THE IMPORTANCE OF FATTY ACIDS ON FEEDS FOR SARDINE Sardina pilchardus MATURATION AND GONAD COMPOSITION

The European sardine (Sardina pilchardus) is an important fish species for Portugal and Mediterranean countries, d ue to its cultural, economic and gastronomic importance. Also, by having an important value for the Portuguese and Spanish canning industry, sardines from the fisheries are traditionally absorbed by this sector. Besides, the stock of sardine populations in the Mediterranean Sea reached very low levels that recently lead to fishing suspension, which raised questions on the viability of the production of the species in captivity. At the EPPO we were able to successful adapt three lots of wild sardines' breeders which are currently on the third year of natural spawns.

Nutrition is an extremely important factor for the success and quality of broodstock eggs and larvae. In this work we intended to evaluate the effect of diets with three different lipid composition in the maturation state and gonad lipid profiles, for breeding purposes, as well  the lipid profile of the muscle,  in attempt to understand the impact on human nutrition when consuming the reared specimens . The sardine's capacity to transform alfa linolenic (ALA) acid into eicosapentaenoic acid (EPA) and/or eventually into d ocosahexaenoic (DHA) acid, as well as the ability to better use EPA and DHA if they are given in the triglycerides or in the phospholipids form was also evaluated . A lot of sardine's breeders with an average weight and length of 63.7 ± 1.7 g and  18.7 ± 0.1 cm , respectively, were randomly distributed. Fish were initially fed with a low-fat diet, in order to reduce highly unsaturated fatty acids (HUFA) levels. After 30 days fish were fed with three different diets (produced by Sparos, Lda.), containing different levels of EPA and DHA and given either as triglycerides or phospholipids (Figure 1). At the end of the trial, gonads were sampled and histologically analyzed . Fish fed with diets containing higher EPA and DHA content s (either  as triglycerides - TAG - or phospholipids - PLM)  presented  better gonad maturation stages.

This results on sardine's production  lead us to consider that sardine's production in aquaculture might be promising in a near future, for demand of fresh fish market and mainly to assure a constant supply for the canning industry. In order to establish an optimal nutritional protocol for sardine production, further and more detailed studies using metabolomics and molecular biology approaches are being conducted.

This study had the support of the project  DIVERSIAQUA  (Mar2020 16-02-01-FMP-0066)  and DIVERSIAQUA II (Mar2020-P02M01-0656P)