Superovulation of rabbits with FSH alters in vivo development of vitrified morulae.
Morulae were flushed from the oviducts and uteri of New Zealand White (NZW) rabbits superovulated with either 6 (3 d) or 8 (4 d) injections of FSH and from non-superovulated controls. The percentages of embryos recovered from 4 d (100%, n = 8) donors was significantly higher (P < 0.01) than that of 3 d (76%, n = 16) and control (87%, n = 22) donors. Overall, fertilization rates were significantly lower for the 3 d embryos (P < 0.01). Most (86 to 90%) morulae were morphologically suitable for vitrification in an ethylene glycol-based solution. Following storage in liquid nitrogen, morulae were rapidly thawed and transferred to the uteri of pseudopregnant recipients. The total number of kits born for the 3 d, 4 d, and control groups was 40, 61 and 48, respectively. The percentage of live kits from morulae transferred was significantly lower for the 3 d (20%, n = 201) than either the 4 d (36%, n = 169; P < 0.01) or the control (31%, n = 157; P < 0.05) group. The mean number of kits born/recipient for the 3 d (2.4 +/- 2.9), 4 d (4.7 +/- 3.5), and control (3.0 +/- 2.2) protocols did not differ (P > 0.05). The estimated overall efficiency of producing kits based on normal morulae collected for control and 4 d groups, however, was nearly two-fold that for females given 6 FSH treatments. We conclude that the 4 d FSH superovulation regimen enhances the efficiency of rabbit reproductive biotechnology after embryo cryopreservation. These findings have important implications for rabbit colony management using embryo cryopreservation.
Kauffman
R D
RD
Molecular Disease Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1666, USA. Rick@mdb.nhlbi.nih.gov
Schmidt
P M
PM
Rall
W F
WF
Hoeg
J M
JM
D000818:Animals; D015925:Cryopreservation; D003451:Cryoprotective Agents; D004624:Embryo Transfer; D005314:Embryonic and Fetal Development / Q000187:drug effects*; D019855:Ethylene Glycol; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage*; D009028:Morula / Q000502:physiology*; D011247:Pregnancy; D011817:Rabbits / Q000196:embryology* / Q000502:physiology; D013480:Superovulation
D003451:Cryoprotective Agents; D005640:Follicle Stimulating Hormone; D019855:Ethylene Glycol