Edwardsiella piscicida has emerged as an important pathogen of channel × blue catfish hybrids cultured in the southeastern United States. With increasing popularity of hybrid catfish and growing concern over E. piscicida, the crossprotective potential of a live‐attenuated E.ictaluri vaccine was evaluated. An immunization bath of E. piscicida (3 × 10⁷ CFU/ml) protected channel catfish against immersion challenge of wild‐type E. ictaluri (1 × 10⁷ CFU/ml) across multiple temperatures and feeding regimens (relative percent survival [RPS]: 89–100%). Channel catfish immunized orally with a live‐attenuated E. ictaluri vaccine/feed admix (3 × 10⁷ CFU/g of feed) were protected against intracoelomic injections of both high (HD) (7.4x10⁵ CFU/fish; RPS = 85%) and low doses (LD) (1.5 × 10⁵ CFU/fish; RPS = 88%) of E. piscicida. Because of limited feed consumption during vaccination, oral immunization of hybrids was followed by a 30‐min immersion bath with cultured vaccine (5 × 10⁶ CFU/ml). Combinatory oral/bath vaccination was ineffective against HD E. piscicida but was protective against LD E. piscicida (48% RPS) and E. ictaluri (96% RPS). Finally, naïve catfish that survived LD E. piscicida injections were protected against E. ictaluri immersion challenge (2 × 10⁷ CFU/ml; RPS: Hybrids 55%; Channels 75%). Results suggest a live‐attenuated E. ictaluri vaccine can also protect channel and hybrid catfish against E. piscicida.

中文翻译：

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减毒的爱德华氏埃克塔里乌拉活疫苗对爱德华氏菌在通道（Ictalurus punctatus）和通道×蓝色（Ictalurus furcatus）杂交cat鱼中的交叉保护潜力

爱德华氏菌已成为美国东南部养殖的蓝channel鱼杂种的重要病原体。随着杂交cat鱼的日益普及和对埃希氏大肠杆菌的关注，评估了活减毒埃希氏菌疫苗的交叉保护潜力。piscicida大肠杆菌（3×10 ⁷ CFU / ml）的免疫浴可保护channel鱼在多个温度和饲喂方案（相对存活率[RPS] ）下免受野生型大肠杆菌（1×10 ⁷ CFU / ml）的浸没攻击。]：89–100％）。用减毒活大肠杆菌疫苗/饲料混合物口服免疫immun鱼（3×10⁷ CFU / g饲料被保护免受高（HD）（7.4x10 ⁵ CFU /鱼; RPS = 85％）和低剂量（LD）（1.5×10 ⁵ CFU /鱼; RPS = 88％）的腔内注射）的E. piscicida。由于疫苗接种过程中饲料消耗有限，因此对杂种进行口服免疫后，再用培养的疫苗（5×10 ⁶ CFU / ml）进行30分钟的浸浴。口服/盆浴联合接种对HD piscicida无效，但对LD piscicida（48％RPS）和ic。Etaltal（96％RPS）具有保护作用。最后，在LD。piscicida注射液中存活的幼稚cat鱼受到了E. ictaluri的保护沉浸挑战（2×10 ⁷ CFU / ml; RPS：杂种55％;通道75％）。结果表明，减毒活的E. taltaluri疫苗也可以保护渠道cat鱼和杂种cat鱼免受E. piscicida感染。