Interpretive Summary: Improvement in feed efficiency and reduction in nutrient loading from rainbow trout farms: the role of selective breeding

By: Antti Kause, Antti Nousiainen, Heikki Koskinen

Resource efficiency, the ratio of inputs to outputs, is essential for both the economic and environmental performance of aquaculture. The data from commercial rainbow trout farms showed that from 1980 onwards, the farm-level feed conversion ratio (FCR) improved by 53.4%, and the specific nitrogen and phosphorus loading from the farms decreased by over 70%. Hence, to produce 1 kg of fish today, only half of the feed is needed compared to the 1980s. Selective breeding is a major contributor to this improvement, and it has resulted in an estimated genetic gain of 1.74% per generation in the FCR. The use of genetically improved rainbow trout, instead of a base population of fish, reduces feed costs and nutrient loading by 18.3% and total production costs by 7.8% at commercial farms. Such improvements in resource efficiency are win–wins for both industry and the environment—the same amount of seafood can be produced with significantly reduced amounts of raw materials and reduced environmental impact.