Scientists find way to increase Vitamin D content of egg to counter deficiency

Consumption of foods rich in Vitamin D such as oily fish or chicken eggs takes care of deficiency.But lifestyle choices prevent many people from getting enough vitamin D. The problem increases even more in the winter months when there is a lack of sunshine precipitating Vitamin D deficiency.

The researchers were therefore looking for a way to increase the amount of vitamin D in food, in this case in eggs. "The idea was to stimulate the natural vitamin D production of chickens. Using UV lamps in the henhouses would increase the vitamin D content of the eggs," says Kühn. In earlier studies, the researchers were able to prove the fundamental success of their approach when they illuminated the legs of the chickens with UV light. "However, the experiments were always conducted under ideal conditions. There was only one chicken per lamp. In chicken farms, there is a much higher stocking density than here, in other words: a lot more animals," Kühn continues. The new study aimed to test the practical feasibility of the method and therefore was conducted on two chicken farms. Comparisons were made between two different chicken breeds, assorted lamps and different durations of light exposure per day.

The researchers not only continuously analysed the vitamin D content of the newly laid eggs during the trial period, they also investigated the impact the additional light had on the animals. "Humans cannot see UV light, but chickens can. Therefore, light regimes are a critical aspect in chicken husbandry because light influences behaviour and laying activity," explains Professor Eberhard von Borell, an expert in animal husbandry at MLU. His working group analysed the behaviour of the animals using video recordings. The researchers also inspected the chickens' plumage for injuries by other members in order to assess their potential for activity and aggression.

The research team's idea worked: After only three weeks of UV light exposure for six hours per day, the vitamin D content of the eggs increased three to four-fold. This value did not increase any further in the following weeks. Also, the additional UV light did not cause any obvious problems for the hens. They neither avoided the area around the lamps, nor did they act any differently. As a result, the researchers conclude that their method also works under practical conditions and that this could represent an important step towards supplying the population with vitamin D.