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Fibers has been considered for many years as a ‘bad’ nutrient that we need to get rid of. But in recent years, fibers are gaining popularity as we are confirming their importance in the lower part of the gut. Fibers (NSP - non-starch polysaccharides) are indeed sources of energy that cannot be digested in stomach of mammals but can be fermented by gut flora in the lower part of the intestine to contribute to their development. Fiber fermentation can represent up to 25% of total energy for adult omnivorous. Nutritionists are now working at increasing NDF level up to 12% in piglet diets and 18% in lactating sow diets. By doing so, they are increasing at the same time the anti-nutritional factors that come with fibers.

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The soluble fiber tends indeed to bind water to form a gel (“the gelling effect”). That is increasing digesta viscosity and slow down the transit. The insoluble fibers are made of vegetal cells walls that both binds the proteins (mostly in corn, cassava and soybean meal) and prevent the digestive endogenous enzymes to access the protein, glucids and lipids inside the cells (“the cage effect”). That can represent a significant loss of nutrients.

This is where NSP enzymes will intervene. By breaking down the long molecules of NSP into smaller pieces, they will reduce the digesta viscosity (limit Gelling effect) and give access to endogenous enzymes to digestible materials inside the vegetal cells (reduce cage effect). These two mechanisms contribute to improve the digestion effectiveness. But the breakdown of the NSP’s has also a prebiotic effect. The NSP enzymes break down the fibers into smaller fragments, the oligosaccharides. These oligosaccharides can be fermented by bacteria inhabiting in the gut. These good bacteria become a bigger part of the microbiota and produce large

quantities of short chain fatty acids, which can function as a direct energy source for intestinal villi, leading to better digestion and reabsorption of water in general. But farmed animals are not equipped by the nature to digest these NSP. These enzymes need to be supplemented into the diet as what we group under the name NSP enzymes or NSPases. That includes several enzymes as xylanase, glucanase, pectinase to break down different types of NSP. The substrate that the enzymes will have to deal with highly depends on each ingredient. As example, arabinoxylans are particularly dominant in wheat whereas pectins and glucans are preponderant in Soybean meal.

To illustrate the efficacy of these NSP enzymes, enzymes manufacturers provide certificates guaranteeing each enzyme activity. But each manufacturer has a different method to measure the activity of their enzymes with often their own unit of activity. On the paper, it is very complex to compare activity when using different unit. The best approach is to compare activities of several enzymes by using the same method. I am sharing below a comparison made by a European supplier on two dimensions that are xylanase and glucanase activity.

Xylanase, Glucanase are indeed the two more popular NSP enzymes used in animal nutrition.

The cheaper one is xylanase as this enzyme is produced in large quantity for textile industry. Glucanase production is more limited with a higher production cost. For those who are looking for enlarging the activity of their mix, pectinase is also an interesting enzyme, especially for the ingredients rich in pectin as soybean meal. I want to underline one point on the graph. This study confirms that the two products containing pectinase, glucanase and xylanase have a superior glucanase activity. This increase of activity is not coming from the presence of pectinase as it could be suggested by the graph. The pectinase activity should actually be measured using a different method. But it turns out that the manufacturers proposing the mix of three enzymes are as well the ones proposing glucanase with the highest activity. It may be a question of fungi strains or of manufacturing process. This graph confirms as well the synergy between enzymes. Some data suggests that glucanase create some spaces for xylanase to reach its substrate resulting in a higher xylanase efficacy. To quantify the energy and amino acids that the NSP enzymes will enable to recover from the diet, the enzymes producers traditionally supply a matrix to be incorporated by the nutritionists in their formulation optimization software. But the competition between producers creates an inflation on matrices with numbers getting higher and higher. Moreover, these matrices value should be adjusted to each diet to consider the nature and quality of the substrate ingredients used. To gain in confidence, nutritionists should validate these matrices first on the field with animal trials. If a tested group has better results than the negative control, that will mean that the matrix is undervaluing the contribution of the enzymes. If at the opposite, the growth performance of animals is below the negative control, the matrix may be too optimistic in the specific context of that diet. To finish, it is important to remember that NSP enzymes are products of fermentation with very variable output. To guarantee a consistent supply, it is important to select suppliers repeatable manufacturing processes and strong registration dossier. As I mention in the introduction, fibers come with anti-nutritional effects as gelling effect and cage effect. For years, nutritionists only saw the anti-nutritional effects and wanted to remove fibers from diets. Nowadays, scientists demonstrate the importance of fibers in the digestion process, both to ensure proper transit but as well to promote a healthy fermentation in the lower portion of the intestine. To be sure that there is no misunderstanding on the importance of fiber, it is important to stress that the beneficial effect of fibers on the gut health is exceeding their anti-nutritional factors. Naturally, the best scenario would be to dream of benefiting from fibers positive effects without having to deal with anti-nutritional factors. Using NSPase partly deals, but not totally, with these side-effects. Another solution to benefit from a NDF source without creating “cage” and “gelling” effect is to use processed lignocellulose. These are 98% NDF source, without soluble fiber, and for which each cell has already been opened by a physical process. NSP enzymes and processed lignocellulose are strong tools available to nutritionists to increase NDF level in Swine and Poultry diets without having to pay for the anti-nutritional factors of fibers.

#Nutrisices #nutricle # enzymeactivities #NSP #NDF

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