Phytase Analysis in Animal Feed

Phytase is an enzyme that catalyses the breakdown of phytic acid (phytate), the primary storage form of phosphorus in plant-based feed ingredients such as grains and oilseeds.
Phytic acid binds phosphorus in a form that is largely unavailable to monogastric animals such as poultry and swine. Phytase hydrolyses this compound, releasing inorganic phosphorus that can be absorbed and utilised by the animal.
In animal nutrition, phytase is commonly added to feed to improve phosphorus availability and overall nutrient utilisation.

Phytase plays a critical role in improving feed efficiency and reducing nutrient losses.
In animal nutrition, phytase contributes to:
‣ Increased availability of phosphorus
‣ Improved digestibility of nutrients such as proteins and minerals
‣ Reduced need for inorganic phosphorus supplementation
‣ Lower phosphorus excretion and environmental impact
‣ Improved growth performance and feed efficiency
Because of these benefits, phytase is widely used in modern feed formulations.

Phytic acid is a naturally occurring compound found in plant seeds, grains, and legumes. It serves as a storage form of phosphorus in plants.
However, phytic acid has strong binding properties and can complex with minerals such as calcium, zinc, and iron, as well as proteins. This reduces the bioavailability of these nutrients in animal diets.
Phytase breaks down phytic acid stepwise, releasing phosphorus and reducing its anti-nutritional effects.

Phytase activity is typically expressed in FTU (phytase units). One FTU is defined as the amount of enzyme that releases 1 micromole of inorganic phosphate per minute from sodium phytate under specific conditions of pH and temperature.
Phytase activity in feed must be carefully controlled to ensure that the intended nutritional benefits are achieved.

Phytase activity can be affected by feed processing conditions, particularly heat during pelleting. High temperatures may reduce enzyme activity if the phytase is not sufficiently heat-stable.
As a result, phytase products are often designed to be thermostable or applied post-pelleting to maintain activity.
Factors affecting phytase performance include:
‣ Temperature
‣ Moisture
‣ pH conditions in the digestive tract
‣ Feed composition

Phytase activity is typically measured using enzymatic assays that quantify the release of inorganic phosphate from a phytate substrate under controlled conditions.
These methods are designed to:
‣ Measure enzyme activity accurately
‣ Confirm label claims in feed products
‣ Assess enzyme stability after processing
Results are reported in FTU per kilogram of feed or premix.

Phytase is widely used in poultry and swine feeds to improve nutrient utilisation and reduce feed costs.
By increasing phosphorus availability, phytase reduces the need for inorganic phosphate supplementation, which can be costly and environmentally impactful.
Phytase also contributes to improved overall nutrient digestibility by reducing the anti-nutritional effects of phytate.

Phytase testing is an important part of feed quality control. It ensures that enzyme activity meets formulation targets and remains stable after processing and storage.
Routine phytase analysis supports accurate feed formulation, regulatory compliance, and optimisation of animal performance.