| Sumario: | Vitamin K (VK) is a fat soluble vitamin required in fish diets for normal growth and development since they are not able to synthesize it de novo. VK can be naturally found as phylloquinone (VK1; vegetable origin) or menaquinone (VK2; microbial or animal origin); and synthetically produced as menadione (VK3). Two major roles of VK metabolites have been described up-to-date. As a co-factor of the enzyme γ-glutamyl carboxylase which performs the conversion of Glu into Gla residues in VK-dependent proteins (VKDPs), through which VK is controlling blood clotting, representing the most widely recognized function of VK. VK also participates in transcriptional regulation, acting as ligand for the steroid xenobiotic receptor or pregnane X receptor (PXR), which is mostly known as a master regulator of xenobiotic metabolism. However, little is known about its metabolism and its specific requirements along fish development. Here, we will briefly review what is known, and identify what still remains to be unveiled about VK and fish physiology. In this sense, new findings regarding VK requirements on early fish development, metabolism and VK cycle regulation under different nutritional conditions will be enumerated. Finally, future perspectives on knowledge gaps, strategies and approaches to be applied will be discussed.
|
|---|
