A series of experiments were conducted with ducklings fed different inorganic phosphorus and phytase levels. Supplementing diets with phytase increased feed intake and growth rate of the ducklings over the 2-19 day experiment. Calcium and phosphorus retention and tibia ash were also increased with the phytase treatment. In one experiment, phytase improved dry matter digestibility and retention of nitrogen and phosphorus. Reductions of 8-10 percent in the phosphorus excreted were observed in experiments when the diets were supplemented with phytase. The researchers concluded that there were a number of benefits from adding phytase to duckling diets. Improved nutrient utilization and bird performance were observed, even though several of the diets appeared to be adequate in available phosphorus.

Farrell, D.J. and E.A. Martin. 1998. Strategies to improve the nutrient value of rice bran in poultry diets. III. The addition of inorganic phosphorus and a phytase to duck diets. British Poultry Sci. 39(5):601-611.