Organic zinc and manganese and 25-hydroxycholecalciferol improves eggshell thickness in late-phase laying hens.

The aim of this study was to evaluate the effects of organic micromineral zinc (Zn) and manganese (Mn) and 25-hydroxycholecalciferol supplementation in late-phase laying hens' diets on performance, egg quality, lipid stability of fresh and stored eggs, and bone quality. The treatments were a basal diet and diets supplemented with 32 mg Zn-Met/kg diet; 26 mg Mn-Met/kg diet; 32 mg Zn-Met/kg diet and 26 mg Mn-Met/kg diet; 1500 IU 25-hydroxycholecalciferol/kg diet; 32 mg Zn-Met/kg diet; 26 mg Mn-Met/kg diet; and 1500 IU 25-hydroxycholecalciferol/kg diet. On performance, the birds supplemented with organic manganese had the lowest feed intake. Regarding egg quality, the birds supplemented with Zn-Met and Mn-Met, with 25-hydroxycholecalciferol alone, and with Zn-Met, Mn-Met and 25-hydroxycholecalciferol presented a greater eggshell thickness than those receiving the basal diet. Lipid stability of the yolk varied only according to storage time. No effect of supplementation was observed on bone quality. Supplementation with Zn-Met and Mn-Met, or associated with 25-hydroxycholecalciferol, or 25-hydroxycholecalciferol alone, improved eggshell thickness in aged white layers. However, the associated or isolated supplementation with these nutrients did not influence performance, lipid stability of fresh and stored egg yolk or bone quality.