Species-Specific Sperm-Egg Interaction Affects the Utility of a Heterologous Bovine In Vitro Fertilization System for Evaluating Antelope Sperm

Abstract

The purpose of this study was to evaluate cryopreserved fringe-eared (FE) oryx (Oryx gazella callotis) sperm function using a heterologous in vitro fertilization (IVF) system previously developed to study scimitar-horned (SH) oryx (Oryx dammah) spermatozoa. Semen was collected by electroejaculation from FE oryx (n = 2) and SH oryx (n = 2), evaluated immediately postcollection, and cryopreserved. Thawed spermatozoa were evaluated for motility, forward progression, and acrosomal status immediately post-thaw, after Percoll-separation, and 1, 2, 3, and 8 h after culture in IVF medium. In vitro-matured cow oocytes (n = 924) were inseminated with either domestic bull, FE, or SH oryx spermatozoa and after an 8-h coincubation period, half the oocytes were fixed and examined for sperm penetration, polyspermy, and male pronuclear formation. The remaining oocytes were placed into in vitro culture and evaluated for cleavage after 48 h. Overall, there were no between-species differences in sperm motility and acrosome integrity. However, an effect of time (P < 0.05) and a species-by-time interaction (P < 0.05) were detected for both parameters. Penetration, male pronuclear formation, and embryo cleavage were high (>90%, >85%, and >70%, respectively) for oocytes inseminated with domestic bull and SH oryx spermatozoa and did not differ (P > 0.05) between species. In contrast, very few oocytes (2.8%, 4 of 141) inseminated with FE oryx sperm were penetrated. Cleavage was rare (8.0%, 16 of 200) in oocytes inseminated with FE oryx spermatozoa and did not differ (P > 0.05) from that in parthenogenetic controls (4.2%, 3 of 72). Furthermore, FE oryx spermatozoa were incapable of penetrating zona-free cow oocytes. These results indicate that species-specific differences in gamete interaction may exist even between very closely related nondomestic bovids.

Developmental Competence of Embryos Derived from Reciprocal In Vitro Fertilization between Yak (Bos grunniens) and Cattle (Bos taurus)

“…The presumptive zygotes were randomly examined for evidence of fertilization according to previously described methods [11,16]. Briefly, at 18 hpi, the ova were removed from the culture dish.…”

“…The number of zygotes that cleaved was recorded at 48 h post insemination (hpi). The culture medium was changed at 96 hpi, and blastocyst development was determined on Days 7 to 9 (Day 0: day of insemination).The presumptive zygotes were randomly examined for evidence of fertilization according to previously described methods [11,16]. Briefly, at 18 hpi, the ova were removed from the culture dish.…”

Heterologous murine and bovine IVF using bottlenose dolphin (Tursiops truncatus) spermatozoa

“…Parthenogenetic activation was within the expected levels [7,75,76] murine. On the other hand, the murine maternal inherited centrosome could confer higher instability, detrimental to hybrid embryo formation.…”

“…Previous 475 studies have described cross species fertilization of zona intact oocytes between phylogenetically related species, such as domestic and endangered felids [4,[41][42][43], or between bovine and equine [44], as well as between bovine and artiodactyls [5][6][7][8]45]. …”

“…Due to the specificity of the zona pellucida, heterologous IVF application is generally limited to phylogenetically closely related species. Heterologous IVF has been successful when co-incubating oocytes and 55 spermatozoa from cat and tiger spermatozoa [4], bovine and goat, ram or antelope [5][6][7] and sheep and deer respectively [8]. Sometimes, it has been necessary to remove the ZP to achieve heterologous IVF as in the case of dolphin spermatozoa and hamster oocytes [9].…”