In the starfish Asterias amurensis, the jelly coat of the eggs contains a glycoprotein essential for the induction of the acrosome reaction in homologous spermatozoa that is termed the acrosome-reaction-inducing substance (ARIS).ARIS is a highly sulphated and fucose-rich glycoprotein of extremely high molecular mass(>104 kDa). ARIS was irradiated with high-energy eletrons in order to estimate the minimum size required for its biological activity. The minimum functional unit or target size of ARIS was estimated to be c. 14 kDa by target size analysis. ARIS was significantly disintegrated by the irradiation, yet the total sugar content was not apparently reduced. The binding of 125I-labelled ARIS to spermatozoa competed with that of irradiated ARIS, although the affinity of ARIS was much reduced after irradiation.

Full-grown ovarian oocytes of the amphibian Bufo arenarum were induced to mature in vitro by removing the follicular layers (spontaneous maturation) or by treatment with progesterone (hormone-induced maturation). These oocytes were then treated with trypsin and inseminated with homologous spermatozoa. Oocytes matured in vivo that had not undergone any influence of the oviducts (coelomic oocytes), inseminated under the same experimental conditions, were used as controls. The results show that oocytes induced to mature in vitro and exhibiting apparently normal signs of activation were polyspermic. In fact, 2 h after insemination numerous functioning pronuclei could be observed in the animal hemisphere. These results suggest that even though the oocytes which matured in vitro were able to undergo activation after insemination, they were unable to establish an effective block to polyspermy.

The present study investigates the effect of different slow chilling curves on the storage of pacu (Piaractus mesopotamicus) embryos submitted to chilling at −8°C. Embryos at the blastopore closure stage were divided into two groups: G1 – embryos exposed to cryoprotectant solution containing methanol (10%) and sucrose (0.5 M), treated as follows: (T1) taken directly from room temperature to the refrigerator without being submitted to the curve; (T2) chilling curve of 0.5°C/min; and (T3) chilling curve of 1°C/min; and G2 – the cryoprotectant solution alone was submitted to these same temperatures, receiving the embryos only after temperature had decreased, corresponding to treatments T4, T5 and T6, respectively. Treatments were kept at −8°C for a period of 6 h. Embryo development was evaluated for each treatment, with six replicates in an entirely randomized design. Survival among embryos not submitted to refrigeration was 94.3 ± 8.05%. Percentage of total larvae (TL) and addled eggs (AE) did not differ statistically between the groups, although percentage of swimming larvae (SL) exhibited higher values in G1 for the 1°C/min curve. Furthermore, when comparing the three chilling curves, a decrease of 1°C/min resulted in the highest TL percentage (90.85%), followed by the 0.5°C/min curve (78.52%). Thus, the use of 1°C/min chilling curves is recommended for P. mesopotamicus embryos stored for 6 h at −8°C.

Although progesterone is the established maturation inducer in amphibians, Bufo arenarum oocytes obtained during the reproductive period (spring–summer) resume meiosis with no need of an exogenous hormonal stimulus if deprived of their enveloping follicle cells, a phenomenon called spontaneous maturation. In this species it is possible to obtain oocytes competent and incompetent to undergo spontaneous maturation according to the seasonal period in which animals are captured. Reinitiation of meiosis is regulated by maturation promoting factor (MPF), a complex of the cyclin-dependent kinase p34cdc2 and cyclin B. Although the function and molecule of MPF are common among species, the formation and activation mechanisms of MPF differ according to species. This study was undertaken to evaluate the presence of pre-MPF in Bufo arenarum oocytes incompetent to mature spontaneously and the effect of the injection of mature cytoplasm or germinal vesicle contents on the resumption of meiosis. The results of our treatment of Bufo arenarum immature oocytes incompetent to mature spontaneously with sodium metavanadate (NaVO3) and dexamethasone (DEX) indicates that these oocytes have a pre-MPF, which activates and induces germinal vesicle breakdown (GVBD) by dephosphorylation on Thr-14/Tyr-15 by cdc25 phosphatase and without cyclin B synthesis. The injection of cytoplasm containing active MPF is sufficient to activate an amplification loop that requires the activation of cdc25 and protein kinase C, the decrease in cAMP levels, and is independent of protein synthesis. However, the injection of germinal vesicle content also induces GVBD in the immature receptor oocyte, a process dependent on protein synthesis but not on cdc25 phosphatase or PKC activity.

The present study examined in vitro development and the cytological status of non-enucleated rat oocytes after microinjection of cumulus nuclei and chemical activation. Oocyte–cumulus complexes were collected from gonadotropin-treated prepubertal female Wistar rats 14 h after human chorionic gonadotropin (hCG) injection. Cumulus nuclei were injected into ovulated oocytes and then stimulated in the presence of 5 mM SrCl2 for 20 min at various time points (0–3.5 h) after injection. Some of the reconstituted eggs were cultured to observe the pronuclear formation, cleavage, and blastocyst formation. The incidences of eggs forming at least one pronucleus or containing two pronuclei were not significantly different among the periods (82.4–83.5% and 43.4–51.9%, respectively). Nor did the incidences of eggs cleaving (86.7–97.7%) and developing to the blastocyst stage (0–3.5%) differ depending on when, after injection, stimulation began. When some of the reconstituted eggs were observed for cytological morphology 1–1.5 h after injection, 71.7% of the eggs caused premature chromatin condensation, but only 46.2% of them formed two spindles around each of maternal and somatic chromatins. However, the morphology of the somatic spindles differed from that of the spindles, which formed around the oocyte chromatins. Only 7.5% of the eggs contained the normal chromosomal number. In many reconstituted oocytes, before activation, an abnormal spindle formation was observed in the somatic chromatins. In conclusion, these results show that non-enucleated rat oocytes injected with cumulus nuclei can form pronuclei and cleave following chemical activation, whereas blastocyst formation is very limited, probably caused by abnormalities in the spindle formation and distribution of somatic chromatids.

During follicular development, granulosa cells undergo functional and structural changes affecting their steroidogenic activity. Oestrogen synthesis mainly occurs in the endoplasmic reticulum and relies on aromatase activity to convert androgens that arise from theca cells. In the present study, indicators of mitochondria-related steroidogenic capacity, as steroidogenic acute regulatory (StAR) protein expression and mitochondrial membrane potential (MMP), have been evaluated in bovine granulosa cells (GCs) and related to follicle growth and atresia. Atresia was estimated by morphological examination of follicle walls and cumulus–oocyte complexes (COC) and assessed by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay for apoptosis detection. Bovine ovarian follicles were macroscopically classified according to their atresia grade and grouped into small, medium or large follicles. After follicle opening, the COCs were morphologically classified for follicle atresia and the GCs were collected. Granulosa cells were fixed for immunofluorescence (IF) and TUNEL assay, frozen for western blotting (WB) or freshly maintained for MMP analyses. StAR protein expression was assessed using both IF and WB analyses. The follicle atresia grade could be efficiently discriminated based on either follicle wall or COC morphological evaluations. Granulosa cells collected from small non-atretic follicles showed a higher (P <0.01) MMP and WB-based StAR protein expression than small atretic follicles. For IF analysis, StAR protein expression in large atretic follicles was higher (P <0.05) than that in large non-atretic follicles. These results suggest a role played by mitochondria in GC steroidogenic activity, which declines in healthy follicles along with their growth. In large follicles, steroidogenic activity increases with atresia and is possibly associated with progesterone production.

It has been reported that different in vitro culture systems affect the birth weight of lambs. The aim of this study was to test body weight and lambing rate of lambs born from five different in vitro culture systems after vitrification. Oocytes of Sarda sheep were matured in TCM-199 plus 0.4% bovine serum albumin (BSA) using systems: (i) 4 mg/ml fatty acid-free BSA (BSA4); (ii) 8 mg/ml fatty acid-free BSA (BSA8); (iii) BSA8–hyaluronan (BSA8–HA); (iv) BSA8–charcoal-stripped FBS (BSA8–CH); or (v) with 10% fetal bovine serum (FBS; serum) and fertilized with fresh semen. The presumptive zygotes were cultured up to the blastocyst stage with BSA8, BSA8-HA, BSA8-CH or serum or BSA4. In the third and fifth days of culture 5% charcoal-stripped FBS was added into BSA8-CH and serum, while 8 mg/ml or 4 mg/ml fatty acid-free BSA was added as BSA8, BSA8-HA and BSA4 respectively; 6 mg/ml HA was added to BSA8-HA. In total, 240 vitrified blastocysts were transferred into synchronized ewes. The lambing rate was not significant different between BSA groups or between serum groups (BSA8-CH and serum), while serum groups showed significant lower values when compared with BSA groups. Only BSA8 groups produced heavy lambs (≥4.5 kg) with a significant difference between BSA4 and BSA8 groups (P < 0.05).

This study aimed to: (i) characterize cultured granulosa cells (GCs) from different follicle sizes morphologically and molecularly; and (ii) select a suitable model according to follicular size that maintained GC function during culture. Buffalo ovaries were collected from a slaughterhouse and follicles were classified morphologically into: first group ≤ 4 mm, second group 5–8 mm, third group 9–15 mm and fourth group 16–20 mm diameter. GC pellets were divided into two portions. The first portion served as the control fresh pellet, and the secondwas used for 1 week for GC culture. Total RNA was isolated, and qRT-PCR was performed to test for follicle-stimulating hormone receptor (FSHR), cytochrome P450 19 (CYP19), luteinizing hormone/choriogonadotropin receptor (LHCGR), proliferating cell nuclear antigen (PCNA), apoptosis-related cysteine peptidase (CASP3), anti-Müllerian hormone (AMH), and phospholipase A2 group III (PLA2G3) mRNAs. Estradiol (E2) and progesterone (P4) levels in the culture supernatant and in follicular fluids were measured using enzyme-linked immunosorbent assay (ELISA). Basic DMEM-F12 medium maintained the morphological appearance of cultured GCs. The relative abundance of FSHR, CYP19, and LHCGR mRNAs was 0.001 ≤ P ≤ 0.01 and decreased at the end of culture compared with the fresh pellet. There was a fine balance between expression patterns of the proliferation marker gene (PCNA) and the proapoptotic marker gene (CASP3). AMH mRNA was significantly increased (P < 0.001) in cultured GCs from small follicles, while cultured GCs from other three categories (5–8 mm, 9–15 mm and 16–20 mm) showed a clear reduction (P < 0.001). Interestingly, the relative abundance of PLA2G3 mRNA was significantly (P < 0.001) increased in all cultured GCs. E2 and P4 concentrations were significantly (P < 0.001) decreased in all cultured groups. Primary cultured GCs from small follicles could be a good model for better understanding follicular development in Egyptian buffaloes.

The developmental ability of reconstructed blastocysts from C57BL/6 strain mouse inner cell masses (ICMs) and Kunming strain mouse trophoblasts was assessed. The procedure of ICM replacement was as follows: C57BL/6 ICMs were separated from the blastocysts using immunosurgery. A slit was made in the zona pellucida of a Kunming blastocyst to allow its ICM to extrude. The C57BL/6 ICM was injected into the Kunming blastocoele, and the extruded Kunming ICM was cut off. The reconstructed blastocysts were able to re-expand (77%) and hatch (27.3%) in vitro. A total of 64 reconstructed blastocysts and 124 Kunming blastocysts were co-transferred into the uteri of 11 pseudopregnant Kunming mice, and an ICM replacement offspring was born. The results indicate that reconstructed embryos obtained by inter-strain ICM replacement have the ability to develop to term. This technique may provide a method to solve the pregnancy failure in interspecific cloning.

Assembly in vitro of vitelline envelope (VE) components, which were precipitated by 50–70% saturated ammonium sulphate from VE extracts, was induced by the action of a sialoglycoprotein that is immunohistochemically localised in cortical alveoli of fish eggs and has serine proteinase activity. The VE components consisted of major bands of molecular mass about 150–120, 110–100, 70 and 27 kDa in addition to about 20 minor bands and contained a chorionic transglutaminase, visualised as two fluorescent bands by monodansylcadaverine staining. The VE component assembly in vitro was Ca2+-dependent, not induced if the sialoglycoprotein was pretreated with a serine proteinase inhibitor, and inhibited by the presence of p-chloromercuribenzoate, iodoacetamide or L-cysteine in the reaction medium system. Electron microscopy revealed that assembly in vitro of the VE components consisted of aggregates of network sheets, consisting of branching and anastomosing thin (approximately 27–52 nm) and thick (approximately 137–376 nm) filamentous substances. Separation by SDS-PAGE showed that a considerable number of VE components participated in the assembly in vitro in various amounts. These results suggest at least partial reproduction of the phenomena that occur in the process of fertilisation envelope (FE) formation, and provide a new approach to investigation of the process of FE assembly in vitro.

The present study investigated whether a recloning procedure would affect the reproductive performance or the germline transmission capacity of recloned transgenic pigs. This study has also laid the foundation for the development of elite transgenic swine breeds in the future. Recloned transgenic pigs were developed from ear tissue fibroblasts of primary transgenic cloned pigs using a recloning procedure, and their reproductive performance and exogenous gene transmission were analyzed. Two transgenic cell lines with different genetic backgrounds (derived from a female miniature pig and a male Landrace pig) with stable expression of green fluorescent protein (GFP) were established successfully. Furthermore, recloned transgenic embryos were developed to full term successfully. One female Chinese experimental miniature piglet (CEMP) (GFP+) and three male Landrace piglets (GFP+) were delivered naturally. Furthermore, the index values for the reproductive characteristics of the recloned transgenic pigs, such as puberty, gestation period, sperm volume and sperm concentration, were not significantly different from those of conventionally bred pigs. In addition, 53% of the F1 offspring of the recloned transgenic pigs were GFP positive. These results demonstrate that ear tissue fibroblasts from primary transgenic cloned pigs efficiently support the full-term development of recloned transgenic embryos. Furthermore, recloned transgenic pigs maintain normal reproductive performance and stable germline (genetic) transmission capacities.

Oocyte cryopreservation has become an important component of assisted reproductive technology with increasing implication in female fertility preservation and animal reproduction. However, the possible adverse effects of oocyte cryopreservation on epigenetic status of the resulting embryos is still an open question. This study evaluated the effects of MII-oocyte vitrification on gene transcripts linked to epigenetic reprogramming in association with the developmental competence and epigenetic status of the resulting embryos at 2-cell and blastocyst stages in dromedary camel. The cleavage rate of vitrified oocytes following intracytoplasmic sperm injection was significantly increased compared with the control (98.2 ± 2 vs. 72.7 ± 4.1%, respectively), possibly due to the higher susceptibility of vitrified oocytes to spontaneous activation. Nonetheless, the competence of cleaved embryos derived from vitrified oocytes for development to the blastocyst and hatched blastocyst was significantly reduced compared with the control (7.7 ± 1.2 and 11.1 ± 11.1 compared with 28.1 ± 2.6 and 52.4 ± 9.9%, respectively). The relative transcript abundances of epigenetic reprogramming genes DNMT1, DNMT3B, HDAC1, and SUV39H1 were all significantly reduced in vitrified oocytes relative to the control. Evaluation of the epigenetic marks showed significant reductions in the levels of DNA methylation (6.1 ± 0.3 vs. 9.9 ± 0.5, respectively) and H3K9 acetylation (7.8 ± 0.2 vs. 10.7 ± 0.3, respectively) in 2-cell embryos in the vitrification group relative to the control. Development to the blastocyst stage partially adjusted the effects that oocyte vitrification had on the epigenetic status of embryos (DNA methylation: 4.9 ± 0.4 vs. 6.2 ± 0.6; H3K9 acetylation: 5.8 ± 0.3 vs. 8 ± 0.9, respectively). To conclude, oocyte vitrification may interfere with the critical stages of epigenetic reprogramming during preimplantation embryo development.

Reference gene selection in mouse oocytes is an important task required to perform further adequate analysis of target gene expression levels. In the current work we have analyzed expression stability of the seven most commonly used reference genes (Actb, Eef1e1, Gapdh, H2afz, Ppia, Rpl4 and Ubc) in mouse oocytes at the germinal vesicle (GV) stage. We have performed analysis of expression stability of the above-mentioned reference genes with the three most commonly used software tools: geNorm, BestKeeper and NormFinder. Taking into account the results obtained from all of these programmes Gapdh, Rpl4 and H2afz seem to be suitable candidate reference genes in GV oocytes of mouse.

Micromanipulation of oocytes is time consuming during ICSI experiments; however the ‘time frame’ to manipulate oocytes without a drop in efficiency is not very wide due to the use of not completely matured and/or aged MII oocytes. Therefore, the aim of this work was to study the effect of a short roscovitine pretreatment for 5 h and two different IVM periods (5R + 40IVM or 5R + 45IVM) and a prolonged IVM time from 45 h (45IVM) to 50 h (50IVM) on parthenogenetic and ICSI embryo development, in order to fit the time frame to manipulate pig oocytes to the whole labour day session. In the first experiment, oocytes, pretreated with roscovitine and IVM cultured for 5 h, showed a similar nuclear stage as non-cultured oocytes and a significantly higher percentage of GVI-GVII oocytes compared with non-roscovitine treated oocytes cultured for 5 h in IVM conditions. When COC were cultured under the 5R + 40IVM system, nuclear maturation and cleavage rates after electrical activation were significantly lower than when COC were cultured under the 45IVM, 50IVM and 5R + 45IVM culture systems (54.2% vs. 72.6–76.8% and 58.8% vs. 81.4–88.3%, respectively). However, this difference was not statistically significant for parthenogenote blastocyst rate. No differences were observed in MII and in parthenogenote and ICSI embryo development among 45IVM, 50IVM and 5R + 45IVM experimental groups. In conclusion, under our conditions and using parthenogenetic and ICSI embryos, we observed that it is feasible to prolong the pig oocyte manipulation ‘time frame’ by at least 5 h with no significant drop in blastocyst rate.

Stem cells are an immortal cell population capable of self-renewal; they are essential for human development and ageing and are a major focus of research in regenerative medicine. Despite considerable progress in differentiation of stem cells in vitro, culture conditions require further optimization to maximize the potential for multicellular differentiation during expansion. The aim of this study was to develop a feeder-free, serum-free culture method for human embryonic stem cells (hESCs), to establish optimal conditions for hESC proliferation, and to determine the biological characteristics of the resulting hESCs. The H9 hESC line was cultured using a homemade serum-free, feeder-free culture system, and growth was observed. The expression of pluripotency proteins (OCT4, NANOG, SOX2, LIN28, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81) in hESCs was determined by immunofluorescence and western blotting. The mRNA expression levels of genes encoding nestin, brachyury and α-fetoprotein in differentiated H9 cells were determined by RT-PCR. The newly developed culture system resulted in classical hESC colonies that were round or elliptical in shape, with clear and neat boundaries. The expression of pluripotency proteins was increased, and the genes encoding nestin, brachyury, and α-fetoprotein were expressed in H9 cells, suggesting that the cells maintained in vitro differentiation capacity. Our culture system containing a unique set of components, with animal-derived substances, maintained the self-renewal potential and pluripotency of H9 cells for eight passages. Further optimization of this system may expand the clinical application of hESCs.

This study aims to evaluate the effects of N-acetylcysteine (NAC) on bovine oocyte maturation, mitochondrial activity and transzonal projections (TZP), as well as on the levels of reactive oxygen species (ROS) and messenger RNA (mRNA) for catalase (CAT) superoxide dismutase (SOD), periredoxin-6 (Prdx6), glutathione peroxidase (GPx), growth and differentiation factor-9 (GDF9), histone H1Foo, cyclin B1 (CCNB1) and c-Mos. Bovine cumulus–oocyte complexes (COC) of medium-sized antral follicles (3.0–6.0 mm) were prematured in TCM-199 for 8 h at 38.5°C in 5% CO2. After prematuration in the presence of forskolin and C-type natriuretic peptide, COCs were matured in TCM-199 alone or with 0.1, 0.5 or 2.5 mM NAC. Then, oocytes were classified according to the stage of chromatin. Furthermore, mitochondrial activity and intracellular levels of ROS and TZP were also evaluated. The levels of mRNAs for CAT, SOD, Prdx6, GPx, GDF9, H1Foo, CCNB1 and c-Mos were evaluated using real-time polymerase chain reaction (RT-PCR). The results showed that NAC significantly increased the percentages of oocytes with resumption of meiosis when compared with those oocytes matured in control medium. Oocytes had homogeneous mitochondrial distribution, and those cultured with 0.1 and 0.5 mM NAC had lower levels of ROS when compared with the control. In addition, 0.5 mM NAC reduced TZP and the levels of mRNA for CCNB1. In contrast, NAC did not influence the expression of CAT, GPx, Prdx6, SOD, GDF9, H1Foo, and c-Mos. In conclusion, 0.5 mM NAC reduced the levels of ROS, TZP and mRNA for CCNB1, and improved in vitro resumption of meiosis in oocytes from medium-sized bovine antral follicles.

This study evaluated the effects of oocyte meiosis inhibitors roscovitine (ROS) and butyrolactone I (BL-I) on in vitro production of bovine embryos. Bovine oocytes were maintained in pre in vitro maturation (pre-IVM) with 25 µM ROS or 100 µM BL-I for 24 h to delay meiosis and for 24 h in in vitro maturation (IVM). Following this treatment, the nuclear maturation index was evaluated. All embryos degenerated following this procedure. In the second set of experiments, oocytes were maintained for 6 or 12 h in pre-IVM with the following three treatments: ROS (25 µM or 12.5 µM), BL-I (100 µM or 50 µM) or a combination of both drugs (6.25 µM ROS and 12.5 µM BL-I). Oocytes were cultivated for 18 or 12 h in IVM. When a meiosis-inducing agent was used during pre-IVM for 24 h, more degenerated oocytes were observed at the end of the IVM period. This effect decreased when the meiotic blocking period was reduced to 6 or 12 h. No significant differences were observed in the blastocyst production rate of oocytes in pre-IVM for 6 h with ROS, BL-I, or ROS + BL-I compared with that of the control group (P > 0.05). However, inhibition of oocytes for 12 h resulted in decreased embryo production compared with that in the controls (P < 0.05). There was no difference in the post-vitrification embryo re-expansion rate between the study groups, showing that the meiotic inhibition for 6 or 12 h did not alter the embryo cryopreservation process.

Intracytoplasmic sperm injection (ICSI) has been widely applied in humans, mice, and some domestic animals to cure human infertility, or produce genetically superior or genetically engineered animals. However, the production efficiency of ICSI in pigs remains quite low. In this study, we developed a new sperm pretreatment method to improve production efficiency of ICSI in pigs. Experiment 1 revealed that pretreating porcine sperm with 2.5 mg/ml lipase before ICSI operation, not only can reduce the adhesion between sperm and the injection pipette without adding polyvinylpyrrolidone (PVP) in the operating medium, but also significantly improve male pronuclei (MPN) formation rate (55.56% vs. 40.00% (0 mg/ml), 42.59% (5.0 mg/ml), 40.00% (10.0 mg/ml), P < 0.05) and enhance developmental competence of ICSI embryos (26.03% vs. 10.87% (0 mg/ml), 10.00% (5.0 mg/ml), 10.13% (10.0 mg/ml), P < 0.05). Experiment 2 showed that this method has a higher MPN formation rate (50.47% vs. 30.78%, P < 0.05) and blastocyst rate (18.81% vs. 7.41%, P < 0.05) than the PVP method, and was better than the Triton X-100 treatment method (50.47% vs. 46.23%, 18.81% vs. 12.75%). Therefore, pretreating porcine sperm with 2.5 mg/ml lipase before ICSI operation is highly recommended, instead of adding PVP in the operating medium.

This study aimed to evaluate to what extent the different interval times between trophectoderm (TE) biopsy and vitrification influence the clinical outcomes in preimplantation genetic testing (PGT) cycles. Patients who underwent frozen embryo transfer (FET) after PGT between 2015 and 2019 were recruited. In total, 297 cycles with single day 5 euploid blastocyst transfer were included. These cycles were divided into three groups according to the interval times: <1 h group, 1–2 h group, and ≥2 h group. Blastocyst survival, clinical pregnancy, miscarriage, and ongoing pregnancy rates were compared. The results showed that, in PGT-SR cycles, survival rate in the ≥2 h group (96.72%) was significantly lower than in the <1 h group (100%, P = 0.047). The clinical pregnancy rate in the ≥2 h group was 55.93%, significantly lower than in the <1 h group (74.26%, P = 0.017). The ongoing pregnancy rates in the 1–2 h group and the ≥2 h group were 48.28% and 47.46%, respectively, significantly lower than that in the <1 h group (67.33%, P < 0.05). The miscarriage rate in the 1–2 h group was 18.42%, significantly higher than that in the <1 h group (5.33%, P = 0.027). In PGT-A cycles, the clinical pregnancy and ongoing pregnancy rates in the <1 h group were 67.44% and 53.49%, respectively, higher than that in the 1–2 h group (52.94%, 47.06%, P > 0.05) and the ≥2 h group (52.63%, 36.84%, P > 0.05). In conclusion, vitrification of blastocysts beyond 1 h after biopsy significantly influences embryo survival and clinical outcomes and is therefore not recommended.

Sperm morphometry can be applied to identify different animal groups and species and to evaluate sperm quality. Furthermore, knowledge on species-specific differences will help to enhance biological information, as well as to develop efficient reproductive technologies. The aims in the present study were to describe sperm morphometry from the recently characterized species S. collinsi and S. vanzolinii, to verify if the morphometric sperm patterns are similar or different between both species, and to determine if the sperm morphometry is affected by the levels of sperm defects using the S. collinsi as a model. Semen was collected from S. collinsi (n = 10) and S. vanzolinii (n = 2) monkeys, and sperm was submitted to morphological analysis. From the 10 samples from S. collinsi, five presented sperm of poor quality and two subgroups were formed for this species, i.e. high and poor quality sperm. Data on sperm motility and vigour were analysed, as well morphometric parameters on sperm head and tail. It was observed the normal morphometry was correlated with high quality sperm. Poor quality sperm presented smaller and 7% more ellipticity in their head, when compared with high quality sperm. Sperm from S. vanzolinii presented larger head than those from S. collinsi, but tail lengths were similar. Sperm morphometry can be used as a complementary tool to predict sperm motility and vigour for the S. collinsi species, and S. collinsi appear as a suitable model for S. vanzolinii.