The search for sustainable fish oil

Strategies to protect the marine environment range from fishing quotas to using concrete blocks as artificial reefs. Now, a field in Hertfordshire is the surprising home of an experiment to improve the health of our seas.

In 2013, for the first time over half of fish consumed by humans came from fish farms. This has led to aquaculture using over 75% of the fish oil harvested annually from the sea. Sadly, farms have a ‘fish in: fish out’ weight ratio of about 4:1 – you get a lot less fish out of the system than you put in.Camelina_sativa

Scientists at Rothamsted Research have used genetic modification to produce ‘fish oils’ in plants. They hope in the long run that their research will lead to providing oils for farmed fish, not from the sea but from our fields.

Ironically, fish can’t make fish oils. The oils are in fact made by microalgae, which aren’t available to fish in cages in farms. We don’t currently have the technology to produce algae on a large scale, so farmed fish are fed oil and meal made from their wild cousins.

The plant chosen for experiments is Camelina sativa (also known as false flax or gold-of-pleasure), which is a distant relative of oil seed rape. One benefit of camelina is that it is naturally high in Omega-3. This isn’t the desired long-chain Omega-3 with its accompanying health benefits, but shorter-chain Omega-3 which acts as a precursor for the Omega-3 LC-PUFA (long-chain poly-unsaturated fatty acids) the study is aiming to produce .

Synthetic genes have been introduced to the plant to produce enzymes for the biochemical pathway required to make the required long-chain Omega-3. The plants will only produce these oils in the seeds.

The modification has been successful in the lab, and there was no difference in seed size and germination compared to non-GM plants. The next step is a small field trial this summer, which will determine whether the modification is stable in the field.

This is the latest step in a long-term project, which could eventually lead to ‘fish oil’ from plants reducing aquaculture’s need for oil from wild-caught fish. Potentially, the oil could even be used for direct human consumption.

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