A team of aquaculture and veterinary experts is investigating the effects of adding spermidine - a compound found in vegetables, grains, and soy products - to fish feed to help break down fatty acids and maintain optimal immune function in adult fish.
The project is led by the University of Edinburgh's Roslin Institute and it recently received over £150,000 (US$189,000) in funding from the UK Seafood Innovation Fund (UK-SIF), with additional support from the Sustainable Aquaculture Innovation Centre (SAIC).
Salmon producer, Mowi, and the University of Stirling's Institute of Aquaculture are also partners in the research.
Absence of vaccines
Supplementing feed with spermidine could maintain the salmon's immune response and natural ability to fight virus-induced diseases such as cardiomyopathies, for which there is currently no vaccine.
As fish age, it becomes more difficult for them to break down their fat reserves into free fatty acids for reuse in a biological process known as lipophagy. Instead of being used for energy and muscle growth, the fat reserves build up in the body and can block the immune system, making the fish more susceptible to health problems.
Boosting the anti-inflammatory response
It is hoped the supplement, which is marketed as a human anti-aging ingredient, will help break down stored fats, giving the fish more energy and helping to maintain the balance between omega-3 and omega-6 that is important for anti-inflammatory processes.
"Harvest stage salmon is old compared to smolt and parr. We hypothesize that similar to humans as fish age, their lipid catabolic pathways slows down and this can be enhanced with spermidine.
"If our current trial is successful, which is mainly to find an effective dosage of spermidine, our next step will be to test spermidine in diets against virus-induced cardiomyopathies in harvest size salmon.
"With the current UK-SIF grant, we are also investigating if the lipid breakdown and the pathways required for breaking lipid slows down in harvest stage salmon compared to smolt and parr," the lead researcher, Kanchan Phadwal, told FeedNavigator.
Spermidine could also be beneficial in other fish species, against virus induced diseases, he added.
Knowledge transfer
The potential impact of that compound on humans has also been explored in numerous studies, including an ongoing clinical trial evaluating spermidine's effectiveness in maintaining immune responses to the Covid-19 vaccine in elderly humans.
Heather Jones, CEO of SAIC, said the research is a notable example of thinking differently and applying the One Health approach, which seeks to transfer knowledge about the health and well-being of one species - in this case humans - to another, salmon.
