肠炎沙门菌疫苗株Sm24/Rif12/Ssq在蛋鸡体内的定殖规律

Colonization Rule of Salmonella enteritidis Vaccine Strain Sm24/Rif12/Ssq in Laying Hens

为明确肠炎沙门菌疫苗株Sm24/Rif12/Ssq在蛋鸡体内的定殖规律,选取50只海兰褐蛋鸡,于0日龄(出雏当日)滴口免疫1羽份(1×10~8 CFU/只)Sm24/Rif12/Ssq疫苗(首免),分别于免疫后1、3、5、7d采集咽拭子、泄殖腔拭子以及盲肠和肝脏样品测定疫苗株定殖水平,并于免疫后30 d采集血液测定抗体水平;随后选取30只经过首免的6周龄蛋鸡和30只经过二免的16周龄蛋鸡,分别滴口免疫1羽份(1×10~8 CFU/只)Sm24/Rif12/Ssq疫苗,即为二免和三免,于免疫后4 d采集泄殖腔拭子,测定疫苗株定殖水平,并于免疫后30、60、100 d采集血液测定抗体水平。结果显示,首免后咽拭子、泄殖腔拭子和盲肠样品中疫苗株载量呈先上升后下降趋势,疫苗株核酸检出率60%~100%,肝脏样品中疫苗株载量呈逐步下降趋势,疫苗株核酸检出率50%-90%,但未从血液样品中检出抗体;二免和三免后泄殖腔拭子中疫苗株核酸检出率为17%~20%,血清抗体阳性率呈逐步上升趋势。结果表明,Sm24/Rif12/Ssq疫苗株易定殖于0日龄蛋鸡肠道,而较难定殖于免疫后的高日龄蛋鸡肠道,并可于加强免疫后诱导蛋鸡产生可检测抗体。本研究阐明了Sm24/Rif12/Ssq疫苗株在蛋鸡体内定殖和抗体产生规律,为疫苗免疫后效果评估奠定了基础。

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 X1o°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(1X10"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 O-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.