162 EFFECTS OF PROLACTIN AND DITHIOTHREITOL ON THE QUALITY AND DEVELOPMENTAL CAPACITY OF IN VITRO MATURED BOVINE OOCYTES

2016 ◽  
Vol 28 (2) ◽  
pp. 211
Author(s):  
G. Singina ◽  
I. Lebedeva ◽  
E. Shedova ◽  
N. Zinovieva
Keyword(s):  
Embryo Development ◽  
In Vitro Maturation ◽  
Inhibitory Influence ◽  
Cleavage Rate ◽  
Subsequent Aging ◽  
Vitro Fertilization ◽  
Blastocyst Rate ◽  
System 1 ◽  
Bovine Oocytes

In vitro maturation (IVM) and IVF of domestic animal oocytes is widely used for commercial and research purposes. The oocyte quality and capacity for further development acquired during in vitro maturation and reduced during the subsequent aging are the main limitative factors affecting the embryo production (Miao et al. 2009 Hum. Reprod. Update 15, 573–585). Our objective was to evaluate effects of prolactin (PRL) and dithiothreitol (DTT) on apoptosis and the embryo development of bovine oocytes matured in vitro using 2 different systems. A total of 1437 slaughterhouse-derived cumulus-oocyte complexes (COC) were matured for 24 h in TCM-199 supplemented with 10% FCS, 0.2 mM sodium pyruvate, 10 μg mL–1 porcine FSH, and 5 μg mL–1 ovine LH. In system 1, 251 COC from a total of IVM oocytes were transferred to the aging medium (TCM-199 supplemented with 10% FCS) and cultured for 24 h in the absence (control) and the presence of either PRL (20 and 50 ng mL–1) or DTT (2.5, 5, and 10 μM). At the end of culture, oocyte apoptosis was detected using the TUNEL method. In system 2, another part of IVM oocytes (1186 COC) was co-incubated for 18 h with sperm in Fert-TALP medium modified by addition of 10 μg mL–1 heparin, PHE (20 μM penicillamine, 10 μM hypotaurine, 1 μM epinephrine), and 0.1% modified Eagle’s medium (MEM) nonessential amino acids. In this case, PRL and DTT (at the above listed concentrations) were added directly to the fertilization medium. After IVF, oocytes were cultured in CR1aa medium for assessment of the cleavage and blastocyst rates on Days 2 and 8, respectively. The nuclear status of blastocysts was evaluated by the cytogenetic method. The data from 3–7 replicates were analysed by ANOVA. Culture of matured COC in the aging medium (system 1) increased the rate of apoptotic oocytes from 8.1 ± 4.7% (0 h) to 48.6 ± 5.8% (24 h) (P < 0.01). This rate was reduced (P < 0.05) up to 22.5 ± 3.1% and 17.8 ± 5.1% in the presence of PRL (20 and 50 ng mL–1) and up to 15.0 ± 6.9% and 19.5 ± 3.7% in the presence of DTT (2.5 and 5 μM). The direct addition of PRL at a concentration of 20 ng mL–1 to the IVF medium raised the blastocyst rate from 21.6 ± 2.2% to 29.8 ± 2.4% (P < 0.05) but did not affect the cleavage rate (72.1 ± 2.2% v. 74.3 ± 2.1%). By contrast, 50 ng mL–1 PRL did not increase the yield of blastocysts and decreased the cleavage rate (from 74.3 ± 2.1% to 62.9 ± 2.4%, P < 0.05). When added to the IVF medium, DTT raised the blastocyst rate only at a concentration of 2.5 μM (P < 0.05). No effects of PRL and DTT on the number of cells in embryos at the blastocyst stage were found. Our findings indicated that PRL and DTT supplements during in vitro fertilization of bovine oocytes may improve their capacity for the subsequent embryo development. This effect was probably due to the inhibitory influence of PRL and DTT on apoptosis of matured oocytes. The study was supported by the Federal Agency for Scientific Organizations and RFBR (project No. 14–48–03681).

scholarly journals Suplementasi Hormon Gonadotropin Pada Medium Maturasi In Vitro Untuk Meningkatkan Perkembangan Embrio Stadium 4 Sel Kambing Bligon

2016 ◽  
Vol 40 (2) ◽  
pp. 83 ◽  
Author(s):  
Dewi Pranatasari ◽  
Kustono Kustono ◽  
Diah Tri Widayati
Keyword(s):  
Embryo Development ◽  
In Vitro Maturation ◽  
Spherical Shape ◽  
Maturation Stage ◽  
Embryo Morphology ◽  
Cleavage Rate ◽  
Vitro Fertilization ◽  
Maturation Medium ◽  
Cell Embryo

The study was carried out to investigate the effect of gonadotropin hormone supplementation into in vitro maturation medium on maturation, fertilization and embryo development of Bligon goats. This research steps consist of oocyte collection, in vitro maturation, in vitro fertilization, and in vitro embryo development. At the maturation stage the oocyte that had been collected and divided into two groups based on the maturation medium, that was tissue culture medium (TCM) with supplementation of GnRH 0 IU/mL and GnRH 25 IU/mL. Oocyte and embryo morphology data were analyzed descriptively. Maturation rate and embryo development data were analyzed by using independent sample t-test. Fertilization data was analyzed descriptively. The result showed the percentages of mature oocytes from gonadotropin supplementation of 0 IU/mL and 25 IU/mL were 54.10±25.97 and 54.89±26.44%, respectively. Expansion cumulus cells surrounding the oocytes might indicated the mature oocytes. Cleavage rate of the 2 cells stage were 13,02±11,09 and 27,01±16,65%; respectively, and for the 4 cells stage were 10,16±10,01% and 16,67±14.91%. Embryos obtained from the treatment, indicated uniform of blastomeres in the size, tight, compact, intact, and round-spherical shape. It could be concluded that supplementation of gonadotropin hormone into in vitro maturation medium could not increase the rate of oocyte maturation and 4 cell embryo development, but it could increase 2 cell embryo development of Bligon goats. Hormone supplementation could improved the maturation and embryo quality.

253 DEVELOPMENTAL COMPETENCE OF BOVINE OOCYTES MATURED IN SERUM-FREE MEDIUM UNDER LOW OXYGEN TENSION

2009 ◽  
Vol 21 (1) ◽  
pp. 224
Author(s):  
M. M. Pereira ◽  
F. Q. Costa ◽  
P. H. A. Campos ◽  
R. V. Serapiao ◽  
J. Polisseni ◽  
...  
Keyword(s):  
In Vitro Maturation ◽  
Embryo Quality ◽  
Cell Number ◽  
Total Cell ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
Total Cell Number ◽  
Blastocyst Rate ◽  
Bovine Oocytes

In vitro maturation (IVM) is a critical step in in vitro bovine embryo production. A number of factors can influence the IVM environment, such as media composition and protein supplementation. Serum and higher O2 tension have been shown to reduce embryo quality; however, little is known about the effects of serum and O2 tension during IVM on embryo quality and development. This study aimed to evaluate the effect of serum and O2 tension on IVM of bovine oocytes. Immature oocytes obtained from slaughterhouse ovaries were randomly distributed in 4 groups of IVM: G1 (n = 253), 0.1% polyvinyl alcohol (PVA) in air; G2 (n = 248), 10% inactivated estrous cow serum (ECS) in air; G3 (n = 270), 0.1% PVA under 5% O2; and G4 (n = 236), 10% ECS under 5% O2. In vitro maturation was performed with TCM-199 culture medium supplemented with 20 μg mL–1 FSH, under 5% CO2 at 38.5°C for 24 h. After maturation, oocytes were in vitro fertilized with 2.0 × 106 sperm mL–1 in Fert TALP medium, supplemented with heparin, for 20 h. Presumptive zygotes were denuded by vortexing and cultured in CR2aa medium with 2.5% fetal calf serum under 5% CO2 and 5% O2 at 38.5°C. Cleavage rate was evaluated 72 h postfertilization, and blastocyst rate and total cell number were evaluated 8 days postfertilization. Morphological classification of embryos was performed at Day 8 according to the International Embryo Transfer Society manual (1998). Cleavage, blastocyst, and grade 1 embryo rates were analyzed by chi-square, and total cell number was analyzed by ANOVA, with means compared by LSD. Results are presented as mean ± SEM. There was no difference (P > 0.05) in cleavage rates among G1, G2, and G4 (61.6, 65.3, and 57.6%, respectively), but cleavage rate was lower (P < 0.05) in G3 (52.5%). Blastocyst rates among G1, G3, and G4 (15.8, 17.7, and 20.3%, respectively) were similar (P > 0.05). However, blastocyst rate in G2 (25.0%) was higher (P < 0.05) than in G1 and G3, but was similar to G4 (P > 0.05). Total cell number was similar (P > 0.05) among G2 (194.1 ± 13.1), G3 (173.3 ± 9.0), and G4 (163.8 ± 8.7), but was lower (P < 0.05) in G1 (124.5 ± 11.4). The grade 1 embryo rate was lower (P < 0.05) in G1 (70.3%) than in G2 (89.5%), but was similar (P > 0.05) to G3 (77.0%) and G4 (83.9%). The results suggest that IVM with PVA in TCM-199 medium under 5% O2 can be performed without reducing embryo development and quality, when compared with ECS. On the other hand, oocyte developmental competence seems to be affected when IVM is performed with PVA under air conditions. Financial support: CNPq, FAPEMIG.

292 INHIBITION OF HSP90 AGGRAVATES THE EFFECTS OF HEAT SHOCK ON DEVELOPMENTAL COMPETENCE OF BOVINE OOCYTES

2015 ◽  
Vol 27 (1) ◽  
pp. 235
Author(s):  
E. D. Souza ◽  
N. C. Rabelo ◽  
T. D. Araujo ◽  
C. M. Assunção ◽  
C. C. R. Quintão ◽  
...  
Keyword(s):  
Heat Shock ◽  
In Vitro Maturation ◽  
Calf Serum ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
Oocyte Developmental Competence ◽  
Significant Difference ◽  
Blastocyst Rate ◽  
Bovine Oocytes

The heat shock protein 90kDa (HSP90) is a chaperone involved in protein homeostasis under normal and stress conditions. Its inhibition by 17-(allylamino)-17-demethoxygeldanamycin (17AAG, Sigma, St. Louis, MO, USA) for 12 or 24 h during in vitro maturation reduces the oocyte's ability to develop after in vitro fertilization (Souza et al. 2014 Reprod. Fert. Dev. 26, 197). This study aimed to evaluate the effect of treatment with 17AAG during the heat shock on oocyte developmental competence. Immature bovine COC were randomly allocated in 4 treatments during IVM: control = no heat shock or 17AAG; HS = heat shock (41.5°C) for the first 12 h of IVM; 17AAG = 2 µM 17AAG for the first 12 h of IVM; and 17AAG + HS = 2 µM 17AAG plus heat shock for the first 12 h of IVM. In vitro maturation was performed in Nunc plate containing 400 µL of TCM199 medium (Invitrogen, Carlsbad, CA, USA) supplemented with porcine FSH (Hertape Calier, Juatuba, Brazil) and 10% oestrus cow serum under 5% CO2 in air, 95% humidity, and 38.5°C for 24 h. Semen was processed by Percoll gradient (Nutricell, Campinas, Brazil) and oocytes were in vitro fertilized for 20 h with 2 × 106 spermatozoa mL–1 under the same IVM atmospheric conditions. Presumptive zygotes were completely denuded in a PBS solution with 0.1% hyaluronidase and then cultured in wells with 500 µL of modified CR2aa medium supplemented with 2.5% fetal calf serum (Nutricell) in an incubator at 38.5°C under 5% CO2, 5% O2, 90% N2, and saturated humidity. Cleavage rate was evaluated 72 h postfertilization and blastocyst rate was evaluated at Day 7 (D7) and 8 (D8). Data from 7 replicates were submitted to analysis of variance and means were compared by Student Newman Keul's test. There was no difference (P > 0.05) on cleavage rate among treatments. Heat shock or treatment with 17AAG, both for 12 h of IVM, decreased (P < 0.05) the blastocyst rate at D7 and D8 when compared to control but no significant difference between HS and 17AAG treatments was found (Table 1). However, the lowest (P < 0.05) blastocyst rate at D7 and D8 was achieved when oocytes were submitted simultaneously to 17AAG and heat shock for 12 h of IVM (17AAG + HS treatment, Table 1). In conclusion, the treatment with 17AAG during IVM worsens the deleterious effect of heat shock on oocyte developmental competence and suggests that HSP90 may also play role on cellular protection during heat shock in bovine oocytes. Table 1.Cleavage and blastocyst (Bl) rates at D7 and D8 for control, 17AAG, Heat Shock (HS), and 17AAG plus HS treatments Financial support comes from CNPq, FAPEMIG, and FAPES.

PSV-5 Relationship between sire conception rate, sperm motility, sperm SERPINA5 relative concentration, and in vitro produced embryos in dairy bulls

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 310-310
Author(s):  
Saulo Menegatti Zoca ◽  
Julie Walker ◽  
Taylor Andrews ◽  
Adalaide C Kline ◽  
Jerica J Rich ◽  
...  
Keyword(s):  
Embryo Development ◽  
Sperm Motility ◽  
Relative Concentration ◽  
Early Embryo ◽  
Conception Rate ◽  
Cleavage Rate ◽  
Blastocyst Rate ◽  
Positive Correlations ◽  
Sire Conception Rate

Abstract Sire conception rate (SCR) is a field measure of fertility among bulls, but it can be influenced by several factors (Sperm transport, sperm-egg binding, early embryo development, etc). The objective of this study was to evaluate the relationship between SCR, sperm motility, SERPINA5 concentrations, and in vitro embryo development. Measurements were performed in 19 bulls with SCR values ranging from -7.7 to 4.45. For each bull, an aliquot of frozen-thawed semen was used for analyses of total (TMOT) and progressive (PROG) motility. Remaining semen was fixed with 2% formaldehyde, and concentration of SERPINA5 was determined by immunolocalization (antibody SERPINA5/Dylight405; PA5-79976-Invitrogen / ab201798-Abcam). Mean fluorescence intensity was determined in ~200 sperm heads/bull. Approximately 149 oocytes/bull were fertilized in vitro for embryo development analysis (cleavage and blastocyst rates). Statistical procedures were performed in SAS (9.4) using the procedures CORR for correlations (SCR, TMOT, PROG, SERPINA5, cleavage and blastocyst) and GLIMMIX for comparison of “field-fertility” (SCR divided in HIGH or LOW) and “field-embryo-fertility” (LOW-SCR sires were divided based on blastocyst rate (HIGH or LOW) resulting in two classifications; LOW-HIGH≥31% and LOW-LOW≤26%, respectively). There were positive correlations (P &lt; 0.05) between cleavage-blastocyst (r=0.50), SERPINA5-cleavage (r=0.48), and TMOT-PROG (r=0.76). Sire SCR was not associated with SERPINA5, TMOT, PROG, cleavage and blastocyst rate (P &gt; 0.52). Among LOW-SCR sires, LOW-LOW sires (-4.83±0.60) tended to have a better SCR score than LOW-HIGH (-6.18±0.42) sires (P = 0.08), but there were no differences (P &gt; 0.43) between LOW-HIGH, LOW-LOW, and HIGH sires for SERPINA5, TMOT, PROG, and cleavage. In conclusion, some LOW SCR sires have good embryo development indicating a different mechanism for their low SCR; however, these differences in SCR could not be explained by TMOT, PROG, SERPINA5, cleavage and blastocyst. There were, however, positive correlations between cleavage-blastocyst rate, and SERPINA5-cleavage rate.

scholarly journals LÍQUIDO FOLICULAR EQÜINO NA MATURAÇÃO IN VITRO DE OÓCITOS BOVINOS

2004 ◽  
Vol 9 (1) ◽  
Author(s):  
M.G.L. PINTO ◽  
M.I.B. RUBIN ◽  
C.A.M. SILVA ◽  
T.F. HILGERT ◽  
M.F. SÁ FILHO ◽  
...  
Keyword(s):  
Follicular Fluid ◽  
In Vitro Maturation ◽  
Mineral Oil ◽  
Control Group ◽  
Sodium Pyruvate ◽  
Vitro Fertilization ◽  
Treatment Groups ◽  
Maturation Medium ◽  
Bovine Oocytes

O desenvolvimento embrionário de oócitos bovinos maturados in vitro (MIV) foi avaliado em meio suplementado com líquido folicular eqüino (Lfe). Foram distribuídos 1045 oócitos em 11 repetições formando três grupos tratamentos (T1, T2, T3) e um controle (C). O meio de maturação utilizado foi o TCM-199 acrescido de piruvato de sódio, hormônio folículo estimulante recombinante (rFSHh) e hormônio luteinizante equino (LHe). Suplementou-se esse meio com 10% de soro de égua em estro para o grupo controle e para T1, T2 e T3, o meio foi suplementado com 5, 10, e 20% de LFe, respectivamente. Os oócitos foram maturados in vitro (MIV) por 24h. A fecundação in vitro (FIV) foi realizada em meio Talp-Fert. A MIV e a FIV foram realizadas em estufa a 39ºC com 5% de CO2 em ar e umidade saturada. Os zigotos foram cultivados em meio SOFaaci, sob óleo mineral no interior de bolsas plásticas gaseificadas. As taxas de clivagem e de blastocistos foram observadas diariamente (D), e em D7, foram superiores (P0,05) às do grupo controle. Em D9, a taxa de blastocistos do T2 foi superior (P0,05). O LFe, na concentração de 10% pode ser utilizado, em substituição ao soro de égua em estro para suplementar o meio de MIV de oócitos bovinos. Equine follicular fluid on in vitro maturation of bovine oocytes Abstract Embryo development of bovine oocytes was evaluated using maturation medium supplemented with equine follicular fluid (eFF). One thousand and forty five (1045) oocytes were distributed in 11 replications forming three treatment groups (T1, T2 e T3) and one Control (C). TCM-199 added with sodium pyruvate, rFSHh and LHe was used as maturation medium. This medium was supplemented with 10% estrous mare serum for Control group, and 5, 10, and 20% eFF, respectively, for T1, T2 e T3 groups. In vitro maturation (IVM) of all groups was performed during 24h. In vitro fertilization (IVF) was performed in TALP-FERT medium. IVM and IVF were carried out in an incubator at 39ºC with 5% CO2 in air and saturated humidity. Zygotes were cultured in SOFaaci medium, under mineral oil in gasified bags. Cleavage and blastocyst rates were daily observed (D), and at D7, were higher (P0.05) for those from control group. At D9, blastocyst rate of T2 was higher (P0.05). The eFF, at a 10% concentration, can replace the use of estrous mare serum to supplement the IVM medium of bovine oocytes.

scholarly journals In vitro fertilizing potential of urethral and epididymal spermatozoa collected from domestic cats (Felis catus)

2017 ◽  
Vol 20 (1) ◽  
pp. 19-24 ◽  
Author(s):  
S. Prochowska ◽  
W. Niżański
Keyword(s):  
Comparative Analysis ◽  
In Vitro Fertilization ◽  
Felis Catus ◽  
Domestic Cats ◽  
Cleavage Rate ◽  
Vitro Fertilization ◽  
Commercial Medium ◽  
Blastocyst Rate ◽  
Epididymal Spermatozoa

Abstract The aim of this study was to provide a comparative analysis of in vitro fertilizing potential of frozen-thawed urethral and epididymal feline spermatozoa. Both types of semen were collected from 7 cats and cryopreserved in liquid nitrogen. To perform in vitro fertilization, both urethral and epididymal samples from the same individual were thawed and spermatozoa were co-incubated with in vitro matured cat oocytes. Obtained embryos were cultured in vitro for 7 days in a commercial medium. Cleavage rate, morula rate and blastocyst rate were calculated. Experiment was run in 10 replicates. The examined parameters showed no significant differences between urethral and epididymal spermatozoa (p>0.05). Cleavage rate and embryo’s development were highly variable between replicates, even for the different sperm samples collected from one individual. There was no significant correlation between fertilizing capacity of two types of spermatozoa collected from the same male. In this study we confirmed that cryopreserved urethral spermatozoa have equally good fertilizing potential as epididymal ones, and both can be successfully used for in vitro fertilization in cats with the use of commercial medium.

286 INFLUENCE OF REVERSIBLE MEIOSIS INHIBITION ON SWINE EMBRYOS PRODUCED BY IN VITRO FERTILIZATION AND PATHENOGENETIC ACTIVATION

2006 ◽  
Vol 18 (2) ◽  
pp. 250
Author(s):  
M. G. Marques ◽  
A. B. Nascimento ◽  
V. P. Oliveira ◽  
A. R. S. Coutinho ◽  
M. E. O. A. Assumpção ◽  
...  
Keyword(s):  
Culture Medium ◽  
Cell Number ◽  
Control Group ◽  
Cleavage Rate ◽  
Vitro Fertilization ◽  
Electric Pulses ◽  
Cell Numbers ◽  
Blastocyst Rate ◽  
And Control

The present work evaluated the reversible meiosis inhibition effect on the development of swine embryos produced by in vitro fertilization (IVF) or parthenogenetic activation (PA). The efficiency of PZM3 and NCSU23 embryo culture media was also evaluated. Oocytes from ovaries collected at a slaughterhouse were subjected to IVM in two different groups: CHX (cycloheximide 5 µM for 10 h) and control, both with TCM-199 + 3.05 mM glucose + 0.91 mM sodium pyruvate + 10% porcine follicular fluid (pFF) + 0.57 mM cystein + 10 ng epidermal growth factor (EGF)/mL + 10 IU eCG/mL + 10 IU hCG/mL for the initial 22 h. In the remaining period (20 h for CHX and 22 h for control), medium without hormones was utilized. After IVM, oocytes were denuded and fertilized for 6 h (IFV) or the matured oocytes were submitted to activation by electric pulses (PA) (2 DC of 1.5 kV/cm for 30 µs), incubated for 1 h in culture medium with 10 μM of CHX, and again submitted to the same electric pulses for 60 µs. Embryo development was evaluated by cleavage rate on Day 3 and blastocyst rate and blastocyst cell number on Day 7 of culture. Cleavage and blastocyst rates were analyzed by the equality-of-two-ratios test and cell number by the Kruskal-Wallis and Mann-Whitney tests (P < 0.05). In relation to IVF, the PZM3 medium was more efficient than NCSU23 for cleavage rate in the CHX group (PZM3: 68.4%, NCSU23: 44.4%) and had a better blastocyst rate in the control group (PZM3: 13.4%, NCSU23: 5.6%). With reference to PA, NCSU23 presented better cleavage and blastocyst rates than PZM3 in the CHX group (NCSU23: 89.5%, PZM3: 78.5% and NCSU23: 20.4%, PZM3: 13.0%, respectively). In the control group, only the NCSU23 blastocyst rate was higher than that for PZM3 (NCSU23: 22.5%, PZM3: 10.8%). No culture medium effect on cell number mean of IVF and PA blastocysts was observed. Maturation block improved cleavage rates in IVF groups cultured with PZM3 (68.4% and 50.6%, respectively, for CHX and control) and in PA groups cultured with NCSU23 (89.5% and 80.3%, respectively, for CHX and control), but no improvement of blastocyst rates in both groups (IVF and PA) was verified. Table 1 below shows that maturation block decreased the IVF and increased the PA blastocyst cell numbers. As older oocytes are more effectively activated, oocytes blocked with CHX achieved the maturation stage faster than the control group, therefore resulting in high-quality PA blastocysts. In conclusion, PZM3 was more efficient for IVF embryo production in contrast to NCSU23, whereas NCSU23 can be indicated for PA embryo production. Moreover, maturation blockage with CHX influenced blastocyst cell number, decreasing in IVF embryos and increasing in PA embryos. Table 1. Mean (±SD) of blastocyst cell numbers for IVF or PA groups after in vitro maturation without (control) or with cycloheximide (CHX) and cultured in NCSU23 or PZM3 medium This work was supported by FAPESP 02/10747–1.

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.

Sign in / Sign up

Export Citation Format

Share Document