Assessment of a bacterial 6-phytase
in the diets of broiler chickens.
The exogenous 6-phytase
enzyme used was produced by a genetically modified Aspergillus oryzae (Ronozyme NP -Razak Corporation Tehran, Iran).
The efficacy of a novel microbial 6-phytase
expressed in aspergillus oryzae on the performance and phosphorus utilization of cold- and warm-water fish: rainbow trout, Oncorhynchus mykiss,
The enzyme used was Quantum Blue[R], an enhanced 6-phytase
from Escherichia coli and with an activity of 6,800 FTU [g.sup.-1].
Alternatively, according to the initiation site of dephosphorylation of the phytate, the ENZYME database (available through the ExPASy Proteomics Server: http://enzyme.expasy.org/) classifies phytases into three groups: 3-phytase (alternative name, 1-phytase; EC 188.8.131.52), 4-phytase (alternative name, 6-phytase
; Ec 184.108.40.206), and 5-phytase (EC 220.127.116.11).
The company has also recently launched Finase[R] EC, its second generation 6-phytase
from E.coli, in Europe.
The enzyme mixture (Axtra XAP 101 TPT, Cedar Rapids, IA, USA) was derived from Bacillus subtilis, Trichoderma longibrachiatum, and Bacillus licheniformis and contained endo-1, 4-beta-xylanase 20,000 U/g, amylase 2,000 U/g and protease 40,000 U/g activities, and 6-phytase
(Axtra PHY 10000 TPT, USA) was derived from Trichoderma reesei, 10,000 U/g activity
The experimental design was completely randomized, in a (4+1) x2 factorial arrangement, with four diets equally deficient in [sub.av]P supplemented with increasing levels of 6-phytase
synthesized by Aspergillus oryzae (0; 750; 1,500 and 2,250FTU [kg.sup.-1] of diet) plus one positive control diet without phytase, formulated according to the nutritional recommendations of ROSTAGNO et al.
Phytases are divided into two categories, 3-phytase (EC 18.104.22.168) and 6-phytase
(EC 22.214.171.124), based on the site where the hydrolysis of the phytate molecule is initiated .