The seasonal and ovarian status effects on in vitro production of domestic cat embryos between Equator and Tropic of Capricorn

Ovarian and Oocyte Morphology During the Spring-Summer and Fall-Winter in Queens (Felis catus) Kept in a Tropical Climate

The objective of this study was to investigate the effects of seasonality and phase of the estrous cycle on ovarian and oocyte morphology in domestic cats kept in a tropical region. The ovaries from 23 queens were collected after elective ovariohysterectomy at different stages of the estrous cycle and were classified according to the season upon collection (spring/summer vs. fall/winter). Based on the findings, we concluded that queens in tropical regions experience no seasonal influence on oocyte quality, but there is a minimal effect on ovarian morphology, with an increase in ovarian length during proestrus/estrus in the spring/summer period.

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

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.

Total Cell Number and its Allocation to Trophectoderm and Inner Cell Mass in In Vitro Obtained Cats' Blastocysts

The aim of this study was to evaluate the developmental kinetics of cats' blastocysts in connection with their morphology and blastomeres allocation to trophoblast or embryoblast cells. We examined gross blastocyst morphology and the total number of blastomeres together with its allocation to inner cell mass (ICM) or trophectoderm (TE) cells in pre-implantation feline embryos obtained from 6th to 9th day of in vitro culture. From all the investigated embryos, 61.8% developed to early blastocyst, 37.4% to full and 7.6% to hatching blastocyst stage. The total cell number (TCN) varied form 58 cells in early day 6 to 245 in hatching day 8 blastocyst, with the mean 84.9 cells in early, 156.7 in full, and 204.4 in hatching ones. Day 8 blastocyst had the highest number of total cells, together with the highest mean number of ICM regardless of its morphological assessment. Early blastocyst (apart from day 6) had the highest number of arrested cells, while dead cells were the highest in full day 9 blastocyst. More data about the relationship between blastocyst development and morphology would facilitate the selection of optimal blastocysts for further procedures.