Colonization Rule of Salmonella enteritidis Vaccine Strain Sm24/Rif12/Ssq in Laying Hens
In order to identify the rule of colonization of Salmonella enteritidis vaccine strain Sm24/Rif12/Ssq in laying hens,50 Hy-line brown hens were orally immunized(initial immunization)with Sm24/Rif12/Ssq vaccines(1×108 CFU/hen)at 0 day of age(the day of birth),then pharyngeal swabs,cloacal swabs,caeca and livers were collected at 1,3,5 and 7 days after immunization to determine the colonization level of the vaccine strain,and blood samples were collected at 30 days after immunization to determine the antibody level;30 each of hens at 6-week age after initial immunization and those at 16-week age after secondary immunization were selected to orally immunized with Sm24/Rif12/Ssq vaccines(1×108 CFU/hen),namely,secondary and tertiary immunization,and cloacal swabs were collected at 4 days after immunization to test the colonization level,and blood samples were collected at 30,60 and 100 days after immunization to test antibody level.The results showed that the load of vaccine strains in pharyngeal swabs,cloacal swabs and caecum samples tended to decline after increasing,with a detection rate from 60%to 100%,and that in liver samples gradually declined,with a detection rate from 50%to 90%,but no antibodies were detected from blood samples.The detection rate of vaccine strains in cloacal samples after secondary and tertiary immunization ranged from 17%to 20%,the positive rate of serum antibodies increased gradually.In conclusion,Sm24/Rif12/Ssq vaccine could easily colonize in the gut of 0-day-old chicks,but difficult in that of high-day-old immunized hens,and induced hens to produce antibodies after booster immunization.The rules of colonization and antibody production of Sm24/Rif12/Ssq vaccine in hens were identified in the paper,laying a foundation for evaluation on immunization effects.
万方数据
维普
