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

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).