Feed formulation using phytase in laying hen diets

Lohmann LSL-Lite and Classic Brown laying pullets were reared and caged at the Agassiz Research Centre following recommendations of the management guides. At 30 wk of age, these hens were fed 1 of 5 diets per strain following the Lohmann nutrient recommendations. In addition to a control treatment, diets were formulated to contain 300 or 600 U/kg of phytase, with or without enzyme inclusion, where the phytase was assumed to cause the release of P, Ca, energy, and protein. Diets were changed at 45 wk to follow a phase-feeding program, but treatments remained the same. These dietary changes did not result in major changes in measures associated with P deficiency, likely because the management guides suggest P levels that largely exceed the requirements of the birds. Rather than adding high levels of inorganic P to layer feeds, the safety margin currently included in recommended dietary specifications could be provided by the addition of phytase. This would reduce the negative environmental effects of intensive poultry production that are associated with P excretion.