Using yeast derivatives to support aquaculture production

The intensification of aquaculture production has increased the need to control pathogens. Studies show that yeast derivatives can support the natural lines of defenses of both freshwater and marine species.



a) Proportion of large granular cells

10 8

4 6

0 2

*p<0.05, compared to control group. 20 ▶ ALL ABOUT FEED | Volume 28, No. 8, 2020 *

t a time of growing concern about the use of anti- microbials in animals used for food, alternative − often preventive − strategies are being sought to promote health and performance in a sustainable

way. Aquatic animals have several natural lines of defenses against external threats. These include the gut, the skin, the gill physical barrier, the associated mucosal immune system and microbiota. All contribute to protecting the animal against an invasion or internal infection for which the animal’s systemic immunity provides the ultimate defence.

Figure 1 - Proportion of large-granular cell; b) Phenoloxidase activity and c) Lysozyme activity in the hemolymph of white shrimp fed a commercial diet non-supplemented (Control) or supplemented with the yeast derivative (YANG) for 4 weeks period. Mean±S.D.

b) Phenoloxidase activity c) Lysozyme activity

200 400 600 800 1000 1200

0 *

1000 2000 3000 4000 5000


Yeast fractions can help balance intestinal microflora and stimulate natural defenses in the host at both the mucosal and the animal level. Trials conducted in fish and shrimp indi- cate that an yeast derivative helps to support those natural lines of defenses in both freshwater and marine species. Out- comes are very positive, both in terms of animal performance and economic benefits for the producer.


Pathogen binding ability A research programme was carried out in order to identify and develop a new generation of yeast fractions with optimal characteristics that might help animals face various challeng- es. The results demonstrated that yeast cell wall properties are linked to the strain, with each strain exhibiting specific structure and functionality in terms of binding properties. Moreover, it was also shown that, for a given strain, binding properties can differ when applying varying production and inactivation processes. Hence, for every selected strain, it is essential to determine the optimal fermentation conditions, as well as the treatment of the live yeast used to obtain the yeast fractions (inactivation technique). Based on these find- ings, a range of yeast strains were screened by scientists at Lallemand in order to select the best candidates for optimal binding of various bacteria in vitro, such as various Vibrio spe- cies which are of particular importance in aquaculture. The best strains were selected for their complementary proper- ties. Transposed to in vivo settings, such properties indicate a potential to agglutinate a larger spectrum of undesirable bacteria inside the gut lumen prior to the potential coloniza- tion of the gut epithelium. Further mechanistic studies also indicated that, when combined, the different yeast fractions exert a synergistic activity on the immune system in vitro. A patent has been filed to cover this synergistic immune effect. The selected yeast fractions were combined into a unique for- mulated solution, which is called YANG (Yeast Association New Generation).

Supporting immunity This year a trial was carried out using white shrimp juveniles

Proportion (%)

Activity (U/min/mg-protein)

Activity (U/ml)

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