Effect of exogenous phytase on egg quality in laying hens

DOI: 10.15414/afz.2014.17.03.79–83Received 13. May 2014 ǀ Accepted 3. June 2014 ǀ Available online 27. August 2014An experiment was conducted to determine the effect of different levels of exogenous phytase on egg quality in laying hens fed diets with low levels of only plant original phosphorus. Twenty four Lohmann Brown hens at 31 weeks of age were housed in individual cages. In total three experiments were successively carried out with the same laying hens. In all three experiments the same diet with the same content of nutrients were always used. The control diet contained no exogenous phytase. Experimental diets differed in the level and sources of exogenous phytase. Eggs were collected daily during period of the experiment to measure egg quality. Measurement of physical parameters such as egg weight and strength of eggshell were performed daily. Shell weight and shell thickness were determined after washing and drying of shells. The shell thickness was evaluated using the micrometer. Shell proportion was calculated. The addition of phytase (150, 200, 250 and 300 FTU/kg diet) did not affect egg weight. Addition of exogenous phytase at levels 150, 200 and 250 FTU/kg had no significant effect (P>0.05) on eggshell quality. Only addition of both phytases (Natuphos and Optiphos) at the level 300 FTU to the same diet had positive effect on eggshell quality (P