The effect of zinc and manganese source in the diet for laying hens on eggshell and bones quality

Abstract

The study was conducted to evaluate the effect of zinc and manganese source (inorganic vs. organic) in the diet for hens on laying performance, eggshell quality and chosen parameters of bones. Experiment was carried out on 84 Hy Line Brown hens, from 25 to 70 weeks of age, allocated to seven experimental groups, each containing 12 hens individually caged on wire-mesh floor. All layers were fed the same basal diet contained in 1 kg 52 mg Zn and 30 mg Mn. In experimental treatments basal diet was supplemented with 30 mg Zn/kg and 50 mg Mn/kg and inorganic forms of Zn (ZnO) and Mn (MnO) were gradually replaced (in 0, 50 or 100%) with their organic sources (amino acid complexes). Egg production, egg weight, feed intake and feed efficiency were not affected by dietary treatments. Substitution of Zn and Mn oxides with amino acid complexes of microelements had also no effect on physical and geometrical parameters of tibia, ash content in tibia and in toes, eggshell percent, eggshell thickness and eggshell density, but improved (<I>P</I> < 0.05) eggshell breaking strength in late phase of laying cycle (at 62 and 70 weeks of age). Obtained results indicate that use of organic complexes of Zn and Mn could alleviate the negative effect of hen age on eggshell breaking strength.