Several advantages with cleaned feed oil
Tests performed by Nofima show that salmon fed with treated fish oil are healthier and get firmer filets, in addition to using the feed better. – This should definitely be taken into consideration when discussing whether or not it is profitable to use treated fish oil or not in salmon feed, claims the research institute.
Some years ago researchers at Nofima have studied how growth, health effects and filet quality are affected, depending on whether or not the fish oil used had been treated.
Their conclusion was unanimous; this had positive effects on growth. The experiment showed a tendency of better growth and feed conversion in those salmon that ate feed with treated fish oil. This was especially true for periods of rapid growth. During these periods the growth and feed conversion were significantly better for fish that got feed with cleaned oil.
Better fish welfare? Another remarkable result was that salmon receiving feed with treated oil seemed to tackle handling stress in connection with slaughtering better – measured in time of drop in pH after death. Different stress markers showed the same tendency.
Healthier food Bente Ruyter, professor and senior researcher at Nofima Marine, was coordinating the measurements of health effects in the study that was performed in co-operation with Jyväskylä University in Finland and the Norwegian School for Veterinary Sciences. She points out that even though t here is no doubt that fish is very healthy and important for our diets, salmon could become even healthier with treated oil.
- Even though there are no significant differences when measuring health markers in the blood, liver, gut and fatty tissues, salmon fed with treated fish oil do score a bit higher on average, says Ruyter.
Wishes to have a closer study of causal relationships All the fish in the experiment kept a nice red colour and good texture, but the tendency was that salmon fed with clean fish oil had a slightly firmer texture. The difference in texture was most prominent after freeze storage. Here the amount of salmon with soft muscles was halved compared to those fed with untreated oil.
Nofima researcher Turid Mørkøre said, when presenting the results of this extensive study, that it seemed that one had scratched on the surface of something we don’t understand fully, yet. But she points out that it seems like one achieves considerable advantages by reducing the amount of foreign substances in the feed.
