The Role Of Xylanase In Animal Nutrition: Mechanisms, Types, and Innovations
Xylanase targets xylan, a major component of hemicellulose found in plant cell walls. It is commonly used in animal nutrition to enhance the digestibility of dietary fiber, particularly in monogastric animals such as poultry and swine. Plant-based feed ingredients, such as corn, wheat, and soybean meal, are rich in non-starch polysaccharides (NSPs), including arabinoxylans, which are difficult for animals to digest efficiently.
Xylanase helps break down these complex NSPs, releasing more simple sugars and other nutrients for absorption in the digestive tract. This not only improves feed efficiency but also reduces the anti-nutritional effects of NSPs, such as gut viscosity and increased microbial fermentation, which can lead to digestive disorders and reduced animal performance.
GH10 xylanases make it possible to incorporate higher levels of cost-effective ingredients
While the GH11 family of xylanases, commonly employed in feed, effectively lowers viscosity levels in broiler gastrointestinal tracts by reducing soluble NSPs in wheat-based diets, they prove less effective when confronted with the more complex arabinoxylan backbone of insoluble NSPs.
The 3D structure of GH11 xylanase explains its limitations. GH11 xylanases require 3-4 consecutive unsubstituted xylan monomers on the backbone to locate an active site, making them less effective in the presence of side chains on arabinose backbones. They are highly specific, favoring low-branching wheat backbones.
In contrast, GH10 xylanases, though not commonly used in feed, offer a distinct advantage. They require only two or fewer consecutive unsubstituted xylan monomers to find an active site, enabling them to act on xylose residues near branches. This results in more and shorter xylo-oligomers than GH11 xylanases produce. Simply put, GH10 xylanases have a shallower cleft, providing greater catalytic versatility (Pollet 2010).
This versatility allows for a broader range of feed ingredients, including co- and by-products, while maintaining performance. Therefore, GH10 xylanases make it possible to incorporate higher levels of cost-effective ingredients, presenting a significant opportunity to reduce overall feed costs.