Non-starch polysaccharides, like beta glucans and arabinoxylans, generally reduce the nutritive value of cereals and of diets. Enzyme preparations can be used for this purpose, but are not always useful. In this second episode, I shall explain when they are and when not.
Click here to see part I
It is quite difficult or impractical to determine the exact level of non-starch polysaccharides before feeding a specific batch of cereals to pigs.
To this end, it is strongly recommended to use an enzyme preparation when the origin of cereals is unknown and/ or of suspected quality, or when the pigs appear unthrifty and exhibit deteriorated feed efficiency and/or signs of looseness in fecal consistency, due to a recent change in type or source of cereals.
Kind of cereal
The proper enzyme to use depends on the kind of the main cereal in the diet. For example, as barley is rich in beta-glucans it is recommended to use a beta-glucanase (enzyme) in diets based solely or mainly in barley.
In contrast, wheat is rich predominantly in arabinoxylans, and thus such diets should be enhanced with a xylanase (enzyme). When both cereals are used in the same diet, then an enzyme ‘cocktail’ is preferable to counter the effects of both types of non-starch polysaccharides.
In my opinion, when a cereal is used in levels below 10-15% in any pig diet, an enzyme preparation specific to this cereal is not likely to confer any beneficial results. Regarding the selection of the appropriate commercial product (brand), it is unfortunate that there is no public information regarding the comparative value of available products.
Use any brand
Therefore, it is recommended to use any brand among the most respectable products in the market at the appropriate level recommended by the supplier.
But, before selecting an appropriate enzyme preparation (brand) for use in pig diets, the cost/benefit ratio should be carefully evaluated.
First, the cost of use (and not the cost per kg of enzyme) should be established based on the enzyme price and its recommended dosage. Thus, the cost of enzyme supplementation per Kg or MT of complete feed should be known and a list of similar figures be prepared for any competitive products.
Weigh the expected benefit
Then, the expected benefit from the use of enzymes must be carefully weighed against the cost of this nutritional intervention strategy. To this effect, it is best to assume that, on average, the use of a suitable enzyme will confer to the diet about 50 Kcal metabolizable energy per kilogramme complete feed.
Again, lacking any comparative research data, it is difficult to assert the exact level of energy contribution under specific conditions.
Finally, the savings in energy, expressed as the cost of animal fat or vegetable oil required to supply these 50 Kcal, should obviously be less than the cost of using enzymes!