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PHYTASE FACT SHEET
Phytase - An enzyme that breaks down the undigestable phytic acid (phytate) portion
in grains and oil seeds; thereby, releasing digestible phosphorus and calcium for the
pig.
Studies have indicated that the inclusion of phytase in swine diets has increased the
availability of phytate phosphorus in a corn-soy diet from approximately 15% to
45%.
Phytase activity is expressed as "phytase units" or "FTU" per unit of feed (i.e. FTU/kg or FTU/lb.) FTU is a worldwide standard unit.
One phytase unit is the activity of phytase that generates 1 micromole of inorganic
phosphorus per minute from an excess of sodium phytate at pH 5.5 and 37 degrees
Celsius.
Manufacturers of Phytase:
BASF - (Natuphos 600a /dry, Natuphos 5000a /dry & liquid, and Natuphos 1000a
/dry -{a = FTU/gram})
Alltech, Inc. - (Allzyme Phytase / dry or liquid)
Roche - ( Ronozyme P / dry or liquid)
The inclusion rate for phytase in all stages of swine diets is 115 to 227 FTU/lb. For a
corn-soy diet without supplemental fat, the inclusion rate would be approximately
115 to 150 FTU/lb. A diet with a significant amount of supplemental fat should be
increased to approximately 150 to 227 FTU/lb. Use a higher inclusion rate in the
initial diet phase and decrease the rate over the duration of the phases. At these
inclusion rates, the total phosphorus level can be reduced approximately 10%. In
addition, calcium should also be reduced approximately 10% to maintain the proper
calcium:phosphorus ratio.
Feeding of phytase will increase trace mineral absorption and it also has the potential
to increase amino acid digestibility.
With the recommended phytase inclusion level, the phytase addition will not
increase the cost of the diet.
Phytase addition to swine diets will reduce the amount of phosphorus in the manure.
The amount of reduction will depend on diet type, inclusion rate of phytase, degree of
replacement of inorganic phosphorus, and the dietary phosphorus relative to the
animal needs.
As a general rule, the amount of phosphorus reduction in the diet will cause a similar
phosphorus reduction in the manure.
With the reduction of phosphorus in the manure, less land would be required for
manure application while still maintaining the appropriate dietary phosphorus
requirement of the pig.
Phytase, a high molecular weight protein, is sensitive to the presence of moisture and
high temperature. Therefore, shelf life of the product must be considered and proper
storage of the product needs to be maintained.
Phytase products should be stored in a dark, cool, and dry area. Check label of the
product for proper storage and length of shelf life. If phytase is contained within a
commercial supplement or pre-mix product, follow the recommended storage method
and review the label for phytase stability

Because of the heat and moisture associated with pelleting, enzymes are destroyed;
therefore, the phytase stability in pelleted diets should be considered. Consequently,
when phytase is added to a pelleted diet, spraying a liquid phytase product onto the
cooled pellet will allow stability of the phytase.
 Example diets with and without phytase inclusion for mixed sex pigs weighing 130
to 180 lbs.
Ingredient*
No Phytase (lbs.)
With Phytase (lbs.) With Phytase (lbs.)
Corn, yellow
1625.35
1640.62
1645
Soybean Meal, 48%
330
322
322
Limestone (Calcium Carbonate)
18.3
19
19.3
Dicalcium Phosphate
15.1
7
2.25
Salt/Vitamin/Trace Mineral
11.25
11.25
11.25
Phytase - BASF Natuphos 5000**
0.00
0.13
0.20
Total lbs.
2000
2000
2000
----------------------------------------- ------------------------- ------------------------- ------------------------Lysine, %
0.71
0.71
0.71
Crude Protein, %
14.3
14.4
14.5
Metabolizable energy, kcal/lb.
1502
1515
1523
Calcium, %
0.58
0.58
0.58
Total Phosphorus, %
0.47
0.40
0.35
Available phosphorus, %
0.20
0.20
0.20
Phytase - FTU/lb.
0.00
150
227
Cost of the diet
$112.87
$112.61
$112.65
*Ingredient Costs: Corn = $2.00/bu., Soybean Meal = $190.00/ton, Dicalcium Phosphate
= $280.00/ton, Phytase = $8.00/lb.
**The phytase product is for example only, not necessarily a recommendation.

The addition of (0.13 lbs.) phytase at the inclusion level of 150 FTU/lb. will replace
8.1 lbs. of dicalcium phosphate. With the maximum addition of (0.20 lbs.) phytase at
the inclusion level of 227 FTU/lb., a replacement of 12.85 lbs. of dicalcium
phosphate can be achieved.
Prepared by Larry K. McMullen, Iowa State University Extension Swine Field Specialist
and reviewed by Dr. Palmer Holden, Iowa State University Swine Specialist.
(11-27-01)
. . . and justice for all
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs
and activities on the basis of race, color, national origin, gender, religion, age,
disability, political beliefs, sexual orientation, and marital or family status. (Not all
prohibited bases apply to all programs.) Many materials can be made available in
alternative formats for ADA clients. To file a complaint of discrimination, write USDA,
Office of Civil Rights, Room 326-W, Whitten Building, 14th and Independence Avenue, SW,
Washington, DC 20250-9410 or call 202-720-5964. Issued in furtherance of Cooperative
Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department
of Agriculture. Stanley R. Johnson, director, Cooperative Extension Service, Iowa State
University of Science and Technology, Ames, Iowa.