Urtica dioica traces of zeaxanthin or between 20 – 60 mg / kg of dry matter. Nettle contains ascorbic acid (vitamin C), riboflavin (vitamin B), pantothenic acid, vitamin K and tocopherols (vitamin E). The highest vitamin contents can be found in the leaves. In laying hens, nettle can be used as an egg yolk colorant instead of artificial pigments or other natural pigments (derived from marigold for yellow). Nettle has high carotenoid contents, especially lutein, β-carotene and zeaxanthin, of which lutein and zeaxanthin act as yellow pigments. Feeding as little as 6.25 g dry nettle per kg feed is as effective as
Vitamin K2 by this vitamin group were revealed to be much more complex. K vitamins play an essential role as cofactor for the enzyme γ-glutamyl carboxylase, which is involved in vitamin K-dependent carboxylation of the gla domain in "Gla proteins" (i.e., in conversion of peptide-bound glutamic acid (Glu) to γ-carboxy glutamic acid (Gla) in these proteins). Carboxylation of these vitamin K-dependent Gla-proteins, besides being essential for the function of the protein, is also an important vitamin recovery mechanism since it serves as a recycling pathway to recover vitamin K from its epoxide metabolite (KO) for reuse in carboxylation. Several human Gla-containing proteins