Maternal Antibody And Its Protection After Immunized Aginst Riemerella Anatipestifer For Laying Duck

This study was carried out based on the indirect enzyme linked immunosorbent assay of lipopolysaccharide(LPS-ELISA) and ultrasonic lysates(PRO-ELISA) of serotype 1 Riemerella anatipestifer, detecting yolk antibody、serum antibody of 6 day old after immunized aginst Riemerella anatipestifer for laying duckand and maternal antibody by LPS-ELISA, PRO-ELISA and tube agglutination test with Protection of ducklings,the results showed that:1. Constructed LPS-ELISA and PRO-ELISA of RA-1LPS-ELISA:The best optimal coating concentration 12.50ng/μL, the best serum dilution 1:800, enzyme-linked antibodies dilution 1:400.PRO-ELISA:The best optimal coating concentration 1.56ng/μL, the best serum dilution 1:400, enzyme-linked antibodies dilution 1:800.The above two methods have good parallel relationship with tube agglutination test.2. Detecting yolk antibody and serum antibody of 6 day old after immunized aginst Riemerella anatipestifer for laying duckandInoculated with the dose of 0.5mL vaccine against riemerella anatipestifer for 60 four months of age ducks. Collected duck’s eggs every 3 days after vaccined,30 eggs per time, 10 eggs for extracted yolk antibody,20 used to hatched ducklings, collected blood each batch of 6 day old ducklings after hatched,separated serum,60 ducks as control group. Detection egg yolk titer by agglutination test and two ELISA methods, the results showed that 6 days after vaccination the antibody begen to appear,27 days the antibody levels reached to top,33 days antibody levels decreased slowly. The results also showed that the dynamic of serum antibody titer was proportional to the changes of yolk antibody titer. The antibody in serum was lower than york, control group was negative.3. The maternal antibody change of ducklings after immunized aginst Riemerella anatipestifer for laying duck and protection for ducklingsInoculated with the dose of 0.5mL vaccine against riemerella anatipestifer for 120 four months of age ducks of farm,80ducks as control group. Carry out two experments:(1) Detecting antibody:Separated serum at 1,6,9,12,15,18,21 days, detected the levels of antibody by three methods. (2)Challenge protection of ducklings:After the ducklings were hatched, they were challenged at 3,6,9,12,15,18,21 day of age, a group of 8 ducks each time, the injection amount is 0.5mL, containing Riemerella anatipestifer 10 CFU/mL. Control group injected bacteria for 6 ducklings, the blank group injected saline water for 4 ducklings. The results showd that with the increase of ducklings days of age, more than 1:8 before 9 days, at 18 days the maternal antibody disappeared, the Challenge tests showed that at 9 days and 12 days the protection of antibody was 75%(6/8) and 50%(4/8), control group were all die. The results showd that before the age of 12 days the protection was well. The maternal antibody level and protection rate for ducklings was positively related to the size.