1 Group of Study for Avian Multiplication, Department of Animal Reproduction, School of Veterinary Science, University of São Paulo, São Paulo, Brazil.
2 Laboratory of Andrology, Department of Animal Reproduction, School of Veterinary Science, University of São Paulo, São Paulo, Brazil.
3 Laboratory of Spermatozoa Biology, Department of Animal Reproduction, School of Veterinary Science, University of São Paulo, São Paulo, Brazil.
4 Group of Study for Avian Multiplication, Department of Animal Reproduction, School of Veterinary Science, University of São Paulo, São Paulo, Brazil. Electronic address: ricpereira@usp.br.