Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, Norway.
Research Institute for Aquaculture No.2 (RIA2), Ho Chi Minh City, Vietnam.
J Fish Dis. 2021 Feb;44(2):191-199. doi: 10.1111/jfd.13277. Epub 2020 Oct 24.
The aim was to carry out a joint genetic analysis of survival and harvest body weight, recorded in a growth performance test in Mekong striped catfish (Pangasianodon hypophthalmus), and susceptibility to bacillary necrosis (caused by Edwardsiella ictaluri), recorded in challenge tests. Data were from two challenge tested year-classes (6,000 fish in both) that both had growth test data available for survival and body weight (13,000 fish each year). Data were analysed with a linear tri-variate sire-dam model without the common environmental effect because otherwise genetic correlations were estimated with large standard errors. Susceptibility to bacillary necrosis was found weakly genetically correlated to both growth and survival in the growth test, while growth was found with moderate favourable genetic correlation to growth survival. To defend continued challenge testing of striped catfish in Vietnam, a strong genetic relationship needs to be established between bacillary necrosis and survival under a natural disease outbreak. This requires another field test (in addition to the growth test) with siblings, without antibiotic treatment and the cause of death continuously monitored. Meanwhile, the routine challenge testing with the aim to indirectly improve field survival through selection should continue.
本研究旨在对湄公河巨型鲶鱼（Pangasianodon hypophthalmus）生长性能试验中的存活和收获体重进行联合遗传分析，并对细菌性坏死病（由爱德华氏菌引起）易感性进行联合遗传分析，这些数据来自两个经过挑战试验的年龄组（每个年龄组约有 6000 条鱼），这两个年龄组都有生长试验数据可用于存活和体重（每年各有 13000 条鱼）。由于共同环境效应，否则遗传相关性的估计会有较大的标准误差，因此采用无共同环境效应的线性三变量 sire-dam 模型进行数据分析。细菌性坏死病易感性与生长试验中的生长和存活呈弱遗传相关，而生长与生长存活呈中度有利遗传相关。为了在越南继续对条纹鲶鱼进行挑战试验，需要在自然疾病爆发下建立细菌性坏死病和存活之间的强遗传关系。这需要进行另一次田间试验（除生长试验外），试验中使用的是无抗生素处理且持续监测死因的同窝兄弟姐妹。同时，应继续进行常规的挑战试验，旨在通过选择间接提高野外存活率。
