What is phytase?
Phytase is a phosphatase enzyme that removes phosphate groups step by step from phytate (myo-inositol hexakisphosphate). In plant seeds, a large part of the phosphorus is stored as phytate, which monogastric animals such as pigs and poultry can digest only poorly because they lack sufficient phytase activity in the gut.
Feed phytases are produced by fermentation using selected microorganisms. They are classed as 3-phytases or 6-phytases according to the position on the inositol ring where they start removing phosphate; many modern feed phytases are bacterial 6-phytases, while earlier products were mostly fungal 3-phytases.
What does it do in animal feed?
- Phosphorus release: makes phytate-bound phosphorus available to the animal, so less dicalcium or monocalcium phosphate needs to be added.
- Environment: lower inorganic phosphate use and better phosphorus digestibility reduce the phosphorus excreted in manure.
- Other nutrients: phytate also binds calcium, zinc, iron and other minerals and can reduce protein and energy digestibility; breaking it down can improve the availability of these nutrients.
- Higher doses: some nutritionists use phytase above the level needed for phosphorus release to break phytate down further and reduce its anti-nutritional effects, an approach often called superdosing.
- Species: used mainly in poultry, pig and aquaculture feeds; ruminants usually need no supplementation because rumen microbes produce phytase.
What does FTU mean?
Phytase activity is expressed in FTU (also written FYT or U, depending on the supplier). One FTU is generally defined as the amount of enzyme that releases 1 micromole of inorganic phosphate per minute from sodium phytate at pH 5.5 and 37 °C under the specified assay conditions.
Because different phytases differ in pH optimum, speed and resistance to digestive proteases, the same number of FTU from two products does not necessarily give the same phosphorus release in the animal. Formulation should therefore use the matrix values recommended for the specific product.
How is phytase use assessed?
The nutritionist decides the phytase activity per tonne of feed and assigns matrix values, the amounts of available phosphorus, calcium and sometimes amino acids and energy credited to the enzyme. These depend on the product, the dose, the phytate content of the raw materials, the calcium level of the diet and the species.
High dietary calcium and limestone particle size can reduce phytase efficacy, so calcium and phosphorus are balanced together. Local regulations and the product label prevail for authorised species and minimum recommended doses.
Quality criteria and stability
- Guaranteed activity (FTU/g) at the end of shelf life, confirmed by the certificate of analysis.
- Heat stability: phytase is a protein and can lose activity during conditioning and pelleting; coated or intrinsically thermostable products, or liquid post-pellet application, are used at high temperatures.
- Storage stability: activity can decline over time, especially in warm, humid conditions; storage in a cool, dry place is important.
- Premix compatibility: contact with trace minerals, choline chloride and moisture in concentrated premixes can reduce enzyme activity, so storage time and premix composition are taken into account.
- Lot traceability and documented activity analysis.
CTF Premix and phytase
Phytase is not part of CTF Premix's standard product range, but it can be evaluated for inclusion in custom premixes on request. Our technical team considers the enzyme form, its stability alongside trace minerals and other components, and the planned storage time. Custom premixes are produced at our Ankara facility under ISO 9001:2015 and GMP with lot traceability.
This page is for general information. Inclusion rates and product choice should be decided with a nutritionist, taking into account the species, the feed formulation and the applicable regulations.