Phytase, an ally in animal feed under correct use

Phytase was introduced in the animal feed industry almost a decade ago. About 60 to 80% of the phosphorus (P) from seeds of cereals and legumes are not bioavailable to many monogastric because they are in the form of phytate. Phytate is an antinutritional factor that has a negative impact on animal performance by interacting with proteins and minerals of the diet (Kumar et al., 2019). Therefore, in diets with high content of ingredients of plant origin, nutritionists turn to phytases, enzymes capable of releasing complex P. Phytase is a type of phosphatase enzyme that specifically acts on phytate, breaking it down to release phosphorus in an absorbable form for animals. Phosphorus (P) is a bio–critical element in nutrition and Earth’s P is being depleted at an alarming rate, though P can be recovered and reused. Phosphorus is important for bone and tissue growth making it the 3rd most expensive component in poultry after protein and energy. It is the second most abundant mineral in the human body surpassed only by Calcium. Therefore it can be stated that phosphorus is one of life’s bottlenecks.

Phytate is the principal storage form of phosphorus in plants. It is primarily stored as phytic acids in feedstock, which is mostly inaccessible for swine and poultry. Phytate enzymatic hydrolysis takes place with the presence of phytase. There are four sources from which phytase may be obtained. It can be bio-generated as microbial phytase, plant phytase, generated by the small intestinal mucosa, and gut-associated microfloral phytase. However the phytase activity of monogastric animals is negligible compared to that of ruminants. Phytase can reduce the antinutritional effect of phytate and improve the digestibility of phosphorous (P), calcium, amino acids and energy, as well as reduce the negative impact of inorganic P excretion to the environment. The benefits of using phytase in animal feed are many and they are well recognized.

Microbial phytase is the most commonly used exogenous enzyme for monogastric animals’ feed. It can be produced using organisms including fungi, yeasts, and bacteria. Using submerged fermentation(SmF) as well as solid-state fermentation (SSF). Submerged fermentation (SmF) has largely been employed as a production technology for commercial phytases, but SSF has recently obtained more attention for large scale phytase production. The purity and quality depend on the type of strain, culture conditions, and the method of phytase production. SmF phytase production is commonly used due to its relatively straightforward operation, upscaling flexibility, and less variability.

Depending on their origin, phytases may have different degrees of thermostability, so high temperatures of extrusion during food processing can affect the residual activity of the enzyme. This information becomes a tool to consider when establishing the act final minimum activity expected from these enzymes in functional food. The characterization of phytases, prior to their use in extruded feed, is key to: estimate the degree of enzymatic dephosphorylation of phytate in the digestive system; define the absolute activity which will be required depending on the product used; and estimate the cost of using the enzyme additive in formula.

Feed enzymes (protease, xylanase, phytase, amylase, cellulase, lipase, b-glucanase) are the newest segment of the $5 billion animal nutrition market, which is growing fast. In the past decade, the global market for phytase has gradually increased over other feed enzymes especially due to the increasing demand for poultry and swine feed manufacturing. Currently, the phytase market will foresee a significant gain over 6% by 2025 with more than $1 billion market share. With the increasing demand for biofuel crops, most of the limited natural phosphates are used towards fertilizer production. This generates greater demand for phytase in feed utilization considering its added advantage in nutrition over inorganic P usage. Nontheless its correct use and applications remain a subject of great discussion.