Abstract :
Two experiments, a performance experiment and a mineral balance study, were conducted on grower–finisher pigs (42 to 101 kg live
weight) to investigate the effects of Peniophora lycii phytase enzyme and 25-hydroxyvitamin D3 (25-OHD3) on growth performance,
carcass characteristics, nutrient retention and excretion, and bone and blood parameters. The two experiments were designed as a
232 factorial (two levels of phytase and two levels of 25-OHD3). The four diets were T1, low-phosphorous diet; T2, T11phytase; T3,
T1125-OHD3 and T4, T11phytase125-OHD3 diet. In all, 25mg of 25-OHD3 was used to replace 1000IU of vitamin D3 in diets T3
and T4. Diets were pelleted (708C) and formulated to contain similar concentrations of energy (13.8 MJ DE/kg), lysine (9.5 g/kg) and
digestible phosphorus (P; 1.8 g/kg). Neither the inclusion of phytase nor 25-OHD3 in the diet had any effect on pig performance. There
was an interaction between phytase and 25-OHD3 on calcium (Ca) and P retention ( P,0.01) and on the apparent digestibility of ash
( P,0.01), P ( P,0.001) and Ca ( P,0.001). Pigs offered phytase diets only, had a higher retention of Ca and P and digestibility of
ash ( P,0.01), P ( P,0.001) and Ca ( P,0.01) compared with pigs offered unsupplemented diets. However, when the combination
of phytase and 25-OHD3 were offered, no effects were detected compared with 25-OHD3 diets only. Pigs fed phytase diets had higher
bone ash ( P,0.01), bone P ( P,0.01) and bone Ca ( P,0.05) concentrations compared with pigs offered non-phytase diets. In
conclusion, pigs offered phytase diets had a significantly increased bone ash, Ca and P than pigs offered unsupplemented phytase
diets. However, there was no advantage to offering a combination of phytase and 25-OHD3 on either bone strength or mineral status
compared to offering these feed additives separately.
Keywords :
phytase , Phosphorus , 25-hydroxyvitamin D3 , pigs
