Comparative evaluation of two phytase preparations in young turkeys fed a wheat-based diet

A 4-week growth and balance experiment involving 240 day-old male turkeys ( strain BUT T9) was conducted in order to compare the effectiveness of two d ifferent microbial phytase sources added to a wheat-based starter diet: A 3 -phytase derived from Aspergillus niger (phytase 1) and a 6-phytase derived from Peniophora lycii (phytase 2) were supplied at two dietary levels. Sev en dietary treatments were compared: - a low-P diet containing 0.20% nP; - two positive control diets containing 0.25% and 0.30% nP, - four- 0.2% nP d iets supplemented with phytase I or 2 at levels of 250 and 500 U/kg. Body w eight, feed intake and feed conversion ratio were monitored as performance parameters. The phosphorus level in excreta and apparent P utilisation were determined as criteria of P availability and intestinal absorption. Bone s tatus of birds was assessed by measuring the percentage of tibia ash at the end of experiment. Phytase added at 250 and 500 U/kg feed resulted in a li near increase in live weight and an improvement (NS) in feed conversion in comparison to the negative control. Phytase addition also significantly inc reased the apparent P Utilisation, reduced P concentration in excreta and i ncreased tibia ash percentage (P < 0.01). No statistically significant diff erence was observed between the 3- and 6-microbial phytases.