Rapeseed modified with flax genes yields fish feed rich in astaxanthin.
A team of researchers at Rothamsted Research has developed a genetically modified rapeseed oil designed to improve the health and nutritional profile of farmed salmon. The oil, derived from crops modified to produce high levels of astaxanthin, offers a natural alternative to synthetic pigments currently used in aquaculture feeds.
Astaxanthin is a red pigment naturally found in wild salmon diets and is responsible for their pink flesh. Farmed salmon, which do not consume the same algae-rich diet, are typically supplemented with synthetic versions of the compound to achieve the same appearance.
The new rapeseed variant, developed using genes from the scarlet flax flower, produces seeds with a high concentration of natural astaxanthin and other antioxidants. In trials, oil derived from the crop was fed to rainbow trout over several months. The fish showed comparable growth rates to control groups and higher levels of beneficial omega-3 fatty acids and antioxidants.
Professor Johnathan Napier, who led the research, said the plant-based pigment source helped reduce the accumulation of pro-inflammatory molecules and could improve fish resistance to stress and disease. The findings were published in Plant Biotechnology and Aquaculture.
The crop cannot currently be grown commercially in the UK due to EU-era legislation restricting GM agriculture. However, the researchers anticipate uptake in the United States within the next decade, where GM foods are permitted.
Napier said the UK’s regulatory barriers risk undermining the commercial potential of domestically funded research: “Tax revenue is being used to fund millions of pounds’ worth of fundamental research in UK universities and institutes. But the potential arising from any useful discoveries is not correctly captured or exploited because of regulatory burdens.”