In vitro maturation of collared peccary (Pecari tajacu) oocytes after different incubation times

Abstract

Oocyte in vitro maturation (IVM) is the first step of the in vitro reproductive technologies that enables mature oocytes to be generated ex vivo and after used for embryo production. In this sense, the establishment of culture environment, as oocyte incubation time, is essential for the success of the IVM. Therefore, the study was carried out to investigate the relationship between the meiotic potential and the IVM times of collared peccary oocytes, wild mammals of great commercial and ecological interest. Thus, ovaries were collected of females derived from captivity and transported to the laboratory within 1 hour of slaughtering. The oocytes derived from follicles (3-6mm in diameter) were recovered by aspirated and sliced. Good quality oocytes (evenly granulated cytoplasm with a least one layer of surrounding cumulus cells) were selected and subjected to culture in TCM 199 supplemented with 10µg/mL FSH, 10% FBS and 100µM cysteamine at 38.5°C, 5% CO2 and maximum humidity for 24 or 48 hours. After the incubation period, the nuclear status, the presence of first polar body and the expansion of cumulus cells of oocytes were assessed. The data obtained were analyzed by Fisher exact test (P<0.05). A total of four sessions (2-3 females per session) were performed, resulting in eighteen aspirated and sliced ovaries with normal morphological characteristics. An oocyte recovery rate of about 83.1% (59/71) was obtained with 3.3 oocytes/ovary and 2.3 viable oocytes/ovary. After different incubation times, differences (P<0.05) were observed in 24 and 48 hours for expansion of the cumulus cells (38.1% vs. 100%), presence of first polar body (52.4% vs. 90.5%) and nuclear status in second metaphase (19.0% vs. 76.2%), respectively. In conclusion, 48 hours is suitable time for the in vitro maturation of oocytes derived from collared peccaries when compared to the time of 24 hours, according to the meiotic potential observed. Additional studies should be conducted to improve the quality of the oocyte culture environment, as medium composition, aiming to obtain viable mature oocytes for other in vitro biotechnologies.

Embryo production by in vitro fertilization in wild ungulates: progress and perspectives – A Review

“…Likewise, in collared peccary, 48 h IVM was more efficient than 24 h for the nuclear stage, similar to the time for swine (76.2% vs. 19.0%; Borges et al, 2018). In vicunas, 41% of oocytes matured in vitro after 27 h, which is a shorter time than for other domesticated camelids (Chaves et al, 2004).…”

Assisted Reproductive Techniques on South American Wild Mammals

“…In this study, ear fragments (9.0 mm 3 ) were vitrified in a solution containing DMEM plus 3.0 M DMSO, 3.0 M EG, 0.25 M sucrose, and 10% fetal calf serum. The histological analysis and IVC showed that few tissue damages were associated with solid-surface vitrification [116]. Moreover, all cells resulting in vitrified and noncryopreserved fragments showed the characteristics of suitable fibroblasts: fusiform features with oval nucleus in the center.…”

“…In collared peccary [114,116], vitrification techniques (conventional or solid-surface vitrification) may be used for cryopreservation of somatic tissue, allowing the isolation of viable cells. In this study, ear fragments (9.0 mm 3 ) were vitrified in a solution containing DMEM plus 3.0 M DMSO, 3.0 M EG, 0.25 M sucrose, and 10% fetal calf serum.…”

Potential role of intraspecific and interspecific cloning in the conservation of wild mammals

“…Already, different hormonal combinations of FSH, LH and 17β-estradiol did not alter the maturation rates in oocytes derived from lions ( Panthera leo ; Fernandez-Gonzalez et al , 2015). In the collared peccary ( Pecari tajacu ), we proved that oocytes need 48 h to achieve maturation instead of 24 h, according to the expansion of the cumulus cells (100% vs. 38.1%), the presence of first polar body (90.5% vs. 52.4%), and the status of the nucleus in the second metaphase (76.2% vs. 52.4%), respectively (Borges et al , 2018c).…”