82 EFFECT OF HIGH FETAL CALF SERUM CONCENTRATION IN THE GENE EXPRESSION PATTERN OF IN VITRO PRODUCED BOVINE EMBRYOS

Even though FCS provides energy substrates, amino acids, vitamins, growth factors, and heavy-metal chelators, its supplementation has been associated with several embryo abnormalities such as mitochondrial degeneration, metabolic deviations, excessive lipid accumulation, and decreased embryo survival after cryopreservation. The aim of the present study was to evaluate the effect of high FCS concentration in the gene expression pattern of in vitro-produced bovine embryos. Slaughterhouse ovaries were used to obtain oocytes (N = 360), which were matured and fertilized in vitro (Day 0). Presumptive zygotes were divided in 2 culture media: with low (SOFaa with 0.5% BSA and 2.5% FCS) or high (SOFaa with 0.5% BSA and 10% FCS) FCS concentration. Cleavage was evaluated on Day 3. Embryo development was evaluated after 7 days under standard culture conditions (at 38.5°C in atmosphere of 5% O2, 5% CO2, and 90% N2). The produced blastocysts were placed in PBS solution and washed five times. A single blastocyst was frozen in a minimal volume of PBS and stored at –80°C until RNA extraction. Total RNA extraction was performed using the PicoPure RNA isolation Kit (Applied Biosystems®, Foster City, CA, USA). Extracted RNA was evaluated through 2100-Bioanalyzer (Agilent Technologies®, Palo Alto, CA, USA) and DNAse treated (Qiagen®, Valencia, CA, USA). RiboAmp RNA Amplification Kit (Applied Biosystems®) was used to amplify the RNA (T7 RNA polymerase-catalysed amplification reaction). The aRNA output was evaluated through NanoDrop ND-1000 (NanoDrop Technologies®, Wilmington, DE, USA). A biotin-labelled cRNA and fragmented cRNA were obtained through 3′IVT Express Kit (Affymetrix®, Santa Clara, CA, USA) to perform the hybridization (N = 3 per group) using GeneChip Bovine Genome Array (Affymetrix®). Following hybridization, probe arrays were washed, stained, and scanned. Microarray data analysis was performed in the software FlexArray 1.6.1.1. Genes with a fold change of at least 1.5 and a probability of P < 0.05 were considered differentially expressed. The data from in vitro embryo production were analysed through the PROC GLM (SAS Institute Inc., Cary, NC, USA). Cleavage rate (81.4 ± 1.5 and 85.5 ± 1.4) and blastocyst production (41.8 ± 2.4 and 47.2 ± 2.8) were not different (P > 0.05) between low and high FCS concentrations, respectively. A total of 40 genes were differentially expressed between low and high FCS concentration. A total of 28 genes were annotated, with 37 genes up-regulated and 3 genes down-regulated by high FCS concentration. The associated network functions of gene expression, RNA damage and repair, and post-transcriptional modification; and cell-to-cell signalling and interaction were generated by Ingenuity Pathway Analysis® (Redwood City, CA, USA). Differentially expressed genes involved in carbohydrate metabolism (GAPVD1, MGAT4A), lipid metabolism (ELOVL5), cellular assembly and organisation (EZR, LRP2), and cell death and survival (DRT8) were identified. In conclusion, high FCS supplementation was associated with different expression profiles of genes regulating carbohydrate and lipid metabolism, cellular assembly and organisation, and cell death and survival. The authors acknowledge support from FAPESP and LNBio-CNPEM.

14 CONCEPTION RATE OF BUFFALO HEIFERS TREATED WITH OESTRADIOL CYPIONATE TO INDUCE OVULATION IN TIMED ARTIFICIAL INSEMINATION PROGRAMS

Reducing animal handling and costs in timed artificial insemination (TAI) systems are of great interest in animal production, regardless of the species. Thus, this study was carried out to investigate the effects of administering oestradiol cypionate (EC) or hCG to induce ovulation in buffalo (Bubalus bubalis) in TAI programs. The 79 Bufalipso heifers housed at Institute of Animal Science, San José de las Lajas, Cuba, were, on average, 24 months of age with a body weight of 310 to 380 kg at the beginning of the experiment. The investigation was conducted out of the breeding season (25 June through 28 July 2012). Heifers were randomly assigned to 1 of 3 treatment groups; either hCG (control group) or EC1 and EC2, in which TAI was performed at either 48 or 56 h after the EC injection, respectively. On the first day of the treatment regime (Day 0), animals received oestradiol benzoate (2 mg i.m.; Sincrodiol®, Ourofino, Brazil), followed by the insertion of an intravaginal device containing 1 g of progesterone (Primer®, Tecnopec, São Paolo, Brazil). On Day 9, an intramuscular luteolytic dose of cloprostenol (500 μg; Ciosin®, Intervet, Brazil) and eCG (500 UI; Novormon®, Intervet) were given in all heifers along with the removal of the intravaginal device. On the same day, 0.5 mg of EC (ECP®, Pfizer, Brazil) was administered intramuscularly in the EC1and EC2 groups. Animals in the hCG group received hCG (1000 IU i.m.; Vetecor®, Hertape Calier, Spain) on Day 11 and were inseminated 14 h later. Pregnancy diagnosis was performed by ultrasound 35 days after TAI. Data were analysed by a chi-squared test, with P < 0.05 taken as significant. There were no differences among treatment groups, with values of 57.7 (15/26), 60.7 (17/28), and 64% (16/25) for the EC1, EC2, and hCG groups, respectively. In conclusion, oestradiol cypionate was effective at inducing ovulation in buffalo heifers in TAI programs comparable to the control group, as evidenced by the conception rates. In addition, animals subjected to the EC protocol pass just 3 times through the corral instead of 4 when receiving hCG, which decreases the animal handling and costs.

161 USE OF FORSKOLIN TO DELAY MEIOSIS AND PRODUCE IN VITRO BOVINE EMBRYOS

The maintenance of oocytes in germinal vesicle (GV) stage for a few hours could result in more competent oocytes for use in biotechnology. This study aimed to show if the use of forskolin is able to inhibit and reverse the maturation in bovine oocytes, producing a higher rate of in vitro embryos without apoptosis rates. Eight replicates in total were performed. Nellore oocytes were matured in TCM-199 and to delay meiosis, the oocytes (n = 584) were maintained for 6 h in medium in presence of 0.025, 0.05, or 0.1 mM Forskolin. Then, the oocytes were cultured for 18 h in agent-free medium to resume meiosis. After resumption of meiosis, the oocytes (n = 336) were stained with Hoechst 33342 to evaluate the state of the nucleus: germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I (MI), metaphase II (MII), or degenerated or unidentified (D/U). Then (Day 0) oocytes were fertilized in human tubal fluid (Irvine, New Zealand) and the presumed zygotes were culture in SOFaa + 0.6% BSA + 2.5% FCS until Day 7, when the blastocyst (n = 177) rate was evaluated. Apoptosis in blastocysts was assessed by terminal deoxynucleotidyl transferase uracil nick-end labeling (TUNEL) reaction. Data were analysed by ANOVA, followed by Tukey test using the general linear model (PROC GLM) of SAS (SAS Institute Inc., Cary, NC, USA). The level of significance adopted was 5%. There were no statistical differences in state of the nucleus, only in MI (Control = GV: 0.0, GVBD: 0.8, MI: 8.3a, MII: 67.7, D/U: 7.3; F 0.025 mM = GV: 2.8, GVBD: 0.7, MI: 20.8ab, MII: 67.7, D/U: 8.9; F 0.05 mM = GV: 0.0, GVBD: 4.4, MI: 15.8ab, MII: 65.9, D/U: 13.7; and F 0.1 mM = GV: 0.0, GVBD: 1.0, MI: 34.1b, MII: 50.2, D/U: 14.6; P < 0.05). There were no statistical differences in blastocyst rate (Control: 36.7, F 0.025 mM: 32.6, F 0.05 mM: 29.2 and F 0.1 mM: 25.1 – P > 0.05). But when we analysed the apoptosis rate, differences were found among groups: (Control: 12.1a, F 0.025 mM: 12.9a, F 0.05 mM: 13.5a and F 0.1 mM: 30b; P < 0.05). Although Forskolin was able to inhibit meiosis and produce embryos at the same rates as controls, the higher dosage of this drug damaged the embryos. The authors acknowledge FAPESP 10/50410-2 for support.

Conditioned medium as a strategy for human stem cells chondrogenic differentiation

Paracrine signalling from chondrocytes has been reported to increase the synthesis and expression of cartilage extracellular matrix (ECM) by stem cells. The use of conditioned medium obtained from chondrocytes for stimulating stem cells chondrogenic differentiation may be a very interesting alternative for moving into the clinical application of these cells, as chondrocytes could be partially replaced by stem cells for this type of application. In the present study we aimed to achieve chondrogenic differentiation of two different sources of stem cells using conditioned medium, without adding growth factors. We tested both human bone marrow-derived mesenchymal stem cells (hBSMCs) and human Wharton's jelly-derived stem cells (hWJSCs). Conditioned medium obtained from a culture of human articular chondrocytes was used to feed the cells during the experiment. Cultures were performed in previously produced three-dimensional (3D) scaffolds, composed of a blend of 50:50 chitosan:poly(butylene succinate). Both types of stem cells were able to undergo chondrogenic differentiation without the addition of growth factors. Cultures using hWJSCs showed significantly higher GAGs accumulation and expression of cartilage-related genes (aggrecan, Sox9 and collagen type II) when compared to hBMSCs cultures. Conditioned medium obtained from articular chondrocytes induced the chondrogenic differentiation of MSCs and ECM formation. Obtained results showed that this new strategy is very interesting and should be further explored for clinical applications.

Tauroursodeoxycholic acid protects retinal neural cells from cell death induced by prolonged exposure to elevated glucose

Diabetic retinopathy is one of the most frequent causes of blindness in adults in the Western countries. Although diabetic retinopathy is considered a vascular disease, several reports demonstrate that retinal neurons are also affected, leading to vision loss. Tauroursodeoxycholic acid (TUDCA), an endogenous bile acid, has proven to be neuroprotective in several models of neurodegenerative diseases, including models of retinal degeneration. Since hyperglycemia is considered to play a central role in retinal cell dysfunction and degeneration, underlying the progression of diabetic retinopathy, the purpose of this study was to investigate the neuroprotective effects of TUDCA in rat retinal neurons exposed to elevated glucose concentration. We found that TUDCA markedly decreased cell death in cultured retinal neural cells induced by exposure to elevated glucose concentration. In addition, TUDCA partially prevented the release of apoptosis-inducing factor (AIF) from the mitochondria, as well as the subsequent accumulation of AIF in the nucleus. Biomarkers of oxidative stress, such as protein carbonyl groups and reactive oxygen species production, were markedly decreased after TUDCA treatment as compared to cells exposed to elevated glucose concentration alone. In conclusion, TUDCA protected retinal neural cell cultures from cell death induced by elevated glucose concentration, decreasing mito-nuclear translocation of AIF. The antioxidant properties of TUDCA might explain its cytoprotection. These findings may have relevance in the treatment of diabetic retinopathy patients.

80 GLOBAL GENE EXPRESSION PATTERNS OF FRESH AND VITRIFIED IN VITRO-PRODUCED BOVINE BLASTOCYSTS

Over the past decades, there have been great advances in in vitro production (IVP) systems with improved culture methods and new knowledge regarding embryo genetics, physiology, ultrastructure, and morphology. Nevertheless, a major obstacle for dissemination of this technology is the great sensitivity of IVP embryos to cryopreservation. The objective was to study the global gene-expression patterns of fresh and vitrified IVP bovine embryos. Oocytes (N = 1290) were matured and fertilized in vitro (Day 0). Presumptive zygotes were cultured in SOFaa with 0.5% BSA and 2.5% of FCS. Cleavage and blastocyst production was evaluated after 3 and 7 days under standard culture conditions (at 38.5°C in atmosphere of 5% O2, 5% CO2, and 90% N2). On Day 7, half of the blastocysts were vitrified (n = 94), warmed (Sudano et al. 2011 Theriogenology 75, 1211–1220), and returned for 24 h of additional culture (re-expansion and hatching; hatched was evaluated 12 and 24 h after warming, respectively) when their RNA was extracted (vitrified group). The remaining embryos returned to culture until Day 8 when their RNA was extracted (fresh group). Total RNA extraction of a single blastocyst was performed using the PicoPure Kit (Applied Biosystems®, Foster City, CA, USA). The RNA samples were DNAse treated (Qiagen®, Valencia, CA, USA), and mRNA was amplified (RiboAmp Kit®). The aRNA output was evaluated with a NanoDrop (Thermo®, Wilmington, DE, USA) and Bioanalyzer (Agilent®, Santa Clara, CA, USA). Biotin-labelled and fragmented cRNA were obtained with the 3′IVT Kit (Affymetrix®, Santa Clara, CA, USA) to perform hybridization (N = 6–7, respectively, for vitrified and fresh groups) using the GeneChip Bovine Array (Affymetrix®). Microarray data analysis was performed with the FlexArray 1.6.1.1. Genes with a fold change of at least 2 and a probability of P ≤ 0.05 were considered differentially expressed. Real-time PCR was used to validate microarray results (N = 11–15, respectively, for vitrified and fresh groups). As a control, a pool of 200 blastocysts was submitted or not to mRNA amplification followed by the reverse transcription and qPCR of 17 genes. For statistical analyses, PROC GLIMMIX, PROC LOGISTIC, and PROC CORR were used. Cleavage and blastocyst production rates were 86.8 ± 1.0 and 32.5 ± 1.9%, respectively. Re-expansion and hatching/hatched rates were 69.3 and 19.3%, respectively. Messenger RNA abundance of amplified and nonamplified RNA had a high correlation (r = 0.89, P < 0.01). The microarray analysis indicated 383 differentially expressed genes (P ≤ 0.05) between fresh and vitrified blastocysts. Genes involved in apoptosis (PRDX2), heat shock (HSPA5), maternal recognition of pregnancy (IFNT2 and PAG2), and cell differentiation and placenta formation (KRT18) were downregulated in vitrified embryos. According to qPCR analysis, mRNA abundance of IFNT2, PRDX2, and KRT18 was downregulated, whereas HSPA5 mRNA levels were upregulated in vitrified blastocysts. Messenger RNA abundance of PAG2 was not different (P = 0.46) between fresh and vitrified embryos. In conclusion, vitrification alters the expression profile of the genes IFNT2, PRDX2, KRT18, and HSPA5 that can be related with embryo postcryopreservation survival capacity. FAPESP and LNBio-CNPEM are acknowledged.

230 EVALUATION OF APOPTOSIS IN IN VITRO-PRODUCED BOVINE EMBRYOS MATURED WITH FORSKOLIN

The maintenance of oocytes in the germinal vesicle stage for a few hours could result in more competent oocytes for use in biotechnology. Related to this, forskolin (Sigma-Aldrich, St. Louis, MO, USA) is an efficient inhibitor of nuclear maturation because of its ability to increase the levels of intracellular cyclic adenosine monophosphate. This study aimed to show whether the use of forskolin would be able to inhibit maturation in bovine oocytes, producing a higher rate of in vitro embryos. Nellore oocytes from a slaughterhouse (n = 960) were matured in TCM-199 with Earle’s salt + 10% FCS, FSH, and LH, in a 5% CO2 atmosphere. To delay meiosis, the oocytes were maintained for 6 h in medium with forskolin at 3 different concentrations, 0. 1 mM (n = 240), 0.05 mM (n = 240), and 0.025 mM (n = 240), whereas untreated oocytes acted as controls (n = 240). The oocytes were then cultured for 18 h in agent-free medium to resume meiosis, completing 24 h of maturation. After 24 h (Day 0) of maturation, oocytes were fertilized in human tubal fluid (HTF, Irvine, New Zealand) under the same conditions as described above. Semen was selected through Percoll gradient, and the concentration was adjusted to 2 × 106 sperm mL–1. The presumed zygotes were cultured in 90-µL droplets of SOFaa + 0.6% BSA + 2.5% FCS in a 5% CO2, 5% O2, and 90% N2 atmosphere until Day 7, when blastocysts were evaluated. Apoptosis in blastocysts was accessed through TUNEL reaction. Data were analysed by ANOVA, followed by Tukey’s test using the general linear models procedure (PROC GLM) of SAS (SAS Institute Inc., Cary, NC, USA). The level of significance adopted was 5%. No statistical differences were observed in blastocyst production rate (n = 297): control (n = 88): 36.7% ± 3.7; 0.1 mM forskolin (n = 61): 25.1% ± 3.7; 0.05 mM forskolin (n = 70): 29.2% ± 3.7; 0.025 mM forskolin (n = 78): 32.6% ± 3.7 (P > 0.05). However, when we analysed the apoptosis rates, differences were found among groups: control: 6.0% ± 6.3a; 0.1 mM forskolin: 33.4% ± 6.3b; 0.05 mM forskolin: 27.2% ± 6.3ab; 0.025 mM forskolin: 10.0% ± 6.3ab (P < 0.05). Although there was no difference in blastocyst rate, the TUNEL technique allowed us to identify that a high dose of forskolin was detrimental for in vitro-produced bovine embryos. FAPESP: 10/50410-2.

Properties of the static NMR response of a confined thin nematic film of 5CB-d2 under crossed electric and magnetic fields: theory and experiments

This work describes an investigation of the static (or quasistatic) nuclear magnetic resonance (NMR) response in a nematic liquid crystal confined between two planar conducting plates and subject to a magnetic field and an electric field produced by a difference of voltage applied on the plates. Deuterium NMR spectroscopy of 4-pentyl-d(2)-4'-cyanobiphenyl (5CB-d(2)) under these conditions has revealed a voltage dependent inhomogeneous director distribution for a particular narrow range of voltages and for a fixed magnetic field (that of the spectrometer). In the ideal setup the two plates are assumed to be rigorously parallel, so that a difference of voltage applied on the plates leads to a constant electric field normal to them. When the magnetic field is parallel to the plates (orthogonal geometry) there exists a threshold value of the electric field for which the effect of both fields exactly compensate; moreover, for stronger electric field the director aligns with the electric field while for weaker electric field the director aligns with the magnetic field. If there is a lack of parallelism between the two plates, the electric field becomes inhomogeneous so that it may be larger than the threshold value in some region of the sample and smaller in the remaining part of the sample. In that case the director will adopt essentially two orientations within the sample, namely, parallel or perpendicular to the magnetic field, and the position of the frontier between the two domains depends on the voltage. This feature is clearly shown by deuterium NMR spectra that exhibit a transfer of intensity between two quadrupolar doublets with increase in the applied voltage. The coexistence of two director populations occurs for a range of voltages that depends on the degree of nonparallelism; accordingly, an estimation of this range by NMR yields an experimental estimation of the lack of parallelism. A tiny tilt of the magnetic field (nonorthogonal geometry) entrains a notably different behavior since a single doublet with voltage dependent splitting is observed in this case. In a first stage (simple model) of this work, the main features observed for the orthogonal and nonorthogonal geometries are interpreted within the framework of Leslie-Ericksen theory by employing the concept of a single effective field replacing the two real fields. However, the spectra reveal an additional director distribution, especially for the orthogonal geometry, that cannot be interpreted by this simple approach. In a second stage (advanced model), these less clear features have been investigated by numerical simulations of a two-dimensional model which includes the effects of inversion walls and of the high relative dielectric anisotropy of 5CB.

In vitro cytotoxic activity of novel protoflavone analogs - selectivity towards a multidrug resistant cancer cell line

BACKGROUND

Protoapigenone (PA), a natural flavonoid possessing an unusual p-quinol moiety on its B ring, is a prospective novel lead compound against cancer currently in development, together with WYC0209, a potent synthetic PA analog. Structure activity relationships (SAR) concerning different 1'-O-alkyl side-chains were also studied on two sets of derivatives.

MATERIALS AND METHODS

Fifteen 1'-O-alkyl protoflavone derivatives were synthesized from genkwanin or 4'-hydroxy-6-methylflavone, thirteen of which are new compounds. All compounds were tested for their cytotoxic effect on four human cancer cell lines, such as HepG2 and Hep3B (hepatic), A549 (lung) and MDA-MB-231 (breast) cell lines, with doxorubicin as a positive control. All compounds, as well as PA, WYC0209 and fourteen of their previously reported analogs were also tested on a multidrug-resistant (MDR) sub-cell line of L5178 mouse T-cell lymphoma and on its parental counterpart (PAR).

RESULTS

In general, derivatives bearing a free hydroxyl group at C-1' exerted the strongest activities, while C-1'-substituted compounds were found to be much weaker. Derivatives of 6-methylflavone exhibited mild, but statistically significant selectivity towards the MDR cell line.

CONCLUSION

The results are in agreement with our previous findings for fundamental SAR of protoflavones. 6-Methylated protoflavones may serve as valuable leads for developing selective compounds against MDR cancer. Identical activity of other derivatives on the PAR and MDR cell lines suggests that cancer cells cannot exhibit resistance to protoflavones by ABCB1 efflux pump overexpression.

Antimicrobial activity of wild mushroom extracts against clinical isolates resistant to different antibiotics

AIMS

This work aimed to screen the antimicrobial activity of aqueous methanolic extracts of 13 mushroom species, collected in Bragança, against several clinical isolates obtained in Hospital Center of Trás-os-Montes and Alto Douro, Portugal.

METHODS AND RESULTS

Microdilution method was used to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). MIC results showed that Russula delica and Fistulina hepatica extracts inhibited the growth of gram-negative (Escherichia coli, Morganella morganni and Pasteurella multocida) and gram-positive (Staphylococcus aureus, MRSA, Enterococcus faecalis, Listeria monocytogenes, Streptococcus agalactiae and Streptococcus pyogenes) bacteria. A bactericide effect of both extracts was observed in Past. multocida, Strep. agalactiae and Strep. pyogenes with MBC of 20, 10 and 5 mg ml⁻¹, respectively. Lepista nuda extract exhibited a bactericide effect upon Past. multocida at 5 mg ml⁻¹ and inhibited Proteus mirabilis at 20 mg ml⁻¹. Ramaria botrytis extract showed activity against Enterococcus faecalis and L. monocytogenes, being bactericide for Past. multocida, Strep. agalactiae (MBCs 20 mg ml⁻¹) and Strep. pyogenes (MBC 10 mg ml⁻¹). Leucopaxillus giganteus extract inhibited the growth of E. coli and Pr. mirabilis, being bactericide for Past. multocida, Strep. pyogenes and Strep. agalactiae.

CONCLUSIONS

Fistulina hepatica, R. botrytis and R. delica are the most promising species as antimicrobial agents.

SIGNIFICANCE AND IMPACT OF THE STUDY

Mushroom extracts could be an alternative as antimicrobials against pathogenic micro-organisms resistant to conventional treatments.

Evolution of functional capacity and health status two years after a pulmonary rehabilitation programme

BACKGROUND

Pulmonary rehabilitation programs (PRP) have been shown to improve exercise capacity and health status and to reduce dyspnoea and use of healthcare resources, in patients with chronic lung disease. These benefits usually wane after the programs conclusion.

AIM

Evaluate functional capacity and health status 2 years after the end of a PRP.

METHODS

Retrospective study of patients who took part in PRP. After PRP, patients who reported a physically active lifestyle were included in the active group (AG). The other patients were considered as the control group (CG). Functional capacity was evaluated with 6minute walk distance (6MWD) and health status with St George's Respiratory Questionnaire (SGRQ).

RESULTS

Thirty-two patients were included, 24 in the AG and 8 in the CG. Immediately after PRP, there was a significant improvement in the 6MWD and SGRQ global score, for both groups. After completing PRP, in the AG, there was a decline in the mean 6MWD when evaluated at 6 months, 1 and 2 years and also in health status. However, after 2 years, the AG continued to show an average improvement of 32 m (p=0.03) in the 6MWD and at least 4 points in SGRQ compared to pre-PRP, while in the CG, there was a clinically significant decline in 6MWD (-34 m) and SGRQ score (13 points worse).

CONCLUSION

Despite the progressive decline of benefits gained after completing PRP, in the AG these are still significantly positive after 2 years. An active lifestyle seems to help maintain the benefits of the Rehabilitation Program.

89 PHENAZINE ETHOSULFATE AND FETAL CALF SERUM EFFECT IN THE ULTRASTRUCTURE AND DEVELOPMENT OF IN VITRO-PRODUCED BOVINE EMBRYOS

Over the past decades, there have been great advances in in vitro production (IVP) systems, with improved culture methods and new knowledge regarding embryo physiology, ultrastructure and morphology. Currently, the major obstacle associated with the extensive use of this technology is the great sensitivity of IVP embryos to cryopreservation. According to the literature, the reduced cryotolerance of IVP embryos is frequently associated with their high lipid content. Although is not clear until now how the lipid accumulation occurs, it may be influenced by the use of undefined culture media, supplemented with fetal calf serum (FCS); or as a result of embryo energy metabolism abnormalities that affect mitochondrial function, leading to the decrease in both the embryo quality and survival after cryopreservation. In this context, phenazine ethosulfate (PES), a reducer of NADPH electrons, which favours pentose–phosphate pathways and also inhibits the fatty acids synthesis, has been used to increase IVP embryo cryotolerance (Sudano et al. 2011 Theriogenology 75, 1211–1220). The aim of the present study was to evaluate the phenazine ethosulfate and FCS effect in the ultrastructure of IVP bovine embryos. A 2 × 2 factorial experiment design was used to test 2 FCS concentrations (0 or 10%) and the addition of PES (without or with PES) in the culture media. Slaughterhouse ovaries were used to obtain oocytes which were matured and fertilized in vitro (Day 0). Presumptive zygotes (n = 1440) were divided in 4 culture media: SOFaa without FCS; SOFaa without FCS + 0.3 μM PES (started on Day 4); SOFaa + 10% FCS; SOFaa + 10% FCS + 0.3 μM PES (started on Day 4). Embryo development was evaluated after 7 days under standard culture conditions (at 38.5°C in atmosphere of 5% O2, 5% CO2 and 90% N2). Transmission electron microscopy (TEM) was performed on Day-7 blastocysts from each group (n = 5) through standard protocol. For the statistical analysis, the arcsine transformation was applied to blastocyst percentage data and submitted to the ANOVA, followed by Tukeys' test through PROC GLM (SAS Institute Inc., Cary, NC, USA). In the absence of significant interactions, only main effect means are presented. The blastocyst production was not affected (P = 0.47) by the use of PES (42.7 ± 3.2 vs 39.3 ± 3.2, respectively for control and PES Day 4). The addition of 10% of FCS increased (P < 0.0001) the percentage of blastocysts (48.9 ± 3.2 vs 33.0 ± 3.2, respectively, for 10% and 0% of FCS). The ultrastructure analysis showed similar features in embryos from all studied groups. However, embryos cultured in the absence of FCS presented fewer and smaller lipid droplets. Moreover, embryos cultured without FCS presented more cellular debris in the perivitelinic space and in the blastocoele, indicating loss of blastomeres. The use of PES was able to reduce lipid droplets and increase the mitochondrial number in serum-produced embryos. Therefore, the PES decreased lipid content and increased mitochondrial number without affecting the development and ultrastructure of IVP bovine embryos. FAPESP 09/54513-3, 10/09922-0.