This project will validate the process of enhancing lipophagy in salmon cells through the provision of a prototype feed supplement to improve farmed salmon health and reduce economic losses to the aquaculture industry.
£151,032.69
18 months
The health of farmed Atlantic salmon has been significantly influenced by recent shifts in aquaculture diets. While beneficial for sustainability, such dietary changes introduce challenges for salmon health and nutritional quality. Vegetable oils are rich in short-chain (< C20) omega-6 polyunsaturated fatty acids (PUFAs), in contrast to fish oils, which contain omega-3 long-chain PUFAs. This alters the omega-3/omega-6 ratio, promoting imbalances that impact salmon health and its nutritional value for humans. Increased omega-6 fatty acids encourage adipogenesis, leading to lipid accumulation in the liver, visceral adipocytes and muscle tissue (that humans directly consume). Over time, these effects contribute to lipotoxicity and inflammation, compromising fish metabolic health and immune responses.
This project provides the first evidence that spermidine supplementation represents a promising strategy to counteract the adverse effects of plant-based diets on salmon metabolism. We found that spermidine enhanced autophagy, a cellular recycling process, leading to the breakdown of palmitic acid — a key lipotoxic fatty acid found in salmon diets. Palmitic acid levels were higher in the muscle of harvest-size salmon compared to smolt and parr, suggesting spermidine supplementation will have strongest impacts during the final grow-out stage of production, where mortality is highest. Spermidine supplementation led to shifts in the lipidome, promoting a transition from a less healthy to a healthier lipid profile. Changes in global lipid profile were evident in muscle, adipose and liver tissues, suggesting broad metabolic improvements. This research has the potential to enhance the performance, health, and robustness of farmed salmon in food production systems.
The Roslin Institute