The effect of zinc and manganese source in the diet for laying hens on eggshell and bones quality
Swiatkiewicz, S.,National Research Inst. of Animal Production, Balice (Poland) | Koreleski, J.,National Research Inst. of Animal Production, Balice (Poland)
The study was conducted to evaluate the effect of Zn and Mn source (inorganic vs. organic) in the diet for hens on laying performance, eggshell and bones quality. The 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 with 52 mg Zn/kg and 30 mg Mn/kg. Experimental diets were 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 no effect on physical and geometrical characteristics of tibia, ash content in tibia and in toes, eggshell percent, eggshell thickness and eggshell density, but improved (P less than 0.05) the eggshell breaking strength in the late phase of the laying cycle (at 62 and 70 weeks of age). Our results indicate that feeding Zn and Mn organic complexes could alleviate the negative effect of hen age on eggshell breaking strength.
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