Beitrag zur Bedeutung nativer und mikrobieller Phytase für die Phosphorverwertung beim Schwein

To study the relevance of native phytase for phosphorus digestibility and for the relation between P-digestibility and the effectiveness of supplements of microbial phytase balance experiments with 5 pigs (40 - 70 kg LW) was designed. Diets based on cereals and soyabean meal were fed, including four treatments with untreated and phytase inactivated cereals, accomplished by extrusion. Both diets were supplemented with the microbial phytase with a dose of 800 U/kg. Reduction of phytase activity decreased P-digestibility of the diets from 45 % to 18 %. Microbial phytase supplements increased P-digestibility in the untreated diet by 7 %-U to 52 % and in the diet with inactivated phytase from 18 % to 47 %. The results document the effects of native phytase activity on P-digestibility and show that the efficacy of supplements of microbial phytase depends basicly on the amount of native phytase activity and correspondingly on P-digestibility.