The potential of cholecalciferol and 25-hydroxyvitamin D3 enriched diets in laying hens, to improve egg vitamin D content and antioxidant availability

Sixty Hy-line brown hens were randomly assigned to four barns (n = 4) to investigate the effects of cholecalciferol (vitamin D₃) versus 25-hydroxyvitamin D3 (25-OH-D₃) enriched diets on egg vitamin D concentration, antioxidant activity and egg quality parameters. Experimental design was a 4 × 4 Latin square consisting of 4 experimental treatments and 4 experimental periods. The treatments were (1) 1500 IU of vitamin D₃ (2) 3000 IU of vitamin D₃ (3) 1500 IU of vitamin D₃ and 37.5 μg of 25-OH-D₃ (4) 75 μg of 25-OH-D₃ per kg of feed. Hens offered 75 μg of 25-OH-D₃ had a higher (P < 0.05) total vitamin D egg yolk content (5.06 μg/egg), and antioxidant activity compared to other dietary treatments. The results demonstrates that the enrichment of hen diets with 25-OH-D₃ may be a useful approach and may contribute between 25 and 33% towards total vitamin D daily requirements while also improving antioxidant status of eggs. Industrial relevance: Vitamin D deficiency is now regarded as a major issue in northern Europe and has been described as a pandemic. A growing interest in vitamin D food fortification in northern Europe to satisfy the current dietary intake recommendations has been observed. The use of a bio-addition approach for increasing vitamin D intake through biofortification of livestock feeds attracts attention. Enrichment of the hen's diet with vitamin D may also supply additional benefits of increasing antioxidant activity. This increase in antioxidant activity may have the ability to increase food quality and extend the shelf life. This study explores the effect of vitamin D enriched diets fed to laying hens on vitamin D egg yolk content and antioxidant activity in the egg. These enriched diets could demonstrate that enrichment of hen diets with 25-hyroxvitamin D₃ may be a useful approach for tackling low vitamin D intakes and improving antioxidant capacity of eggs.