Chironomus larvae as a dietary vehicle for Nothobranchius furzeri. Effects of an enrichment with Punicic acid

Details

Supervisors

Page, Melissa ; Schraverus, Hélène

Faculty

Faculté des sciences

Degree label

Master [120] en biochimie et biologie moléculaire et cellulaire, à finalité approfondie

Abstract

Several studies have demonstrated that specific fatty acids, such as punicic acid, can have a negative impact on cancer cell viability. The molecular mechanisms allowing this feature are still poorly understood but evidence suggests the involvement of a newly characterized cell death pathway: ferroptosis. We want here to assess the influence of punicic acid on hepatic tumor development in a vertebrate model: Nothobranchius furzeri. N. furzeri is a rising new model to study the ageing processes and that has been shown to spontaneously develop a high incidence of hepatic tumors correlated with age. The aim of this thesis is to use larva of the Chironomus riparius species, a favored food in aquaculture that can exhibit rapid changes in its fatty acid content depending on its diet, to enrich the diet of the fish with punicic acid. A complete rearing of C. riparius has been installed in our laboratories to reproduce a complete life cycle of this insect to produce a continuous production of enriched food for the fish. The development and survival of this insect is greatly influenced by environmental conditions. Indeed, the survival and growth of the larva are highly influenced by their diet and by the water parameters, such as temperature, pH, hardness, and conductivity. On another hand, adult reproduction is affected by the relative humidity in the air. The efficiency of this rearing therefore depends on all these factors influencing different stages of the life cycle of this insect. Several methods have been used to enrich the diet of C. riparius larvae. One method that allowed its enrichment is a diet change method, allowing a division of the rearing into a larva growth part and an enrichment part using a mix of porcine gelatin and pomegranate seed oil, that contains a large proportion of punicic acid, as an enrichment food. In order to obtain more convincing results, this experiment will have to be replicated. It is true that the use of these C. riparius larvae to enrich the diet of N. furzeri requires a large production, which implies great constraints; While the use of brine shrimp (Salina nauplii) for the same purpose requires fewer constraints and seems more efficient. However, the use of this C. riparius enrichment method could be promising in other research themes, such as ecotoxicology for which this species is often used as a model, and which do not require such mass production as required here.