THE EFFECT OF MICROBIAL PHYTASE IN FEED MIX FOR EARLY WEANING ON PHOSPHORUS AND CALCIUM DIGESTIBILITY AND UTILIZATION IN PIGLETS

A phytase containing enzymic preparation was used in metabolism trials ; it was produced in a pilot plant of the institute of Microbiology in the Academy of Sciences of the Czech Republic in Praha-Krc, using rec ently isolated strain 921 of Aspergillus niger (phytase CZ). Phytase a ctivity of this preparation was determined to be 490 PU/g. The phytase containing enzymic preparation was applied at concentrations of 0, 50 , 100, 150 g per 100 kg in the first metabolism trial on piglets to de termine its most efficient concentration in feed mix for early weaning of piglets without dicalcium phosphate (DiCaP). The calculated coeffi cient of P digestibility was highest in the group of piglets receiving diet (1a(2)) containing 100 g of phytase per 100 kg feed. An increase against the control 1a(0) was 7.3%. Daily P retention was also highes t in the group of piglets 1a(2), corresponding to a difference of 6.8% in comparison with the control group of piglets. Similarly like in ph osphorus, the coefficient of Ca digestibility had the highest value in the group of piglets receiving diet 1a(2) 83.9%, which is by 3.8% mor e than in the control. Daily Ca retention was also highest in the pigl et group 1a(2), by 16.3% in comparison with the control group of pigle ts. P and Ca outputs in excrements were decreasing proportionately wit h increasing phytase concentrations. The effectiveness of optimum conc entrations of phytase containing enzymic preparation was studied in th e second metabolism trial on piglets using different DiCaP contents in feed mix for early weaning of piglets. The coefficient of P digestibi lity ranged within the boundaries of natural variability in all groups of piglets. The highest coefficient of P digestibility 69.2% was calc ulated for the experimental group of piglets receiving a diet with 75% DiCaP (2a(1)), which is by 10.8% more than in the control group, in w hich the piglets received a diet with 100% DiCaP. Daily P retention wa s highest in the group of piglets on a diet for early weaning of pigle ts containing phytase and 25% DiCaP (2a(3)), which was a difference of 13.8% against the control group of piglets. Reduction in the content of inorganic P in phytase containing feed mixes resulted in a signific ant decrease in P output in urine and excrements. Referring to the exp erimental results, DiCaP content in feed mix for early weaning of pigl ets should be decreased if the effective phytase containing enzymic pr eparation is used.