A phytase (EC 3.1.3.8) with a high affinity for phytic acid was found in Aspergillus niger SK-57 and purified to homogeneity in four steps by using ion-exchange chromatography (two types), gel filtration, and chromatofocusing. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme gave a single stained band at a molecular mass of approximately 60 kDa. The Michaelis con...

An experiment was conducted to determine the influence of 2 levels of dietary Ca from limestone and 3 levels of phytase on broiler performance, bone ash, gastrointestinal pH, and apparent ileal digestibility (AID) of Ca, P, and amino acids. Cobb 500 broilers (n = 576) were allowed access to one of 6 corn-soy diets from 0 to 16 d. Experimental diets contained 1.03% or 0.64% Ca from limestone and...

AIMS To isolate, clone and express a novel phytase gene (phy) from Bacillus sp. in Escherichia coli; to recover the active enzyme from inclusion bodies; and to characterize the recombinant phytase. METHODS AND RESULTS The molecular weight of phytase was estimated as 40 kDa on SDS-polyacrylamide gel electrophoresis. A requirement of Ca(2+) ions was found essential both for refolding and activi...

Hens were fed corn-soybean meal diets containing 0.35, 0.25, 0.15, or 0.10% nonphytate phosphorus (NPP) (40 to 60 wk). Phytases A and B were added at 0.25, 0.15, and 0.10% at 250 to 300 units of phytase (FTU)/kg feed in a 3 x 3 factorial; 0.35% was a control diet. Treatments were replicated with eight cages per treatment (five hens per cage) in a randomized complete block design. Phytase supple...

Both intrinsic and exogenous phytase in poultry feeds can alter phytate utilization and the solubility of P excreted. This experiment determined the effects of feeding diets varying in cereal grain, P concentration and phytase addition on phytate and P utilization and P characterization of ileal digesta and excreta. Twelve treatments, consisting of diets based on corn, wheat, barley, or high fa...

The rate of phytate P removal from feed (level of dephosphorylation, DL) and the extent to which the molecule of phytic acid is deprived of phosphate moieties (conversion degree, CD) were studied in vitro and in a feeding trial with broilers fed corn-soybean diets. In the in vitro model, phytase A asymptotically increased DL and CD. Phytase B influenced DL only at low dosages of phytase A [0 or...

BACKGROUND Although fungal phytase is frequently used as an additive to animal feed few investigations of its allergenic property have been conducted. METHODS Fifty-three subjects occupationally exposed to powdered phytase from Aspergillus niger were studied. Exposure data and symptoms were registered by the company physician. RESULTS Thirty-eight subjects complained of work-related respira...