All animal care and procedures used to collect semen were performed in accordance
with the Spanish Animal Protection Regulation, RD233/1988, which conforms to
European Union Regulation 86/609 and adheres to guidelines established for care and use
of Laboratory Animals promulgated by the Society for the Study of Reproduction.
All the chemicals, unless otherwise stated, were reagent grade and purchased from
Sigma-Aldrich Quı ´mica S.A. (Alcobendas, Madrid, Spain). The experiment was carried
out at the Department of Animal Science (Universidad Polite ´cnica de Valencia. Spain).