Research on Phosphorus Requirements in Red-Mini-Rock Hens Fed on Different Cereal-Based Diets

The aim of this paper was to determine the available phosphorus requirements in Red-Mini-Rock hens fed on wheat and maize-based diets combined with different levels of phosphorus supplemented in the form of mono- and dicalcium phosphate, based on the effect on the main properties of the eggs. Three diets based on wheat (50%) having three levels of phosphorus, 4.5, 3.0 and 1.5 g/100 g dry matter diet, respectively, and three diets based on maize (58%), with the same supplemented phosphorus levels were designed. Feed intake, laying performance and egg weight were not modified by feeding. The thickness and weight of the egg shell were higher (P˂0.05) in groups of hens fed on phosphorus supplemented levels of 3.3 and 4.4 g/100 g diet in both wheat-based and maize-based diets. Breaking strength of the eggshell was significantly higher (P˂0.05) in the groups of hens fed on maize-based diets supplemented 4.5 and 3.0% in phosphorus, respectively. The internal characteristics of the eggs were not significantly altered, excepting the color of the yolk, which showed a significantly higher reflectivity absorption capacity (P˂0.05) in the groups fed on maize-based diets.