Effect of deslorelin acetate treatment in oocyte recovery and in vitro embryo production in domestic cats

Abstract

Objectives The present study investigated the effect of contraceptive treatment with deslorelin acetate on in vitro embryo production and oocyte recovery in domestic queens. Methods Twenty-one mature domestic cats were used. Eleven queens (treated group) and one tom were kept in an experimental cattery, and 10 queens were privately owned (control group). When in interestrus or diestrus (day 0) a deslorelin acetate implant (Suprelorin, 4.7 mg/animal) was inserted into the subcutaneous tissue of the interscapular region in all queens in the treated group. After 6 months of treatment, all animals were ovariohysterectomized, and the ovaries were used for in vitro embryo production. Percentage of cleavage was determined 18 h after oocyte insemination and blastocyst formation was assessed on the eighth day of culture. The rate of cumulus-oocyte complexes (COCs) recovery was analyzed by an unpaired t-test. The cleavage and blastocyst rates were expressed as percentages and analyzed by Fisher's exact test. All analyses were performed using GraphPad Prism v5.0, with P <0.05 set as the level of significance. Results In the treated group, we recovered 8.3 ± 1.15 grade I COCs per queen; the cleavage rate was 60% and the blastocyst rate was 36%. In the control group, we recovered 18.4 ± 3.21 grade I COCs per queen; the cleavage rate was 55.97% and the blastocyst rate was 34%. Forty percent of treated females did not produce any blastocysts. In the treated group, we observed a significant decrease in COC recovery. Although there was no significant difference in cleavage and blastocyst rates between groups, 40% of treated females did not produce any blastocysts. Conclusions Recovery of grade I COCs is negatively affected by deslorelin treatment in domestic cats. Regarding embryo production, new studies are still necessary to evaluate the success of this technique owing to the individual effect caused by deslorelin acetate.

Reversible Control of Reproduction In Queens: Mastering the use of reproductive drugs to manipulate cyclicity

“…Feline anoestrus in privately owned queens following use of the 9.4 mg deslorelin implant is reported to last 26 ± 4 months. 93 Fertility following deslorelin-induced anoestrus has been confirmed in all studies in which this has been investigated, based on the capacity to ovulate, 83 the return to normal seasonal cyclicity, 84 the production of fertilisable oocytes 85 and queens conceiving and giving birth to normal litters following the use of the 4.7 mg, 84 as well as the 9.4 mg, 93 implant. The scope to induce such a prolonged phase of reproductive quiescence that then allows for full reversibility to normal fertility is a great advantage for feline practitioners.…”

“…82 When 10 queens were implanted during the follicular phase (2-4 days after the beginning of oestrus), oestrus manifestations stopped 4 days later, but resumed in one queen on day 6. 84 Indeed, the occasional occurrence of vaginal epithelial keratinisation and/or resumption of oestrus manifestations has been reported during the first few months following implanta-tion; 81,82,84,85,87,88 such heats, which are difficult to explain, tend to be isolated and self-limiting.…”

“…82 Additionally, galactorrhoea was observed in a queen 2 months following implantation with deslorelin; the queen was not pregnant and early abortion was ruled out. 85 As mammary signs did not resolve following two courses of treatment with meter-goline, the implant was removed and 20 days later milk secretion ceased. 85…”

“…85 As mammary signs did not resolve following two courses of treatment with meter-goline, the implant was removed and 20 days later milk secretion ceased. 85…”

“…Almost all studies on the use of deslorelin in queens have documented the occurrence of oestrus post-treatment in varying proportions of the cats. [81][82][83][84][85][86][87] Such oestrus is fertile and the queen will conceive if mismated 87 or artificially inseminated. 74 The occurrence of oestrus depends on the stage of the reproductive cycle at the time of treatment.…”