Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870, Frederiksberg C, Denmark.
National Institute of Aquatic Resources, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
Acta Vet Scand. 2023 Jun 26;65(1):28. doi: 10.1186/s13028-023-00692-z.
Vibriosis is a bacterial disease in fish caused by the Gram negative bacterium Vibrio anguillarum with severe impact on rainbow trout (Oncorhynchus mykiss) farming. Sustainable control methods should be developed and we here show that marker assisted selective breeding of fish naturally resistant to the disease is feasible. We have validated the use of a single nucleotide polymorphism (SNP) marker SNP AX-89,945,921 (QTL on chromosome 21). The QTL was previously found associated with resistance to vibriosis and described following a genome wide association analysis (GWAS) of trout exposed to the bacterium. For this validation spawners were genotyped by use of the 57 K Axiom®Trout Microarray (Affymetrix) and homozygous male fish carrying the allele with the SNP AX-89,945,921 were then selected and used to fertilize eggs from outbred female trout resulting in fish all carrying the SNP (QTL-fish). Control fish (non-QTL fish) were produced by fertilizing the same batch of eggs by use of male parents negative for the SNP. The fish were exposed in freshwater to V. anguillarum (water bath infection) at 19 C°. A total of 900 fish were challenged in a common garden set-up in triplicate. A bacterial solution of V. anguillarum (serotype O1) was added to each of three freshwater fish tanks, each with 150 QTL and 150 non-QTL fish. Fish were tagged by tail fin cut (upper/lower) to discern the two groups, whereafter fish were monitored around the clock to detect disease signs and remove moribund fish. Clinical vibriosis developed within two days in non-QTL-fish (overall morbidity of 70%). QTL fish developed clinical signs later and the morbidity was significantly lower and did not reach 50%. Rainbow trout farming may benefit from using the QTL associated with higher resistance towards vibriosis. The effect may be optimized in the future by use of both male and female parents homozygous for the marker allele.
弧菌病是一种由革兰氏阴性细菌鳗弧菌引起的鱼类细菌性疾病，对彩虹鳜（Oncorhynchus mykiss）养殖有严重影响。应开发可持续的控制方法，我们在此证明，对自然抵抗疾病的鱼类进行标记辅助选择性育种是可行的。我们已经验证了使用单个核苷酸多态性（SNP）标记 SNP AX-89,945,921（第 21 号染色体上的 QTL）的有效性。该 QTL 先前与抗弧菌病有关，并在对暴露于该细菌的鳜鱼进行全基因组关联分析（GWAS）后进行了描述。为此，通过使用 57 K Axiom®鳜鱼微阵列（Affymetrix）对繁殖者进行基因分型，并选择携带 SNP AX-89,945,921 的纯合雄性鱼，然后用其授精来自杂交雌性鳜鱼的卵，从而产生携带 SNP（QTL 鱼）的鱼。通过使用不携带 SNP 的雄性亲本授精同一批卵来产生对照鱼（非 QTL 鱼）。在 19°C 的淡水中，将鱼暴露于鳗弧菌（水浴感染）下。在一个普通的花园设置中，总共用三批重复对 900 条鱼进行了挑战。在每个装有 150 条 QTL 和 150 条非 QTL 鱼的三个淡水鱼缸中添加鳗弧菌（血清型 O1）的细菌溶液。用鱼尾鳍切口（上/下）标记鱼，以区分两组，此后，全天候监测鱼以发现疾病迹象并清除濒死的鱼。非 QTL 鱼在两天内出现临床弧菌病（总体发病率为 70%）。QTL 鱼出现临床症状较晚，发病率明显较低，且未达到 50%。虹鳜养殖可能受益于使用与抗弧菌病更高抗性相关的 QTL。未来，通过使用携带标记等位基因的雄性和雌性亲本的组合，可以优化该效果。
