Different approaches to enrich Nothobranchius furzeri diet with punicic acid

Nothobranchius furzeri (killifish) has been gaining interest since early 2000’s as an experimental model in aging research as this fish possesses the shortest recorded vertebrate lifespan in captivity (four to six months median lifespan). Killifish aging phenotypes have been successfully modulated using dietary intervention such as diet supplementation with resveratrol which resulted in lifespan extension and delayed onset of several aging-related markers. Dietary modification being one of the most universally effective aging interventions, diet standardization happen to be a fundamental need for model organisms used in aging research. This observation led to believe the development of a formulated diet that can be enriched with different bioactive compounds would be relevant to test their effect on killifish age-related diseases and lifespan. In an attempt to achieve this goal, an oil-enriched artificial bloodworm (ABW) diet had been previously developed. This diet was made out of alginate, filtered bloodworm homogenate (bloodworm juice) and pomegranate seed oil; an oil rich in punicic acid (PunA) which has been reported to have health promoting properties including anti- oxidant and anti-cancer effects. The present work focused on the optimization of these ABW as well as on the development of new oil-enriched diets in an attempt to maximize killifish intake of artificial diets. Subsequently, killifish were fed the optimized diets and their fatty acid profiles were analyzed to evaluate the ability of the diets to enrich killifish with PunA. Results showed that the best way to enrich killifish fatty acid profile in PunA was by feeding them ABW made from a mixture of sodium alginate (1% w/v), pomegranate seed oil (10% v/v) and artemia homogenized in water (60% v/v) to replace the previously used bloodworm juice. This resulted in 0.48% of PunA in the total identified fatty acids in killifish fed this diet. Feeding killifish ABW made with bloodworm juice resulted in similar but lower enrichment (0.34%). Attempts in developing new oil-enriched diets need to be further investigated as the oil was escaping from these diets. Overall, attempts in demonstrating killifish can be weaned from bloodworms onto an artificial diet in order to enrich its fatty acid profile in PunA were not conclusive.