The Use of Enzymes in Poultry Nutrition: An Opportunity for Feed Enzymes

The goal of animal nutrition is to increase the digestibility of nutrients (such as minerals) for example, by the use of diverse feed treatment techniques or the application of exogenous enzymes. For example, phosphorus (P) is primarily stored in the form of phytates in plant seeds, thus being poorly available for monogastric livestock, such as poultry. As phytate is a polyanionic molecule, it has the capacity to chelate positively charged cations, especially calcium (Ca), iron (Fe), and zinc (Zn). Furthermore, it probably compromises the utilization of other dietary nutrients, including protein, starch, and lipids. Reduced efficiency of utilization implies both higher levels of supplementation and increased discharge of the undigested nutrients to the environment. The enzyme phytase catalyzes the stepwise hydrolysis of phytate. Moreover, poultry are often fed with cereal grains, which provide them with the necessary energy. However, these grains contain anti-nutritional factors such as non-starch polysaccharides (NSP), which birds cannot digest due to the lack of vital enzymes in their intestines. This may also lead to an increase in intestinal viscosity, slowing down the migration and absorption of nutrients and causing competition within gut microbiota for digestible nutrients, which in turn affects the overall health of the birds and may increase production costs. Additionally, carbohydrases supplementation plays an important role in poultry diets with high NSP contents. This chapter will discuss the main exogenous enzymes used in poultry to improve feed digestibility and utilization and enhance growth performance.