1. Laboratory of Manipulation of Oocytes and Preantral Follicles Department of Faculty of Veterinary; State University of Ceara; Itaperi Campus Fortaleza CE 60740-903 Brazil
2. Group of Research in Biology of Reproduction - Department of Animal Science; Federal University of Ceará; Fortaleza CE Brazil
3. Department of Animal Sciences; University of Illinois; Urbana-Champaign Urbana Illinois