Fisheries Laboratory, University of Tokyo, Hamamatsu, Shizuoka, 431-0214, Japan.
Veterinary Research Center, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan.
Sci Rep. 2020 Nov 17;10(1):19976. doi: 10.1038/s41598-020-77069-z.
Parasite resistance traits in aquaculture species often have moderate heritability, indicating the potential for genetic improvements by selective breeding. However, parasite resistance is often synonymous with an undesirable negative correlation with body size. In this study, we first tested the feasibility of genomic selection (GS) on resistance to heterobothriosis, caused by the monogenean parasite Heterobothrium okamotoi, which leads to huge economic losses in aquaculture of the tiger pufferfish Takifugu rubripes. Then, using a simulation study, we tested the possibility of simultaneous improvement of parasite resistance, assessed by parasite counts on host fish (HC), and standard length (SL). Each trait showed moderate heritability (square-root transformed HC: h = 0.308 ± 0.123, S.E.; SL: h = 0.405 ± 0.131). The predictive abilities of genomic prediction among 12 models, including genomic Best Linear Unbiased Predictor (GBLUP), Bayesian regressions, and machine learning procedures, were also moderate for both transformed HC (0.248‒0.344) and SL (0.340‒0.481). These results confirmed the feasibility of GS for this trait. Although an undesirable genetic correlation was suggested between transformed HC and SL (r = 0.228), the simulation study suggested the desired gains index can help achieve simultaneous genetic improvements in both traits.
水产养殖物种的寄生虫抗性特征通常具有中度遗传力，这表明通过选择性育种进行遗传改良的潜力。然而，寄生虫抗性通常与体型的不良负相关同义。在这项研究中，我们首先测试了基于基因组选择（GS）对异双盘吸虫引起的异双盘吸虫病抗性的可行性，这种寄生虫会导致养殖的虎斑河豚 Takifugu rubripes 遭受巨大的经济损失。然后，通过模拟研究，我们测试了同时改善寄生虫抗性的可能性，寄生虫计数（HC）和标准长度（SL）来评估。每个特征都表现出中度遗传力（平方根转换的 HC：h=0.308±0.123，标准误差；SL：h=0.405±0.131）。12 种模型中的基因组预测能力也适中，包括基因组最佳线性无偏预测（GBLUP）、贝叶斯回归和机器学习程序，对于转换后的 HC（0.248-0.344）和 SL（0.340-0.481）都是如此。这些结果证实了该性状进行 GS 的可行性。尽管转换后的 HC 和 SL 之间存在不良遗传相关（r=0.228），但模拟研究表明，所需的增益指数有助于实现两个性状的同时遗传改良。
