BACKGROUND: Phytase enzyme (EC 3.1.3.8), is used to increase the availability of phosphorus in the feeding of monogastric animals. Increasing public attention to environmental issues, improving livestock nutrition and human health have led to considerable attempts to increase its activity or prevent its inhibition as a food additive. OBJECTIVES: Determination of inhibitory or activating effect of methanolic extract from aerial parts of some herbs, as rich sources of secondary metabolites. METHODS: Phytase was partially purified from wheat barn. After preparation of methanolic extracts from aerial parts of plants, their effects on phytase activity were measured at four concentrations of 0.001, 0.01, 0.1 and 1 mg/ml. Micro plate assays were performed at 405 nm. RESULTS: Among analysed plant samples, extracts from Pedicularis sibthorpii Boiss, Phlomis persica Boiss, Solenanthus Circinatus Ledeb, Stachys lavandulifolia Vahl, had appreciable inhibitory effect, while extracts from Astragalus caraganae Hohe, Hypericum scabrum L, Linum album Ky.ex Boiss, Valeriana sisymbriifolia Vahl, Euphorbia denticulate Lam, Rindera lanata (Lam.) Bge, had a considerable activation effect. CONCLUSIONS: According to the results of this report, plants with positive effect on phytase activity, could be used as food additive along with phytase to improve phosphoros uptake. On the other hand, plants with negative effect on phytase could be viewed as unwanted sources in monogastric animals feeding.

BACKGROUND: There are different kinds of phytase from different sources used in poultry nutrition.OBJECTIVES: The present study aimed to evaluate the effects of addition of 2 sources of 6- phytase to the diet of male broilers in terms of growth performance, Tibia biometric, breacking straight, mineralization, blood biochemical parameters, and carcase yield.METHODS: Herein, we recruited 216 1-d-old male Ross broilers and divided them to three experimental groups and six replications for 42 D. The treatment (T) diets included: T1 (without phytase (control)), T2 (supplemented with 500 FTU/kg diet of Aspergillus niger phytase (fungi phytase)), T3 (supplemented with 500 FTU/kg diet of phytase produced by a genetically modified strain of Aspergillus oryzae by doner Citrobacter braakii gene (genetically modified phytase)).RESULTS: Serum P in the birds supplemented by genetically modified phytase was higher compared with that in the control birds (P<0.05). Additionally, Tibia P in this group was higher than that of birds supplemented by fungi phytase (P<0.05). However, Tibia breaking straight in birds supplemented by genetically modified phytase did not differ significantly with those fed with a diet with fungi phytase. Meanwhile, Tibia breaking straight in birds supplemented by genetically modified phytase was higher than control (P<0.05). Growth performance, Tibia length, diameter, ash, Ca, dry weight, average serum HDL, Triglyserid, Cholesterol, Ca, Alkalin phosphatase, Glucose, Total Protein, and Carcase yeild were not significantly different among any of the treatments.CONCLUSIONS: Supplementation of male broilers diet with genetically modified phytase (500 FTU/kg), without any differences in terms of performance, could increase P of serum, P of Tibia and breacking straight of Tibia compared to supplementation diet with Aspergillus niger phytase.