Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 16:30:0020/09/2023 16:45:00Europe/ViennaAquaculture Europe 2023ZOOTECHNICAL BENEFITS AND HEALTH FONCTIONALITY OF GRADED INTAKE OF A YEAST-BASED PARAPROBIOTIC IN EUROPEAN SEABASSStolz 1The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


E. Leclercq a*, Ana Gonçalvesb ;  M. Rawlingc; J. Diasb ; M. Castexa


a Lallemand SAS, 19 rue des Briquetiers, 31700, Blagnac, France

b S PAROS LDA, Area Empresarial de Marim, Lote C, 8700-221 Olhao , Portugal

c  School of Biological and Marine Sciences, University of Plymouth, Drake Circus, PL48AA, UK




F unctional  health feeds  are  a pillar of modern aquaculture.  Inactivated yeast cell wall  (YCW) fractions  are widely documented to conditionally confer health and/or performance  benefits  across a diversity of species . However ,  only  few dose-response studies  have been reported and  none in marine species  limiting the optimal application of this biotechnology .  The aim of this study was to document the  animal  performance and  mucosal  health response to graded intake of a specific YCW paraprobiotic with the view to inform the strategic use of this ingredient.  The specific  YCW tested  in this study  was previously selected based on its specific  parietal  features and promising  functional  benefits on  the  intestinal barrier and immune homeostasis (YCW 2; Rawling et al., In Press).

Materials and Methods

The 9-week trial (Riasearch Lda ; Murtosa, Portugal ) tested 4 diet s  in  quadruplicate tanks (500 L tanks flow-through indoor , pumped-ashore natural seawater ~ 22 °C; ~36 ppt )  in  juvenile European seabass (BWi  = 11.3 g ; 45 fish/tank)  reared under  ideal  conditions  (43 days)  then  chronically  exposed to  environmental and handling stress (20 days) (Fig 1 ).  The basal diet was formulated to the species requirements  and according to current commercial practices ( 55% plant meal , 20%  fish meal;  15%  LAPs;  6% fish oil, 6.5%  rapeseed oil ;  46.3% crude protein; 16,4% crude lipid; gross energy 21.1 MJ/kg). Test diets were prepared by incorporating  graded level of  a  selected,  proprietary YCW ingredient (Lallemand Animal Nutrition, Blagnac, France) “ on-top” the basal recipe a t 0 (Control), 1.5; 3.0 or 4.5 kg/T feed and manufactured by  traditional hot extrusion. Test d iets were hand-fed to apparent satiation 4 times daily over the trial’s duration.

 Growth and feed performance were assessed over phase I, phase II  and the overall trial’s duration  based on total  tank biomass, individual body-weight (15 fish/tank) and apparent daily feed intake per tank. Tissues were sampled at T1 and T2 as follow: crude skin mucus quantity (4 fish/tank, surgical absorbent sponges) , skin mucus , faeces ,  gill, gut and skin (3 fish/tank).  Skin mucus and plasma were assayed for immune biomarkers; faeces for intestinal health markers ; mucosae histology focussed on morphometry and goblet cell population and  mucosal gene expression was performed using tissue-specific panels of 20 genes  (immune, cellular and oxidative stress,  epithelium barrier function) . D ata  were  analysed by 2-way ANOVA and post hoc analysis with significance accepted at P < 0.05.


Growth performance increas ed with increasing YCW  level (Fig 2a, b). M ean body-weight  was  significantly higher  in YCW 4.5  compared to the Control at the end of Phase I and II, with  YCW 1.5 and 3.0 showing intermediary values.  Similar trends were evident for SGR  although differences were significant  over the full trial  period only  for YCW 3.0 (+4.5%)  and YCW 4.5 (+ 6.8%) compared to the Control.

There was a significant diet effect on FCR which was increasingly improved with increasing YCW intake over the  whole trial’s duration (Fig 2c).  FCR  overall improve d by  up to  8.3 %  in YCW 4.5  compared to Control with, interestingly, an a pparent mitigation of its degradation over the period of chronic-stress exposure (Phase II) in this group.

 Skin mucus excretion  was significantly higher  in YCW 4.5  compared to the C ontrol  at the end of the trial (Fig 2d) with numerical increases at  lower  YCW intakes. S imilar trends  were  measured at the end of  the Phase I (ideal conditions).

Further tissues analysis will be presented.


 There was a positive dose relationship between  dietary intake of YCW and zootechnical performance as well as skin mucus excretion . In particular, t he highest level of YCW tested (4.5 kg/T feed) appeared to mitigate the degradation of the zootechnical performances  but also  to boost  skin  mucus excretion during chronic-stress exposure .

 Taken together,  this YCW paraprobiotic  as the potential to support  the performance and robustness of  European  seabass  juveniles. The  feed  supplementation  strategy can be tailored to  the levels of  challenge  expected and  of benefits targeted.

Rawling M, Schiavone M, Merrifield DL, Apper A, Castex M, Leclercq E, Foey A 2023.  Yeast cell wall extracts from Saccharomyces cerevisiae varying in structure and composition differentially shape the innate immunity and mucosal tissue responses of the intestine of Zebrafish (Danio rerio). Front. Immunol.  Vol 14, doi: 10.3389/fimmu.2023.1158390.