ISSUE FOCUS FEED & ADDITIVE MAGAZINE May 2024 35 found in both corn-soy and wheat-soy diets. It offers unprecedented flexibility in incorporating cost-effective ingredients into diets, thus stabilizing feed costs. Additionally, its ability to generate a diverse array of prebiotics like xylooligosaccharides and arabino-xylanoligosaccharides supports a healthier microbial environment in the gastrointestinal tract, enhancing overall bird health and performance. GH-10 XYLANASES: UNLEASHING A SPECTRUM OF PREBIOTIC BENEFITS Since the mid-90s, it has been recognized that xylanase not only aids in feed digestion but also influences microbial activity within the gastrointestinal tract through the creation of fermentable oligosaccharides. The GH10 xylanases have shown superior capability in breaking down a variety of fiber components into valuable prebiotics such as xylooligosaccharides (XOS) and arabino-xylanoligosaccharides (AXOS). These compounds are instrumental in promoting the growth of fiber-degrading bacteria within the intestine, which has beneficial effects on the host’s health. Research indicates that bifidobacteria and lactobacilli, which are among the most prominent probiotic strains, vary in their utilization of XOS and AXOS. For instance, Bifidobacterium adolescentis can utilize both AXOS and XOS, whereas Lactobacillus brevis only utilizes XOS. This differential consumption leads to the production of butyrate, a short-chain fatty acid that enhances gut barrier function and reduces the colonization of pathogens like Salmonella in broilers. Furthermore, the presence of these oligosaccharides has been shown to improve overall performance by reducing feed conversion ratios. The GH10 xylanase requires only two consecutive unsubstituted xylan monomers to cleave the xylan main chain, whereas a GH11 xylanase requires 3 or 4 consecutive unsubstituted xylan monomers. Therefore, the number of potential AXOS and XOS oligomers is higher from the action of the GH10 xylanase. This results in a wider range of oligomers, quite valuable as the effect is spread across the large intestine, each oligomer having a different fermentation rate. Consequently, the colon microbial activity becomes saccharolytic, which potentially reduces the undesirable products of proteolytic degradation, such as phenols and cresols. Prebiotic combinations will vary depending on the substrate available. However, there is more flexibility in breaking down insoluble NSPs across different feedstuffs using GH10 xylanase compared to GH-11 xylanase. STRATEGIC IMPLICATIONS FOR FUTURE XYLANASE APPLICATIONS The strategic development of a GH10-based xylanase represents a pivotal advancement in animal Less branched molecule Axxess XY Require only 1 to 2 unsubstituted Xylans for active site Can also cleavage substituted Xylans Most commercial Xylanases Require at least 3-4 unsubstituted Xylans for active site Heavily branched molecule Axxess® XY is effective against soluble and insoluble arabinoxylans Soluble AX GH10 GH11 Insoluble AX
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