Yeast extracts, B-glucans and the development of immunity in fish

Dear colleagues,

This week we have chosen a review of B-Glucans and their effects on fish immunity and mechanism of action.

It is well known that the use of purified beta-glucans from yeast cell walls boosts the immune system of animals and is particularly useful in fish nutrition, where vaccines are sometimes not effective enough. It is also worth noting that the more purified they are, the better, because more active bonds will be released in the molecule.

Regarding the mechanism of action, although it is not entirely clear, it appears that after oral administration, β-glucans pass slowly through the first sections of the intestine and are captured by macrophage receptors present in the intestinal wall, activating them to produce bactericidal compounds such as lysozyme, reactive oxygen radicals, and N-oxides. Subsequently, the cells begin to produce various cytokines, which activate the surrounding phagocytes and leukocytes, responsible for inducing specific immunity that is distributed throughout the body.

Furthermore, certain studies show that they are capable of promoting the formation of Th1 lymphocytes to the detriment of Th2 cells, reducing the risk of autoimmune responses or allergies, so it may be possible to increase resistance to allergens present in certain plant proteins.

In this article, we will review the mode of action and effects of B-glucans, including a newly reported effect that could explain the medium-term effects of B-glucans, namely the phenomenon of ‘trained immunity’.

To conclude, here are some tips that NBG MicroShield already uses.

– Use Beta-(1,3/1,6)-Glucans, for example from yeast, as other types may even have anti-nutritional effects.

– Use purified sources of B-Glucans because the more purified they are, the more free bonds and activity they will have.

– Use fast-acting natural antimicrobials such as protected organic acids or phytogenic extracts, which will compensate for the time needed for B-glucans to activate the immune system.

– B-glucans are good immunostimulants, and the activation of the innate immune system produces reactive oxygen species and other oxidative molecules. I also recommend the use of powerful natural antioxidants such as hydroxytyrosol.

In an upcoming article, we will show how to achieve long-term action against a pathogenic outbreak using another well-known yeast immunomodulatory product, nucleotides, and how to evaluate the quality of the product.
Enjoy the article.