title: Breeding salmonids for feed efficiency in current fishmeal and future plant-based diet environments.
abstract: The aquaculture industry is increasingly replacing fishmeal in feeds for carnivorous fish with soybean meal (SBM). This diet change presents a potential for genotype-environment (G x E) interactions. We tested whether current salmonid breeding programmes that evaluate and select within fishmeal diets also improve growth and efficiency on potential future SBM diets. A total of 1680 European whitefish from 70 families were reared with either fishmeal- or SBM-based diets in a split-family design. Individual daily gain (DG), daily feed intake (DFI) and feed efficiency (FE) were recorded. Traits displayed only weak G x E interactions as variances and heritabilities did not differ substantially between the diets, and cross-diet genetic correlations were near unity. In both diets, DFI exhibited moderate heritability and had very high genetic correlation with DG whereas FE had low heritability. Predicted genetic responses demonstrated that selection to increase DG and FE on the fishmeal diet lead to favourable responses on the SBM diet. Selection for FE based on an index including DG and DFI achieved at least double FE gain versus selection on DG alone. Therefore, current breeding programmes are improving the biological ability of salmonids to use novel plant-based diets, and aiding the aquaculture industry to reduce fishmeal use.
authors.affiliation: MTT Agrifood Research Finland, Biotechnology and Food Research, Biometrical Genetics, 31600 Jokioinen, Finland. cheryl.quinton@mtt.fi
authors.forename: Cheryl D
authors.initials: CD
authors.lastname: Quinton
authors.forename: Antti
authors.initials: A
authors.lastname: Kause
authors.forename: Juha
authors.initials: J
authors.lastname: Koskela
authors.forename: Ossi
authors.initials: O
authors.lastname: Ritola
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001947:Breeding; D004032:Diet / Q000662:veterinary*; D004777:Environment; D005396:Fish Products; D005838:Genotype; D012487:Salmonidae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D012641:Selection, Genetic; D013025:Glycine max