EFFECT OF PHYTASE ON APPARENT DIGESTIBILI TY AND GROSS UTILIZATION OFFE, CU, ZN AND MN AT DIFFERENT LEVELS OF CALCIUM SUPPLY IN PIGLETS AND BROILERS

In a 2factorial experiment with piglets and broilers microbial phytase was added to the diet and Ca contents were modified. The phytase leve ls were 0 U/kg, 300 U/kg, 600 U/kg, 1000 U/kg (piglets) and 0 U/kg, 20 0 U/kg, 400 U/kg, 600 U/kg, 1000 u/kg (broilers), the Ca content 0.65 % vs. 0.81 % (piglets) and 0.62 % vs. 0.79 % (broilers). Dietary P con tents were kept constant at 0.46 % (piglets) and 0.59 % (broilers). Co ntents of Fe, Cu, Zn and Mn were 199 ppm, 136 ppm, 24 ppm and 74 ppm i n the piglet diet and 250 ppm, 17 ppm, 73 ppm and 80 ppm in the broile r diet. In the piglet trial the apparent digestibility increased curvi linearily with rising phytase levels up to 5.4 (Fe), 5.7 (Cu), 5.6 (Zn ) and 2.9 (Mn) percentage units. High dietary Ca contents changed appa rent digestibilities by -2.0 (Fe), +4.1 (Cu), +0.5 (Zn) and +2.9 (Mn) as compared to low Ca diets. In broilers rising phytase levels increas ed gross utilization in a curvilinear manner up to 5.1 (Fe), 4.5 (Cu), 8.4 (Zn) and 3.8 (Mn) percentage units. With high dietary Ca contents the gross utilization changed by -2.2 (Fe), +1.5 (Cu), -3.4 (Zn) and +1.4 (Mn) percentage units.