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Yeast cell walls support fish health

Optimize fish health with yeast cell walls in aquafeed. Studies show enhanced growth, feed conversion, and mucosal barriers in European seabass.

Yeast cell walls (YCWs) have great potential as aquafeed ingredients to enhance fish health and performance, according to recent studies presented at the Congress of the European Aquaculture Society, Aquaculture Europe 2023. Let’s dive in!


Enhancing European seabass health and performance

One study highlights the potential of YCW ingredients to optimize health, performance and reduce production costs in seabass, particularly around challenges such as handling and transfer to sea-pens. Our team tested the inclusion of a specific YCW (OPTIWALL) in the diet of juveniles in a dose-response manner. Results showed:1

  • The YCW can boost performance in a dose response manner: Growth and feed conversion (FCR) were both improved by up to 8.3%.
  • Mucosal barriers were also improved. For example, skin mucus excretion was increased and gut immunity activated.
  • The YCW at the highest inclusion rate tested (4.5 kg/T feed) helped maintain FCR and enhanced gut and skin barrier functions — and, therefore, integrity — when exposed to a chronic challenge (handling).

The authors concluded the YCW had the potential to support the performance and robustness of European seabass juveniles. The feed supplementation strategy can be tailored to the level of challenge expected and of benefits targeted.

Not all yeast cell walls are equal!

In another study, the team looked into the relationship between the YCW structure and immune benefits in an animal model for vertebrates (Zebrafish), highlighting the different functionalities of distinct yeast products.2

In the study, four different YCWs from different yeast strains were tested in aquafeed at similar inclusion rates. The team found a relationship between certain structural characteristics (e.g. MOS and β-glucan chain length) and the interaction with host cell receptors. Each YCW elicited distinct immune responses, indicating the potential for each ingredient to confer protection against specific infectious agents or non-infectious pathologies.

These findings demonstrate the importance of the molecular and biochemical properties of YCW fractions when assessing their potential to elicit targeted immune functionalities.

This new study provides a perfect illustration of our statement that not all yeasts nor YCWs are equal when it comes to their biological activity, paving the way for precision functional nutrition in aquaculture.


  1. Leclercq E., Gonçalves A., Rawling M., Dias J., Castex M. 2023. Zootechnical benefits and health functionality of graded intake of a yeast-based paraprobiotic in European seabass. Aquaculture Europe 2023, Vienna, Austria.
  2. Rawling M., Schiavone M., Merrifield D. L., Apper E., Castex M., Leclercq E., Foey A. 2023. Yeast cell wall derived from Saccharomyces cerevisiae differentially shape intestinal innate immunity and mucosal tissue response of Zebrafish (danio rerio).

Published Jan 29, 2024


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