EFFECT OF PHYTASE SUPPLEMENTATION TO A WH EAT-BARLEY-SOYA DIET ON PRODUCTION PERFORMANCE AND APPARENT DIGESTIBILITY OF P, CA AND MG AT VARYING DIETARY P-LEVELS IN PIGLETS

In a 2factorial (2 x 4) experiment with 96 piglets (7 kg initial weigh t) microbial phytase was added to a wheat-barley-soya diet in levels o f 0 U/kg vs. 500 U/kg and dietary P was modified between deficient and excessive contents in levels of 0.36 %, 0.44 %, 0.52 % and 0.60 %, re spectively. Production performance and apparent digestibility of phosp horus, calcium and magnesium was recorded. Production performance incr eased with rising dietary P content up to P levels matching the requir ement (0.52 %). Phytase supplementation was without effect in the lowe st P level but increased production performance under marginal P suppl y (0.44 % P). Apparent digestibility of phosphorus was increased by ph ytase with maximal effects at marginal P supply (+10.0 percentage unit s). Ca digestibility showed a curvilinear response to increasing dieta ry P levels with a maximum at 0.52 % P (control) and 0.44 % P (phytase groups), respectively. The reaction pattern of Mg digestibility was o pposit to that of Ca. The values increased in tendency by 2.4 percenta ge units due to phytase supplementation.