The effect of combined use of ethylene diamine tetra acetic acid and microbial phytase in diet on the egg qualityes of eggs

This experiment was carried out in Mr. Amin Vakili’s layer farm with 15000 laying hens in Azarshahr, East Azarbayjan (autumn, 2003). This research was carried out in order to survey the combination effect of ethylen ediaminetetraacetic acid (EDTA) and microbial phytase on the egg quality characteristics in commercial laying hens of Hy-line (W-36) strain in 53-64 week of age. In this experiment 192 laying hens were examined. The experimental design was completely randomized design with a 3×2 factorial arrangement with three levels (0.0, 0.1% and 0.2%) of ethylene diamine tetra acetic acid and two levels (0.0 and 300 units/kg) of microbial phytase in low available phosphorus diets with 6 treatments, 4 replicates and 8 hens in each replicate. The criteria used to assess were specific gravity, eggshell thickness, Hough unit, eggshell weight and eggshell ash. The results showed that interaction effect of ethylene diaminetetraacetic acid × phytase on specific gravity, Hough unit and eggshell weight was significant (p<0.05). Adding of ethylene diamine tetra acetic acid to low available phosphorus diets had not influence on the egg quality characteristics in laying hens. Phytase addition in low available phosphorus diets, increased eggshell weight and eggshell thickness significantly (p<0.05). Also, phytase addition in low available phosphorus diets did not improve eggshell ash.