1. Introduction
Environmental regulations have set strict limits on the
level of P to be discharged in swine effluents (Vats et al., 2005;
Selle and Ravindran, 2008). In addition, the inclusion of
excessive levels of inorganic P results in higher feed costs.
Because available P reserves are finite, even higher costs are
expected in the future (Cordell et al., 2009). Hence, there is a
need to develop nutritional strategies to use the concept of P
bioavailability, thus, we can provide only adequate P to satisfy
the animal's needs. Supplementing phytase is becoming
increasingly common as a method to improve the availability
of P in plant ingredients containing high levels of phytate P
(Selle and Ravindran, 2008).
Previous research has shown that substantial bone
formation occurs during the first 12 weeks of life, concurrent
with the period of extensive muscle formation and weight
Livestock Science 138 (2011) 152–158
⁎ Corresponding author. Tel.: +353 1 7167128; fax: +353 1 7161103.
E-mail address: john.vodoherty@ucd.ie (J.V. O'Doherty).
1871-1413/$ – see front matter © 2010 Elsevier B.V. All rights reserved.