November 19, 2017

20/11/2017: Discussing antioxidant strategies and Selenium yeast production secrets

by Lallemand Nutrition

To mark the launch of the newly authorised formulation of its premium Selenium enriched yeast, ALKOSELR397 3000, Lallemand Animal Nutrition recently hosted its “Antioxidant Days” in Grenaa, Denmark, home of the company’s yeast plant


Participants from all over Europe gathered for this technical seminar dedicated to the understanding of oxidative stress in animal production and the use and applications of antioxidant solutions ALKOSEL and MELOFEED in animal nutrition.

The event closed on a tour of the yeast plant where participants got an insight of selenium enriched yeast production process.
 

www.lallemand.com

What is Selenium enriched yeast?

Kaspar Kevvai, R&D Project Manager at the Centre of Food and Fermentation Technologies, in Tallinn, Estonia, is an expert in yeast fermentation processes and he shared his knowledge on selenium-enriched yeast production.

Selenium-enriched yeast, or Se yeast is baker’s yeast (Saccharomyces cerevisiae) that contains high levels of organic selenium (Se) compounds such as selenomethionine and selenocysteine. As he explains, yeast itself does not need Se and contains little of it.

To produce Se yeast, inorganic selenium compound, such as sodium selenite, is gradually added to the yeast growth medium. The growing cells organically incorporate selenium atoms within amino acids in place of sulphur (selenomethionine or selenocysteine) (Figure 1).

Hence, the production of Se yeast is a delicate process. First of all, to ensure optimal incorporation of organic Selenium within yeast cells, scientists at Lallemand have selected a specific yeast strain (Saccharomyces cerevisiae NCYC R397), based on key criteria, in particular its ability to accumulate important levels of organic Se and the consistent distribution of Se within the different molecular fractions of the cells, as well as batch-to-batch reliability.

Then they have developed a specific production process to ensure optimal and constant quality of the product. ALKOSEL R397 is produced by fed-batch culture: nutrients, including selenium, are supplied incrementally to the growing cells (Figure 1).

Kaspar Kevvai explains, “The crucial part is to add the right amount of selenium over the right time. Adding too little results in a low concentration of selenium in the final product, whereas adding too much will inhibit the growth of yeast.”

The new Se yeast formula, ALKOSELR397 3000, which has just been authorised by the European Commission1 as a nutritional feed additive is the first Se yeast with a guaranteed minimum selenium content of 3,000 – 3500 mg/kg mg/kg to be available in the EU market for all animal species. It is the fruit of important investments in production process optimization.

Both ALKOSELR3972000 (minimum content of 2,000 mg/kg) and the new ALKOSELR3973000 are guaranteed to contain 97 to 99 percent of organic selenium and at least 3150 ppm and 4700 ppm of selenomethionine respectively (63%).

How to assess Se yeast quality?
Se yeast ALKOSEL is documented as a highly bioavailable source of Se for animal nutrition when compared to inorganic Se but also to synthetic selenomethionine sources (bioavailability is assessed through Se transfer rate from feed to animal blood, milk or egg) (Figure 2), which indicates that SeMet may not be the only important compound for Se metabolism.

Analyses have shown that, besides SeMet, ALKOSEL contains other forms of organic Se, in particular selenocysteine, and Se metabolic pathways in the body involve not only SeMet but also other amino acids, in particular selenocysteine.

Therefore, the combined presence of SeMet and SeCys in ALKOSEL could offer optimal balance for Se uptake and utilixation by the animal, explaining its superior bioavailability2. All Se yeasts are not equivalent and K. Kevvai gave further insight about Se yeast analysis.

According to him, total Se content measurement is not sufficient, it is important to also measure the content of key organic selenium compounds such as selenomethionine, which is an indicator of successful incorporation of selenium into the highly bioavailable organic molecules.


For tables, figures, and to read the full article click, HERE.
 

The Global Miller
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