Khang Pham Van, Phuong Truong Ha, Dat Nguyen Khac, Knibb Wayne, Nguyen Nguyen Hong
GenCology Research Centre, University of the Sunshine Coast, Maroochydore, QLD, Australia.
Department of Science, Technology and Environment, Ministry of Agriculture and Rural Development, Hanoi, Vietnam.
Front Genet. 2018 May 29;9:191. doi: 10.3389/fgene.2018.00191. eCollection 2018.
Selective breeding for marine finfish is challenging due to difficulties in reproduction, larval rearing, and on-growth in captive environments. The farming of Asian seabass () has all these problems and our knowledge of the quantitative genetic information (heritability and correlations) of traits necessary for commercial exploitation is poor. The present study was conducted to address this knowledge gap and to provide information that can be applied to sea bass and other aquaculture species. We carried out a comprehensive genetic evaluation for three traits (body weight, total length, and survival) collected from a breeding population for Asian seabass over an eight-year period from 2010 to 2017. Statistical analysis was carried out on 4,567 adult fish at 105, 180, 270, 360, 450, and 570 days post-hatch (dph). The heritabilities (h) estimated for body weight and length using linear mixed model were moderate to high (0.12 to 0.78 and 0.41 to 0.85, respectively) and they differed between the measurement periods. Survival during grow-out phase was analyzed using threshold logistic and probit models. The heritability estimates for survival rate on the underlying liability scale ( ) varied from 0.05 to 0.21. When the observed heritability obtained from the linear mixed model was back-transformed to the liability scale, they were similar but not significant. In addition, we examined effects of genotype by environment (G × E) interaction on body traits. The genetic correlation for body weight between tank and sea cage cultures were high (0.91-0.94) in the first and second rearing periods (180 and 270 dph) but the correlation was decreased to 0.59 ± 0.33 at 360 dph. This suggests that the genotype by environment interaction is important for body traits in this population. Furthermore, the genetic correlations of body weights between different measurement periods were moderate but different from one. This suggests that body weights measured at different time points may be different traits and selection for improved early weight may not capture all genetic expressions in subsequent rearing periods in Asian seabass. Selection of the nucleus in sea cages may produce genotypes that do not perform equally well in tanks, although this deserves further studies to determine a suitable selection environment and optimize the breeding program. This paper discusses challenges encountered during implementation of the selection program for .
由于在人工养殖环境中繁殖、幼体培育及生长存在困难，海洋硬骨鱼类的选择性育种颇具挑战性。尖吻鲈（）养殖存在所有这些问题，而且我们对商业开发所需性状的数量遗传信息（遗传力和相关性）了解不足。本研究旨在填补这一知识空白，并提供可应用于尖吻鲈及其他水产养殖物种的信息。我们对2010年至2017年八年间从尖吻鲈育种群体收集的三个性状（体重、全长和存活率）进行了全面的遗传评估。对4567尾孵化后105、180、270、360、450和570天（dph）的成年鱼进行了统计分析。使用线性混合模型估计的体重和体长的遗传力（h）为中度到高度（分别为0.12至0.78和0.41至0.85），且在不同测量时期有所不同。使用阈值逻辑模型和概率模型分析了养成阶段的存活率。潜在责任量表上存活率的遗传力估计值（）在0.05至0.21之间变化。当将从线性混合模型获得的观察到的遗传力反向转换到责任量表时，它们相似但不显著。此外，我们研究了基因型与环境（G×E）互作对身体性状的影响。在第一和第二饲养期（180和270 dph），池塘养殖和海水网箱养殖之间体重的遗传相关性较高（0.91 - 0.94），但在360 dph时相关性降至0.59±0.33。这表明基因型与环境互作对该群体的身体性状很重要。此外，不同测量时期体重的遗传相关性为中度但各不相同。这表明在不同时间点测量的体重可能是不同的性状，在尖吻鲈中，为提高早期体重进行的选择可能无法涵盖后续饲养期的所有基因表达。在海水网箱中选择核心群可能产生在池塘中表现不佳的基因型，尽管这值得进一步研究以确定合适的选择环境并优化育种计划。本文讨论了在实施尖吻鲈选择计划过程中遇到的挑战。
