Pretreatment of SBM with phytase increased P retention in salmon (Cain and Garling, 1995; Ramseyer et al., 1999) and Nile tilapia (Riche et al., 2001). However, Riche et al., 2001 reported that the pretreatment of SBM with phytase had no effect on the ADC of CP and decreased the ADC of lysine and methionine in diets fed to Nile tilapia.