Comparison of the Morphology and Developmental Potential of Oocytes Obtained from Prepubertal and Adult Domestic and Wild Cats

Abstract

The aim of the study was to compare the morphology and developmental potential of oocytes obtained from adult and prepubertal domestic cats (Felis catus) and wild cats (Lynx lynx, Leptailurus serval, Felis manul, Panthera tigris altaica). The average number of oocytes obtained from an adult domestic cat was 23 ± 11, which was significantly lower than from kittens (43 ± 29). A similar number of oocytes was derived from adult Pallas’s cats (28 ± 8), and serval (30). The lowest number of oocytes was collected from the lynx (5 ± 3). No oocytes were obtained from newborn Amur tiger while in the case of older domestic and Pallas’s cat and lynx kittens (1–3 months) 43, 48 and 41 oocytes were collected, respectively. Significant differences (p < 0.001) were observed between the number of oocytes with dark cytoplasm from adult and prepubertal animals of all analyzed species. The diameter of oocytes from adult and prepubertal animals was similar in all species, and was on average 161 ± 4 µm for oocytes with dark cytoplasm and 150 ± 18 µm for oocytes with light cytoplasm. In all species, oocytes with light cytoplasm were significantly smaller (p < 0.05) than dark ones, and their population was more diverse. Results of in vitro maturation of the domestic and wild cat′s oocytes obtained from adult and prepubertal females were similar (47–52%). The cleavage rate after in vitro fertilization (IVF) was lower for prepubertal than adult domestic cats (42 vs. 51%; p < 0.05%). Moreover, we observed differences in the quantity (28 vs. 39%; p < 0.05) and quality of blastocysts and even greater problems with hatching blastocysts from prepubertal kittens (8 vs. 19%; p < 0.001). More blastomeres were detected in blastocysts of adult cats. They also demonstrated significantly higher number of inner cell mass (ICM) (p < 0.001) and higher number of trophoblast cells (TE) (p < 0.05).

Current State of In Vitro Embryo Production in African Lion (Panthera leo)

“…Slightly more oocytes could be retrieved from prepubertal females, and surprisingly, developmental competence was also higher than after puberty. This is in contrast to the findings of other researchers who described superior developmental potential of oocytes of adult animals in mice, sheep, cattle, and felids [ 29 , 30 , 31 , 32 ], but this might be founded in the heterogeneity of the adult lioness group, including severely sick, hormonally affected (e.g., due to contraception), or post-reproductive females. Post-reproduction under human care conditions means the absence of pregnancies in formerly proven breeders and can be overcome to some extent by assisted reproduction as long as oocyte retrieval is still possible.…”

“…In contrast to domestic cats, however, extensive cumulus expansion in lion oocytes could practically never be observed, and maturation was therefore previously extended to 32–36 h. The optimal insemination time point was defined as after 32 h for the domestic cat [ 3 ], but with progress in culture systems, contemporary research groups tend to reduce maturation to 24 h [ 26 , 29 ]. However, a domestic-cat-adapted culture system might be suboptimal for African lions, suggesting a prolonged time is necessary to complete maturation.…”

Prevalence of Protozoa Infections in Domestic Cats

“…Another factor that influences protozoal infection is gender. Female cats have a higher risk of infection than male cats because female cats are more active in looking for food to support their reproductive status, such as being pregnant for the continuation of the fetus [20]. Age affects the incidence of infection at the level of protozoa.…”

Polish Journal of Veterinary Sciences

“…Besides, the gonads of prepubertal cats were indicated as a potentially rich source of good-quality oocytes for assisted reproductive techniques. Studies have emphasized that the number and quality of oocyte decrease with age (Kochan et al 2021). The highest GDF-9 levels in prepubertal cats suggest that GDF-9 may reflect the number and quality of oocytes, and aging may affect the concentrations of this factor.…”