Vitamin K is a lipid-soluble vitamin that acts as a co-factor of the enzyme glutamyl-carboxylase (GGCX). Several proteins involved in blood coagulation (clotting factors) and bone mineralisation depend on the action of GGCX to transform a glutamic residue to ϒ-carboxy glutamic to become active . Vitamin K deficiency might lead to longer coagulation time and changes in bone mineralisation . To our knowledge, there are not studies carried out in European Sea bass (Dicentrarchus labrax).
There was no correlation between increasing vitamin K in the diet and SGR, (Figure 1), feed intake or FCR. For blood variables , increasing dietary vitamin K content did not change aPTT results of fish ). Fibrinogen content was higher in diets containing 4 mg or more of vitamin K/kg compared to the non-supplemented diet (F igure 2).
Based on the results the optimal vitamin K supplementation for European s ea bass seems to be at the low range of dietary supplementation.