• macroalgae;
  • mineral feed additives;
  • laying hens;
  • feeding experiment;
  • biofortified eggs


This study presents results obtained from feeding experiment on laying hens, which were fed with the diet supplemented with two marine macroalgae: Enteromorpha prolifera and Cladophora sp., enriched with microelements [Cu(II), Zn(II), Co(II), Mn(II), Cr(III)]. The applicability of the preparation was tested on five experimental groups of laying hens and one control group. In the control group, microelements were supplemented in the inorganic form, whereas in experimental groups, Cu, Zn, Co, Mn and Cr were replaced by macroalgae enriched with a given microelement ion. During feeding experiment, weight of laying hens, weight of eggs, eggshell thickness and mineral content of blood, feathers, droppings, eggs content (separately yolk and egg white) and eggshell were measured. Also egg number was counted and microclimate (temperature and relative humidity) was monitored. Supplementing bio-metallic feed additives to the diet of laying hens resulted in higher microelement transfer to eggs and enhanced the colour of yolk. It was also found that the presence of Enteromorpha prolifera and Cladophora sp. in laying hens diet influenced advantageously eggs weight, eggshell thickness as well as body weight of hens. On the basis of these results, it could be concluded that Enteromorpha prolifera and Cladophora sp. enriched with microelement ions could be potentially used as mineral feed additives in laying hens feeding.