Effect of different phosphorus levels on the performance and egg quality of laying hens fed wheat- and maize-based diets.

The effects of diet type (wheat- or maize-based) and concentration of available phosphorus (AP; about 4, 3 and 2 g/kg) on the parameters of hen performance and egg quality as well as shell calcium (Ca) and phosphorus (P) contents were examined. Two experiments were carried out in which 240 and 120, respectively, older ISA Brown hens were housed in enriched cages. The interaction of diet type and AP concentration was ascertained for all evaluated characteristics except the amount of Ca and P deposited in shells in the first experiment. In the second experiment, the interaction of diet type and AP concentration was found for feed intake, egg weight, shell thickness and weight as well as the albumen quality parameters. Furthermore, Ca deposition in shells increased ( P < 0.001) with the wheat diet. Hens fed a maize-based diet (P < 0.001) laid heavier eggs. The highest level of AP (4.1 g/kg) in the wheat-based diet significantly (P < 0.001) decreased albumen height, albumen index and Haugh units (HU). These trends were the same in both experiments. The results indicate that 0.27% AP in wheat-based diet and 0.30% AP in maize-based diet are adequate for hens with the intake 115 g of feed with 3.5% of Ca without a negative impact on per - formance or egg quality.