Genetic effects of ibreeding on growth trajectories in turbot (Scophthalmus maximus)

In order to investigate genetic effects of inbreeding on growth trajectories in turbot (Scophthalmus maximus), we produced multiple families by out-crossing for one generation, and then self-crossing for one or two continuous generations, and repeatedly measured body weight (BWE), body length (BL), and body width (BW) on 1082 fish. The random regression models (RRMs) were constructed by fitting changes in fixed and random effects with optimal growth curve, 3-order Legendre polynomial for each trait. Comparison in genetic effects among three inbreeding groups indicated that inbreeding affected BL more strongly than BWE and BW, and BWE showed the lowest inbreeding depression among the three growth traits. In course of growths, inbreeding depressions of the analyzed traits were not necessarily linear with inbreeding degrees, also depended on days of ages. Meanwhile, the dynamic heritabilities for the three growth traits tended to exhibit a parabolic tendency between 300 and 900 growth days, with ranges of 0.382-0.913. The growth traits in the early growth days consistently showed low genetic correlations with those in the later growth days, with estimates of 0.313 above. When the inbreeding coefficients were excluded from relationship matrix, the heritabilities and genetic correlations were underestimated.

Automated summary

The study on genetic effects of inbreeding on growth trajectories in turbot revealed that inbreeding had a larger impact on body length compared to body weight and body width. The genetic effects were not linear with increasing inbreeding degrees and varied depending on the age of the fish. Additionally, there were low genetic correlations between growth traits in early growth days and later growth days.