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ARS Home » Southeast Area » Raleigh, North Carolina » Soybean and Nitrogen Fixation Research » Research » Publications at this Location » Publication #160073
Title: REDUCING PHYTATE VERSUS ADDING PHYTASE TO REDUCE FECAL PHOSPHORUS IN POULTRY

Author
item BRAKE, JOHN - NC STATE UNIV
item MAGUIRE, RORY - NC STATE UNIV
item BURTON, JOSEPH
item KWANYUEN, PRACHUAB
item GERNAT, ABEL - NC STATE UNIV

Submitted to: American Oil Chemists' Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/20/2004
Publication Date: 5/9/2004
Citation: Brake, J.T., Maguire, R., Burton, J.W., Kwanyuen, P., Gernat, A. 2004. Reducing phytate versus adding phytase to reduce fecal phosphorus in poultry. American Oil Chemists' Society Meeting. p. 118.

Interpretive Summary:

Technical Abstract: Sustainability of the poultry industry is somewhat dependent upon development of strategies to minimize environmental impact. In areas with intensive animal production, the phosphorus (P) content of land-applied litter (manure plus bedding) may exceed local crop requirements to such an extent that local water quality may be threatened. The P consumed by poultry in feed may be quantified as total P (TP) of which much is bound to phytate (PP) and unavailable to the monogastric animal. The P available (avP) to the bird may be largely derived from organic P, non-phytate bound P (nPP), and the inorganic P (iP) typically added to animal feeds. The P in litter may be roughly characterized as TP and soluble P (solP). The solP in litter is of the utmost importance from an environmental perspective as increased solubility may increase losses in runoff from agricultural fields following litter application. This situation has led to new land application rules for poultry litter based upon P content but the additional land needed to meet these rules does not exist and the optimum approach is not clear, e.g. initial legislative actions in Maryland aimed at solP reduction required the addition of the microbial enzyme phytase to poultry feed. Unfortunately, the enzymatic value given to the phytase underestimated its activity with the net result being more solP being produced in litter. More recent studies using diets with and without phytase, where P was more appropriately adjusted, concluded that solP was dependent upon P concentration fed, but not on the added phytase. This is consistent with the fact that 50% of fecal P comes from soybean meal (SBM) in typical diets but this value decreases to only 20% if low PP SBM is used. There have also been conflicting data concerning runoff with dietary phytase either having no effect or increasing solP in runoff. Despite the great promise of feed additives such as the enzyme phytase and high P availability soybeans to decrease TP concentration in litter, there has not yet been a consensus as to how their use will affect solP in litter and litter-amended soils but it is clear that a reduction in P in feed ingredients such as SBM will be a very important tool.