaluate the effect of egg yolk antibody on the treatment of chicken coccidiosis.The results showed that after feeding the yolk antibody,the average weight gain,lesion score,oocyst reduction rate and ACI of each test group were better than those of the infection control group and the negative control group.