Over recent decades, the growing understanding of live yeast's mechanism and precise benefits, coupled with increased demand for natural feed additives, has led to heightened popularity for supplementing animal feed with such probiotics.

The viability of a live probiotic is a key parameter to ensure its metabolic activity once ingested by the animal.

Many experts insist that probiotics must be alive and viable to exert an effect on the microflora within the digestive system.

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Indeed, several national authorities will only authorise a claim for performance (such as improved milk production or feed efficiency) when the probiotic microorganism is viable. For example, the European Commission considers microorganisms as probiotic feed additives only in their live form.

Like many other biological feed additives such as vitamins and enzymes, live yeast can be sensitive to external stresses such as heat, moisture, pressure or contact with certain chemicals or trace elements (Figure 1).

These factors can impact yeast stability or metabolic activity and, therefore, its efficacy. As a result, protection can be necessary for specific probiotics to ensure their stability through the feed pelleting process and during storage.

Live Yeast Stability Trial - IFF Institute, Germany, 2017

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The objective of the trial was to compare the stability and the resistance of a specific live yeast protection technology LEVUCELL SB & SC (TITAN coated beadlets) vs other yeast sources (non-coated beadlets) under different pelleting conditions and over a three-month storage duration.

Pelleting conditions

Equipment: Single press / Ring-die pelleting press Salmatec.

Out-flow: 1000kg/hour.

Pellet diameter: 5 mm.

Die thickness: 50mm.

This trial compares TITAN (LEVUCELL SC & SB) protected live yeast with three commercially available yeast sources (Beadlets A, B & C).

These four live yeast products are commercially described as a “thermo-resistant forms” by their producers.

However, we can observe from the pictures that only TITAN offers a unique coating matrix.

  • At 65°C, TITAN and two non-coated yeast sources are at the expected count.
  • At 75°C, only one non-coated yeast source out of TITAN still resists, but we start to observe a drop in CFU. TITAN remains perfectly stable at both temperatures.
  • At 85°C, simple bead technologies (non-coated) do not survive and show a significant drop of CFU. TITAN is the only product remaining perfectly stable throughout these conditions of the feed manufacturing process. (Figure 2)
  • Stability is also about feed storage conditions and shelf life. Once probiotics are included in the feed, in order to be active and efficient in the animal, they must survive throughout the storage duration at the feed mill and/or on farm.

    RESULTS: TITAN PROBIOTIC YEAST REMAINS STABLE IN FEED FOR AT LEAST 3 MONTHS

    Looking at stability results (Figure 3) over of the batch pelleted under the less challenging conditions (65°C), we observe that:

  • At T0, products all still within the acceptable tolerance range.
  • At T1 month, only TITAN and beadlet C remained stable.
  • At T2 month, only TITAN is stable.
  • At 75°C and 85°C, the results are even clearer: only TITAN remains stable after one month.

    After three months of storage, TITAN still reaches the guaranteed level of CFU/g.

    Conclusion

    Even though yeasts with non-coated bead technology are sometimes marketed as 'stable and alive' after pelleting, it seems that the yeast cells can be strongly damaged and can die during standard storage duration. When selecting a probiotic yeast, it is crucial to ensure the live yeast will: survive feed or premix processing; tolerate the combination of other ingredients; and endure storage prior to reaching the animal.

    Is your live yeast provider willing to offer feed analysis to ensure the recovery of probiotic cells at the declared CFU level on your feed ticket?

    For further information on TITAN please click here or you can contact Lallemand Animal Nutrition business manager for Ireland, Bryan Buckley on +353 (0) 86 8482466 or email animalireland@lallemand.com