Renewed interest in the mode of action for fiber-degrading enzymes — known as NSPase for the non-structural polysaccharide degrading enzyme complex — is behind new research suggesting changes in the animal gut microbiome to more efficiently degrade fiber, according to a recent announcement from AB Vista, which markets a range of NSPases.
The production of oligosaccharides by NSPases and subsequent fermentation of these by the gut microbiota to generate a "prebiotic" effect is regarded as one of the mechanisms for NSPase activity, AB Vista said. Now, new research from AB Vista and Alimetrics explores how NSPase mode of action is due to more than improved fiber digestibility and fermentation of the oligosaccharides generated, the company said.
An in vitro study looking at the fermentative capacity of cecal contents of birds at 35 days showed significant differences in the ability to ferment exogenously added xylan. Cecal contents of xylanase-fed birds showed significant enrichment of bacterial species capable of fermenting NSP that, in turn, produced greater quantities of volatile fatty acids, including butyrate -- a valuable energy source for enteroctyes and supporting gut function, AB Vista said.
Dietary xylanase was shown to effectively increase the capacity of the cecal contents to digest insoluble xylan in addition to soluble xylo-oligosaccharides, the company said. This highlighted a possible “training” effect on the cecal microbiome, resulting in adaptive changes towards a greater capacity to degrade xylan.
AB Vista research director Dr. Mike Bedford, who presented the findings at the 2018 Poultry Science Assn. annual meeting in San Antonio, Texas, said, “We need to think of NSPases as tools to accelerate the ability of the bird to digest fiber. Rather than quantitively degrading plant cell wall fiber, the enzyme is, in effect, increasing the intrinsic fiber-digesting capacity of the bird. This has significant implications with regard to selection of NSPase enzyme classes and dose rate.”