280 PORCINE BLASTOCYSTS DERIVED FROM IN VITRO-MATURED OOCYTES INJECTED INTRACYTOPLASMICALLY WITH SPERM FROM TESTICULAR TISSUE XENOGRAFTED INTO NUDE MICE

2006 ◽  
Vol 18 (2) ◽  
pp. 247 ◽  
Author(s):  
K. Kikuchi ◽  
M. Nakai ◽  
N. Kashiwazaki ◽  
M. Ozawa ◽  
N. Maedomari ◽  
...  

The utilization of spermatogonia from testicular tissue after xenografting into immuno-deficient mice should lead to new insights for the conservation of male gametes. However, successful embryo production using sperm cells from xenografted testicular tissues has been limited to rhesus monkeys (Honaramooz et al. 2004 Biol. Reprod. 70, 1500-1503). In the present study, the objective was to establish this new technology for pig conservation in combination with intracytoplasmic sperm injection. Testes were obtained from male piglets 6 to 15 days old, in which most of the germ cells were gonocytes; these were minced into pieces of approximately 1.5 � 1.5 � 1.5 mm. Approximately 20 fragments were transplanted under the back skin of castrated nude mice 5 to 8 weeks old. The testicular grafts were recovered between 125 and 192 days after xenografting, minced in Dulbecco's phosphate-buffered saline, and centrifuged several times, to serve as a sperm suspension. In vitro maturation of the recipient oocytes (Kikuchi et al. 2002 Biol. Reprod. 66, 1033-1041) and injection with an intact spermatozoon, followed by electrical stimulation at 1 h post-injection (Nakai et al. 2003 Biol. Reprod. 68, 1003-1008), were carried out. The putative zygotes were cultured in vitro for 6 days (Kikuchi et al. 2002), and were then fixed, stained, and assessed for embryonic development and quality. From a total of 27 mice that were xenografted with testicular tissues, spermatids and spermatozoa were obtained in 19 of the mice (70.4%). Most of the spermatozoa were matured morphologically, showing faint motility after release into the collection medium. From a total of 253 oocytes (four replications) that were injected with sperm, 63 (24.9 � 7.1%) oocytes developed to the blastocyst stage. The average total cell number was 41.9 � 3.9. These values are comparable to those in in vitro fertilization by frozen-thawed spermatozoa, resulting in developmental ability to piglets after embryo transfer (25.3% and 48.7 cells; Kikuchi et al. 2002). These results suggest the possibility of embryo production using porcine spermatozoa that are differentiated from gonocytes within the xenografts.

2006 ◽  
Vol 18 (2) ◽  
pp. 248
Author(s):  
S.-G. Lee ◽  
C.-H. Park ◽  
D.-H. Choi ◽  
H.-Y. Son ◽  
C.-K. Lee

Use of blastocysts produced in vitro would be an efficient way to generate embryonic stem (ES) cells for the production of transgenic animals and the study of developmental gene regulation. In pigs, the morphology and cell number of in vitro-produced blastocysts are inferior to these parameters in their in vivo counterparts. Therefore, establishment of ES cells from blastocysts produced in vitro might be hindered by poor embryo quality. The objective of this study was to increase the cell number of blastocysts derived by aggregating 4–8-cell stage porcine embryos produced in vitro. Cumulus–oocyte complexes were collected from prepubertal gilt ovaries, and matured in vitro. Embryos at the 4–8-cell stage were produced by culturing embryos for two days after in vitro fertilization (IVF). After removal of the zona pellucida with acid Tyrode’s solution, one (1X), two (2X), and three (3X) 4–8-cell stage embryos were aggregated by co-culturing them in aggregation plates followed by culturing to the blastocyst stage. After 7 days, the developmental ability and the number of cells in aggregated embryos were determined by staining with Hoechst 33342 and propidium iodide. The percentage of blastocysts was higher in both 2X and 3X aggregated embryos compared to that of 1X and that of intact controls (Table 1). The cell number of blastocysts also increased in aggregated embryos compared to that of non-aggregated (1X) embryos and controls. This result suggests that aggregation might improve the quality of in vitro-fertilized porcine blastocysts by increasing cell numbers, thus becoming a useful resource for isolation and establishment of porcine ES cells. Further studies are required to investigate the quality of the aggregated embryos in terms of increasing the pluripotent cell population by staining for Oct-4 and to apply improved aggregation methods in nuclear-transferred (NT) porcine embryos. Table 1. Development, cell number, and ICM ratio of aggregated porcine embryos


2002 ◽  
Vol 14 (5) ◽  
pp. 291 ◽  
Author(s):  
N. W. Kurniani Karja ◽  
Takeshige Otoi ◽  
Masako Murakami ◽  
Minori Yuge ◽  
Mokhamad Fahrudin ◽  
...  

The effects of protein supplementation in culture medium on development to the hatching and hatched blastocyst stages of cat in vitro-fertilized embryos were investigated. In the first experiment, presumptive zygotes derived from in vitro maturation and in vitro fertilization (IVF) were cultured in modified Earle's balanced salt solution (MK-1) supplemented with 0.4% bovine serum albumin (BSA) or 5% fetal bovine serum (FBS) for 9 days. There were no significant differences between the BSA and FBS groups with respect to the proportion of cleavage and development to the morula and blastocyst stages of zygotes. However, the presence of FBS in the medium enhanced development to the hatching blastocyst stage of zygotes compared with the BSA group (31.4% v. 7.8%). Moreover, 2.9% of zygotes cultured with FBS developed to the hatched blastocyst stage. The mean cell number of blastocysts derived from zygotes cultured with FBS was significantly higher (P<0.01) than that from zygotes cultured with BSA (136.6 v.101.5). In the second experiment, embryos at the morula or blastocyst stage, which were produced by culturing in MK-1 supplemented with 0.4% BSA after IVF, were subsequently cultured in MK-1 with 0.4% BSA or 5% FBS. Significantly more morulae developed to the blastocyst (P<0.05) and hatching blastocyst stages (P<0.01) in the FBS group than in the BSA group (71.5% and 53.6% v. 44.9% and 6.0%, respectively). Although none of the morulae cultured with BSA developed to the hatched blastocyst stage, 11.5% of morulae cultured with FBS developed to the hatched blastocyst stage. Moreover, the proportion of development to the hatching blastocyst stage of blastocysts was significantly higher (P<0.01) in the FBS group than in the BSA group (68.7% v. 9.8%). None of the blastocysts cultured with BSA developed to the hatched blastocyst stage, whereas 7.3% of blastocysts cultured with FBS developed to the hatched blastocyst stage. The results of the present study indicate that supplementation with FBS at different stages of early embryo development promotes development to the hatching and hatched blastocyst stages of cat IVF embryos.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debora Agata Anzalone ◽  
Luca Palazzese ◽  
Marta Czernik ◽  
Annalaura Sabatucci ◽  
Luca Valbonetti ◽  
...  

AbstractThe current protocols of in vitro fertilization and culture in sheep rely on paradigms established more than 25 years ago, where Metaphase II oocytes are co-incubated with capacitated spermatozoa overnight. While this approach maximizes the number of fertilized oocytes, on the other side it exposes them to high concentration of reactive oxygen species (ROS) generated by active and degenerating spermatozoa, and positively correlates with polyspermy. Here we set up to precisely define the time frame during which spermatozoa effectively penetrates and fertilizes the oocyte, in order to drastically reduce spermatozoa-oocyte interaction. To do that, in vitro matured sheep oocytes co-incubated with spermatozoa in IVF medium were sampled every 30 min (start of incubation time 0) to verify the presence of a fertilizing spermatozoon. Having defined the fertilization time frame (4 h, data from 105 oocytes), we next compared the standard IVF procedures overnight (about 16 h spermatozoa/oocyte exposure, group o/nIVF) with a short one (4 h, group shIVF). A lower polyspermic fertilization (> 2PN) was detected in shIVF (6.5%) compared to o/nIVF (17.8%), P < 0.05. The o/nIVF group resulted in a significantly lower 2-cell stage embryos, than shIVF [34.6% (81/234) vs 50.6% (122/241) respectively, P < 0.001]. Likewise, the development to blastocyst stage confirmed a better quality [29% (70/241) vs 23.5% (55/234), shIVF vs o/nIVF respectively] and an increased Total Cell Number (TCN) in shIVF embryos, compared with o/n ones. The data on ROS have confirmed that its generation is IVF time-dependent, with high levels in the o/nIVF group. Overall, the data suggest that a shorter oocyte-spermatozoa incubation results in an improved embryo production and a better embryo quality, very likely as a consequence of a shorter exposure to the free oxygen radicals and the ensuing oxidative stress imposed by overnight culture.


2018 ◽  
Vol 30 (1) ◽  
pp. 188
Author(s):  
M. Duque ◽  
A. Sestelo ◽  
D. F. Salamone

The Puma concolor population has been decreasing during the last 30 years. Semen cryopreservation of this species has been accomplished successfully and offers the possibility of preserving endangered species. We previously showed that fertilizing capability of wild felid spermatozoa can be evaluated using intracytoplasmic sperm injection (ICSI) with in vitro-matured domestic cat oocytes (Moro et al. 2014 Reprod. Domest. Anim. 49, 693-700). Due to the lack of homologous oocytes, we evaluated the capability of the Puma concolor sperm to induce domestic cat oocyte fertilization and subsequent pre-implantation embryo development. In the present study, cryopreserved sperm obtained by electroejaculation from five different males were used for IVF of in vitro-matured (IVM) domestic cat oocytes. Straws were thawed by exposing them to air for 10 s and then immersing in a 37°C water bath for 30 s. The contents of the straws were poured into a sterile 1.5-mL microtube pre-warmed to 37°C. The sperm suspension was diluted (1:3 v/v) by the slow (drop-by-drop) addition of a modified Tyrode’s solution. For IVF, IVM oocytes (n = 370) were co-incubated with 0.5 × 105 motile spermatozoa mL−1 in an atmosphere of 21% O2 in air at 38.5°C for 18 to 20 h. Presumptive zygotes were cultured in vitro in 50-μL drops of modified Tyrode’s medium on 6.5% CO2 in air at 38.5°C. Cleavage was determined at 48 h post-fertilization, and 5% FBS was added at Day 5 of in vitro culture. Blastocyst stage was evaluated at Day 8. Results (mean ± SEM) showed a high cleavage rate (179/370, 49.0 ± 4.0%), and a high development to morula stage (137/370, 34.4 ± 7.2%), and to blastocyst stage (94/370, 23.4 ± 4.7%) for all males. These results indicated that Puma concolor spermatozoa can induce domestic cat oocyte activation and development to blastocyst stage in similar rates to domestic cat homologous IVF: IVM oocytes (n = 291), cleavage rate (199/291, 67.1 ± 6.1%), development to morula stage (144/291, 47.8 ± 4.9%), and to blastocyst stage (86/291, 30.1 ± 1.6%). In conclusion, we demonstrated that domestic cat oocyte can be used to evaluated cryopreserve sperm samples from another felid species.


2018 ◽  
Vol 30 (1) ◽  
pp. 200 ◽  
Author(s):  
A. Lucas-Hahn ◽  
B. Petersen ◽  
M. Nowak-Imialek ◽  
U. Baulain ◽  
R. Becker ◽  
...  

Recently (Spate et al. 2017 Reprod. Fertil. Dev. 29, 150), a new medium [TCM-199 supplemented with hCG 10 IU, pregnant mare serum gonadotropin (PMSG) 10 IU mL−1, fibroblast growth factor (FGF) 40 ng mL−1, leukemia inhibitory factor (LIF) 2000 U mL−1, IGF-1 20 ng mL−1, epidermal growth factor (EGF) 10 ng mL−1], termed FLI medium, was demonstrated to improve porcine oocyte maturation in vitro. The effects on embryo development and quality have not yet been investigated. The purpose of the present study was to compare the FLI medium in porcine in vitro embryo production (IVP) with our standard maturation medium (DMEM supplemented with 10 IU mL−1 PMSG and hCG, 50 ng mL−1 EGF, 100 ng mL−1 IGF1, and 5 ng mL−1 FGF). Briefly, gilt oocytes were collected via aspiration of follicles from abattoir ovaries and matured for 44 h in either FLI or standard DMEM medium at 39°C, 5% CO2 in humidified air. In vitro fertilization was performed with freshly ejaculated sperm (250,000 mL−1) of a multi-transgenic boar (GGTA1-KO/hCD46/hCD55/hCD59/hHO-1/hA20) by co-incubation with the matured oocytes in PGMTac4 medium for 4 h. Zygotes were washed twice and then cultured for 6 days in PZM3 medium. Development to the blastocyst stage was recorded at Day 6 of culture. Blastocysts were fixed and Hoechst33342 stained for counting the nuclei. Each of the experiments was repeated 3 times. In a second step, Day 5 blastocysts derived from the FLI medium were transferred to synchronized pubertal gilts to test the in vivo developmental competence of the IVF embryos. Maturation of oocytes in FLI medium resulted in a significantly higher blastocyst rate (49.3 vs. 13.5; P ≤ 0.001, Chi-squared test) and nuclei number (41.3 ± 12.2 vs. 35.3 ± 10.8; P ≤ 0.001, one-way ANOVA) compared with the standard medium, whereas the cleavage rate was not affected. Transfer of Day 5 blastocysts (average 35 embryos/recipient) derived from the FLI system using 8 recipients resulted in 7 pregnancies (87.5%) as determined by ultrasound scanning on Day 25 of gestation. At the time of writing, one recipient had delivered 5 healthy piglets after a gestation length of 114 days. Results indicate that the FLI medium significantly improves blastocyst rates and the cell number of the resulting blastocysts (Table 1) and yields pig IVF embryos with a high developmental capacity in vivo. By producing high-quality porcine embryos, this FLI-based IVF system provides an efficient method to modify the porcine genome by cytoplasmic microinjection of CRISPR/Cas molecules into IVF-derived zygotes. Table 1.Results of maturation of oocytes in FLI medium compared with DMEM


2006 ◽  
Vol 18 (2) ◽  
pp. 190
Author(s):  
N. W. K. Karja ◽  
K. Kikuchi ◽  
M. Fahrudin ◽  
O. Manabu ◽  
T. Somfai ◽  
...  

The present study was conducted to elucidate the effects of glucose addition during Days 0 to 2 (the day of in vitro fertilization was defined as Day 0) on the developmental competence, intracellular reactive oxygen species (ROS) level, and glutathione (GSH) concentration of in vitro-produced pig embryos. Zygotes were obtained as reported previously (Kikuchi et al. 2002 Biol. Reprod. 66, 1033-1041), and cultured in NCSU-37 supplemented with 1.5, 3.5, 5.5, 10, and 20 mM glucose (glucose groups) or in NCSU-37 supplemented with 0.17 mM pyruvate and 2.73 mM lactate (Pyr/Lac group) from Days 0 to 2. Subsequently, embryos in all groups were then cultured in NCSU-37 added with 5.5 mM glucose until Day 6. Data were analyzed by ANOVA and are presented as percentage for blastocyst rate and as mean � SEM for blastocyst cell number. The blastocyst rates and blastocyst cell numbers in glucose groups were significantly lower compared to those in the Pyr/Lac group (blastocyst rate: 5.2, 13.8, 12.6, 16.3, and 13.5%, respectively, vs. 26.3%); blastocyst cell number: 41.8 � 3.2, 41.6 � 2.3, 42.2 � 3.2, 43.0 � 3.3, and 39.2 � 2.8, respectively, vs. 52.7 � 4.1). The ROS levels of Day 1 embryos were significantly higher when they were exposed to glucose, whereas the ROS levels of Day 2 embryos were higher only in the 1.5 mM and 3.5 mM glucose groups, compared to levels in embryos in Pyr/Lac group. There were no differences in the GSH concentrations of Day 1 embryos among the glucose groups and the Pyr/Lac group. Of Day 2 embryos, the GSH concentration was significantly lower only in 1.5 mM glucose group, compared to that in embryos in the Pyr/Lac group. These results indicate that (1) the presence of glucose during the first 2 days of culture causes a decrease in the development of in vitro-produced embryos to the blastocyst stage, which might be related to the rise in ROS generation in Day 1 embryos; and (2) except for the 1.5 mM glucose group, the ability of Day 2 embryos in glucose groups to maintain GSH concentration at levels needed for their development might provide them with preferable intracellular conditions for the development to the blastocyst stage.


2004 ◽  
Vol 16 (2) ◽  
pp. 255 ◽  
Author(s):  
B. Gasparrini ◽  
L. Boccia ◽  
A. De Rosa ◽  
D. Vecchio ◽  
R. Di Palo ◽  
...  

The identification of an optimal in vitro fertilization system is critical in order to improve the in vitro embryo production efficiency in buffalo species. The aim of this work was to evaluate the effects of fertilization media and sperm motility inducing factors (SMIF) on cleavage and blastocyst rates in buffalo species. Cumulus-oocytes complexes (n=516), recovered from slaughtered animals, were matured in vitro in TCM 199+10 % FCS, 0.5μgmL−1 FSH, 5μgmL−1 LH, 1μgmL−1 17β-estradiol and 50μM cysteamine, at 38.5°C under 5% CO2 in humidified air for 24 hours. The mature oocytes were randomly assigned to four groups for fertilization. In particular, IVF was carried out at 38.5°C under 5% CO2 in humidified air in either Tyrode’s modified medium or Brackett Oliphant medium, in the presence of 0.01mM heparin;; each medium was supplemented with either a mixture of 0.2mM penicillamine and 0.1mM hypotaurine or 5mM caffeine. Frozen-thawed sperm from a tested bull was treated by the swim-up procedure and used at a final concentration of 206mL−1. After 20–22h presumptive zygotes were cultured in SOF medium, supplemented with essential and non-essential amino acids and BSA, in a gas atmosphere of 5% CO2, 7% O2 , and 88% N2, up to the blastocyst stage. Cleavage rates and blastocyst yields were analyzed by a full factorial model 2×2 with medium and SMIF effects (SPSS 11.0). The analysis used permits the identification of statistical differences between treatments irrespective of an interaction (Searle SR. 1971. Linear model. Ed. John Wiley &amp; Sons;; XXI:533). The comparison of the two media, irrespective of the SMIF used, did not show any difference in cleavage rate (43.7% v. 39.3%, respectively, in TALP and BO). On the contrary higher cleavage rates were recorded with hypotaurine-penicillamine v. caffeine (47.7% v. 35.3%; P&lt;0.05), regardless of the medium employed. However, a significant interaction between media and SMIF was found;; in fact the addition of hypotaurine and penicillamine significantly improved cleavage rate compared with caffeine in TALP medium (59.6% v. 27.9%; P&lt;0.05) whereas no differences were observed in BO (35.9% v. 42.7%, respectively). With regard to blastocyst yield a significant effect of medium was also found, with the highest embryo production in TALP v. BO (13.9% v. 6.8%; P&lt;0.05). Blastocyst rate was improved in the presence of hypotaurine-penicillamine v. caffeine (13.6% v. 7.2%; P&lt;0.05). Furthermore there was a significant interaction between medium and SMIF, with the highest embryo yields in the presence of hypotaurine-penicillamine v. caffeine in TALP (20.7% v. 7.1%, respectively;; P&lt;0.05) but not in BO (6.4% v. 7.2%, respectively). The differences we found disappeared when the embryo yield was calculated in relation to the cleaved eggs, with the exception of a lower efficiency of BO v. TALP (15.9% v. 31.1%; P=0.057), suggesting an influence of BO also on post-fertilization development.


2005 ◽  
Vol 17 (2) ◽  
pp. 276 ◽  
Author(s):  
J. Pryor ◽  
S. Romo ◽  
D.D. Varner ◽  
K. Hinrichs ◽  
C.R. Looney

In commercial bovine in vitro fertilization (IVF) companies, there is a continuous need to improve results. Efforts to maximize in vitro embryo production have included modifications in the use of sperm separation gradients. The development of commercially available sperm centrifugation gradients represents a new possibility of increasing the number of viable sperm that can be obtained from low concentration (fresh or frozen, sexed or unsexed) semen samples in order to improve the efficiency of the IVF system to make embryo production as efficient as possible. The objective of this study was to compare two different separation gradients, as follows: Group 1: Percoll (Sigma, St. Louis, MO, USA), in 45% and 90% gradients; Group 2: EquiPure (Nidacon, Gathenburg, Sweden), in top and bottom layers. Before and after separation, sperm were evaluated at 200× magnification for total motility, and then stained to assess viability at 400× with fast-green/eosin stain (Sigma). Sperm separation was performed using frozen/thawed semen from one bull. Semen was separated by centrifugation at 200g for 30 min in both density gradients. Results obtained from Groups 1 and 2 were compared by chi-square test. Sperm separation with Percoll yielded lower numbers of sperm (average sperm concentration after separation of 92 × 106, vs. 159 × 106 sperm/mL for EquiPure; P < 0.05) but resulted in higher motility (60% vs. 39%, respectively; P < 0.05) of separated sperm. Rates of live sperm cells were not significantly different between groups (69.5% vs. 70%, respectively; P > 0.1). These results indicate that the commercial separation medium EquiPure may be associated with higher sperm concentration levels but with lowered sperm motility when compared to Percoll for bovine sperm separation. However, Equipure provided similar percentages of live sperm when compared to Percoll, which is currently used in our laboratory.


Zygote ◽  
2016 ◽  
Vol 24 (6) ◽  
pp. 890-899 ◽  
Author(s):  
A.L.S. Guimarães ◽  
S.A. Pereira ◽  
M. N. Diógenes ◽  
M.A.N. Dode

SummaryThe aim of this study was to evaluate the effect of adding a combination of insulin, transferrin and selenium (ITS) and l-ascorbic acid (AA) during in vitro maturation (IVM) and in vitro culture (IVC) on in vitro embryo production. To verify the effect of the supplements, cleavage and blastocyst rates, embryo size and total cell number were performed. Embryonic development data, embryo size categorization and kinetics of maturation were analyzed by chi-squared test, while the total cell number was analyzed by a Kruskal–Wallis test (P < 0.05). When ITS was present during IVM, IVC or the entire culture, all treatments had a cleavage and blastocyst rates and embryo quality, similar to those of the control group (P < 0.05). Supplementation of IVM medium with ITS and AA for 12 h or 24 h showed that the last 12 h increased embryo production (51.6%; n = 220) on D7 compared with the control (39.5%; n = 213). However, no improvement was observed in blastocyst rate when less competent oocytes, obtained from 1–3 mm follicles, were exposed to ITS + AA for the last 12 h of IVM, with a blastocyst rate of 14.9% (n = 47) compared with 61.0% (n = 141) in the control group. The results suggest that the addition of ITS alone did not affect embryo production; however, when combined with AA in the last 12 h of maturation, there was improvement in the quantity and quality of embryos produced. Furthermore, the use of ITS and AA during IVM did not improve the competence of oocytes obtained from small follicles.


2004 ◽  
Vol 16 (2) ◽  
pp. 202 ◽  
Author(s):  
W.F. Swanson ◽  
A.L. Manharth ◽  
J.B. Bond ◽  
H.L. Bateman ◽  
R.L. Krisher ◽  
...  

Domestic cat embryos typically are cultured in media formulated for somatic cells or embryos from rodents or livestock species. Under these conditions, blastocyst development has been inconsistent and delayed relative to embryos grown in vivo, and embryo viability following transfer has been low. Our goal is to systematically define the culture requirements of the feline embryo to improve embryo development and viability. The objective of this study was to determine the ionic (NaCl, KCl, KH2PO4, and CaCl2:MgSO4) preferences of domestic cat IVF embryos. Anestral female cats were injected (i.m.) with 150IU eCG followed 84h later by 100IUhCG. Oocytes were recovered via laparoscopic follicular aspiration approximately 24h post-hCG injection (Day 0). Semen was collected from one of two males by means of an artificial vagina and washed once in HEPES-buffered IVF medium. Mature cumulus-oocyte complexes were co-incubated with 2.5–5×105 motile sperm mL−1 in IVF medium (100mM NaCl, 4.0mM KCl, 1.0mM KH2 PO4, 2.0mM CaCl2, 1.0mM MgSO4-7H2O, 25.0mM NaHCO3, 3.0mM glucose, 0.1mM pyruvate, 6.0mM L-lactate, 1.0mM glutamine, 0.1mM taurine, 1×MEM nonessential amino acids, 50μgmL−1 gentamicin, and 4.0mgmL−1 BSA) for 19 to 22h in 6% CO2 in air (38.7°C). Cumulus cells were removed and embryos cultured (8–11 embryos/50μL drop; 6% CO2, 5% O2, 89% N2, 38.7°C) in media containing 100.0 or 120.0mM NaCl, 4.0 or 8.0mM KCl, 0.25 or 1.0mM KH2PO4, and 1.0mM:2.0mM or 2.0mM:1.0mM CaCl2:MgSO4 (2×2×2×2 factorial design). The remaining components of the culture medium were identical to the IVF medium (but w/o gentamicin). Development to the blastocyst stage by Day 6, metabolism (glycolysis and pyruvate) of each blastocyst, and final cell number (Hoechst 33342 staining) of all embryos were evaluated. Final cell number of cleaved embryos and development to the blastocyst stage were analyzed using analysis of variance in the GLIMMIX macro of SAS. A total of 236 oocytes were inseminated, yielding 128 cleaved embryos (54%), including 6 blastocysts (4.7% of cleaved embryos). Cell number was not (P&gt;0.05) affected by NaCl, KCl, or KH2PO4 concentrations, but tended (P=0.057) to be higher after culture in 2.0mM:1.0mM CaCl2:MgSO4. Treatments did not significantly affect (P&gt;0.05) development to the blastocyst stage, but numerically more blastocysts were produced in 100.0mM NaCl (4/6), 8.0mM KCl (5/6), or 1.0mM KH2PO4 (5/6). Both CaCl2:MgSO4 ratios resulted in 3 blastocysts. Blastocysts contained 61.08±5.1 (mean±SEM, n=6) cells and actively metabolized glucose (glycolysis, 3.7±0.8pmol/embryo/3h or 0.06±0.01pmol/cell/3h) and pyruvate (0.75±0.27pmol/embryo/3h or 0.013±0.005pmol/cell/3h). These results suggest that the ionic composition of culture media influences the in vitro development of cat IVF embryos. (Supported by NIH grant RR15388.)


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