Acuinuga. Acuicultura y Nutrición de Galicia


17-07-15 |

One less dependency on fishing

A new strategy has provided a critical breakthrough in the old dependency on fishing for the production of polyunsaturated fatty acids, better known as omega-3, which are essential ingredients in fish feed. 

Omega-3 fish oils - specifically the long-chain fatty acids eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) - are recognized for their health benefits, important in the prevention of vascular and neurodegenerative diseases. So far, EPA and DHA could only be obtained from marine sources, at least in useful condition for human consumption. Marine fish, like humans, accumulate them by feeding on other organisms (microalgae, zooplankton, other fish), while farmed fish secure their supply through the fish meal and fish oil included in the fish feed. Therefore aquaculture fish production has always depended on fishing to obtain these essential raw materials.

Although in recent decades aquaculture has experienced strong growth globally, displacing fishing for the first time in 2013 as the main source of fish for human consumption, it was unclear how it could overcome these limitations, particularly in view of the present stagnation of world catches. In 2011, approximately 85% of the total fish oil produced globally was used in aquaculture. But new data recently released confirms the ability of a new strategy to produce these ingredients on land, from agricultural crops, opening great opportunities for the sustainable development of this industry dedicated to the production of aquatic animals.

The fieldwork carried out at Rothamsted Experimental Station in Britain, with Spanish participation, demonstrates the ability of the Camelina sativa plant or false flax seeds to accumulate omega-3 oils, making it suitable for the industrial rendering of these key ingredients. Camelina is highly resistant to cold and drought, with a short cycle and low production costs resulting from its moderate fertilizer requirements, grown in fallow fields or in rotation with other cereal crops because of the high (30%) oil content in its seeds. Unfortunately camelina's oil is not the omega-3 type.

 Rothamsted scientists had already proved possible the successful design of camelina plants in order to produce EPA and DHA, by introducing a set of seven genes based on DNA sequences found in certain photosynthetic marine organisms. Although previous greenhouse experiments had suggested this might work, the last field trials at Rothamsted show for the first time the stability of this trait under environmental conditions similar to those of traditional agricultural crops. Modified camelina plants synthesized up to 15% of EPA and DHA without any negative effects on performance, seed protein content or impact on adjacent crops. Likewise the monitoring of field tests showed no obvious phenotypic differences in growth, flowering pattern or seed structure between genetically modified and control plants.