Use of purified FSH and LH for embryo production, cryopreservation by conventional freezing or vitrification and transfer of embryos in dairy ewes
Three experiments were carried out with the aim of evaluating the efficiency of techniques of in vivo production, storage<br />and transfer of embryos in dairy sheep. Experiment I - For embryo production, thirty-one ewes were synchronized with<br />FGA (vaginal sponges, 40 mg, 9 d) and P...
Main Authors: | , |
---|---|
Format: | Article |
Language: | English |
Published: |
Taylor & Francis Group
2010-01-01
|
Series: | Italian Journal of Animal Science |
Subjects: | |
Online Access: | http://www.aspajournal.it/index.php/ijas/article/view/146 |
Summary: | Three experiments were carried out with the aim of evaluating the efficiency of techniques of in vivo production, storage<br />and transfer of embryos in dairy sheep. Experiment I - For embryo production, thirty-one ewes were synchronized with<br />FGA (vaginal sponges, 40 mg, 9 d) and PGF2α (ICI; 50 μg, 7th d), and subdivided into three groups corresponding to the<br />following superovulatory treatments over 3 days with purified gonadotrophic preparations: A) control, FSH/LH ratio = 1<br />(250 IU p-FSH : 250 UI p-LH); B) FSH/LH ratio = 2 (250 IU p-FSH : 125 IU p-LH) and daily FSH/LH ratio of 3.4 – 1.7 –<br />0.8 in the 3 days of treatment, respectively; C) FSH/LH ratio = 2 (250 IU p-FSH : 125 IU p-LH) and daily FSH/LH ratio<br />of 5.0 – 1.0 – 0.3. On the 7th day after oestrus and mating, ovarian response and embryo production were evaluated.<br />Experiment II – Three freezing methods were evaluated based upon post-thaw embryo quality: CF) conventional slow<br />freezing by 1.5 M ethylene glycol (EG); V-1) one-step vitrification based on exposure of the embryos to one solution (EG<br />7.15 M + ficoll 2.5 mM); V-3) vitrification in three steps, corresponding to three solutions at increasing concentration of<br />glycerol (GLY) and EG (GLY 1.4 M; GLY 3.4 M + EG 1.4 M; GLY 4.6 M + EG 3.4 M). V-1) and V-3) frozen embryos were<br />directly plunged in liquid nitrogen. At thawing, embryo viability was evaluated on the basis of morphological features.<br />Experiment III – For embryo transfer, a total of 26 recipient ewes were synchronized with donors. On the 7th d from<br />oestrus, 11 recipient ewes received fresh embryos (Group FE – control) and 15 recipients received vitrified-thawed<br />embryos (Group VTE). Each recipient received 2 embryos. Superovulatory treatment B) significantly advanced the onset<br />of oestrus compared to the control (27.3 vs 34.7 h; P<0.05). Ovulation rate did not differ among the groups (6.5 to<br />10.8). Transferable embryos in Group B) (7.2) resulted similar to Group A) (5.3) and significantly (P<0.05) different when<br />compared to Group C) (3.2). V3-method resulted in the highest (P<0.01) transferable embryos (74.5%) compared to<br />CF- and V1-methods. After transfer, in FE and VTE recipient ewes were comparable in fertility rates (72.7 vs 73.3%;<br />P>0.05) and embryo survival (63.6 vs 56.7%; P>0.05). In conclusion, the results demonstrated that treatments B) and<br />C) did not improve superovulatory response compared to A); for embryo cryopreservation the V3 method can successfully<br />be used for embryo transfer in ewes. |
---|---|
ISSN: | 1594-4077 1828-051X |