In a recent study at the University of Tasmania – Australia, it was clearly shown that pretreatment of soya protein (HP 300) with phytase gave better results than adding same amounts of phytase to the feed. HP 300 provided most of the protein in a low fishmeal (4.5%) diet.
Four different levels of phytase were added to the feed to check the effect of phytase on a soya based diet. Next to these groups three groups had feed in which the HP 300 was pretreated with phytase to give the same level of phytase in the feed.
Daily gain was highest in the pretreated HP 300 groups. Already the lowest dosage of phytase in the pretreated groups gave similar results as the highest levels in the groups where phytase was added directly to the feed. There were significant differences in P, Mg and Zn digestion between treatments.
One should bear in mind that pretreatment with phytase in HP 340 is under more optimal conditions and during a longer time than in the pretreatment in this trial. Results with HP 340 can be expected to be superior to the already good results obtained in this trial.
Read the article "Low fishmeal diet for Atlantic salmon, Salmo salar L., using soy protein concentrate treated with graded levels of phytase" here:
