Can plant oils stimulate omega-3 production in rainbow trout?
Reidun Lilleholt, Nofima for APC
Western Canadian oilseed crops such as rapeseed are tried out in feed for rainbow trout. The scientists think the fish can transform the fatty acids from this oil into omega-3. Photo: Kyla Randall
PhD student Kyla Randall will investigate if and to what extent fish cells transform fatty acids from plants into omega-3. She will do experiments with plant diets free of marine ingredients at the Aquaculture Protein Centre in Norway.
The oils used in the experiment are linseed oil, rapeseed oil and camelina oil grown in Saskatchewan, Canada. Randall wants to see if the production of the essential omega-3 fatty acids EPA and DHA in rainbow trout is enhanced by these oils. Her target is no less than making feed production independent of fish oil.
The feed she uses contains no marine resources. To her knowledge, trials using these oils, which are free of marine oils are minimal. The feed is therefore well suited to study how efficient the conversion from plant oils to omega-3 is.
Coriander and cells
To help out, Randall introduces coriander oil to the diet. This oil contains petroselinic acid (18:1n-12) which is a fatty acid known to reduce the level of the omega-6 fatty acid ARA in mice. It is probable that it might also stimulate omega-3 production within the fish.
She will feed rainbow trout for two weeks with feed containing a mix of canola oil, antioxidants and coriander oil at inclusion levels of 0.5, 1 and 1.5 %. She will then extract liver cells and incubate them with radio labelled fatty acids.
By radio labelling the fatty acids, she can track where the fatty acids are transported in the cells, how it transforms, and how genes involved are up- and down regulated.
Prospects
High levels of ARA causes inflammation of cells. If the effect of the rather expensive coriander oil on reduction on ARA is significant in fish at low levels then it can easily be added to diets.
Kyla Kyla Randall. Photo: Reidun Lilleholt.
Randall is a PhD student at the University of Saskatchewan in Canada, and is visiting the Norwegian University of Life Sciences for doctorate courses and experiments. Randall is supervised by Dr. Murray Drew of the University of Saskatchewan and Dr. Margareth Øverland at APC, and co-supervised by Dr. Bente Ruyter at Nofima.
