Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 10:30:0020/09/2023 10:45:00Europe/ViennaAquaculture Europe 2023UNDERSTANDING THE FUNDAMENTAL CONTRIBUTION OF LIVE FOOD IN THE FEEDING REGIMES FOR MARINE FISH LARVAE: A CASE STUDY OF THE GILTHEAD SEABREAM Sparus aurata L.Stolz 1The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


T. De Wolf*1 , G.Franchi1, V.Carbone1 , D.Troiano1 , J.Teske2, A.Miccoli3,4, V. Pianese3 , S.Picchietti3 and G.Rombaut2


 1 Inve Aquaculture Research Centre, Via P.Gigli snc, 57016 Rosignano Solvay (LI), Italy

 2 INVE Technologies NV, Hoogveld 93, 9200 Dendermonde, Belgium

 3  Tuscia University – Dep. for Innovation in Biological, Agro -food and Forest systems, Via S.Camillo de Lellis , 01017 Viterbo

4 Consiglio Nazionale delle Ricerche , Inst. for Marine Biological Resources and Biotechnology (IRBIM), Largo Fiera della Pesca 2, 60125 Ancona (current affiliation)




 Live food consumptions in the feeding regimes of marine fish larvae have been decreased considerably during the last decades , making the producers less reliant on the success of rotifer cultures and  reducing the amounts of  Artemia  that are being used. A lot of progress has been made in diet formulations and  production techniques, proving  that  early starter feeds are accepted well by marine larvae as soon as  mouth opening occurs. In the meantime,  quantities of live feed consumed during larval rearing have been reduced considerab ly. Despite  these improvements ,  excluding completely the live preys from the me nu does not result in successful larval production for any of the commercially most important  marine  species.

 As nutrition has a large impact on fish gut mucosal health status, larval mucosal architecture and microstructure, larvae were examined  through histology to evaluate diet-induced alterations . Additionally , transcriptome analysis by 3’ end RNA-sequencing of pools of larvae  was conducted  to perform an in-depth analysis of the impact of live food deprivation on the fish larval health status.  Fish growth and  survival were evaluated as ultimate outcomes .

Materials and methods

Test set-up

Nearly hatched seabream larvae, originating from the same pool of eggs, were stocked at a density of 100 larvae per liter in 390L tanks . Seawater was provided through a semi-closed water renewal system at a temperature of 18±1°C . Dissolved oxygen levels were kept around 100% saturation. Larvae were rear ed  under green water conditions. A standard live food regime (LFC ) was compared to a treatment where no live food (No LF) was  introduced, providing  a  special early start-feeding diet from the onset of exogenous feeding.

Weekly biometrics

2 0 Larvae per tank were sampled every week and controlled for Standard Length (SL).


6 Larvae per group were sampled at 20 and 35dph for histological analyses of the posterior intestine (PI). Whole larvae were fixed in Bouin’s  fixative  and stained with May-Grünwald /Giemsa. PI folds  height, width and enterocyte height were measured.

 3end RNA-sequencing

270 Larvae were sampled from the 2 experimental groups (LFC and No LF) a t 20dph. Larvae were washed with PBS, proceeding with RNA extraction with Genezol .  RNA concentration, purity and  integrity were checked  before proceeding with the RNA sequencing. A bioinformatic p ipeline was applied to statistically analyze differentially expressed genes (DEGs) and assess enrichment of  Gene Ontology (GO).


 The weekly length measurements showed very e arly  significant differences between the No LF and LFC groups and the last survivor in the No  LF group died at 36dph , indicating the poor biological performance of the latter.

Histomorphometric analyses of distal intestine from larvae at 20 and 35 dph revealed significantly shorter and narrower villi, and shorter enterocytes in the No LF compared to LFC treatment. Nevertheless, no coarse histological damages were visible in the gut mucosa in the No LF group.

 RNA sequencing performed on pools of larvae at 20 dph highlighted 486 Differentially Expressed Genes (DEGs) between  both  groups: 260 and 226 were down- and up-regulated, respectively, in the No LF treatment compared to LFC. Based on statistical significance and extent of gene expression change, the absence of live food resulted in the disturbance of many Gene Ontology biological processes such as lipid transport, proteolysis, immune response, glycolysis and cartilage development.


 This study indicates the types of biological processes  that  are  highly influenced when the live food is removed from the standard larval feeding protocol. Live food remains fundamental ,  ensuring proper development and growth of gilthead seabream larvae and  assesses its efficacy as a naturally derived functional feed.