About the Authors

Natalia Ziółkowska

Contributed equally to this work with: Natalia Ziółkowska, Bogdan Lewczuk

ntrzaska@o2.pl

Affiliation Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland

Bogdan Lewczuk

Contributed equally to this work with: Natalia Ziółkowska, Bogdan Lewczuk

Affiliation Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland

Wojciech Petryński

Affiliation Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland

Katarzyna Palkowska

Affiliation Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland

Magdalena Prusik

Affiliation Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland

Krystyna Targońska

Affiliation Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland

Zygmunt Giżejewski

Affiliation 2Institute of Animal Reproduction and Food Research of Polish Academy of Sciences, Olsztyn, Poland

Barbara Przybylska-Gornowicz

Affiliation Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Olsztyn, Poland

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: NZ BL. Performed the experiments: NZ BL MP ZG WP KP KT. Analyzed the data: NZ BL BPG WP KP. Wrote the paper: NZ BL.