NSP enzyme

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Introduction

In recent years, the increase in the market for non-viscous diets has resulted in an increase in the use of non-starch polysaccharide (NSP) enzymes. In the late 1980s and early 1990s, people began to use the NSP enzyme in poultry diets because of its ability to correct the wet litter and variable apparent metabolizable energy (AME) problem associated with the use of high levels of barley or wheat. More and more scientists are beginning to study NSP enzymes, exploring the anti-nutritional properties of viscous NSP in certain grains, and alleviating these negative effects by supplementing appropriate endo-acting enzymes. The viscosity argument has been so convincing that it has become the norm to use NSP enzymes when appreciable amounts of barley, rye or wheat are available in the feed industry. Although it has been observed that many wheat varieties have not caused serious viscosity challenges, this practice continues, so the response to supplemental endo-xylanase cannot be explained in terms of 'correcting' the viscosity problem.

Choct et al. believe that the enzyme reaction is not only related to viscosity reduction, but there must be alternative mechanisms that have not been fully discovered and explored. This opened a new era of academic and commercial research, which target to explore the application of NSP enzymes in non-viscous grains, especially corn. According to a recent global survey, the penetration rate of NSP enzymes in poultry diets now exceeds 70%, indicating that the feed industry generally accepts these enzymes. The feed industry has a variety of products to choose from, including mono-component single enzymes, cocktails with more than one activity enzymes, and the main activity, several non-targeted activities within one product. People's choice of products reflects their understanding of the potential mode of action of NSP enzymes. Various mechanisms have been proposed to explain the role of NSP enzymes, including removing the nutrient encapsulation of plant cell walls, providing bioactive oligomers with potential prebiotic effects, regulating the gut micro-flora, and reducing viscosity, etc.

Prebiotic sugar generation

Recently, it has been proposed that prebiotic oligosaccharides produced by NSP enzymes are the main reason for growth promotion, especially in low-viscosity diets. This statement is thought to improve animal performance by directing the microbiota to be more conducive to optimal performance and reducing the likelihood of pathogenic challenge. Interestingly, Rosen et al. predicted that NSP enzymes would work more effectively in an antibiotic-free diet. If this assumption is correct, the goal of adding NSP enzymes to the diet is not to hydrolyze, but to produce specific oligosaccharides. If an oligosaccharide type (such as arabino-xylo-oligosaccharide, AXOS) can deliver the response on its own, this hypothesis further challenges the claim that multiple endogenous enzymes are required to produce multiple oligosaccharide types.  More importantly, it shows that the goal should be a limited degree of hydrolysis, so as to generate oligosaccharides without further degradation into shorter and less effective disaccharides or monosaccharides that are no longer prebiotic. The dosage and type of enzymes are very important. These enzymes can depolymerize oligosaccharides, thereby inactivating them. If this hypothesis is accepted, the future development direction of NSP enzymes will be more aimed at the products released by the enzyme, rather than the extent of hydrolysis achieved. If this is the case, NSP enzymes are likely to be supplemented or replaced by exogenous oligosaccharides.