A reduction of phosphorus (P) levels in feed increases the importance of having sure and sufficiently high digestibility coefficients of P. Phytase is, therefore, generally used in feed. However, high digestible mineral P sources are still important for the delivery of sufficient levels of digestible P to the animal. 

An adequate phosphorus supply is needed for health and optimal growth. P has an important function in a large number of biological processes. A few of its numerous functions: it’s necessary for bone (and teeth) growth, it is a key element in energy metabolism, plays a role in acid-base buffering in blood, and is a component of tissue cell walls.

In plant materials, about 65% of the phosphate is present in the form of phytate. Monogastric animals lack the enzyme necessary to degrade the phytate, resulting in a low P-digestibility of feed ingredients of plant origin. Addition of highly digestible inorganic phosphates to the diets is needed to fulfil the animal’s P requirement. High total P levels in the diets, result in high P excretion in the manure, leading to environmental pollution. To increase P digestibility in feed and reduce P excretion in the manure, phytases were developed. Phytase addition to the diet leads to an increased digestibility of phytate-P. Due to the anti-nutritional properties of phytate, mainly complexing with protein and free amino acids, degradation of phytate also improves protein digestibility. Therefore, matrix values of phytases are used to predict the total effects of phytase addition on nutrient digestibility and thus performance of animals.

Makkink (2011) described a Dutch experiment in which two phytases were compared. Phyzyme XP, which is an E-Coli 6-phytase produced by a yeast, was compared with a competitor phytase and monocalciumphosphate as a positive contro