A critical review of methods used to determine phosphorus and digestible amino acid matrices when using phytase in poultry and pig diets

    Phytase is applied in animal feed based on its standard activity measured at pH 5.5, however the relative activity at pH 3 (e.g. stomach pH, the main site for the breakdown of phytate) varies among the commercial phytases, ranging from 56% (an E coli phytase) to 235% (Buttiauxella phytase). These diverse sources of phytases have varying capability for degrading phytate and, correspondingly, different P, digestible amino acid and metabolisable energy matrix values. In addition, the matrix values recommended by different phytase suppliers are not comparable, as different methodologies have been used to determine them. Phosphorus (P) and other matrix values can be determined by direct measurement of digestible P (dP) improvements by the addition of phytase above a negative control in large numbers of in vivo studies using increasing phytase doses. Alternatively, matrix values can be assessed by indirect measurement, using inorganic P (usually mono- or dicalcium sources) as a reference, typically based on tibia or metacarpal ash as a response parameter to estimate available P equivalence, either at a single or different phytase doses. When using the indirect measurement, the available P equivalence with increasing phytase doses may be calculated based on a log linear model. Although both methods are acceptable methodologies, direct measurement may under-estimate and indirect measurement may over-estimate matrix values, and a large number of in vivo studies give the best estimates of matrix values. Phytase efficacy can be influenced by phytase source, dose level, dietary composition (Ca level and Ca: P ratio). Phytase end users are encouraged to be aware of the methods used by suppliers to determine matrix values, before applying them in their feed formulations.
    Document information
    Product / service: Phytases
    Publication date: 23/01/2019
    Species: Poultry, Pig, Multi-species
    Authors: Dersjant-Li Y, Evans C, Greiner, R, Hruby M
    Doctype: Publications & Citations
    Publication / conference: Journal of Applied Animal Nutrition
    Regions and countries:
    Keywords: diets, phytase, phosphorous, amino acid, matrix
    Production challenge(s):
    Diets: All diets
    Resource ref:
    Recently viewed

    Your single source for articles, publications & citations, product information and more...

    Much of the content on this site is freely available. Register now to receive email notifications based on your content preferences. Partners may also request access to the restricted area of the Knowledge Centre for technical product information such as trial data, reports and much more.

    Register for content notifications

    DuPont's Nutrition & Biosciences and IFF are coming together

    This isn't about forming another industry giant. This is about merging curiosity and capability to create unique, leading-edge solutions at the intersection of science and creativity.

    To learn more about IFF and the merger, go to www.iff.com.