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Journal of Environmental Quality Abstract - Surface Water Quality

Influence of Phytase on Water-Soluble Phosphorus in Poultry and Swine Manure


This article in JEQ

  1. Vol. 34 No. 2, p. 563-571
    Received: Mar 27, 2004

    * Corresponding author(s): wpowers@iastate.edu
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  1. C. Roselina Angela,
  2. Wendy J. Powers *b,
  3. Todd J. Applegatec,
  4. Nada M. Tamima and
  5. Mary C. Christmana
  1. a Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742
    b Department of Animal Science, Iowa State University, Ames, IA 50011
    c Department of Animal Science, Purdue University, West Lafayette, IN 47907


The effect of dietary non-phytin phosphorus (NPP) and phytase (PHY) concentration on total phosphorus (TP) and water-soluble phosphorus (WSP) excretion was determined. Diets tested in broiler experiments were: National Research Council nutrient requirements for non-phytin phosphorus (NRC), NRC + PHY, reduced non-phytin phosphorus (RED), and RED + PHY. Turkey and swine experiment diets included NRC, RED, and RED + PHY. For all experiments, except broiler Experiment 1, excreta were: (i) boiled, antibiotic added, then frozen; (ii) boiled, antibiotic added, incubated (37°C for 72 h), then frozen; and (iii) incubated, boiled, antibiotic added, then frozen. In Experiment 1, excreta were collected and frozen or incubated for 24 or 48 h. In broiler Experiment 1, WSP was not affected by phytase but increased with post-excretion incubation. In a broiler Experiment 2, reducing NPP resulted in reduced excreta TP and WSP (11.3 to 8.3 and 5.3 to 2.7 g kg−1). Feeding RED + PHY diets resulted in less TP and WSP (7.6 and 0.6 g kg−1) as compared with NRC + PHY (11.2 and 3.9 g kg−1, Experiment 3). Incubation resulted in increased WSP, irrespective of phytase addition such that WSP as a percent of TP was similar among treatments. Addition of antibiotics before incubation prevented the increase in WSP. Similar results were observed with turkey and swine. Therefore, when phytase is used properly (i.e., with a simultaneous reduction of NPP), WSP or WSP as a percent of TP are not affected. The increase in WSP as a percent of TP post-excretion is a function of excreta microbial activity and not dietary phytase addition.

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