Selective breeding combined with fish- and soya-free feed
INRAE, the Aqualande group and its selective breeding company Les Sources de l’Avance, and the French Poultry and Aquaculture Breeders Technical Center (SYSAAF) recently reviewed data from 20 years of a rainbow trout breeding programme they were involved in. Growth and nutrition needs of rainbow trout from this programme were compared with those of an unselected trout population. The findings, published in an open access paper in Aquaculture Reports, show that selected rainbow trout need 17% to 20% less feed to achieve the same growth as unselected ones, indicating that the environmental impacts of fish farming can be reduced. A locally produced feed, made without fish oil, fishmeal or soy, was also tested on both groups of fish. Rainbow trout fed this feed, which has similar nutritional characteristics, achieved similar growth performance. The results show that selective breeding and innovative feed sources can be effectively combined to make aquaculture more sustainable.
The Aqualande group conducted a selective breeding programme on 10 generations of rainbow trout between 1997 and 2019, based on the principles established by INRAE and SYSAAF. Unselected rainbow trout from the same original population were also maintained. To determine the genetic gains in performance, INRAE, Aqualande and the SYSAAF participated in the collaborative European research programme AquaImpact, during which they compared the growth, morphology, yield and fillet lipid content of the selected and unselected groups of fish. A sustainable feed based on INRAE research was developed without fish oil, fishmeal or soya. This feed was produced with ingredients such as potato protein and microalgae (from France and other parts of Europe). Rainbow trout from both groups were given this feed for 110 days, while others were fed a standard commercial feed containing fishmeal and fish oil.
Rainbow trout from the selective breeding programme required 17% to 20% less feed than the unselected trout to achieve the same growth; their fillets also had a higher lipid content, which improves their nutritional and taste profiles. Growth rates were not affected by either feed. The addition of microalgae to the sustainable feed also enhanced the nutritional quality of the fillets, which contained just as much omega-3 long-chain fatty acids as fillets from trout given the standard feed containing fish oil.
The findings show that selective breeding and the development of sustainable feeds play an important role in reducing the environmental impact of farmed fish production.
Vandeputte M, Corraze G, Doerflinger J, Enez F, Clota F, Terrier F, Horat M, Larroquet L, Petit V, Haffray P, Skiba-Cassy S, Dupont-Nivet M. Realised genetic gains on growth, survival, feed conversion ratio and quality traits after ten generations of multi-trait selection in rainbow trout Oncorhynchus mykiss, fed a standard diet or a “future” fish-free and soy-free diet. Aquaculture Reports 27: 101363, doi: https://doi.org/10.1016/j.aqrep.2022.101363 (open access)