| Avian influenza（AI）and Newcastle disease（ND）viruses which are mainly infected in poultry are acute and highly contagious infectious diseases and have multiple clinical characteristics.They are widely spread with high mortality and bring serious threats and harms to the poultry industry all over the world.Poultry breeding is one of the important industries of agriculture in China,and in the process of breeding vaccination is one important methods to prevent and control the occurrence and prevalence of epidemic diseases.At present,there are many studies on the immune procedure of AI and ND,but due to series changes of poultry species,breeding methods,epidemic strains and epidemic environment,the immune procedure still needs to be continuously optimized.Monitoring of serum antibody level after vaccine immunization is an important basis for evaluating the immune effect of vaccine and formulating reasonable immune procedure.This expriment studied on the growth or decline pattern of maternal antibody mainly used hemagglutination / hemagglutination inhibition test（HA / HI）and continuously tested the levels of serum antibody and yolk antibody of various subtypes of AI（H5-11,H5-12,H7-2 and H9 subtypes）and ND,and carried out epidemiological investigation and antibody level detection on chicken farms in some areas of Shandong and Henan province.This research was hoped to provide a methodological reference for antibody monitoring in chicken farms and a theoretical basis for the effective prevention and control of avian influenza and other diseases.1.The chicken after birth were collected from the 1,4,7,10,14,21,28 and 31 d,and the maternal antibody level was detected continuously.The average antibody titers（log2）of AI H5-11 subtype were 4.80,4.43,4.06,3.43,2.10,0.70,0.06 and 0.00 respectively.The average antibody titers of H5-12 subtype were 4.83,4.56,3.76,3.13,2.20,0.76,0.10 and 0.00 respectively.The average antibody titers（log2）of H9 subtype were 4.56,4.40,3.86,3.33,1.66,0.80,0.40 and 0.20 respectively.The average antibody titers（log2）of h H7-2 subtype were 4.36,4.53,3.83,3.20,2.13,1.10,0.33 and 0.10 respectively.The average antibody titers（log2）of Nd were 4.80,4.70,3.96,3.33,2.16,1.20,0.53 and0.33 respectively.The results showed that the maternal antibody level of AI / ND had a protective effect after hatching,and then showed a downward trend which decreased slowly 10 days before,and rapidly after 10 days,and the maternal antibody almost attenuated at 28 d.2.Chick vaccinated at the age of 10 d were detected continuously the antibody levels on the 10,17,24,31,38,45,52 and 60 d born.The average antibody titers（log2）of H5-11 were 4.03,5.16,5.90,6.33,6.90,6.66,5.73 and 5.33 respectively;The average antibody titers（log2）of H5-12 were 3.10,4.70,5.36,6.16,6.73,6.63,5.60 and 4.46 respectively;The average antibody titers（log2）of H9 were 3.30,4.60,5.50,6.20,6.60,6.60,5.63 and 4.43 respectively;The average antibody titers（log2）of H7-2 were2.90,4.66,5.23,6.10,6.40,6.36,5.56 and 4.46 respectively;The average antibody titers（log2）of ND were 3.40,4.60,5.16,6.03,6.60,6.66,5.76 and 4.93 respectively.The level of maternal antibody in chicks was low at 10 days old.The antibody level reached the peak 21～28 d after vaccine injection.The antibody level of H5-11 is higher than that of H5-12,H9,H7-2 and ND,which indicated that its produces had better antibody effect in the body.3.The serum antibody and yolk antibody 5 subtypes of of AI and ND were detected in some farms immunized in Shandong Province,and the change rule of antibody levels were analyzed.The levels of serum antibody and yolk antibody of AI H5-11 subtype in laying hens farm wre detected,the serum antibodies results were 9.2 log2 and 8.9 log2,9.5 log2 and 8.7 log2 respectively measured at 20,40,60 and 90 days after immunization,and the yolk antibodies were 8.9 log2,7.8 log2,7.8 log2 and 6.9log2 respectively.The results showed that the level change of the yolk antibody was positively correlated with the serum antibody produced in chickens after vaccination.The antibody level reached the highest value at 40 d after vaccination and began to decline at 60 d.However,the antibody titer of serum samples was higher about 0.5 ～ 2 titers than that of egg yolk samples.4.The clinical symptoms of chickens infected with avian influenza suspected were depression,loss of appetite,dyspnea and neurological symptoms（stargazing）.The pathological changes were mainly laryngeal and tracheal bleeding,glandular gastric papilla and mucosal swelling,congestion and ulcer,and other organs bleeding at different degrees.128 samples of suspected AIV were tested etiology and the positive detection rates in the four regions were 33.33%,36.11%,39.28% and 36.36% respectively,and the total physical examination rate was 35.93%.5.The average antibody titer of AI H9 subtype of 960 serum samples collected randomly was8.87 log2,and the qualified rate of antibody（HI≥4 log2）was 93.26%（900/960）.The detection results of egg yolk antibody in 1600 eggs samples showed that the average antibody titer of H9 subtype AIV was7.68 log2,and the qualified rate of antibody was 90.06%（1441/1600）.Directed against the comprehensive analysis of the immunization situation of the farm,the level of yolk antibody showed lower,so it was necessary to strengthen immunization and improve immunization procedures further. |
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