Yeast cell walls (from Saccharomyces cerevisiae) – better known as mannan-oligosaccharides (MOS) – are indigestible carbohydrates. This fermentable, prebiotic substrate, is able to bind E.coli and salmonella within the intestine and has a positive influence on the gut microflora and immune system (Swanson et al 2004).
Saccharomyces cerevisiae (SC) is an eukaryotic, single-celled microorganisms which converts carbohydrates to carbon dioxide and alcohols by fermentation. For thousands of years, it has been used for better tastes in breads or alcohol fermentation and in beer production.
Nowadays we have different kind of yeasts which we use in food and feed industries. In an in vitro gas production technique, MUSCO et al (2016) used different commercial products, based on brewers, alcohol (ethanol) or baker ́s yeast cell walls showing different MOS and glucan concentrations.
Comparing the substrates, it seems evident that the production process affects the chemical composition of the yeast cell wall in terms of crude protein, ether extract and ash content.
Consequently, the in vitro fermentation process was significantly different among substrates for volume of gas, short- chain fatty acids (SCFA) and ammonia production. Brewer’s yeast cell walls showed very high percentage of organic matter degradability, gas and SCFA production.
On the contrary, baker’s yeast cell walls appeared to be less degradable and fermentable, probably due to their high content of ether extract. The findings of MUSCO et al (2016) suggest that the type of production process can significantly influence nutritional properties of cell walls derived from Saccharomyces cerevisiae showing significant differences in chemical composition as well as in vitro pathway and fermentation kinetics.
Prebiotic effect on canine gastrointestinal tract
In collaboration with Ghent University, Leiber GmbH carried out a study with the aim of assessing the potential of the prebiotic activity of Biolex® MB40 within the canine gastrointestinal tract. This product consists of cell walls of real brewers ́ yeast (100% Saccharomyces cerevisiae) and is distinguished among other factors by its high natural β-glucan and MOS contents.
For the study, an in vitro system (SCIME™ Simulator of the Canine Intestinal Microbial Ecosystem) was deployed, which can retrace the entire canine digestive tract with all its microbiological processes under controlled conditions.
The SCIME™ delivered not only detailed information about the prebiotic activity of the product by measuring various biomarkers, but also the precise location of the area where it is active.
In the study a prebiotic effect of Biolex® MB40 on the canine gastrointestinal tract could be demonstrated. It is digested moderately and selectively, in particular by the canine microflora in the distal colon on a dose-depended way. Among other effects a significant increase of butyrate (Figure 1), lactate, acetate and propionate (Figure 2) was seen.
Propionate is, in addition to acetate and butyrate, one of the main energy supplier for the gut epithelium (Cummings, 1987). Therefore, it significantly contributes to the health and protection
of the gut against inflammatory processes.
Propionate is supposed to influence the reduction of cholesterol and fatty acid synthesis in the liver (LIN et al 2007, Berggren et al 2007) and regulate immune status in adipose tissue (AL Lahhan et al 2010 & 2012).
In dogs, propionate production has been shown to play a role in the stimulation of gastrointestinal saturation hormones such as GLP-1 and PYY. Massimo et al (1998) reported that the secretion of GLP – 1 by enteroendocrine L-cells, which are predominantly present in the distal part of the gastrointestinal tract (Holst et al 2007), was increased with dietary supplements in healthy dogs.
In addition, Pappas et al (1986) showed that the perfusion of fatty acids increased the peripheral PYY concentration in the dog ́s intestine. Le Paul (2003) also suspects that propionate is involved in stimulating PYY release by activating receptors GRP41 and GRP 43, both expressed by enteroendocrine L – cells in the distal part of the gastrointestinal tract.
So, a higher propionate production could have a positive impact on hormonally controlled feeling of satiety, so at the end on weight control or adipose tissues.
Brewer’s yeast cell walls support development and integrity of the intestine
In the study with Biolex® MB40 changes in the metabolic activity were able to be directly associated with specific changes to the microbiota, e.g. the stimulation… of propionate–producing families, such as Porphyromonadaceae and Prevotellaceae.
Even an increase of butyrate concentration could be demonstrated through butyrate producers in Porphyromonoadaceae family and through “cross feeding effect” related to the increase of Enterococcaceae in the proximal colon (lactate production).
‘Cross feeding’ means that the product is presumably broken down by a proportion of the microorganisms and fermented into acetate and lactate, which are then consumed by other microbes, which then form propionate and butyrate.
At the same time, it was shown that potential pathogens, such as Enterobacteriaceae and Fusobacteriaceae were decreased through the product.
High adsorption capacities of mycotoxins & pathogens
Mannan-oligosaccharides (MOS) are known for their binding capacity to type 1 fimbria of the intestinal mucosa and the reduction of pathogens in the gastrointestinal tract.
Strickling et al. (2000) discovered a reduction of Clostridium perfringens in the faeces of MOS fed dogs. Middelbos et al (2007) found a numerical reduction of E.coli in the faeces of adult dogs.
The examination of the adhesive behaviour of pathogenic enterobacteria like E.coli and Salmonella Typhimurium toward IPEC – J2 cells with Brewer’s yeast showed a dose –dependent inhibition.
Compared to a control group, E.coli bacteria were reduced by over 30% and Salmonella by
more than 50%. In an experiment conducted at the University of Vienna in Austria (FRUHAUF et al., 2012), it was examined to what extent various commercial toxin binders and yeast cell wall products can absorb Zearalenone (ZEA).
The experiments were conducted using synthetic buffer solution and porcine gastrointestinale juice. Biolex® MB40 showed a 45% ZEA adsorption capacity in gastrointestinal juice which was even higher than capacity of toxin binders or other MOS – products.
Active support & relief of the immune system
In another study at the University of Ghent, BIOLEX® MB40 was used in a canine immune in vitro system, to test the immune response of the non-specific and specific defence. Biolex® MB40 indicates ROS (reactive oxygen species) stimulation at 200 μg/ml – so an activation of the non-specific immune system.
It also inhibits pro-inflammatory and anti–inflammatory interleukins, such as IL-6, IL-8 (Figure 3), IL-17A (Figure 4) and IL – 10 at 200 μg/ml and 20 μg/ml. IL-8 attracts inflammation cells, such as neutrophil granulocytes and Tcells, to the location of inflammation.
Therefore, it is a key element for chronic inflammatory reactions. IL-17A is a signal cytokine of Th17 cell types, which is associated with various autoimmune diseases, such as chronic inflammatory bowel disease (IBD). Biolex® MB40 stops the IL – 17A secretion completely at 200 μg/ml.
So, the product showed a direct immune modulation effect especially on the inhibition of the pro – inflammatory interleukins. In addition to the prebiotic effect, this product appears to be a promising measure for the improvement and protection of intestinal health, but also to therapies that treat chronic inflammatory processes.
BIOLEX® MB40 – for intestinal health and protection!
A prebiotic effect of Biolex® MB40 on the canine gastrointestinal tract could be clearly demonstrated. This product appears to have a positive influence on the metabolic markers like propionate and butyrate and the composition and activity of the microorganisms.
Therefore, it is a promising natural tool for the improvement and protection of intestinal health. It increases directly the intestinal barrier as the first defensive line against the ingress of potential pathogens.
At the same time, it inhibits interleukins, which is very advantageous in chronical inflammatory processes. Compared to other 100 percent post-consumer recycled content, which are fermented relatively quickly especially in the proximal colon (Mcfarlane & Gibson, 1992 & Calabró 2013), Biolex® MB40 is moderately and selectively fermented in the distal colon.
The use of this product as a prebiotic, pure or in combination with other oligosaccharides (Swanson et al, 2002 c, Grieshop et al 2004, Middelbos et al 2007a), appears to be a promising way of improving and protecting gut health.
Leiber refines brewers’ yeast into innovative products for humans and animals. The company conducts its own research in its own laboratories and develops tailor-made solutions for healthy animal nutrition, biotechnology and agricultural applications.
The company reliably supply excellent products – and have been upcycling at world-market level since 1954. Literature is available on request!
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Article contributed by Maike Rakebrandt, Senior-Product Management Companion Animals (Pet & Equine), Leiber GmbH, Germany.
