Utilization of feed resources in the production of rainbow trout (Oncorhynchus mykiss) in Norway in 2020

The utilization of feed resources in Norwegian farming of Atlantic salmon has been reported for 2010, 2012, 2016 and 2020. The present paper is a corresponding documentation for farming of rainbow trout in Norway in 2020. 89,667 tonnes of rainbow trout were produced, which is 6 % of the amount of salmon produced. The 116,990 tonnes of ingredients used for feed sold as trout feed were produced from 13.4 % marine protein sources, 10.8 marine oils, 39.7 % vegetable protein sources, 19.9 % vegetable oils, 12.1 % carbohydrate sources and 3.9 % micro ingredients, which include vitamin and mineral premixes, crystalline amino acids and astaxanthin. In addition, was 0.2 %, or 257 tonnes, of single cell protein, insect meal, fermented products and microalgae used in trout feed. Norwegian fish meal and fish oil constituted 8.8 % of the ingredients, and the remaining 91.2 % were imported ingredients. The economic feed conversion factor (FCR) was 1.30, 1.21 or 1.44 if calculated from feed ingredients ‘as is’, feed ingredients on dry matter basis, or from registered traded feed, respectively. The trout retained 37 %, 43 %, 33 %, 63 % and 63 % of the feed’s dry matter, energy, protein, fat and EPA+DHA, respectively, in the whole body. In fillet, the corresponding retention values were 21 %, 25 %, 23 %, 34 % and 35 %, respectively. The feed utilization in trout was slightly overestimated because of some salmon feed used in the trout production. The feed ingredients used and the feed utilization in trout farming in 2020 were similar to the data for salmon farming, but trout is produced in a smaller quantity