antioxidants and show partly pro-vitamin A activity. Antoxidative capacity of
colorants is yet not very intensively investigated in poultry as the major antioxidants
in diets are selenium and vitamin E. Provitamin A activity is normally of minor
interest as commercial diets are supplemented with sufficient amounts of vitamin
A. Due to the normally low supplementation level of phytobiotics to broiler diets
the colouring effect is less pronounced.
Various phenolic compounds are included in phytobiotics with flavonoids and
chicoric acid being the dominating ones (Panda et al., 2006; Nasir and Grashorn,
2009). The pharmacological effects of phenolic compounds are still not known
very well, but, it is believed that they exhibit antioxidative effects due to their
chemical structure.