Animal Reproduction Science 118 (2010) 324–329 Contents lists available at ScienceDirect Animal Reproduction Science journal homepage: www.elsevier.com/locate/anireprosci Out-of-season sperm cryopreserved in different media of the Amazonian freshwater fish pirapitinga (Piaractus brachypomus) A.F. Nascimento a , A.N. Maria b , N.O. Pessoa c , M.A.M. Carvalho c , A.T.M. Viveiros b,∗ a Dept Veterinary Medicine, Federal University of Lavras, UFLA, P.O. box 3037, Lavras, MG, 37200-000, Brazil b Dept Animal Sciences, Federal University of Lavras, UFLA, P.O. box 3037, Lavras, MG, 37200-000, Brazil c Laboratory of Semen Technology, State University of Ceará, UECE, Paranjana, 1700, Campus do Itaperi, Fortaleza, CE, 60740-000, Brazil article info Article history: Received 30 January 2009 Received in revised form 20 June 2009 Accepted 15 July 2009 Available online 23 July 2009 Keywords: Fish Piaractus brachypomus Sperm Cryopreservation Motility abstract The pirapitinga (Piaractus brachypomus) is a freshwater fish that inhabits the Amazon and Orinoco River basins. The use of cryopreserved sperm has been considered to facilitate pro- cedures during the artificial reproduction. The aim of the present study was to develop a freezing protocol for pirapitinga sperm collected outside the spawning season. Sperm samples were diluted in four freezing media prepared by a combination of two extenders (glucose and BTS TM —Beltsville Thawing Solution) and two cryoprotectant agents (DMSO and methylglycol) loaded into 0.5-mL straws, frozen in a nitrogen-vapor shipping dewar (dry-shipper) and stored in liquid nitrogen at -196 ◦ C. Post-thaw sperm motility was eval- uated both subjectively using a light microscope and by a computer-assisted sperm analyzer (CASA). Curvilinear, average path and straight-line velocities were also determined. There were no differences (P > 0.05) in post-thaw sperm motility between evaluations performed subjectively and using the CASA. Sperm samples cryopreserved in glucose-methylglycol yielded the greatest post-thaw sperm motility (81%) and fastest sperm velocities when compared to the samples frozen in the other three media (P< 0.05). Out-of-season sperm cryopreserved in glucose and methylglycol under the conditions described above is of high quality and can therefore be used to facilitate artificial reproduction procedures, as only females will need handling for hormonal induction and gamete collection during the spawning season. Although the CASA system provides precise data on sperm motil- ity, the subjective evaluation is practical and can be conducted by well-trained personnel at commercial fish farms as an acceptable evaluation of sperm quality. © 2009 Elsevier B.V. All rights reserved. 1. Introduction The pirapitinga (Piaractus brachypomus Cuvier 1818) belongs to the Characiformes order, Characidae family, Serrasalminae sub-family and the same genus as pacu (Piar- actus mesopotamicus). The pirapitinga is a round fish native to the Amazon and Orinoco river basins and can reach up to 20 kg in body weight (BW) (Alcântara et al., 1990). ∗ Corresponding author. Tel.: +55 3538291223; fax: +55 3538291231. E-mail address: ana.viveiros@ufla.br (A.T.M. Viveiros). The pirapitinga is a rustic, fast-growing species, prized for its meat and offering excellent conditions for fish farm- ing (Fresneda et al., 2004). It has considerable economic importance for farming on a commercial scale in Colombia, Brazil, Peru, Venezuela and Central America. Under natu- ral conditions, the pirapitinga migrates between June/July and October and spawns from November to February when water temperatures reach 27 ◦ C after the first rains in response to the rising flood waters (Hernández, 1994). Males of this species raised in northeastern Brazil produce sperm all year round and collection is possible after hor- monal induction. Females, however, are more sensitive to the yearly cycle; some do not respond to hormonal induc- 0378-4320/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.anireprosci.2009.07.002