FEATURED QUESTION: What’s the future for fibre in monogastric nutrition?

The concept of stimbiotic involves products that have the ability to stimulate the development of a fibre fermentable microbiome.

The stimbiotic concept is different to how prebiotics are described; rather than adding a product in high concentration to be used as a substrate for hindgut fermentation, the stimbiotic concept is about including a low concentration of products that are used as a signal or kickstarter, driving the microbiome to ferment the fibre that is already present in the gut.

Mike Bedford, AB Vista Research Director

Yes I do because the net result of the above is to increase the proportion of trials where we get a response and increase the size of the response as well.  Consistency is a problem with current NSPases which is far less of a problem with a good stimbiotic.

Mike Bedford, AB Vista Research Director

For a long time, it was thought that fibre caused a negative impact – and so diets were formulated without it. However, it has become increasingly clear that fibre plays a vital role in the development of the microbiota, since it is a key substrate for bacterial growth.

As the total dietary fibre content of monogastric diets tends to be higher than people expect when measuring only crude fibre, there is a huge opportunity for nutritionists to harness the ‘treasure trove’ of potential laying within. As we further unravel the complexities of fibre, so we improve the provision of nutrients to the gut microbiota – for better performance. This is of course especially significant in the age of antibiotic-free diets.

Mike Bedford, AB Vista Research Director

It seems we may be on the verge of entering an exciting new era: one where nutritionists simultaneously consider nutrition for the microbiota – or the ‘second brain’ – in addition to nutrition for the animal. This is where the better understanding of dietary fibre in the diet and the impact of enzymes and oligosaccharide provision in the hindgut shows an exciting future for animal nutrition.

Mike Bedford, AB Vista Research Director

I think it needs to be a combination – the AXOS are only part of the story as we believe they stimulate fibre fermenting bacteria to produce their own enzymes to break down fibre and ferment it. The xylanase we add produces soluble fibre from insoluble fibre, which acts as a better fuel for these fibre fermenting bacteria to attack.  In addition the xylanase we add damages the surface of the insoluble fibre making it more accessible and fermentable than it would otherwise be. So the AXOS provide the signal to start fibre fermentation and the added xylanase provides the substrate for the bacteria that have been stimulated to attack.

Mike Bedford, AB Vista Research Director

Although viscosity remains a problem for wheat and barley, it plays only a very small part of the response observed when using fibre-degrading enzymes in corn-soy diets.

In terms of the cell wall mechanism, when we look at how much enzyme and how much time is needed to break down cell walls completely, it is far in excess of what we actually feed the animal in real-life conditions. As a result, we don’t believe the cell wall mechanism plays much of a role, even in a corn-soy diet.

In contrast, the prebiotic mechanism is emerging as the strongest for corn-soy diets – and we feel that the ‘prebiotic’ theory should in fact more accurately be referred to as a ‘signalling’ mechanism.

The term ‘signalling’ refers to how oligosaccharides generated by fibre-degrading enzymes ’signal’ to bacteria in the gut, stimulating them to produce their own xylanases.

This process has a beneficial effect on fibre fermentation, both in poultry and swine. This theory suggests that xylanase affects the microbiome, changing the concentrations of short chain fatty acids (SCFAs) in the large intestine in such a way that these SCFAs are feeding back to the stomach, telling it to slow down – resulting in a significant improvement in terms of protein digestion.

Mike Bedford, AB Vista Research Director

Central to the signalling hypothesis is the theory that an enzyme which can produce xylo-oligosaccharides will eventually improve the ability of the microbiome to digest the arabinoxylan fraction of the diet. This gives far greater benefits in terms of energy and signalling back to the stomach – thus, we believe that feeding the right xylanase that can produce the right signals will give you the best response in commercial feed today.

It is important for feed manufacturers, producers and nutritionists to examine the complex nature of fibre and best harness its intrinsic value in order to formulate a diet that optimises animal performance – and business profitability.

Mike Bedford, AB Vista Research Director