Saginala S, Nagaraja T G, Tan Z L, Lechtenberg K F, Chengappa M M, Kemp K E, Hine P M
Department of Animal Sciences, Kansas State University, Manhattan 66506, USA.
Am J Vet Res. 1996 Apr;57(4):483-8.
To determine the efficacy of leukotoxin-based Fusobacterium necrophorum vaccines and dietary tylosin in providing protection against experimentally induced hepatic abscesses in steers.
30 steers assigned randomly to 6 treatment groups of 5 steers each: 1, phosphate-buffered saline solution (PBSS; control); 2, PBSS control, fed tylosin (100 mg/steer) daily; 3, inactivated whole-cell culture with oil emulsion adjuvant; 4, culture supernatant (crude toxoid) with oil emulsion adjuvant; 5, semipurified leukotoxoid with oil emulsion adjuvant; and 6, semipurified leukotoxoid with saponin adjuvant.
Steers were inoculated SC with emulsified antigen or PBSS on days 0 and 21. Blood samples were collected at weekly intervals to monitor serum antileukotoxin antibody titer. On day 42, all steers were challenge exposed intraportally with F necrophorum culture. Three weeks later (day 63), steers were euthanatized and necropsied to examine liver and assess protection.
Antileukotoxin antibody titers of all vaccinated groups markedly increased from baseline values, and mean titers of vaccinated groups were higher than those of the control and tylosin-treated groups. Steers vaccinated with culture supernatant with oil emulsion adjuvant or semipurified leukotoxoid with saponin adjuvant had the highest mean antibody titers. All 5 steers in the control group developed liver abscesses. Tylosin feeding did not protect steers challenge exposed with F necrophorum intraportally.
Culture supernatant was more protective than whole-cell culture or semipurified leukotoxin against experimentally induced hepatic abscesses. Partial purification of leukotoxin appeared to reduce its protective immunity.
确定基于白细胞毒素的坏死梭杆菌疫苗和日粮泰乐菌素在预防实验性诱导的公牛肝脓肿方面的效果。
30头公牛随机分为6个处理组，每组5头：1组，磷酸盐缓冲盐水溶液（PBSS；对照组）；2组，PBSS对照组，每日饲喂泰乐菌素（100毫克/头）；3组，含油乳佐剂的灭活全细胞培养物；4组，含油乳佐剂的培养上清液（粗类毒素）；5组，含油乳佐剂的半纯化白细胞毒素；6组，含皂苷佐剂的半纯化白细胞毒素。
在第0天和第21天给公牛皮下接种乳化抗原或PBSS。每周采集血样以监测血清抗白细胞毒素抗体滴度。在第42天，所有公牛经门静脉接种坏死梭杆菌培养物进行攻毒。三周后（第63天），对公牛实施安乐死并进行剖检，检查肝脏并评估保护效果。
所有接种疫苗组的抗白细胞毒素抗体滴度均较基线值显著升高，且接种疫苗组的平均滴度高于对照组和泰乐菌素处理组。接种含油乳佐剂的培养上清液或含皂苷佐剂的半纯化白细胞毒素的公牛平均抗体滴度最高。对照组的所有5头公牛均发生了肝脓肿。饲喂泰乐菌素未能保护经门静脉接种坏死梭杆菌攻毒的公牛。
在预防实验性诱导的肝脓肿方面，培养上清液比全细胞培养物或半纯化白细胞毒素更具保护作用。白细胞毒素的部分纯化似乎降低了其保护性免疫。
