With limited access to marine oils, the aquafeed industry is increasingly seeking alternative ingredients that support the health and growth of farmed fish. In a recent study, Scottish and Norwegian researchers tested oil derived from a genetically modified variant of the plant Camelina sativa in rainbow trout diets.
The Camelina plant was engineered to produce the long-chain omega-3 fatty acids EPA and DHA, as well as the pigment astaxanthin. “In addition to providing red coloration, astaxanthin is also an important antioxidant for fish,” explained Pauline Wischhusen, a researcher at the Norwegian Institute of Marine Research.
Researchers formulated two experimental diets: one containing the transgene-derived Camelina oil and the other a conventional blend of fish and vegetable oils. The diets were fed to quadruplicate tanks of 30 rainbow trout over a 10-week period.
Results showed that fish fed the genetically modified Camelina oil had higher levels of omega-3 fatty acids in their fillets, without any adverse effects on growth or health. “Rainbow trout that were given the alternative feed reached the same final weight as the fish that received traditional feed,” said Angelico Madaro, also a researcher at the Norwegian Institute of Marine Research. “Fillet quality was also similar, with slightly higher omega-3 levels in the group fed with the new oil.”
However, fillet pigmentation and tissue carotenoid levels were lower in fish fed the transgenic oil compared to the supplementation of synthetic astaxanthin, which suggests that it might be advantageous to formulate feed based on equal astaxanthin rather than total carotenoid levels in future studies.
Researchers also examined whether the feed could have any consequences for fish health and welfare through an exercise session in a swim tunnel prior to sampling. Researchers did not find differences in stress responses, concluding the feed does not affect fish welfare.
To assess potential effects on fish welfare, researchers conducted a swim tunnel exercise test prior to sampling. No differences were observed in swimming capacity or stress responses, indicating that the genetically modified feed does not negatively affect fish welfare.
Overall, the study highlights the potential of genetically modified Camelina sativa as a sustainable source of essential fatty acids and antioxidants, paving the way for more resilient and nutritionally rich aquafeed options.
Reference:
Pauline Wischhusen, Angelico Madaro, Malthe Hvas, Richard Broughton, Lihua Han, Karla Fernandez Quiroz, Kasidis Chaiyasut, Akhil Gupta, Rolf Erik Olsen, Stéphanie Fontagné-Dicharry, Johnathan A. Napier, Mónica B. Betancor. Growth performance, swimming capacity, and fillet quality in rainbow trout fed a transgene-derived omega-3 and carotenoid-enriched oil. Aquaculture, Volume 604, 2025, 742453, ISSN 0044-8486, https://doi.org/10.1016/j.aquaculture.2025.742453
