1. Laboratory of Developmental BiologyInstitute of Animal Physiology and Genetics of the Czech Academy of SciencesLiběchov Czech Republic
2. Department of Animal Production, Faculty of AgricultureCairo UniversityGiza Egypt
3. Department of Zoology and AnthropologyFaculty of Natural Sciences, Constantine the Philosopher University in NitraNitra Slovak Republic
4. Biology of Reproduction DepartmentInstitute of Animal Science, Prague, Uhrineves Czech Republic
5. Department of Functional MorphologyFaculty of Veterinary Medicine, Ss. Cyril and Methodius University in SkopjeSkopje Republic of Macedonia