Think Beyond The Obvious: Exogenous Enzymes as Part of Strategy to Reduce Use of Antibiotics in Poultry Production

Poultry production is entering an era of antibiotic reduction or production without antibiotics. In such a situation, nutrition plays a crucial role and enzymes can help by reducing feed costs; however, enzymes are more than a nutrient matrix. As science of application of enzymes in feed and their effects on digestion kinetics in the gut evolve, it is becoming increasingly clear how enzymes influence the conditions in the gastrointestinal tract (GIT). Dietary challenges posed by fibre content in the diet (especially soluble arabinoxylans) include increased digesta viscosity and transit time, leading to lower nutrient digestibility and absorption. This promotes the proliferation of microflora in the small intestine, competition for available nutrients, and overgrowth of pathogenic bacteria. Additionally, microbial activity promotes reduction in nutrient digestibility, especially of fat, through deconjugation of bile salts. These events can be reversed by the addition of exogenous xylanase; by degrading soluble arabinoxylans the enzyme reduces viscosity, limiting the proliferation of microflora in the small intestine. Furthermore, the degradation of arabinoxylan, by xylanase, in the upper gastrointestinal tract, produces xylo-oligosaccharides which have a prebiotic effect on the beneficial microbial population in the lower GIT. A reduction in growth of pathogenic bacteria in the digesta by the application of xylanase in the diet has been shown in several studies. The beneficial shift in microbial activity in the upper and lower GIT positively impacts gut health, reducing the risk of disease, and consequently the need for antimicrobial treatments. As enzymes work on crucial factors that directly influence gut environment, a positive effect of a combination with feed additives that have direct effects on microbial community and host immune system -such as probiotics and phytomolecules- can be hypothesized.

Therefore it is also being studied in more depth how enzymes help to enhance the performance of other gut health feed additives. The holistic effects of xylanase on the digestion process in the small intestine makes it a fundamental part of the diet, which should also be considered within an overall antibiotic reduction strategy.