Why Use Enzymes?

Recently, many carbohydrase or non starch polysaccharide-degrading (NSP) enzymes have become available commercially for use in poultry rations. Over 50% of poultry feed now contains supplemental NSP enzymes. NSP enzymes have clearly reached the “tipping point” of acceptability.

These products exist in several forms:

• Pure enzyme products which exhibit only one specific enzyme activity
• Blends of pure enzymes commonly referred to as “cocktails”
• Multi-enzymes (i.e., enzyme products produced from a single organism which expresses multiple enzyme activities)

Monogastric animals, such as poultry, possess endogenous enzymes which aid in the breakdown of different nutrients for digestion and absorption. For instance, poultry possesses protease which helps to break down protein, lipase which helps to digest fat, and amylase which helps to digest starch.

However, monogastrics have no endogenous enzymes capable of digesting non-starch polysaccharides. NSPs are complex carbohydrate structures which make up part of the cell walls of cereal grains and oilseeds. The two tables below show the amount of NSPs in various grains and oilseeds.

Bach-Knudsen, Knud Erik, 1997. Carbohydrate and lignin content of plant materials used in animal feeding. Anim. Feed Sci. Tech. 67: 319 - 338.

NSPs exert negative effects on digestion beyond their inability to be digested. NSPs exist in both soluble and insoluble forms. The soluble NSPs negatively impact digestion by forming viscous solutions in the gut, which can also result in issues such as wet droppings. The insoluble NSPs are thought to impede digestion by simply creating physical barriers which limit the access of endogenous enzymes to carbohydrates, fats and proteins.

As monogastrics possess no endogenous enzymes for NSP digestion, they must be provided in the diet. Feeding carbohydrase enzymes allows for improvements in digestibility, allowing poultry to utilize more of the energy and amino acids present in grains and oilseeds.

I will be writing a series of emails on various carbohydrase enzyme activities and why they are needed. In the next email, I’ll examine xylanases and how they work to break down a portion of the NSP found in grains like corn.