Pasteurellosis (Pasteurella infection) is one of the most common bacterial infections in rabbits on commercial farms and in laboratory facilities. Curative treatments using antibiotics are only partly efficient, with frequent relapses. Breeding rabbits for improved genetic resistance to pasteurellosis is a sustainable alternative approach. In this study, we infected 964 crossbred rabbits from six sire lines experimentally with Pasteurella multocida. After post-mortem examination and bacteriological analyses, abscess, bacteria, and resistance scores were derived for each rabbit based on the extent of lesions and bacterial dissemination in the body. This is the first study to use such an experimental design and response traits to measure resistance to pasteurellosis in a rabbit population. We investigated the genetic variation of these traits in order to identify potential selection criteria. We also estimated genetic correlations of resistance to pasteurellosis in the experimental population with traits that are under selection in the breeding populations (number of kits born alive and weaning weight). Heritability estimates for the novel response traits, abscess, bacteria, and resistance scores, ranged from 0.08 (± 0.05) to 0.16 (± 0.06). The resistance score showed very strong negative genetic correlation estimates with abscess (− 0.99 ± 0.05) and bacteria scores (− 0.98 ± 0.07). A very high positive genetic correlation of 0.99 ± 0.16 was estimated between abscess and bacteria scores. Estimates of genetic correlations of the resistance score with average daily gain traits for the first and second week after inoculation were 0.98 (± 0.06) and 0.70 (± 0.14), respectively. Estimates of genetic correlations of the disease-related traits with average daily gain pre-inoculation were favorable but with high standard errors. Estimates of genetic and phenotypic correlations of the disease-related traits with commercial selection traits were not significantly different from zero. Disease response traits are heritable and are highly correlated with each other, but do not show any significant genetic correlations with commercial selection traits. Thus, the prevalence of pasteurellosis could be decreased by selecting more resistant rabbits on any one of the disease response traits with a limited impact on the selection traits, which would allow implementation of a breeding program to improve resistance to pasteurellosis in rabbits.

中文翻译：

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利用新型反应性状对兔巴氏杆菌病抗性的遗传参数。

巴氏杆菌病（巴斯德氏菌感染）是商业农场和实验室设施中的兔子中最常见的细菌感染之一。使用抗生素进行的治疗仅部分有效，且复发频繁。繁殖兔子以改善对巴氏杆菌病的遗传抗性是一种可持续的替代方法。在这项研究中，我们实验性地用多杀巴斯德氏菌感染了来自六个父系的964只杂交兔。经过验尸和细菌学分析，根据病变程度和细菌在体内的传播情况，得出每只兔子的脓肿，细菌和抵抗力得分。这是首次使用此类实验设计和反应性状来测量兔种群对巴氏杆菌病的抵抗力的研究。为了确定潜在的选择标准，我们调查了这些性状的遗传变异。我们还估计了实验种群对巴氏杆菌病的抗性与育种种群中正在选择的性状之间的遗传相关性（活着的成套工具数量和断奶的体重）。对于新的反应性状，脓肿，细菌和抵抗力评分的遗传力估计范围为0.08（±0.05）至0.16（±0.06）。抗药性得分显示非常强的负遗传相关估计，脓肿（-0.99±0.05）和细菌得分（-0.98±0.07）。脓肿和细菌评分之间的正遗传相关性非常高，为0.99±0.16。接种后第一周和第二周，抵抗力评分与平均日增重性状的遗传相关性估计为0。98（±0.06）和0.70（±0.14）。接种前平均日增重与疾病相关性状的遗传相关性估计是有利的，但标准误较高。疾病相关性状与商业选择性状的遗传和表型相关性估计值与零没有显着差异。疾病反应性状是可遗传的，并且彼此高度相关，但是与商业选择性状没有显着的遗传相关性。因此，可以通过对任何一种疾病反应性状选择更具抗性的兔子来降低巴氏杆菌病的患病率，而对选择性状的影响有限，这将允许实施育种计划来提高兔子对巴氏杆菌病的抵抗力。接种前平均日增重与疾病相关性状的遗传相关性估计是有利的，但标准误较高。疾病相关性状与商业选择性状的遗传和表型相关性估计值与零没有显着差异。疾病反应性状是可遗传的，并且彼此高度相关，但是与商业选择性状没有显着的遗传相关性。因此，可以通过对任何一种疾病反应性状选择更具抗性的兔子来降低巴氏杆菌病的患病率，而对选择性状的影响有限，这将允许实施育种计划来提高兔子对巴氏杆菌病的抵抗力。接种前平均日增重与疾病相关性状的遗传相关性估计是有利的，但标准误较高。疾病相关性状与商业选择性状的遗传和表型相关性估计值与零没有显着差异。疾病反应性状是可遗传的，并且彼此高度相关，但是与商业选择性状没有显着的遗传相关性。因此，可以通过对任何一种疾病反应性状选择更具抗性的兔子来降低巴氏杆菌病的患病率，而对选择性状的影响有限，这将允许实施育种计划来提高兔子对巴氏杆菌病的抵抗力。