Aquaculture Europe 2021

October 4 - 7, 2021

Funchal, Madeira

Add To Calendar 06/10/2021 16:50:0006/10/2021 17:10:00Europe/LisbonAquaculture Europe 2021PIGMENT QTL GENEOTYPE BY DIET INTERACTION ON GROWTH IN ATLANTIC SALMON Salmo salarFunchal-HotelThe European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982

PIGMENT QTL GENEOTYPE BY DIET INTERACTION ON GROWTH IN ATLANTIC SALMON Salmo salar

 

P. Sae-Lim*, S. Boison ,  S. Gonen, M. Baranski , J. Å. Stene, G. Rosenlund, B. Hatlen, B. Ruyter ,  R. Fontanillas , L. Martinez Rubio and A. Norris

 

Mowi  Genetics AS, Sandviksbodene 77AB, 5035 Bergen, Norway

 Email: Panya.Sae-Lim@mowi.com

 



Introduction

 Growth and fillet color are two important traits  in  farmed Atlantic salmon. The color  of the  fillet results from  an uptake of supplementary astaxanthin - an antioxidant which has  a positive effect on growth in early life (Bazyar Lakeh et al., 2010) . However, t he ability  of fish  to utilize and retain astaxanthin is limited while  astaxanthin in the diet accounts for approximately 2–4% of feed cost . This trait is highly heritable , and in recent years there has been progress in understanding the  underlying biological pathways, including identification of a number of QTLs and candidate genes that explain a large portion of the genetic variance (Helgeland et al., 2014). The relationship between astaxanthin deposition and growth is not fully understood but are likely to be connected because of the antioxidant effect of the pigment . Furthermore,  such association  or interaction may depend on the amount of marine omega-3 in the diet which has a positive effect on  fillet color and robustness (Bou et al., 2021).  The aim of this study was to examine the  pigment  QTL  genotype by diet interaction in Atlantic salmon in terms of its effect on growth.

Materials and Methods

 Data  in this study was from AquaIMPACT project (H2020 BG2018-818367).  Previously, Mowi Genetics had performed genome-wide association studies for pigment levels in several year classes of fish from the breeding nucleus using a ThermoFisher Axiom genotyping array containing approximately 55,000 single nucleotide polymorphism (SNP) markers distributed over the salmon genome. From this data, two major QTLs were mapped, with the locus having the largest effect being subsequently used in this study. In June 2020, 959 Atlantic salmon  with known  pedigree and  pigment  QTL genotype  from  the Mowi breeding nucleus in Norway w ere distributed across six 5x5m2 sea pens  located in Averøy, Norway. The sea pens were evenly split between two different diets (3 replicates each)  from Skretting ARC:  a common extruded feed kernel coated with a standard oil mix rich in vegetable oil (standard diet or K ) or  coated with an oil mix (Veramaris ®)  enriched with omega-3-PUFA from microalgal oil ( diet H ). A bivariate animal mixed model, where  body weights  from  different diets  (measured in March 2021) were treated as different traits, was fitted using REML in WOMBAT with genomic relationship matrix (GRM) generated from 53, 186  SNP markers. The  genomic based heritability (h2) for growth, genetic correlation (rg) – as a measure of genotype re- ranking  and their SE were subsequently estimated.

Results

The genomic based h2  for growth with diet H (0.40±0.01) was slightly higher than for growth with  diet K (0.35±0.01) .  The rg was close to unity (0.94±0.09) , indicating marginal or no genotype re-ranking of growth between H and K diets. The plot of phenotype-genotype association shows no re-ranking of pigment  QTL genotypes across different diets (Fig 1 ).  For  the  K diet, high pigment deposition genotype (PP) had higher and significant  (P<0.05) mean weight (2.80 kg) than low  pigment deposition  genotype (pp; 2.67 kg). The use  of  H diet resulted in  considerably positive effect on growth in both genotypes but  the difference in mean weight between  PP and pp  genotypes became less and statistically non-significant (P>0.05). Mean genomic EBVs shows the same pattern.

 Discussion and Conclusions

To the best of our knowledge, this is the first report on the association between pigment QTL genotype and growth in Atlantic s almon.  The  genomic based h2 for growth is in the upper range with the  previous estimates reported in literature . H igher growth in PP than in pp indicates that pigment genotypes may  be associated with growth but it may be diet-dependent trait as the difference in growth is less in H  than in K. Selection for PP genotype not only increases astaxanthin deposition , leading to less pale fillet and higher level of antioxidant for health benefits, but also higher growth . F urther study to confirm this finding should be conducted.

References

Bazyar Lakeh , A.A., Ahmadi, M.R., Safi, S., Ytrestøyl , T., Bjerkeng, B., 2010. Growth performance, mortality and carotenoid pigmentation of fry offspring as affected by dietary supplementation of astaxanthin to female rainbow trout (Oncorhynchus mykiss ) broodstock. Journal of Applied Ichthyology 26, 35–39.

Bou , M., Berge, G.M., Baeverfjord , G., Sigholt , T., Østbye , T. K., Ruyter, B., 2021. Low levels of very-long-chain n-3 PUFA in Atlantic salmon ( Salmo salar ) diet reduce fish robustness under challenging conditions in sea cages.  Journal of Nutritional Science 6, 1–14.

Helgeland , H., Sandve , S.R., Torgersen, J.S., Halle, M.K., Sundvold, H., Omholt, S., Våge , D.I., 2014. The evolution and functional divergence of the beta-carotene oxygenase gene family in teleost fish—Exemplified by Atlantic salmon. Gene 543, 268–274.