Riboflavin for laying hens fed organic winter diets: effects of different supplementation rates on health, performance and egg quality

For reasons of aspired naturalness and cost reduction, vitamin additions should be kept low in organic livestock systems. To define safe lower threshold levels of riboflavin supplementation in organic poultry feeding, 135 hybrid layers were allocated to three dietary treatments supplemented with either 4.5 (R4.5), 3.0 (R3.0) or 1.5 mg (R1.5) GMO-free riboflavin added per kg feed. This resulted in total measured concentration averages of 5.0, 4.5, and 3.1 mg kg−1 feed for R4.5, R3.0 and R1.5, respectively.

Effects of riboflavin supplementation level on health, performance, and fertility of organic broiler parent stock and their chicks

Data from breeder hens and chicks are particularly critical for the development of vitamin B2 recommendations for organic poultry. To test safe thresholds of supplementation, 100 breeder hens (Hubbard JA 57 K) and ten cockerels were allocated to ten housing groups, with each receiving supplementation of either 4.0 (treatment CON) or 2.5 mg (treatment RED) riboflavin per kg feed. After 15 weeks of experimental feeding, 256 eggs were incubated.