Reducing Vitamin B2 supplements for laying hens is possible in organic systems (Relacs Practic Abstract)

- Laying performance (always close to 100%), body weight development and health and welfare indicators did not differ between the three feeding treatments. - Egg quality parameters (weight, stability of the eggshell and colour of the yolk) were also not affected by the reduc-tion of vitamin B2 supplements. - However, the vitamin B2 concentrations in the egg yolks and livers of the 1.5mg/kg-treatment group declined by week 7 compared to the other two treatments. - Subsequently, the values remained stable until the end of the experiment in week 18. - We therefore conclude that despite the declining vitamin B2 concentrations in the yolks and livers of the hens sup-plemented with only 1.5 mg/kg feed, this level was sufficient with regard to animal health, welfare and performance. - The results for the 3 mg/kg-treatment were always equal those of the 4.5mg/kg supplement treatment. - Therefore, we consider it safe to reduce the amount of vitamin B2 supplements in layers’ feed to 3 mg/kg in organic feeding conditions.