AUTHOR=Kristjánsson Ólafur H. , Gjerde Bjarne , Ødegård Jørgen , Lillehammer Marie 

TITLE=Quantitative Genetics of Growth Rate and Filet Quality Traits in Atlantic Salmon Inferred From a Longitudinal Bayesian Model for the Left-Censored Gaussian Trait Growth Rate

JOURNAL=Frontiers in Genetics

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2020.573265

DOI=10.3389/fgene.2020.573265

ISSN=1664-8021

ABSTRACT=<p>In selective breeding programs for Atlantic salmon, test fish are slaughtered at an average body weight where growth rate and carcass traits as filet fat (<italic>F</italic><italic>F</italic>), filet pigment (<italic>F</italic><italic>P</italic>) and visceral fat index (<italic>F</italic><italic>F</italic>) are recorded. The objective of this study was to obtain estimates of genetic correlations between growth rate (GR), and the three carcass quality traits when fish from the same 206 families (offspring of 120 sires and 206 dams from 2 year-classes) were recorded both at the same age (<italic>SA</italic>) and about the same body weight (<italic>SW</italic>). In the <italic>SW</italic> group, the largest fish were slaughtered at five different slaughter events and the remaining fish at the sixth slaughter event over 6 months. Estimates of genetic parameters for the traits were obtained from a Bayesian multivariate model for (potentially) truncated Gaussian traits through a Gibbs sampler procedure in which phantom <italic>GR</italic> values were obtained for the unslaughtered, and thus censored <italic>SW</italic> group fish at each slaughter event. The heritability estimates for the same trait in each group was similar; about 0.2 for <italic>FF</italic>, 0.15 for <italic>FP</italic> and 0.35 for <italic>VF</italic> and <italic>GR</italic>. The genetic correlation between the same traits in the two groups was high for growth rate (0.91 ± 0.05) visceral index (0.86 ± 0.05), medium for filet fat (0.45 ± 0.17) and low for filet pigment (0.13 ± 0.27). Within the two groups, the genetic correlation between growth rate and filet fat changed from positive (0.59 ± 0.14) for the <italic>SA</italic> group to negative (−0.45 ± 0.17) for the <italic>SW</italic> group, while the genetic correlation between growth rate and filet pigment changed from negative (−0.33 ± 0.22) for the <italic>SA</italic> group to positive (0.62 ± 0.16) for the <italic>SW</italic> group. The genetic correlation of growth rate with <italic>FF</italic> and <italic>FP</italic> is sensitive to whether the latter traits are measured at the same age or the same body weight. The results indicate that selection for increased growth rate is not expected to have a detrimental effect on the quality traits if increased growth potential is realized through a reduced production time.</p>