The present study evaluated these earlier findings under practical conditions in commercial aquaculture production, to verify the results of the laboratory trials. Reduced protein content was combined with high fishmeal substitution in diets and the diets tested as compared to the commercial diets used by partners in the three Nordic countries involved.
The evaluation was carried out at four arctic charr farms, two in Iceland and one in Norway, in addition a fourth trial, with triplicate groups carried out in Sweden. An additional trial was set up in Iceland to study the effects of different amount of protein and plant protein on the environment and fish welfare. The quality of the fish produced was evaluated in all trials, either through sensory evaluation tests or by ordinary consumer tests.
In summary, the trials shoved somewhat variable effects of the novel diets on fish growth as compared to the control diet, with a somewhat reduced growth of fish observed in theIcelandic tests, while improved growth was obtained in the test carried out in Norway and equal growth in the Swedish trial. In addition, the Icelandic tests showed a tendency towards poorer feed utilisation of the test diets as compared to the control diet, while the opposite results were obtained in Norway and an equal feed utilisation between the groups was observed in the Swedish trial. No significant differences in quality of the fish produced were observed related to the different diets tested.