The mode of action is often complex, with benefits coming from:
- outcompeting pathogens for nutrients or physical space
- producing beneficial compounds
- increasing the digestion and/or absorption of nutrients
- improving the gut barrier function
- reducing gut inflammation
- interacting with the immune system
- or a combination of the above (FAO, 2016)
In line with current understanding of the microbiota, the use of probiotics has rapidly increased, and with good reason: when administered correctly, they contribute to improvements in animal performance. However, the growth of commercial products has increased exponentially over the years as well. This has made choosing the right probiotic more difficult than ever. Luckily, considering the following three questions will help to make the final choice easier.
1. What is the intended benefit?
When looking at probiotics as a group, it is imperative to understand that probiotic bacteria differ. Some are more focused on digestion, whilst others eliminate pathogens more effectively (Figure 1). Keeping the intended benefit in mind when choosing a probiotic is essential, as probiotics also have their limitations.
Closely related to this is the fact that strains differ, and thus matter. Strains are identified with a number (B. licheniformis DSM 28710 for example), indicating which strain is included in the product. This is because B. licheniformis strains differ and will not have the same (level of) benefits for example. As such, it is important to make the distinction. In practical terms this also means that the technical information of each product should always be assessed on a strain-level: claiming benefits associated with a specific species without supporting trials for the specific strain raises a red flag.
2. Is the probiotic stable and can it be used in standard feed processing?
There are great differences in stability among probiotic products, most noticeably between spore formers and non-spore formers. A spore is a metabolically inactive form of the vegetative bacterial cell, formed when the environmental conditions are unfavourable to the survival of the bacteria. During this spore-forming process, the bacteria achieves a dormant state and forms multiple protective layers to safeguard its core DNA (Figure 2). As a result, the spore is extremely durable and stable. This brings a distinct advantage in terms of stability, both during feed processing and within the animal itself. For example, in its spore form the probiotic can pass through the more hostile environment in the initial stages of the gastrointestinal tract, without loss of viability. Once the spore reaches the right location in the gut, the spores yield active vegetative cells, ready to exert their beneficial effects.
3. Are multiple probiotics used in the same product?
If multiple probiotics are used in one product, an aspect of inherent competition might be introduced, especially if the strains used are part of the same genus (Bacillus for example). Due to their similarities, the strains are expected to compete for similar requirements such as nutrients and space, potentially diminishing the intended beneficial effect. As this is evidently not the goal, single-strain probiotic products are the preferred choice.
Asking these three questions in the current market, it is clear that spore-forming, single-strain probiotics are the products of choice, of which B-Act® (Bacillus licheniformis DSM 28710) is a great example. Firstly, it is a single-strain product, therefore avoiding the risk of introducing any inherent competition. Secondly, B. licheniformis DSM 28710 forms spores, and as such has great stability during storage, feed processing and within the animal itself. Thirdly, there is plenty of research available for this specific strain, providing scientific proof of the expected beneficial effects.
In addition to supporting general gut health, this strain can produce potent bioactive metabolites, such as lichenicidin. This peptide has shown great activity against Gram-positive bacteria, such as pathogenic Clostridium perfringens. As C. perfringens plays as pivotal role in the development and severity of necrotic enteritis and dysbacteriosis, B-Act® can thus be used to mitigate these production challenges on-farm, whilst at the same time supporting growth performance.
As understanding of the microbiota and its importance for animal production continues to develop, so will the relevance of probiotics. Adding these beneficial bacteria to animal feeds leads to healthier, more productive animals, as well as better profitability. Probiotics are scientifically proven feed additives, combining economics with health standards in the most rewarding way.