Quantity and quality of oocytes recovered from donor bitches of different ages

Quantification of multi-oocyte follicles in ovaries of bitches

ABSTRACT The objective of this study was to quantify the number and frequency of monocyte (MnOF) and multi-oocyte (MtOF) follicles in ovaries of bitches subjected to ovary salpingohysterectomy (OSH). Right and left ovaries of 38 bitches were collected after OSH, prepared, and a histological analysis was carried out. The ovaries were subjected to surface and deep histological cuts; the follicles were classified, and the number of follicles and cumulus oophorus complexes (COC) per follicle were quantified for each histological cut. MnOF and MtOF were found in all ovaries, at different developmental stages; primary follicles were grouped in the ovarian cortex, and follicles at other follicular stages presented a random distribution. MtOF containing two, three, four, or more COC were found in the ovaries of bitches, with a decreasing frequency trend, according to the number of COC in the MtOF. The effect of the age, number of estrus, estrus interval, and number of progenies per delivery was not significant for the number and frequency of MtOF in the ovaries of the bitches, whereas the size, number of pregnancies, use and number of contraceptive applications had some effect on the number and frequency of MtOF in the ovaries of the bitches.

Mummified papyraceous fetuses in the abdominal cavity of an elderly female dog with pyometra

This paper reports on a rare case of fetal papyraceous mummification after asymptomatic uterine rupture in an elderly female dog with pyometra. The patient had a history of mating six months before the examination but no apparent signs of gestation or parturition. Exploratory laparotomy was used to identify a rupture of the left uterine horn and the presence of cystic endometrial hyperplasia and pyometra. Two mummified papyraceous fetuses were observed in the abdominal cavity and had adhered to the spleen, pancreas, intestine and omentum. Ovariehysterectomy and corrective surgery were performed. The patient had remained healthy after uterine rupture until a new estrous cycle and the development of pyometra. Bitches that are 10 years old or more are predisposed to implantation failure, pregnancy or parturition problems and they should not be breed to avoid complications.

Increasing age influences uterine integrity, but not ovarian function or oocyte quality, in the cheetah (Acinonyx jubatus)

Although the cheetah (Acinonyx jubatus) routinely lives for more than 12 yr in ex situ collections, females older than 8 yr reproduce infrequently. We tested the hypothesis that reproduction is compromised in older female cheetahs due to a combination of disrupted gonadal, oocyte, and uterine function/integrity. Specifically, we assessed 1) ovarian response to gonadotropins; 2) oocyte meiotic, fertilization, and developmental competence; and 3) uterine morphology in three age classes of cheetahs (young, 2-5 yr, n = 17; prime, 6-8 yr, n = 8; older, 9-15 yr, n = 9). Ovarian activity was stimulated with a combination of equine chorionic gonadotropin and human chorionic gonadotropin (hCG), and fecal samples were collected for 45 days before gonadotropin treatment and for 30 days after oocyte recovery by laparoscopy. Twenty-six to thirty hours post-hCG, uterine morphology was examined by ultrasound, ovarian follicular size determined by laparoscopy, and aspirated oocytes assessed for nuclear status or inseminated in vitro. Although no influence of age on fecal hormone concentrations or gross uterine morphology was found (P > 0.05), older females produced fewer (P < 0.05) total antral follicles and oocytes compared to younger counterparts. Regardless of donor age, oocytes had equivalent (P > 0.05) nuclear status and ability to reach metaphase II and fertilize in vitro. A histological assessment of voucher specimens revealed an age-related influence on uterine tissue integrity, with more than 87% and more than 56% of older females experiencing endometrial hyperplasia and severe pathologies, respectively. Our collective findings reveal that lower reproductive success in older cheetahs appears to be minimally influenced by ovarian and gamete aging and subsequent dysfunction. Rather, ovaries from older females are responsive to gonadotropins, produce normative estradiol/progestogen concentrations, and develop follicles containing oocytes with the capacity to mature and be fertilized. A more likely cause of reduced fertility may be the high prevalence of uterine endometrial hyperplasia and related pathologies. The discovery that a significant proportion of oocytes from older females have developmental capacity in vitro suggests that in vitro fertilization and embryo transfer may be useful for "rescuing" the genome of older, nonreproductive cheetahs.

Attempts at in vitro fertilization and culture of in vitro matured oocytes in sei ( Balaenoptera borealis) and Bryde's ( B. edeni) whales

The cumulus-oocyte-complexes (COCs) recovery rates with respect to reproductive status per sei (Balaenoptera borealis) and Bryde's (B. edeni) whales were determined in Experiment 1. The number of COCs recovered ranged from 16.0 to 30.6 and from 6.7 to 26.8 per sei and Bryde's whales, respectively. The effects of COCs grades and protein supplementation in embryo culture medium on development of in vitro fertilized (IVF) embryos were evaluated in sei and Bryde's whales in Experiment 2. The COCs were classified into either Grade A (COCs with five or more layers of compact cumulus cells) or Grade B (COCs with less than five layers of compact or expanded cumulus cells) before being cultured for IVM. The cleavage (12.0 to 19.5%), 4-cell (8.0 to 12.0%) and 8-cell (4.0 to 8.0%) formation rates in sei whales did not vary significantly between embryos derived from either grade A or B oocytes and between embryos cultured in either fetal whale serum (FWS)- or bovine serum albumin (BSA)-supplemented medium. The cleavage (4.0 to 14.8%), 4-cell (0.0 to 7.5%) and 8-cell (0.0 to 2.6%) formation rates in Bryde's whales did not vary significantly between embryos derived from either grade A or B oocytes and between embryos cultured in either FWS- or BSA-supplemented medium. The grade B oocytes cultured in FWS-supplemented medium developed to morula stage (1.1%) in sei whales. In conclusion, the present study indicates that IVF in sei whales is possible to achieve cleaved embryos developing to morula stage. This is the first in vitro embryo production attempt in sei and Bryde's whales.

Recovery rate, morphological quality and nuclear maturity of canine cumulus-oocyte complexes collected from anestrous or diestrous bitches of different ages

Canine cumulus-oocyte complexes (COC) were recovered from ovaries of post-pubertal animals (1-3, 4-6 and 7-10 years old) at different ovarian estrous phases (anestrus and diestrus). The number of COCs, and the number and nuclear maturity of high-quality (grade-1) oocytes were assessed. For all animals, no significant differences were found between the two reproductive phases relatively to the total number of COCs and grade-1 oocytes recovered. However, significant higher numbers of COCs were recovered from young than from elderly animals, and the proportion of grade-1 oocytes was also significantly higher in the younger group than in the other two age-groups. Of 226 grade-1 oocytes, 73% were at the germinal vesicle stage (GV), 10% had resumed meiosis (9% at germinal vesicle breakdown; 1% at metaphase-I) and 17% were degenerated. A significant effect of the reproductive phase on oocyte nuclear maturity was found only for adult animals, with a higher number of GV oocytes being found at anestrous (79%) due to higher rates of meiosis resumption (34%) at diestrous. The high number of grade-1 oocytes with meiosis resumption and fragmented or unidentified nuclear contents, indicates that current criteria for the selection of viable canine COCs are not optimized and need a new definition.