Effects of semen extenders and storage temperatures on characteristics of frozen-thawed Bryde's (Balaenoptera edeni) whale spermatozoa.
The present study investigated effects of three semen extenders and storage temperatures on post-thaw characteristics of Bryde's whale spermatozoa. Spermatozoa were collected from the vasa deferens of three mature Bryde's whales captured during the Japanese whale research in the north-west Pacific (May to August 2007) after death. The three semen extenders used for freezing were 1) a commercialized synthetic extender (AndroMed: AM), 2) Tris-based + 10% bovine serum albumin (BSA) and 3) Tris-based + egg yolk (EY). The sperm samples from the three whales were frozen with the three extenders, and the post-thaw spermatozoa were stored at three different temperatures (35 C; 20-25 C, room temperature; and 5 C) for 0, 6, 12, 24, 48 and 96 h. At each time-point, total and progressive motility (PM), viability (live or dead), the hypo-osmotic test, defective acrosomes and malformation were examined. Immediately after thawing, AM resulted in similar recovery rates (60.4 and 83.3%) in 2 of the 3 whales examined and had comparable post-thaw recovery rates to those obtained using the EY and BSA extenders. Immediately after thawing, the proportion of PM in EY (17.6%) was higher (P<0.05) than that in BSA (15.0%). In the hypo-osmotic test, the proportions of AM (26.0%) and BSA (25.2%) were higher (P<0.05) than that of EY (17.3 %). The three extenders had similar viabilities (36.7, 37.9 and 32.1%, respectively), but the viability of BSA was higher (P<0.05) than that of EY. The present study showed that a synthetic semen extender, AndroMed, could be used for cryopreservation of whale spermatozoa in addition to Tris-based extenders containing bovine serum albumin or egg yolk. Storage of the post-thaw Bryde's whale spermatozoa was better at 5 C than at room temperature or 35 C. The frozen-thawed Bryde's whale spermatozoa maintained their motility and viability for at least two days at room temperature and for four days at 5 C.
Hiwasa
Mami
M
Laboratory of Animal Reproduction, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
Suzuki
Yo
Y
Watanabe
Hiroyuki
H
Bhuiyan
Mohammad Musharraf Uddin
MM
Matsuoka
Kohji
K
Fujise
Yoshihiro
Y
Ishikawa
Hajime
H
Ohsumi
Seiji
S
Fukui
Yutaka
Y
D000177:Acrosome / Q000187:drug effects; D000818:Animals; D050616:Balaenoptera; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004530:Egg Yolk; D008297:Male; D009997:Osmotic Pressure; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D012710:Serum Albumin, Bovine; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects / Q000473:pathology; D013696:Temperature; D013997:Time Factors; D014325:Tromethamine
D003451:Cryoprotective Agents; D014325:Tromethamine; D012710:Serum Albumin, Bovine