First attempts for vitrification of immature oocytes in donkey (Equus asinus): Comparison of two vitrification methods

Metabolic profiling of preovulatory follicular fluid in jennies

“…The time interval between animal death and harvesting of PFF samples could lead to postmortem accumulation of lactate (Tews et al, 1963), as reported by a previous study carried out with equine oviductal fluid (González-Fernández et al, 2020). TCM-199 is the basic culture medium most used for the formulation of IVM media in horses and in the attempts carried out so far in donkeys (Goudet et al, 2015;Deleuze et al, 2018;Zhao et al, 2011;Abdoon et al, 2014;Douet et al, 2019). When comparing our results to the metabolites described in TCM-199 culture medium (see Table 2), we detected that only 11 of the 27 metabolites found in jenny PFF were present in TCM-199 medium.…”

“…In addition, acetate and valine concentrations were considerably higher in donkey PFF than in TCM-199 medium, whereas glycine, isoleucine, leucine, and threonine were less concentrated in the former than in the latter. Although the TCM-199 medium is routinely enriched with fetal bovine serum (FBS) to perform oocyte IVM (Goudet et al, 2015;Deleuze et al, 2018;Zhao et al, 2011;Abdoon et al, 2014;Douet et al, 2019), this supplement only provides eight additional metabolites (Caseiro et al, 2018). According to the metabolites described in two available commercial FBS formulations by Caseiro et al (Caseiro et al, 2018), supplementation with FBS would provide a series of metabolites.…”

“…Furthermore, three of the eight metabolites added through FBS supplementation (isoleucine, leucine, and threonine) are in excess in TCM-199 compared to jenny PFF (see Table 2). These differences suggest that the established maturation medium used for IVM of horse oocytes (i.e., TCM-199 + FBS) may not be suitable for donkeys, which could contribute to explain the poor results hitherto obtained (Goudet et al, 2015;Deleuze et al, 2018;Zhao et al, 2011;Abdoon et al, 2014;Douet et al, 2019).…”

“…In addition, IVP of embryos and their cryopreservation would allow the preservation of the male and female genetics, being a fast method to restore a breed (Douet et al, 2017;Woelders et al, 2012). Although the first experiments of oocyte IVM (Goudet et al, 2015;Deleuze et al, 2018;Zhao et al, 2011;Abdoon et al, 2014), in vitro fertilization (IVF) (Goudet et al, 2015;Deleuze et al, 2018) and even vitrification (Douet et al, 2019) were performed in jennies, maturation and sperm penetration rates are still very low and no IVP embryos have been obtained yet.…”

New Strategies for Conservation of Gentile di Puglia Sheep Breed, an Autochthonous Capital of Millennial Tradition in Southern Italy

“…However, IVM is challenging for cryopreserved immature COCs due to membrane damage to CCs [12] and their physical/functional detachment from the oocyte, caused by transzonal projections' sensitivity to cryoprotectants and low temperatures [12,13]. In the last 20 years, the vitrification/warming of immature COCs from adult subjects has been applied to several domestic large (sheep [12,[14][15][16][17][18][19][20][21][22], cow [23][24][25][26][27], buffalo [28][29][30], goat [31], pig [32][33][34][35], horse [36][37][38][39][40][41], donkey [42]) and small (cat [43][44][45][46][47][48], dog [49]) animal species, with various results, depending on intrinsic species-specific oocyte features. Although the results of IVM, embryo development, and blastocyst rate following immature COC vitrification are still less satisfactory compared to fresh COCs, live births have been reported in bovine [50], swine [33], equine [38,…”