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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #78893
Title: EFFECTIVENESS OF A NEW PHYTASE ON THE IN VITRO HYDROLYSIS OF PHYTATE- PHOSPHORUS AND RELEASE OF IRON AND ZINC IN FEEDS

Author
item HAN, Y - CORNELL UNIVERSITY
item STAHL, C - CORNELL UNIVERSITY
item House, William
item LEI, X - CORNELL UNIVERSITY

Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: We determined the effectiveness of a new phytase produced by a yeast expression system on the hydrolysis of phytate-phosphorus and the release of iron and zinc from commonly-used feeds. In experiment 1, samples of corn, soybean meal and wheat middlings were suspended in .2 M citrate buffer (pH 5.5) and incubated with phytase at either 0, 100, 250, 500 or 1000 units/kg for 4 h at 37oC. Supernatant of the hydrolysate was collected to measure inorganic phosphorus concentrations. Compared to controls, phytase released phytate-phosphorus from both corn and soybean meal (P<.01) but not from wheat middlings. The hydrolysis of phytate- phosphorus by phytase reached a plateau at 250 units/kg with corn and at 500 units/kg in soybean meal. In experiment 2, samples of soybean meal were mixed with citrate buffer and incubated with phytase at either 0, 500, 750, 1000 or 1,250 units/kg for 4 h at 37oC. Concentrations of iron and zinc in the supernatant of the hydrolysate were determined after phytate was removed. Phytase incubation resulted in an increase (P<.05) in the concentrations of free iron and zinc in the supernatant. Approximately 70% of phytate-bound iron or zinc was released from soybean meal at the highest phytase activity. In conclusion, phytase expressed in the yeast system effectively hydrolyzed phytate-phosphorus from corn and soybean meal and released phytate-bound iron and zinc from soybean meal.