Seeds for feeds

A collaborative project undertaken by the University of Stirling and Rothamsted Research saw scientists develop genetically modified (GM) plants that can produce up to 20% of eicosapentaenoic acid (EPA), one of the two omega-3s that confer health benefits to humans. The extracted oils from the plants, which were grown in a glasshouse, were then used as a replacement for marine fish oil in feeds for Atlantic salmon. The results of the study, which were published in the journal Scientific Reports in January, demonstrated that growth performance, feed efficiency, fish health and nutritional quality for the human consumer were unaffected when dietary fish oil was substituted with oil from the GM plants. Rothamsted Research scientists, strategically funded by the Biotechnology and Biological Sciences Research Council (BBSRC), have being carrying out research in metabolically engineering plants to produce omega-3 fish oils for more than 15 years. In the current study they used five microalgal and fungal genes to engineer Camelina sativa plants in order to generate a renewable terrestrial sustainable source of omega-3 fish oils. The oil extracted from these glasshouse-grown GM plants was then used to test effective incorporation in fish feeds and the suitability of these feeds for Atlantic salmon. Dr Monica Betancor, who carried out the experiments at the University of Stirling, commented: “With this work we had the opportunity to test the potential of this novel source of EPA to substitute for fish oil in fish feeds. We used three diets – one containing the standard fish oil used routinely in the fish feed industry, one containing oil from Camelina plants that have not been genetically engineered and one that contained oil derived from plants that have been engineered to produce 20% EPA in their seeds. Each diet was tested with three separate groups of Atlantic salmon for 7 weeks. “At the end of the experiment we examined fish from the different treatments and found that the oil derived from the GM plants can effectively substitute for fish oil in salmon feeds. This is highly significant because fish oil is a finite and limited resource, very expensive and the increasing demands for it by the fish farming industry will not be met in the future. So we really need to develop effective alternatives like this one.” Professor Johnathan Napier, leading the GM Camelina programme of research at Rothamsted Research, said: “It is very exciting for us to see the results of this study. For us the development of metabolically engineered Camelina plants has been a fascinating project. The findings of the present study are very encouraging as we have always worked towards providing a sustainable source for the omega-3 fish oils – our results here confirm another step in that direction.” Professor Douglas Tocher, leading the salmon feeding study at the University of Stirling, commented: “There is a fundamental lack of omega-3 LC-PUFA to satisfy the recommended dietary requirements for humans, and fish are our main dietary source. The development of these novel plant oils, tailored to human requirements, represent a sustainable way to farm fish with high levels of omega-3 fish oils that maintain their high nutritional value to the human consumer while preserving wild fish stocks.”