Phytases entered commercial use in the early 1990s and are now widely included in monogastric diets. However, phosphorus (P) replacement values determined by controlled trials are not always replicated in the field, and feed manufacturers have becomewary of recommendations, often reducing the P matrix value applied to the phytase.The phytase matrix is the nutrient savings made on the inclusion of the enzyme in the diet and is responsible for the feed cost savings over and above the cost of the enzyme.With rising feed costs, decisions made on the phytase P matrix and the P requirements of the animal are now under intense scrutiny. Safety margins in dietary P are under pressure, challenging the matrices of all phytases. Feed producers should consider how matrices are derived, taking into account safety margins, to evaluate product efficacy.
展开▼
