The purpose of this study was to evaluate the effects of including increasing levels of phytase enzyme in pig diets for growing pigs, using the mathematical model. Data from 20 crossbred male piglets, castrated and weighing 26.80 kg on average was used. The animals were housed in individual metabolic cages to collect feces and urine in a 17 day period. A randomized block experimental design containing five treatments and four repetitions was used. The experimental diet provided to piglets contained corn and soybean and was supplemented with five increasing levels of phytase enzyme (0, 250, 500, 750 and 1000 UF/kg), corresponding to 0.00 %, 0.01 %, 0.02 %, 0.03 % and 0.04 % respectively. The variables evaluated were: intake, excretion, output flow of P in the digestive tract, bloodstream, bones and soft tissues. The phytase enzyme did not affect the P intake (P>0.05 (F 10), the P excreted in urine (F02) and the output flow of P in the bones (F32 e F23) and soft tissue (F42 e F24) , however, there was a reduction in P excreted in feces (F01) of 8.92 %, 26.76 %, 22.53 % and 28.64 % to the levels 0, 250, 500, 750 e 1000UF/kg, respectively and showed a positive linear effect (P<0.08) for the endogenous P (F12) . Corn and soybean meal based diets can be used with 50% of P by dicalcium phosphate, adding 250UF/kg diet for growing pigs, and may cause a reduction of 27 % of P excretion in feces.
environmental pollution; nutrition; phosphorus; phytase enzyme; phytate; swine