Exogenous enzymes: a tool for maintaining intestinal health

Practical approach to the benefits of using exogenous enzymes

The actions of enzymes on anti-nutritional factors present in diets, such as phytate and non-starchy polysaccharides and on the activity of endogenous enzymes, increasing the availability of nutrients (calcium, phosphorus and amino acids) and energy are frequently mentioned (Alabi et al., 2019;  Bedford & Cowieson, 2020) and are reflected in the reduction of costs.

However, this text makes a practical approach to the benefits, in addition to the economic, emphasizing the mechanisms of action of enzymes in the maintenance of intestinal health of birds.

Non-starch polysaccharides

Non-starch polysaccharides, in addition to interfering with the digestion of other nutrients, can favor the growth of undesirable microorganisms, triggering inflammatory responses through intestinal receptors (Kogut et al. , 2018;  Dal Pont et al. , 2020). [register]

Proteins

In a similar manner, when proteins remain undigested, these can undergo fermentation which results in the production of toxic metabolites for the animal’s organism (Windey, 2012). As well as altering the homeostasis of microbiota.

Mode of action of enzymes

Recent research addresses different ways in which exogenous enzymes can benefit gastrointestinal tract physiology in animals. Such influence depends on factors like:

• Enzyme type
• Diet (substrate)
• The age of animals

Primary action

The primary action of enzymes on anti-nutritional factors increases nutrient digestibility ,as well as reducing the previously mentioned impacts. Resulting in intestinal microbiota with a differential composition and metabolic functions.

Substrate modifications reduce the colonization of pathogenic microorganisms through competitive exclusion. In addition, products resulting from the hydrolytic actions of enzymes can promote gut health.

Xylanase

Xylooligosaccharides obtained from xylanase hydrolysis of arabinoxylans can be used by beneficial bacteria as substrate. This results in prebiotic functions for the body (Craig et al., 2020).

Protease

A greater amino acid availability due to the the action of protease can favor processes like: energy generation by enterocytes, cells responsible for the absorption of nutrients, as well as the production of mucin which acts as a protective physical barrier(Cowieson & Roos, 2014).

Beneficial microbiota

The establishment of a beneficial microbiota is fundamental due to its influence on various metabolic processes, including:

• Nutrient absorption
• Immune system modulation
• Pathogen control

It has been reported that enzyme supplementation can influence the composition of intestinal microbiota. Liu et al.  (2017) observed that the inclusion of a multienzyme complex increased:

+The ileal content of Lactobacillus and Bifidobacteria

and reduced:

-The content of Clostridium perfringens, the main cause of necrotic enteritis in chickens;

-Intestinal lesions derived from the presence of this bacteria.

Bacteriocins

Complementing the competitive exclusion action, enzyme supplementation can increase the number of bacteria of the genus Enterococcus and Lactobacillus (Borda-Molina et al., 2019). The bacteria belonging to these genera are capable of producing substances known as bacteriocins. These act agaisnt pathogenic microorganisms such as protozoan species belonging to the genus Eimeria. The latter is responsible for avian coccidiosis, which causes the greatest economic impacts on poultry at a global scale.

• The dynamic balance of intestinal microbiota is still not fully understood. However, evidence indicates that diversity of intestinal microbiota is closely related to the productive performance of birds.

In an experiment carried out by the Poultry Research Group of the State University of Western Paraná – Unioeste – (article in the process of publication) it was observed that performance restoration was only achieved when a combination of amylase, xylanase and protease enzymes was added to the diets of birds fed with nutritional restrictions (-100 kcal / kg of metabolizable energy), during the 1 to 21 days period.

Simultaneous inclusion of these three enzymes balanced the cecal microbiota of birds under a nutritionally restricted regime for the control group.  Meeting their nutritional requirements in terms of presence/absence and abundance of microorganisms, as well as their predicted metabolic functions.

These results demonstrate that microbiota modulation is a feasible mechanism through which exogenous enzyme supplementation can improve bird performance.

Analytical method

Nutrient diversion towards the activation of immune responses directly influences animal productive rates.

1) For example, Leung et al.  (2019) observed that when birds were challenged by Eimeria acervulina and Eimeria maxima at 10 days of age:

– The energy allocated to weight gain at 35 days of age, known as caloric efficiency, was reduced by 15.5% .

– This energy was used to activate the immune response and repair intestinal epithelium damage.

2) Jiang et al. (2018) observed a reduction in gene expression of the pro-inflammatory cytokine IL-1β in the gut of birds fed diets containing high doses of phytase.

Considering that this protein influences the activity and synthesis of immune cells, this result shows that the inclusion of this enzyme contributed to reducing intestinal inflammatory processes.

Conclusion

• Good intestinal health in birds, allows the gastrointestinal tract to efficiently perform digestion and absorption processes which is a key focus point for poultry production.
• The previously mentioned evidence regarding exogenous enzymes and their actions within the animal organism, although not completely understood, demonstrate great potential. Suggesting that this type of additive should be considered as part of a strategy to maintain intestinal health in poultry with the  purpose of optimizing bird performance.

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