The present study evaluated, in an 18-month gilthead sea bream trial, the time course effects of genetics on individual size variation and growth compensation processes in families selected by heritable growth in the PROGENSA^® breeding program. Families categorized as fast, intermediate, and slow growing had different growth trajectories with a more continuous growth in fast growth families. This feature was coincident with a reduced size variation at the beginning of the trial that clustered together the half-sib families sharing the same father. Regression analysis evidenced that the magnitude of compensatory growth was proportional to the initial size variation with no rescaling of families at this stage. By contrast, the finishing growth depensation process can mask, at least partially, the previous size convergence. This reflects the different contribution across the production cycle of genetics in growth. How early-life experiences affect growth compensation at juvenile stages was also evaluated in a separate cohort, and intriguingly, a first mild-hypoxia pulse at 60–81 days post-hatching (dph) increased survival rates by 10%, preventing growth impairment when fish were exposed to a second hypoxia episode (112–127 dph). The early hypoxia experience did not have a negative impact on growth compensatory processes at juvenile stages. By contrast, a diminished capacity for growth compensation was found with repeated or late hypoxia experiences. All this reinforces the use of size variation as a main criterion for improving intensive fish farming and selective breeding.

本研究评估，在18个月的金头鲷鱼试验中，家庭由PROGENSA遗传的生长来选择个体大小变化和成长补偿处理遗传学的时间过程的影响^®繁殖计划。分为快速，中等和缓慢增长的家庭具有不同的增长轨迹，而快速增长家庭的增长更为连续。该功能与试验开始时尺寸减小的同时发生，该试验将同一个父亲的半同胞家庭聚在一起。回归分析表明，代偿性增长的幅度与初始规模的变化成正比，而在这一阶段家庭没有重新调整规模。相反，精整生长分配过程可以至少部分地掩盖先前的尺寸收敛。这反映了遗传学在生长的整个生产周期中的不同贡献。另一个独立的研究小组也评估了早期生活经历如何影响青少年阶段的生长补偿，有趣的是，孵化后60-81天（dph）的第一个轻度低氧脉冲将存活率提高了10％，从而防止了鱼类暴露于第二次低氧发作（112-127 dph）时的生长损害。早期的缺氧经历对少年阶段的生长补偿过程没有负面影响。相比之下，反复缺氧或晚期缺氧导致生长补偿能力下降。所有这些都加强了使用尺寸变化作为改善集约化鱼类养殖和选择性育种的主要标准。反复或晚期缺氧的经验发现生长补偿能力下降。所有这些都加强了使用尺寸变化作为改善集约化鱼类养殖和选择性育种的主要标准。反复或晚期缺氧的经验发现生长补偿能力下降。所有这些都加强了使用尺寸变化作为改善集约化鱼类养殖和选择性育种的主要标准。