The Efficacy of a Novel Microbial 6-phytase Expressed in Aspergillus Oryzae on the Performance and Phosphorus Utilization in Swine

Three studies were carried out to evaluate a novel microbial 6 phytase, expressed via the use of synthetic genes in Aspergillus oryzae in weaned piglets and also in growing pigs. In the first study, the enzyme was fed to piglets in three dietary treatments at 0, 4,000 and 40,000 FYT/kg feed to test its tolerance. In the second and third study the efficacy of the enzyme was tested at 0, 500, 1,000, 2,000 and 4,000 FYT/kg in piglets and at 0, 500, 1,000, 1,500, 1,750, 2,000 and 3,000 FYT/kg in growing-finishing pigs. Performance, haematological and blood biochemical parameters were determined in the tolerance study. The digestibility and excretion of phosphorus (P) and calcium (Ca) were measured in both the piglet and the grower studies. In addition, growth performance and blood P, Ca and alkaline phosphatase levels were measured in the piglet efficacy study. In the tolerance study the enzyme significantly improved the growth performance. At the very high level of the enzyme, animals did not show any clinical signs of health problems. In both efficacy trials the enzyme increased the utilisation and reduced faecal excretion of P and Ca in a dose dependent manner. Blood P, Ca and alkaline phosphatase concentrations were restored to their physiologic levels in the piglets receiving the phytase in comparison to non-supplemented diets. In conclusion, results suggest that the animals can tolerate the phytase and that the enzyme significantly increased P and Ca availability in piglets and pigs.