Artemia as a vehicle to enrich Nothobranchius furzeri in punicic acid

Details

Supervisors

Page, Melissa ; Larondelle, Yvan

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences agronomiques, à finalité spécialisée

Abstract

Nowadays, primary liver cancer accounts for 8.3% of all cancer deaths and is the third lethal cancer following lung and colorectal cancers. Among the approaches for the prevention and treatment of cancers, the use of conjugated linoleic acids (CLAs) and conjugated linolenic acids (CLnAs) has raised attention in the past years. This Master’s thesis falls within the framework of a study investigating in vivo the combined impact of dietary docosahexaenoic acid (DHA) and punicic acid (PunA) on hepatocellular carcinomas. African turquoise killifish (Nothobranchius furzeri) were chosen as a model because they were initially reported to spontaneously develop liver tumors. The cancerous origin of these liver lesions has recently been questioned but, given the numerous health benefits attributed to DHA and PunA, the impact on hepatic health of a diet containing both those fatty acids remains a topic worth investigating. N. furzeri are known to be reluctant to feed on artificial dry or gelatin-based food and previous attempts to develop a PunA enriched diet they would accept remained unsuccessful. Herein this Master’s thesis focuses on a different strategy to administrate PunA to N. furzeri, relying on food chain transfer following the enrichment of Artemia, a crustacean zooplankton commonly used in killifish laboratory rearing protocols. The adaptation of existing enrichment protocols made it possible to successfully incorporate PunA into Artemia. After optimisation, concentration reached 19.92 ± 0.23 mg PunA·g-1 lyophilized tissue, which corresponds to 11.16 ± 0.06 % total identified fatty acids. N. furzeri fed these enriched Artemia for eight days contained 0.85 ± 0.19 mg PunA·g-1 fresh matter (4.72 ± 0.90 % of total identified fatty acids). As PunA is initially absent from the killifish fatty acid profile, its presence in experimental fish testifies they were eating the enriched Artemia. Levels of PunA that were achieved are significantly higher than what was recovered in previous attempts where, after one week on an artificial enriched diet, PunA accounted for only 0.48% of total identified fatty acids in killifish. Taken all together, these results suggest enriched Artemia represent a promising vehicle to administrate dietary PunA, and more generally any bioactive fatty acid, to N. furzeri.