ARS | Publication request: Genetic parameter estimates for feed intake, body composition, and fillet quality traits in a rainbow trout population selected for improved growth

Submitted to: International Symposium on Genetics in Aquaculture
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2012
Publication Date: June 30, 2012
Citation: Leeds, T.D., Kenney, P., Manor, M.L. 2012. Genetic parameter estimates for feed intake, body composition, and fillet quality traits in a rainbow trout population selected for improved growth [abstract]. International Symposium on Genetics in Aquaculture. p. 259.

Technical Abstract: A selection program is ongoing at the National Center for Cool and Cold Water Aquaculture to improve growth performance in rainbow trout. Current selection criteria include 10-month body weight (10-mo BW) and thermal growth coefficient (TGC) measured during the growth period between 10 and 13 months of age. Third-generation families (n = 98) from the selection line were characterized at approximately 13 months of age (body weight approximately equal to 900 grams) for novel traits including (number of records in parentheses): feed efficiency (673), percent skinless fillet yield (471), belly flap thickness (470), objective color measurements (L*, a*, and b*) on the raw fillet (471), fillet fat percentage (471), and shear force of cooked fillets using a 5-blade Allo-Kramer attachment (466). Feed efficiency (gain:feed) was estimated in triplicate on individual fish over a two-week period by incorporating x-ray opaque glass beads into the diet. The objective of this study was to estimate genetic (co)variance parameters from these data and three-generation 10-mo BW and TGC data (6,574 and 6,418 records, respectively) using multiple-trait animal models. A total of 6,906 animals were used in the calculation of the additive relationship matrix. Heritability estimates were 0.47+/-0.06 (10-mo BW), 0.19+/-0.05 (TGC), 0.20+/-0.13 (feed efficiency), 0.55+/-0.26 (fillet yield), 0.63+/-0.27 (belly flap thickness), 0.47+/-0.26 (L*), 0.17+/-0.17 (a*), 0.81+/-0.28 (b*), 0.58+/-0.17 (fillet fat percentage), and 0.39+/-0.15 (shear force). Variance attributable to family effects was 10% for 10-mo BW and TGC and less than 8.5% for all other traits. Estimates of genetic correlations (rg) with growth traits (10-mo BW and TGC) ranged from 0.14 to 0.27 for fillet yield, 0.02 to 0.28 for L*, -0.09 to -0.17 for a*, 0.18 to 0.56 for b*, and 0.38 to 0.89 for shear force. However, for feed efficiency (rg = 0.61 and -0.10), belly flap thickness (rg = -0.22 and 0.23), and fillet fat percentage (rg = -0.52 and 0.36), genetic correlations with 10-mo BW and TGC, respectively, were less consistent and differed in sign between the growth traits. These data suggest that the current population will respond favorably to direct genetic selection on the novel traits described herein, although selection response may be modest for feed efficiency and a*. Fast growth appears to be genetically associated with increased fillet yield and paler fillets with firmer cooked texture in this population.