Effects of organic, inorganic and hydroxy sources of manganese, zinc and copper sources on the performance of aged laying hens

The aim of this trail was to evaluate the effects of the use of Mn, Zn and Cu from different sources (inorganic, organic and hydroxy) in the diet on egg and eggshell quality of aged laying hens. A total of 240 Hy-Line w36 Leghorn, from 55 to 65 weeks of age, were used. The experiment carried out in a completely randomized design, with four treatments, four replicates, each containing 15 hens. The experimental treatments included: 1. The control diet, consisted of sulphate source of Mn, Zn and Cu, 2. The diet consisted of Mn, Zn or Cu-Methionine chelate, 3. The diet consisted of Mn, Zn or Cu Hydroxy, and 4. The diet consisted of Mn, Zn and Cu Hydroxy, only 70% level relative to treatment 3. In the most of experimental weeks, the Mn, Zn and Cu hydroxy and chelate forms increased egg weight and improved significantly feed conversion ratio in the 62, 64 and 65 weeks of age, compared with the sulphate group of these elements (P<0.05). But there was no difference between 70% hydroxy and sulphate groups. Also, there were no differences in feed intake, eggshell thickness, strength and weight, yolk index, Haugh unit, yolk color and shape index of egg and blood alkaline phosphatase, cereluplasmin, Zn, Cu and Ca levels among the treatments. The chelate source only increased blood Mn level significantly (P<0.05). There was the significant increase in eggshell and yolk Mn and yolk Zn levels and also significant decrease in the levels of Mn, Zn, Fe and Cu of excreta using hydroxy and chelate forms compared with the sulphate and 70% hydroxy forms (P<0.05). These results indicated that the Mn, Zn and Cu hydroxy and chelate forms in the diet improved the performance of aged laying hens.