An experiment was carried out with the objective of evaluating the addition of 25-hydroxycholecalciferol (25(OH) D3) in diets of broiler breeder hens. The experiment used Cobb 500 broiler breeder hens and was allotted to a complete randomized design with four treatments and eight replications of twenty females and two males each. The treatments consisted of vitamin premixes with 2,000 and 3,400 IU/kg diet vitamin D3 as the only source of vitamin or 2,000 IU D3 plus 35 or 69 mg/t of 25(OH) D3. Results of this experiment indicated that 25(OH) D3 had no significant effect on egg production parameters from 32 to 67 weeks. The supplementation of 25(OH) D3 resulted in better quality egg shells evaluated by the specific gravity at 60 weeks of age, regardless of the dosage. No significant differences were observed for hatchability of broiler breeder fertile eggs at 54 and 64 weeks. At 64 weeks, the hatch residue breakout showed less embryo mortality at the third week for treatments receiving 2,000 UI D3 in the diet and less embryo mortality at the second week of development from hens aged 67 weeks and supplemented with 2,000IU D3 and 2,000IU D3+ 69 mg 25(OH)D3. It was concluded that the supplementation with 25-hydroxycholecalciferol with cholecalciferol had similar effects as the diets with vitamin D3 as the only source on the productive performance of broiler breeder hens.
The biological activity of 25-hydroxycholecalciferol, a metabolite of vitamin D3.
