Omega-3 fish oils can be grown in fields using genetically modified oilseed crops, British researchers said as they released trial results this week.

The discovery could, subject to further research, eventually mean the creation of a more sustainable supply of fish oil for fish farms, which need them to nurture their produce.

The oils come from seeds in crops grown by scientists in Camelina oilseed plants at Rothamsted Research, north of London.

Farmed fish consume large quantities of fish oils either directly or in fish meal, which has led to concern about their environmental impact.

The plants were specially engineered by introducing a set of synthetic genes based on DNA sequences found in marine organisms.

Researchers unveiled the first year results of a trial in a paper in the journal Metabolic Engineering Communications Tuesday.

"This is a globally-significant proof of concept and a landmark moment in the effort to develop truly sustainable sources of feed for fish farms," said the programme's leader, Professor Johnathan Napier.

It is thought unlikely that humans would consume the seeds from the plants directly.