Effect of clinically-related factors on in vitro blastocyst development after equine ICSI

Male Factors Affecting the Success of Equine In Vitro Embryo Production by Ovum Pickup-Intracytoplasmic Sperm Injection in a Clinical Setting

“…We found that only the stallions with almost all immotile spermatozoa after thawing (D) were not able to produce any embryo, after ICSI of abattoir oocytes, while the other three categories of stallions, were able to generate embryos after ICSI at the same rate ( Table 2). Some variability between stallions were also reported by Choi et al [2] comparing a control high fertility ICSI stallion with two stallions of which one (FD) was frozen-thawed twice before use (Table 3). Moreover in another ICSI study done in our laboratory using abattoir oocytes, Colleoni et al [13] compared the frozen semen of five in vivo fertile stallions with the semen of five stallions (fresh semen of 2 stallions, frozen semen of 3 stallions) unable to establish pregnancy in vivo but with motile spermatozoa available for ICSI (Table 4).…”

“…For ICSI this is not a critical aspect since usually few motile spermatozoa are required to fertilise the oocytes available in any given day. Choi et al [2] compared 4 preparation techniques for one stallion of low fertility and found that the combination of DG and SU was the best both for cleavage and blastocyst development ( Table 6). We have compared retrospectively the clinical data of three stallions where the semen was prepared either by DG or SU (Table 7).…”

“…These batches might have been produced in different stallion stations and times, at different age of the stallion and be stored in optimal or sub optimal conditions or stored and managed inappropriately up to even being inadvertently thawed-refrozen and irreparably damaged. Choi et al [2] used such damaged semen (liquid nitrogen failure) for ICSI on abattoir oocytes and found low cleavage and no embryo development. When they combined ICSI of these immotile spermatozoa with parthenogenetic activation they observed an increased cleavage rate but still no embryo development (Table 8), as we found in our previous study [12] with one particular stallion that had all immotile spermatozoa.…”

“…Equine assisted reproductive technologies such as Ovum Pick Up (OPU), intracytoplasmic sperm injection (ICSI), embryo culture and slow freezing of in vitro produced embryos have been developed over the last fifteen years and are becoming an established service offered by a increasing number of clinics [1][2][3][4]. The candidates for these technologies are both mares and stallions that are destined to ART for a variety of reasons related to infertility, subfertility, season, age, commercial demand for a progeny, desire not to interfere with sporting activities.…”

“…In a later study in a larger sample of stallions [13] M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 we found however a male factor effect both early at cleavage stage and later at blastocyst development stage. Other authors identified stallions with different performances after ICSI [2,14].…”