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