The first GM crop trial in the UK of plants enriched with omega-3 nutrients is nearly ready to be harvested.

Scientists at Rothamsted Research have been growing a plant known as Camelina sativa (false flax) that was genetically modified to produce omega-3 fatty acids.

The small-scale field trial began in mid-May this year with the sowing of GM camelina seeds on the Rothamsted estate in Hertfordshire.

Now the crop, which looks like a mustard crop, is due to be harvested by the end of August. The seeds will then be taken away and analysed for their oil content and omega-3 levels.

Omega-3s are polyunsaturated fats found naturally in oily fish, nuts, seeds and leafy green vegetables. They are associated with many health benefits including prevention of heart disease and stroke.

If the trials are successful, the plants could be grown and fed to fish, such as salmon, to boost their omega-3 levels. The oils could also be added to foods or taken as a supplement.

“It is only a small trial, but it’s a major step forward,” lead scientist Prof Jonathan Napier told the Daily Telegraph.

“Fish get fish oil from their diet when they swim in the sea, but when you put them in a cage they can’t do that and you have to feed them smaller fish, otherwise fish would have no more omega-3 in them than chickens.

“The problem is that there aren’t plenty of fish in the sea. One million tons of fish oil is removed from the seas every year and most of that goes into fish farming through fishmeal. It’s unsustainable.

“So this would eventually be used to make farmed fish healthier. But it could also provide direct nutrition to people by being included in other foods, such as margarine or yoghurt.”

Read also: GM omega-3 plants trial approved at Rothamsted

The field trial, which is set to run every year until 2017, is part of Rothamsted’s strategic programme of research designing seeds for nutrition and health, which receives financial support from the Biological Sciences Research Council (BBSRC).

Professor Jackie Hunter, BBSRC chief executive, said: “This research is trying to provide an alternative source of omega-3 oil for the aquaculture industry, which is seeking new ways to maintain and increase its sustainability.”

However, anti-GM groups have criticised the trial and branded it “risky” to the environment and a “waste of money”.

Soil Association policy officer Louise Payton said: “These GM plants have had more genetic modification done to them than most other GM plants that you see out there – this potentially increases the risks that the tweaking of genes has resulted in unintended adverse effects.

“And field trials always run the risk of plants or seeds escaping, making this GM experiment very risky.

“There are examples to prove this. For example, only last year an Oregon farmer found GM wheat contaminating his field – wheat that had only ever been grown in US experimental field trials [and therefore not approved for sale].”

Meanwhile, Rothamsted is still analysing the results of a field trial of GM wheat which was modified to repel aphids .