Nutritional and metabolic responses of pigs fed diets supplemented with microbial and cereal phytase was determined in studies re ported in the Journal of Animal Science. Forty-eight crossbred pigs were allocated to four dietary treatments (a low-phosphorus, corn- soybean meal basal diet; the basal diet plus 1,000 units/kg microbial phytase; the basal diet supplemented with cereal phytase; or th e basal diet supplemented with inorganic phosphorus). Growth performance; phosphorus, calcium and nitrogen balance; metatarsal and metacarpal bone strength; serum concentrations of phosphorus, calcium and 1,25-dihydroxycholecalciferol; and serum alkaline p hosphatase activity were measured. The pigs fed the basal diet supplemented with microbial phytase and pigs fed the basal diet sup plemented with inorganic phosphorus showed almost identical response in all variables. Improvements in apparent digestibility of diet ary phosphorus and nitrogen reduced fecal excretion in the phytase treatments compared to pigs fed supplemental inorganic phospho rus. The researchers concluded that it is physiologically feasible, and environmentally advantageous, to replace supplemental inorga nic phosphorus ingredients with microbial or cereal phytase in corn-soybean meal diets fed during the entire growing-finishing period.

Han, Y.M., and co-workers. 1997. Supplemental phytases of microbial and cereal sources improves dietary phytate phosphoru s utilization by pigs from weaning through finishing. J. Animal Sci. 75(4):1017-1025.