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Live Yeast: Ensuring its viability for optimal efficacy

The viability of a 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.

Vincent Couture
Brand Manager
Lallemand Animal Nutrition
Sylvie Roquefeuil
Communications and PR Manager
Lallemand Animal Nutrition
Jean-François Hupé
R&D Manager
Lallemand Animal Nutrition

 

 

 

 

 

 

 

 

INTRODUCTION
Over the past decades, the growing understanding of live yeasts’ 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 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

Figure 1: Titan beadlet section in scanning electron microscopy

system. Indeed, several national authorities will only authorize 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.

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. Today, the increased demand for pelleted feed, with more and more stringent processes, could limit the inclusion of probiotic yeast in this form of feed. Thanks to continuous investments in process development, scientists at Lallemand Animal Nutrition have

Figure 2: Factors influencing viability and activity of sensitive biological additives such as live yeast.

developed a unique patented yeast protection technology (Fig. 1), Titan, that ensures optimal yeast survival and stability during industrial feed processing steps and feed storage.

OVERCOMING THE STRESS OF PELLETING AND STORAGE

Like many other biological feed additives, such as vitamins or enzymes, live yeast can be sensitive to external stresses such as heat, moisture, pressure or the contact with certain chemicals or trace elements (Fig. 2). These factors can impact yeast viability or metabolic activity — and, therefore, its efficacy. As a result, protection can be necessary for specific probiotics to ensure their stability through the feed pelletizing process and during storage. Titan technology has been developed to ensure protection of probiotic yeast throughout industrial pelleting processes and feed storage.

Figure 3: The Titan yeast production process combines a specific fermentation and drying process to result in a unique and patented microencapsulation technology.


A SPECIFIC INDUSTRIAL PROCESS

When producing live yeast, each and every step can impact its viability. When the process optimization team at Lallemand worked on developing Titan, they scrutinized the whole process. They adapted the fermentation and drying processes and combined this with an extra step: a protective microencapsulation.

Figure 4: Visual aspect of different forms of live yeast products. As seen on electron microscopic images, only Titan has a protective layer.

When producing Titan yeast, the fermentation and drying conditions are specific. Following fermentation, the conventional active dry yeast (ADY) process is typically extruded into a vermicelli particle form. This form of ADY is suitable for less stringent applications such as mash feed.

For Titan production, the yeast particles are submitted to a particular drying process to form beadlets. The dried beadlets are then coated in a batch fluid bed with a specifically formulated lipid-based solution (Fig. 3).

This coating step, or microencapsulation, specific to ADY has been patented (EP 2099898B1). While many products on the market are described as “protected” or “heat resistant,” Titan is a unique yeast microencapsulation technology in animal feed additives (Fig. 4).

RESISTANCE TO FEED MANUFACTURING PROCESSES
Titan technology protects the live yeast against the constraints of the production process and ensures stability through storage time. Titan protects the live yeasts against the pelleting process (heat, pressure and humidity) as well as interaction with other chemical compounds used in feed manufacturing. This has been extensively proven in numerous trials, both from independent institutes and commercial feed manufacturers under various industrial feed mill conditions; in various countries; and in all feed types such as complete feed, mineral, and diets for ruminants, swine and poultry (Fig. 5). In certain cases, Titan was even able to resist drastic pelleting processes, thanks to its specific coating (e.g.: temperatures up to 120 °C, expender processes). In cases of drastic conditions with a high amount of constraints, a validation plan — including accurate sampling and ad hoc microbiological analysis — should be set up in feed manufacturing conditions.

Figure 5: Various trials showing the consistent capacity of Titan yeast to resist standard pelleting conditions (70 to 85°C after the die)
* Standardization of the expected counts to 107 CFU to facilitate comparison.
Figure 6: Stability of different yeast sources to pelleting process at die temp of 85°C.
* Standardization of the expected counts to 107 CFU to facilitate comparison
(Note: The data on vermicelli were based on multiple studies but were not part of the same IFF trial).

 

Moreover, an independent analysis was conducted by the independent institute IFF in Germany to compare the stability and the resistance of a Titan live yeast form to other commercial yeast sources under different pelleting conditions. This study shows that only Titan yeast remains stable throughout the various pelleting processes (at least 85°C) (Fig. 6).

FROM THE FEED…
Probiotic stability is not only about feed processing, it is also about feed storage conditions and shelf life. Once probiotics are included in the feed, the products must survive storage time at the feed mill and farm up until it is consumed by the animal. Trials have shown that Titan technology allows yeasts to remain stable in the feed through standard storage period (Fig. 7).

Figure 7: Stability of Titan yeast in pelleted feed along a product shelf life (IFF, Germany 85°C pelleting)

…TO THE GUT
Finally, stability and availability also is important at the end of the chain — just prior to feed consumption. The lipid-based protective coating of Titan is solubilized in the host’s digestive tract, releasing the living, active yeast in the gut to interact with and benefit the host.

For example, in ruminants, it was shown in vivo (cannulated ruminants INRA) that live yeast cells were released in the rumen fluid from Titan live yeast form with similar efficacy than uncoated LEVUCELL SC 20. In the same way, studies in swine and poultry (which have a short digestive tract) show effective release of the live yeast cells in the digestive tract.

HOW TO USE TITAN TECHNOLOGY?
Titan technology is available to all probiotics yeast strains produced by Lallemand Animal Nutrition for both ruminants and monogastrics. Lallemand Animal Nutrition is committed to controlling performance of its product in its customers or end-users feed facilities thanks to a dedicated technical support and lab analyses services. Lallemand offers technical support and dedicated analyses services to make sure that Titan technology perfectly matches with industry conditions.

THE EXPERT’S VIEW
INTERVIEW WITH JEAN-FRANÇOIS HUPE, R&D MANAGER – PRODUCT AND PROCESS DEVELOPMENT

“TITAN IS NOT ONLY ABOUT COATING! THE DEVELOPMENT OF THIS TECHNOLOGY IS A TRULY INTEGRATED APPROACH”

What is Titan?
Titan is a live yeast protection technology adapted for pelleted feed applications. Titan includes a unique and patented yeast microencapsulation technology, but Titan is not only about coating! The development of this technology is a truly integrated approach. We optimized the fermentation and drying conditions and each downstream processing step to ensure optimal resistance and viability of the live yeast in customer applications. Even packaging is important. All this ensures that Titan offers a consistent and optimal stability to our live yeast probiotics.

What are the applications of Titan?
Thanks to its unique properties, Titan technology shows a high resistance to feed pelleting manufacturing processes and remains stable over storage durations when compared to other commercial live yeast technologies. Titan protects live yeast against pressure, heat, moisture and constraints that can be found in feed pelleting, as well as against chemical compounds and redox reactions. Under drastic pelleting conditions (e.g. at least 85°C and up to 3 months storage), Titan shows superior stability vs. non-encapsulated products.

Tell us about the technical services associated to Titan?
Lallemand has an international process development platform as part of our R&D department, dedicated to the process optimization and the application of Titan. Under a large variety of feed processing conditions, the feed industry can benefit from on-site support to assist in feed process monitoring and sampling. Our feed industry partners have also access to dedicated services such as sample analysis and compatibility studies, for instance.

THE COLONY-FORMING UNIT (CFU)
How to count live yeast?
The measurement of the active yeast concentration in feed is most commonly expressed in colony-forming units (CFU) per gram, which represents the number of live yeast cells that are able to reproduce per gram of feed sample.

In practice, it is a plate-counting technique based on counting yeast colonies growing on a Petri plate provided a selective medium (or nutrients for growth and antibiotics to inhibit bacterial growth). Each colony represents the reproduction of a live yeast cell for a given duration. The results are expressed in Log10 to account for the dilution procedure applied in the lab.

The CFU method is the official control method recognized by most authorities.

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