248 IN VITRO PRODUCTION OF CATTLE × BUFFALO HYBRID EMBRYOS USING BOVINE OOCYTES AND AFRICAN BUFFALO (SYNCERUS CAFFER CAFFER) EPIDIDYMAL SPERM

2007 ◽  
Vol 19 (1) ◽  
pp. 240
Author(s):  
O. D. Owiny ◽  
D. M. Barry ◽  
M. Agaba ◽  
R. A. Godke
Keyword(s):  
Bison Bison ◽  
Abnormal Development ◽  
African Buffalo ◽  
Syncerus Caffer ◽  
Epididymal Sperm ◽  
In Vitro Production ◽  
Cleavage Rate ◽  
Cell Stage ◽  
Bovine Oocytes

Interspecies hybridization of bovids occurs between domestic cattle and at least 3 other species: the American bison (Bison bison), yak (Bos grunniens), and banteng (Bos banteng). Birth of a cattle � buffalo hybrid was reported in Russia, but the report was never authenticated. Such hybrids could be important in improving livestock production and managing diseases that impede production in tropical Africa. We investigated hybridization between cattle and their closest African wild relative, the African buffalo (Syncerus caffer caffer). In an attempt to produce pre-implantation cattle � buffalo hybrid embryos in vitro, matured bovine oocytes were subjected to a standard IVF procedure with either homologous (n = 1166 oocytes) or heterologous (n = 1202 oocytes) buffalo epididymal sperm. After IVF, 67.2% of the oocytes inseminated with homologous sperm cleaved. In contrast, insemination with buffalo sperm resulted in a 4.6% cleavage rate. Cleavage was also slower in hybrids than in cattle embryos. Up to 52.2% of cleaved homologous embryos progressed to the morula stage compared with 12.7% for hybrids. No hybrid embryos developed beyond the 16-cell stage, whereas 40.1% of the cleaved bovine embryos developed to the blastocyst stage. Developmental anomalies such as polyspermy, uneven cleavage, vacuolization, and absence of nuclei in some blastomeres were common in the hybrid embryos. We conclude that interspecies fertilization of cattle oocytes with African buffalo sperm occurs in vitro and that the barrier to hybridization is in the early stages of embryonic development. Also, chromosomal disparity is the likely cause of fertilization abnormalities, abnormal development, and subsequent arrest, impairing the formation of pre-implantation hybrid embryos. Investigation into developmental abnormalities, including reciprocal hybridization and genetic studies of the hybrid embryos, are recommended.

In-vitro production of african buffalo (Syncerus caffer) embryos derived from follicular oocytes and epididymal sperm

1995 ◽  
Vol 43 (1) ◽  
pp. 322 ◽  
Author(s):  
D.G. Shaw ◽  
A. Kidson ◽  
J.O. van Schalkwyk ◽  
P. Bartels ◽  
N.M. Loskutoff ◽  
...  
Keyword(s):  
African Buffalo ◽  
Syncerus Caffer ◽  
Epididymal Sperm ◽  
In Vitro Production ◽  
Vitro Production

44 IN VITRO DEVELOPMENT OF INTERSPECIES NUCLEAR TRANSFER EMBRYOS GENERATED WITH BOVINE OOCYTES AND EQUINE SKIN FIBROBLASTS

2011 ◽  
Vol 23 (1) ◽  
pp. 128
Author(s):  
J. Lee ◽  
J. Park ◽  
Y. Chun ◽  
W. Lee ◽  
K. Song
Keyword(s):  
Nuclear Transfer ◽  
Polar Body ◽  
Donor Cell ◽  
Skin Fibroblasts ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
Cell Stage ◽  
Bovine Oocytes

Study for equine somatic cell nuclear transfer (SCNT) is an attractive field for research, but it has not been a major field of study because it is hard to obtain a sufficient number of ovaries and it takes a lot of time and effort for the recovery of oocytes matured in vivo by ovum pickup. It was reported that the bovine cytoplast could support the remodelling of equine donor cells (Zhou et al. 2007 Reprod. Domest. Anim. 42, 243–247). The objectives of this study are 1) to monitor the early events of equine SCNT by interspecies SCNT (isSCNT) between bovine cytoplast and equine donor cell, and 2) to investigate the developmental competence of isSCNT embryos. Bovine oocytes were recovered from the follicles of slaughtered ovaries, and matured in TCM-199 supplemented with 10 mU mL–1 FSH, 50 ng mL–1 EGF, and 10% FBS at 39°C under 5% CO2 in air for 22 h. Fibroblasts derived from bovine or equine skin tissues were synchronized at G0/G1 stage by contact inhibition for 72 h. After IVM, oocytes with polar body were enucleated and electrically fused with equine or bovine skin fibroblasts (1.0 kV cm–1, 20 μs, 2 pulses). Fused couplets were activated with 5 μM ionomycin for 4 min followed by 5 h culture in 10 μg mL–1 cycloheximide (CHX) and/or 2 mM 6-DMAP, and cultured in modified synthetic oviduct fluid (mSOF) at 39°C under 5% CO2, 5% O2, and 90% N2 for 7 days. All analyses were performed using SAS (version 9.1; SAS Institute, Cary, NC, USA). The cleavage rate of isSCNT embryos derived from equine cell was not different (252/323, 78.7%; P = 0.94) from that of SCNT embryos derived from bovine cell (230/297, 79.2%). However, the rate of isSCNT embryos developed to over 8-cell stage was lower (3.3%; P < 0.0001) than that of bovine SCNT embryos (39.4%), and total cell number of isSCNT embryos developed to over 8-cell stage was lower (17.5, n = 12; P < 0.0001) than that (80.8, n = 110) of bovine SCNT embryos. Also, the rate of blastocyst formation of isSCNT embryos (0/323; 0.0%) was lower (P < 0.0001) than that of bovine SCNT embryos (83/297; 29.3%). Meanwhile, reconstructed oocytes for isSCNT were fixed at 8 h after activation to investigate the formation of pseudo-pronucleus (PPN) after post-activation treatment with CHX or CHX+6-DMAP. The ratio of oocytes with single PPN after treatment with CHX+6-DMAP (26/35; 74.3%) was not different (P = 0.63) from that of oocytes treated with CHX (24/36; 68.1%). Although isSCNT embryos derived from bovine cytoplast and equine donor cell could not develop to more than the 16-cell stage, it is believed that the results of this isSCNT study could be used for the preliminary data regarding the reprogramming of donor cell in equine SCNT.

57 DEVELOPMENTAL CHARACTERISTICS OF LATER-STAGE PORCINE EMBRYOS PRODUCED IN VIVO OR IN VITRO

2016 ◽  
Vol 28 (2) ◽  
pp. 158 ◽  
Author(s):  
H. Callesen ◽  
P. Holm
Keyword(s):  
In Vitro Culture ◽  
Cell Mass ◽  
Morphological Characteristics ◽  
Viable Cell ◽  
Outer Diameter ◽  
In Vitro Production ◽  
Cleavage Rate ◽  
Cell Stage

Kinetics and morphological characteristics during pre-implantation embryo development are well established in most mammals. In porcine, such studies are few because of limited use of in vitro culture, but this has changed in recent years due to increasing use of in vitro production and cloning. Therefore, additional characterisation of especially later stage porcine embryos is needed. Here we studied in vitro development of porcine in vivo- and in vitro-derived zygotes collected from weaned, inseminated sows (slaughtered 2 days after first insemination; in vivo group, n = 112) or produced from immature oocytes from sow ovaries (matured and fertilized: Theriogenology 63, 2040–2052; in vitro group, n = 210). Both types were cultured for 7 days in vitro (Theriogenology 63, 2040–2052) in a time-lapse system (Theriogenology 50, 1285–1299) with images recorded every 0.5 h. Individual embryos were followed and characterised for stage and quality from first cleavage. The following was recorded: (i) zygote: inner (i.e. ooplasma) and outer diameter [i.e. including zona pellucida (ZP)], ZP thickness; (ii) compact morula: areas of compacted inner cells and of cellular debris; (iii) blastocyst: partial or total collapse of blastocoelic cavity and diameter at maximal expansion immediately before hatching. At the 1-cell stage, no difference was found between in vivo v. in vitro zygotes in ZP diameter (approximately 150 µm) and thickness (approximately 15.6 µm). In both groups, cleavage rate was around 65%, but more in vivo (85%) than in vitro (28%) zygotes developed beyond the morula stage. Embryos of both types that did not develop to this stage (n = 212) blocked predominantly at the 1st (50%) or 2nd (21%) cell cycle. Cell cycles were generally shorter in in vivo v. in vitro zygotes from compact morula until the hatched blastocyst stage (mean 128 v. 139 h from the 2-cell stage for in vivo v. in vitro; P < 0.05). Compacted in vivo morulae were 25% larger than in vitro, and the debris area was more than twice as large in in vitro. Hatching occurred after approximately two collapses in both in vivo and in vitro but at a larger ZP diameter in vitro. See Table 1 for further details. This study illustrates differences and similarities between morphology and developmental kinetics of in vivo- and in vitro-derived porcine zygotes, but also how various morphological characteristics indicate some of the possible causes of the reduced developmental ability of in vitro embryos. The in vitro period seems to result in more stressful conditions for the embryos, both during early development, but also during the later stages leading to the hatching process. Thus, further optimization of in vitro culture conditions is still needed in porcine. Table 1.Compact morula (CM) viable cell mass and debris, hatched blastocyst (HB) diameter, and early-hatched blastocyst (EB-XB) and expanded-hatched blastocyst (XB-HB) collapses for in vivo- and in vitro-derived zygotes

IGF-I slightly improves nuclear maturation and cleavage rate of bovine oocytes exposed to acute heat shock in vitro

Zygote ◽  
2014 ◽  
Vol 23 (4) ◽  
pp. 514-524 ◽  
Author(s):  
Qi Meiyu ◽  
Di Liu ◽  
Zvi Roth
Keyword(s):  
Growth Factor ◽  
Heat Shock ◽  
Developmental Competence ◽  
Cortical Granule ◽  
Cleavage Rate ◽  
Cell Stage ◽  
Nuclear Maturation ◽  
Igf I ◽  
Bovine Oocytes

SummaryAn in vitro model of embryo production was used to examine the effects of insulin-like growth factor (IGF)-I on maturation and developmental competence of oocytes exposed to heat shock. Cumulus–oocyte complexes were matured at 38.5°C or exposed to acute heat shock (HS; 41.5°C), with or without 100 ng/ml IGF-I, for 22 h through in vitro maturation. The experimental groups were control (C), C + IGF-I, HS, and HS + IGF-I. Oocytes were fertilized at the end of maturation, and the proportion of cleaved embryos was recorded 44 h later. HS during maturation increased the proportion of TUNEL-positive oocytes (P < 0.05). HS did not have any effect on cortical granule translocation but impaired resumption of meiosis, expressed as a decreased proportion of oocytes with nuclei in metaphase I (P < 0.05) and metaphase II (MII; P < 0.05). HS decreased the proportion of oocytes that cleaved (P < 0.05), in particular those oocytes that further developed to 4-cell-stage embryos (P < 0.05). IGF-I alleviated, to some extent, the deleterious effects of HS on the oocytes as reflected by a reduced proportion of TUNEL-positive oocytes (P < 0.03). While not significant, IGF-I tended to increase the proportion of MII-stage oocytes (P < 0.08) and 4-cell-stage cleaved embryos (P < 0.06). Further examination is required to explore whether IGF-I also affects the developmental competence of oocytes exposed to HS.

Efficiency of different incubation systems for the in vitro production of bovine embryos

Zygote ◽  
2018 ◽  
Vol 26 (4) ◽  
pp. 314-318 ◽  
Author(s):  
Camila M. Cavalcanti ◽  
Iana S. Campelo ◽  
Mirelly M.A.S. Silva ◽  
João V.S. Albuquerque ◽  
Luciana M. Melo ◽  
...  
Keyword(s):  
Oxygen Species ◽  
Bovine Embryos ◽  
In Vitro Production ◽  
Cleavage Rate ◽  
Significant Difference ◽  
Maturation Rate ◽  
Blastocyst Rate ◽  
Vitro Production ◽  
Bovine Oocytes

SummaryThis study aimed to compare the efficiency of different incubation systems for in vitro embryo production in bovine. Oocytes/embryos were cultured in three incubators: conventional – CONV, mini bench – MINI and portable – PORT. After in vitro maturation (IVM), oocytes were verified for maturation rate. The remaining structures were submitted to in vitro fertilization and culture to verify cleavage (day 2) and blastocyst (day 7) rates. Reactive oxygen species (ROS) were evaluated in post-IVM oocytes and embryos (days 2 and 7) using arbitrary fluorescence units (AFUs). No significant difference (P>0.05) was observed for maturation rate. The CONV system (74.0%) produced the highest cleavage rate (P<0.05) when compared with PORT (59.5%), but similar (P>0.05) to MINI (65.0%). The same pattern and differences were observed for blastocyst rate: CONV (33.3%), MINI (32.3%) and PORT (21.9%). ROS levels were not different (P>0.05) in post-IVM oocytes: CONV (35.6±4.5), MINI (29.4±4.0) and PORT (35.6±4.5). For day-2 embryos, ROS levels were higher (P<0.05) in MINI (44.2±3.1) in comparison with CONV (27.7±3.7) and PORT (33.3±3.2). No significant difference (P>0.05) was observed in blastocysts. In conclusion, although it produced high ROS levels at day 2 of culture, the MINI system was as efficient as the CONV system for blastocyst production. This option may be an interesting and economical for the in vitro embryo industry.

scholarly journals 57EMBRYO DEVELOPMENT FOLLOWING INTERSPECIES NUCLEAR TRANSFER OF AFRICAN BUFFALO (SYNCERUS CAFFER), BONTEBOK (DAMALISCUS DORCUS DORCUS) AND ELAND (TAUROTRAGUS ORYX) SOMATIC CELLS INTO BOVINE CYTOPLASTS

2004 ◽  
Vol 16 (2) ◽  
pp. 150 ◽  
Author(s):  
M. Matshikiza ◽  
P. Bartels ◽  
G. Vajta ◽  
F. Olivier ◽  
T. Spies ◽  
...  
Keyword(s):  
South Africa ◽  
Nuclear Transfer ◽  
Somatic Cells ◽  
Blastocyst Stage ◽  
Critically Endangered ◽  
African Buffalo ◽  
Syncerus Caffer ◽  
Cell Stage ◽  
Wildlife Species ◽  
Interspecies Nuclear Transfer

Wildlife conservation requires traditional as well as innovative conservation strategies in order to preserve gene and species diversity. Interspecies nuclear transfer has the potential to conserve genes from critically endangered wildlife species where few or no oocytes are available from the endangered species, and where representative cell lines have been established for the wildlife population while numbers were still abundant. The purpose of this study was to investigate the developmental ability of embryos reconstructed with transfer of somatic cells from the African buffalo (Syncerus caffer), bontebok (Damaliscus dorcus dorcus) and eland (Taurotragus oryx) to enucleated domestic cattle (Bos taurus) oocytes. Skin tissue from the three wildlife species were collected by surgically removing approx. 1.0×1.0cm ear skin notches from animals immobilized with a combination of etorphine hydrochloride (M99; South Africa) and azaperone (Stressnil, South Africa). The biopsies were placed into physiological saline and transported to the laboratory at 4°C within 2h, cleaned with chlorohexidine gluconate and sliced finely in Minimal Essential Medium supplemented with 10% fetal calf serum. The resultant tissue explants were treated as previously described (Baumgarten and Harley 1995 Comp. Biochem. Physiol. 110B, 37–46) and actively growing fibroblast cultures made available for the nuclear transfer process. Nuclear transfer was performed using the HMC technique (Vajta et al., 2003 Biol. Reprod. 68, 571–578) using slaughterhouse-derived bovine oocytes. Culture was performed in SOFaaci (Vajta et al., 2003 Biol. Reprod. 68, 571–578) medium supplemented with 5% cattle serum using WOWs (Vajta et al., Mol. Reprod. Dev. 50, 185–191). Two identical replicates were made with somatic cells of each species. After successful reconstruction, 57, 42 and 48 nuclear transferred and activated buffalo, bontebok and eland embryos were cultured, respectively. All except for 2 buffalo embryos cleaved; 22 (39%) developed to or over the 8-cell stage, and 2 (3.5%) of them to the blastocyst stage. All but 3 bontebok embryos cleaved, 17 (40%) developed to or over the 8-cell stage, but none of them reached the compacted morula or blastocyst stage. Sixteen (33%) of the eland embryos developed to or over the 8-cell stage with one (2%) reaching the blastocyst stage. In conclusion, buffalo, bontebok and eland embryos developed from reconstruction using their respective somatic cells combined with bovine cytoplasts, however, in vitro developmental ability to the blastocyst stage was limited. Additional basic research that establishes the regulative mechanisms involved with early preimplantation development together with optimising nuclear transfer techniques may have the potential to one day play a role in the conservation of critically endangered wildlife species.

Abnormal development of pre-implantation mouse embryos grown in vitro with [3H]thymidine

Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 601-615
Author(s):  
M. H. L. Snow
Keyword(s):  
Specific Activity ◽  
Inner Cell Mass ◽  
Cell Damage ◽  
Cell Mass ◽  
Cell Number ◽  
Mouse Embryos ◽  
Abnormal Development ◽  
Tritium Concentration ◽  
Cell Stage

Mouse embryos were grown in vitro from the 2-cell stage to blastocysts in the presence of [3H]thymidine. Methyl-T-thymidine and thymidine-6-T(n) were used and both forms found to be lethal at concentrations above 0·1 μCi/ml. Both forms of [3H]Tdr at concentrations between 0·01 and 0·1 μCi/ml caused a highly significant (P &lt; 0·001) reduction in blastocyst cell number. The reduction in cell number, which was positively correlated with specific activity and tritium concentration, was associated with cell damage typical of radiation damage caused by tritium disintegration. Thymidine-6-T(n) also significantly reduced the number of 2-cell embryos forming blastocysts whereas methyl-T-Tdr did not. This difference in effect is assumed to be caused by contamination of one form of [3H]Tdr with a by-product of the tritiation process. A study of the cleavage stages showed that almost all the reduction in cell numbers could be accounted for by selective cell death occurring at the 16-cell stage. Cells which survive that stage cleave at a normal rate. The cells that are most susceptible to [3H]Tdr damage were found to normally contribute to the inner cell mass. The [3H]Tdr-resistant cells form the trophoblast. It is possible to grow blastocysts in [3H]Tdr such that they contain no inner cell mass but are composed entirely of trophoblast. Comparatively short (12 h) incubation with [3H]Tdr at any stage prior to the 16-cell stage will cause this damage. Possible reasons for this differential effect are discussed, and also compared with damage caused by X-irradiation.

scholarly journals 81 EFFECT OF SUCROSE CONCENTRATION IN WARMING MEDIUM ON THE DEVELOPMENT POTENTIAL OF VITRIFIED BOVINE OOCYTES

2005 ◽  
Vol 17 (2) ◽  
pp. 190
Author(s):  
W.C. Chang ◽  
J. Xu ◽  
S. Jiang ◽  
X.C. Tian ◽  
X. Yang ◽  
...  
Keyword(s):  
Sucrose Concentration ◽  
Control Group ◽  
Bovine Oocyte ◽  
Cell Stage ◽  
Significant Difference ◽  
Humidified Air ◽  
Bovine Oocytes ◽  
Experimental Group ◽  
One Way Anova

The aim of this experiment was to determine the effect of the sucrose concentration (0 to 0.33 M) in the dilution medium on the viability, fertilizability, and development of vitrified bovine oocytes. Bovine oocyte-cumulus complexes were collected from slaughterhouse ovaries and in vitro-matured as reported previously. After 24-h maturation in TCM199-based medium under 5% CO2 humidified air at 39°C, these were exposed to hyaluronidase and carefully pipetted to remove all except the 3–5 innermost layers of cumulus. Oocytes were put into the pre-equilibration medium for 3 min and then into vitrification solution containing HEPES-buffered TCM199 supplemented with 20% FBS, ethylene glycol, and dimethylsulphoxide for 25–30 s; they were then vitrified by modified solid surface vitrification (Dinnyes et al. 2000 Biol. Reprod. 63, 513–518).The oocytes were warmed at 39°C by placing them in holding medium with 0, 0.08, 0.17, 0.25, or 0.33 M sucrose. Non-vitrified oocytes were used as controls. Oocytes were inseminated 30 min after warming, and the presumptive zygotes were cultured in CR1-aa medium supplemented with 6 mg/mL BSA at 39°C in a humidified atmosphere of 5% CO2, 5% O2, and 90% N2 for eight days. Data were analyzed by one-way ANOVA. As shown in Table 1, there was no significant difference in survival rate (P > 0.05) of the vitrified oocytes that were placed in dilution solution containing 0.17, 0.25, or 0.33 M sucrose and the non-treated controls. On Day 2 (fertilized on Day 0), cleavage to the 8-cell stage was similar for the 0.17, 0.25, and 0.33 M dilution groups, but the rates for all three were significantly lower (P < 0.05) than for the control group. The blastocyst rate on Day 8 was significantly higher for the 0.25 M group than for any other experimental group but still significantly lower than for the control. In conclusion, this study suggests that with this vitrification/warming procedure the optimum concentration of sucrose in the dilution solution is 0.25 M. Table 1. Oocyte survival after vitrification/warming and subsequent embryo development The authors would like to thank Ms Colleen Shaffer for the preparation of bovine oocytes.

119 HETEROLOGOUS BOVINE IN VITRO FERTILIZATION USING CRYOPRESERVED BOTTLENOSE DOLPHIN SPERMATOZOA

2012 ◽  
Vol 24 (1) ◽  
pp. 172 ◽  
Author(s):  
M. J. Sanchez-Calabuig ◽  
P. Beltran-Brena ◽  
E. Martinez-Nevado ◽  
D. Rizos ◽  
J. F. Perez-Gutierrez ◽  
...  
Keyword(s):  
Bottlenose Dolphin ◽  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
Sperm Chromatin ◽  
Cleavage Rate ◽  
Vitro Fertilization ◽  
Sperm Penetration ◽  
Pronuclear Formation ◽  
Bovine Oocytes

Assisted reproductive technologies are of great importance for increasing genetic diversity in captive animals without displacing them. The development and improvement of these techniques require accurate methods to assess sperm function. The ability of the sperm to bind the zona pellucida and the formation of a male pronucleus have been shown to have a high predictive value for fertilization outcome. The use of zona-intact bovine in vitro–matured oocytes in heterologous fertilization with dolphin spermatozoa could provide valuable information on its fertilizing ability. The aim of the present study was to evaluate male pronuclear formation in zona-intact bovine oocytes after coincubation with frozen-thawed bottlenose dolphin spermatozoa. A total of 1546 immature cumulus oocytes complexes (COC) were obtained from bovine ovaries collected at slaughter. The COC were matured for 24 h in TCM-199 supplemented with 10 ng mL–1 of epidermal growth factor and 10% FCS. Matured COC were inseminated with frozen-thawed Bovi-pure (Nidacon International, Mölndal, Sweden) separated bovine (control) or dolphin spermatozoa. At 18, 20, 22, 24, 26 and 28 h post-insemination (hpi), half of the presumptive zygotes from each group were fixed and stained with Hoechst 33342 to examine sperm penetration, polyspermy and pronuclear formation and the remainder were cultured in synthetic oviduct fluid supplemented with 5% FCS for evaluating fertilization rates by cleavage on Days 2 and 4 (Day 0 = day of IVF). As expected, in the control a higher percentage of 2 pronuclear formation was observed at 18 hpi (74.5%), with a decrease at 20 and 22 hpi (57.4 and 43.2%, respectively) and was significantly lower (P ≤ 0.001) at 24 hpi (13.3%), reaching the lowest values at 26 and 28 hpi. However, in the heterologous group significantly less oocytes with both pronuclear formed (P ≤ 0.001) were observed at 18, 20 and 22 hpi (1.2, 3.4 and 3.0%, respectively) compared with 24, 26 and 28 hpi (22.5, 11.4 and 8.9%, respectively). No polyspermy was detected in oocytes coincubated with dolphin spermatozoa. Moreover, the cleavage rate at Day 2 and 4 in heterologous fertilization was 13.0 and 34.8%, respectively, whereas for the control it was 90.0%. In conclusion, these results indicate that dolphin spermatozoa can penetrate bovine oocytes and induce the block to polyspermy and the differences found regarding pronuclear formation times between the 2 species could be due to distinct sperm chromatin organisation or condensation. In conclusion, our preliminary results show that heterologous fertilization using bovine oocytes is useful for characterising the viability of dolphin thawed spermatozoa, which also could be helpful in performing a more complete sperm evaluation. Further studies are necessary to provide more consistent evidence of the efficiency of this test. The authors thank the staff at Zoo Aquarium Madrid for their dedicated work toward dolphin semen collection.

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