A meal made from the wasted stems and leaves of harvested broccoli has been found to improve the nutritional density of poultry diets and deepen the colour of egg yolks.
Researchers at the University of California, Davis, have concluded an initial study into the inclusion of broccoli, which it is noted contain anti-allergic, anti-cancer and anti-obesity characteristics.
During the harvesting of broccoli, florets are separated out for human consumption, leaving the stems and leaves – an estimated 75% of the plant – to be returned to the soil.
They are high in calcium, vitamins, colouring agents, carotenoids and antioxidants, the stems and leaves are often deposited in landfill.
The carotenoids in particular may be of interest to egg farmers, the researchers explain. In broccoli they are yellow, orange or deep red and can deepen the yellow-orange tint of the egg yolk.
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In an initial enquiry, researchers added a relatively high percentage of the broccoli meal to the corn-soy diets of White Leghorn inbred crosses. Compared to a control group fed a conventional diet, feed consumption, body weight, feed conversion, egg production, egg weight, albumen height, Haugh units and eggshell thickness were statistically similar.
No harmful effects from the glucosinolates found in broccoli were observed, and yolk colour scores were “significantly higher”.
The researchers concluded that the work demonstrated the need for larger studies into the use of broccoli in poultry diets.
The full paper can be found in California Agriculture, Volume 72, Number 4