There are many factors that affect the effectiveness and results of enzyme feed additives. The most important of these is enzyme stability, which means that enzymes must maintain their activity levels throughout the processing and digestion of animal feed.
Inherent stability properties are encoded by the molecular structure and by the amino acid sequence that determines the structure and biological sequence.
The enzyme structure must be flexible and rigid. Flexibility is very important because the degree of enzyme stability is determined by its rigidity and brittleness.
Enzyme stability during feed processing
Feed processing exposes enzymes to very high temperatures that can cause denaturation (loss of activity). Choosing an enzyme that is thermostable (meaning that it naturally withstands high temperatures) is one of the best ways to ensure that the enzyme is at its full energy level during the feeding process to the animal.
Enzyme stability during digestion
When a chicken eats a feed containing a feed enzyme additive, the enzyme must be able to break down the target substrate in a short time. Enzymes maintain their stability by resisting a wide range of pH and proteolysis by endogenous enzymes.
The chicken digestive tract is a harsh environment that limits the ability of an enzyme to catalyze compared to catalysis in vitro.
The enzyme activity levels quoted by manufacturers are usually based on in vitro conditions, however, conditions in the body are quite different and require approximately 4.5 hours from ingestion to elimination for digestion, so enzymes must exert their effect within a short time frame.
Enzymes vary in the optimal pH range under which they can act to break down materials.
Depending on the feeding program, the retention time of feed in the crop and gizzard may be very short. Therefore, an enzyme with a wide pH range has more capabilities than an enzyme with a narrow pH range and can perform more activities.
For example, some enzymes have an optimal pH range between 4 and 6, which will not indicate that they will function in the gizzard and proventriculus.
Enzymes with a pH range between 3 and 7 can operate in more areas of the digestive tract. Thus, the enzymatic effect is compensated by an enzyme that can operate in a wide pH range.
Another challenge to enzyme stability is the presence of proteolytic digestive enzymes; such as pepsin and trypsin in the digestive tract of animals.
In this endogenous digestion, enzymes have the ability to inactivate exogenous enzymes or limit their activity. Therefore, stable enzymes can resist proteolytic degradation.
Conclusion
Enzyme feed additives are useful for optimizing nutritional and enteral benefits and need to be considered for the stability of any product.
And this can be done by testing the enzymes to challenge their ability to survive at different Ph.
The proteolytic enzymes and their duration of activity have been selected with desirable characteristics and must be tested in vivo to confirm it and the mentioned characteristics must be fully investigated.
Source:
How Enzyme Stability Impacts Efficacy
( https://en.engormix.com/pig-industry/enzymes-swine-nutrition/how-enzyme-stability-impacts_a40653/)
