Sesame extract could double fish feed production from available fish oil

 

 

Research at the Swedish Universityof Agricultural Sciences has revealed that a component of sesame oil added to fish feed may enable salmonid fish to produce the long-chain omega-3 fatty acid DHA from linolenic acid in plant oils.

 

Potentially this discovery, which won the DSM Innovation Award at AquaVision 2008, could enable fish feed makers to double production from the currently available fish oil while providing farmed fish that still have the omega-3 fatty acid content that make fish a healthy food for the consumer.

 

Professor Jana Pickova who led the research team said that it was known that substances from many plant species are known to be active modulators in animal metabolism. Examples for this are antioxidants, plant estrogens and others.

 

Pickova and team explored the potential of some of these compounds to modulate lipid metabolism to improve EPA and DHA content in the fish fillets.

 

Pickova's colleague, Sofia Trattner had investigated sesame and the composition of sesame oil. It led to a test of a component of the oil, a lignan known as sesamin, in feed for rainbow trout. The experimental feeds used only linseed and sunflower oils and were made with de-fatted fishmeal to minimize the marine oil present. Sesamin was only present in one of them.

 

The fish fed on the sesamin diet had significantly higher levels of DHA, up by around 37 percent compared with the control group on the non-sesamin diet. The extra DHA came from a metabolic process in the fish, stimulated by the sesamin that converted linolenic acid into DHA. There were no adverse effects on fish growth or health. In a parallel study, similar results were found in which a-lipoic acid increased EPA levels.

 

The research was recognised at the AquaVision 2008 conference in Stavanger, Norway, by the presentation of the first DSM Innovation Award of EUR 10,000 to the Swedish research pair.

 

The pair started initial trials with rainbow trout weighing 50g at the outset and are continuing their work with a second trial beginning with fish at 300g. The results will become available next spring.

 

Professor Pickova concluded that if this work can be translated into commercial practice, the amount of fish feed produced from the fish oil that is sustainably available can be significantly increased.

 

At the same conference, Knut Nesse of Skretting Salmon Feeds announced that 800, 000 salmon produced at the Centre for Aquaculture Competence (CAC) in Norway had yielded more fish protein than was used to produce their feed, without reducing the omega-3 level in the fish flesh.

 

The results demonstrate that commercially farmed salmon can be net fish protein producers, producing more fish protein compared to the wild fish used in the feed.

 

Both research demonstrate that limits in the supply of marine raw materials do not need to limit growth in the aquaculture industry.