Characterization of northern pintail (Anas acuta) ejaculate and the effect of sperm preservation on fertility.
Northern pintail duck semen and sperm traits were characterized, and the fertility of cold-stored spermatozoa was investigated using artificial insemination. Excellent quality ejaculates containing high proportions of motile spermatozoa were collected from drakes within 20 s by a massage technique. Semen was collected in Beltsville poultry semen extender, pooled and cold-stored (4 degrees C) for 0, 24, 48 or 72 h. Hens were inseminated with 100 microl twice a week, and eggs were assessed for fertilization and hatch success. Fertilization success was similar (P > 0.05) for semen cold-stored for 0 (51.6%), 24 (51.5%), 48 (41.1%) and 72 h (22.3%; P > 0.05). Similar (P > 0.05) percentages of fertilized eggs hatched to live offspring (73.1, 71.4, 87.0 and 80.0%, respectively). Fresh semen was also equilibrated with 1 or 4% dimethylsulphoxide or glycerol, and cryopreserved at the following rates: (1) approximately 60 degrees C min(-1) (in liquid nitrogen [LN(2)] vapour) for 10 min; (2) 1 degrees C min(-1) to -20 degrees C, LN(2) vapour for 10 min; and (3) 1 degrees C min(-1) to -35 degrees C, all followed by immersion in LN(2). After thawing for 30 s at 37 degrees C or 20 min at 4 degrees C, sperm motility and viability were assessed. The highest numbers of motile spermatozoa were recovered after slow-fast freezing (2) and thawing at 0 degrees C (P < 0.05), but survival was inadequate to allow artificial insemination. Nonetheless, cold storage provides an effective means of short-term storage with no loss of fertility in this waterfowl species.
Conservation and Research Center, National Zoological Park, Smithsonian Institution, Front Royal, VA 22630, USA. Lindap@wogilman.com
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Penfold
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Harnal
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D000818:Animals; D002470:Cell Survival; D015925:Cryopreservation; D004372:Ducks / Q000502:physiology*; D004542:Ejaculation; D005260:Female; D005298:Fertility; D007315:Insemination, Artificial; D008297:Male; D012661:Semen / Q000502:physiology; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology*