Effect of Ethanol on Parthenogenetic Activation and α-Tocopherol Supplementation during In Vitro Maturation on Developmental Competence of Summer-Collected Bovine Oocytes

The use of α-tocopherol during in vitro maturation (IVM) is an alternative to minimize the adverse effects of heat stress on oocyte competence. However, α-tocopherol is diluted in ethanol, which can induce oocyte parthenogenetic activation (PA). This study aimed to evaluate the role of ethanol concentration on PA and the effect of α-tocopherol supplementation during IVM on the developmental competence and the expression of key genes in blastocysts derived from summer-collected oocytes. All in vitro embryo production was conducted at 5% O2, 5% CO2 at 38.5 °C. Experiment 1: oocytes were cultured with or without 0.05% ethanol. As positive PA control matured oocytes were subjected to 3% or 7% ethanol for 7 min. Oocytes from all groups were placed in fertilization medium (22 h) and culture medium (9 days). Ethanol at 0.05% during IVM did not induce oocyte PA, however, 3% and 7% ethanol were effective parthenogenetic inductors. Experiment 2: oocytes were cultured in maturation medium supplemented with 0, 50, 100 and 200 μM α-tocopherol, diluted in 0.05% ethanol. After in vitro fertilization and embryo culture, we assessed blastocyst apoptotic index and the transcription of a panel of genes. The results showed that supplementation with 100 μM α-tocopherol reduced apoptotic index and increased the expression of SOD2. In conclusion, 100 μM α-tocopherol, diluted in 0.05% ethanol, can be used during IVM to embryonic quality.

The Chemical Environment at Maturation Stage in Pinus spp. Somatic Embryogenesis: Implications in the Polyamine Profile of Somatic Embryos and Morphological Characteristics of the Developed Plantlets

Changes in the chemical environment at the maturation stage in Pinus spp. somatic embryogenesis will be a determinant factor in the conversion of somatic embryos to plantlets. Furthermore, the study of biochemical and morphological aspects of the somatic embryos could enable the improvement of somatic embryogenesis in Pinus spp. In the present work, the influence of different amino acid combinations, carbohydrate sources, and concentrations at the maturation stage of Pinus radiata D. Don and Pinus halepensis Mill. was analyzed. In P. radiata, the maturation medium supplemented with 175 mM of sucrose and an increase in the amino acid mixture (1,100 mgL–1 of L-glutamine, 1,050 mgL–1 of L-asparagine, 350 mgL–1 of L-arginine, and 35 mgL–1 of L-proline) promoted bigger embryos, with a larger stem diameter and an increase in the number of roots in the germinated somatic embryos, improving the acclimatization success of this species. In P. halepensis, the maturation medium supplemented with 175 mM of maltose improved the germination of somatic embryos. The increase in the amount of amino acids in the maturation medium increased the levels of putrescine in the germinated somatic embryos of P. halepensis. We detected significant differences in the amounts of polyamines between somatic plantlets of P. radiata and P. halepensis; putrescine was less abundant in both species. For the first time, in P. radiata and P. halepensis somatic embryogenesis, we detected the presence of cadaverine, and its concentration changed according to the species.

The supplementation of ovine oocyte maturation medium with triiodothyronine affects the embryo development and apoptotic gene expression

Triiodothyronine (T3) plays an essential role in different animal species’ embryonic development. The present research was designed to identify the effect of triiodothyronine on the in vitro ovine embryonic development and the expression of apoptotic genes.A total of 436 immature cumulus-oocyte complexes (COCs) were cultured for 24 h in the oocyte maturation medium supplemented with two concentrations of T3 (T-10 and T-100 ng/mL) or without T3(T-0: control group). Oocyte maturation, cleavage, and blastocyst rates were assessed under an inverted microscope as crucial indicators of embryo development.The relative mRNA abundance of BCL-2-associated X protein (BAX) and anti-apoptotic B-cell lymphoma-2 (BCL2) were determined at blastocysts (day 8 after IVF on day 0)by quantitative reverse transcription PCR.The data were analyzed by logistic regression using the GLIMMIX procedure followed by Chi-Square, and one-way ANOVA tests. The higher concentration of T3(100 ng/mL) significantly decreased cumulus expansion and blastocyst rate compared to controls (P<0.001). Additionally, a significantly higher expression level of BAX(P<0.001) and a dramatically lower expression level of BCL2 (P<0.01) were detected in the T-100ng/mL group compared to the controls.However, the relative mRNA level of BCL-2 was significantly higher in the T-10 ng/mL group compared to the control group (P<0.01).It appears that the supplementation of ovine oocyte maturation medium with T3 at high concentration (100 ng/mL) suppresses the ratio of blastocyst formation.

The Role of Ca2 + in Maturation and Reprogramming of Bovine Oocytes: A System Study of Low-Calcium Model

[Ca2+]i is essential for mammalian oocyte maturation and early embryonic development, as those processes are Ca2+ dependent. In the present study, we investigated the effect of [Ca2+]i on in vitro maturation and reprogramming of oocytes in a lower calcium model of oocyte at metaphase II (MII) stage, which was established by adding cell-permeant Ca2+ chelator BAPTA-AM to the maturation medium. Results showed that the extrusion of the first polar body (PB1) was delayed, and oocyte cytoplasmic maturation, including mitochondrial and endoplasmic reticulum distribution, was impaired in lower calcium model. The low-calcium-model oocytes presented a poor developmental phenotype of somatic cell nuclear transfer (SCNT) embryos at the beginning of activation of zygotic genome. At the same time, oxidative stress and apoptosis were observed in the low-calcium-model oocytes; subsequently, an RNA-seq analysis of the lower-calcium-model oocytes screened 24 genes responsible for the poor oocyte reprogramming, and six genes (ID1, SOX2, DPPA3, ASF1A, MSL3, and KDM6B) were identified by quantitative PCR. Analyzing the expression of these genes is helpful to elucidate the mechanisms of [Ca2+]i regulating oocyte reprogramming. The most significant difference gene in this enriched item was ID1. Our results showed that the low calcium might give rise to oxidative stress and apoptosis, resulting in impaired maturation of bovine oocytes and possibly affecting subsequent reprogramming ability through the reduction of ID1.

PSX-B-11 Comparing effects of FGF2 and IGF1 on the development competence of parthenogenetic activated bovine oocytes maturing in vitro

The oocyte quality acquired during in vitro maturation (IVM) are the main limitative factors affecting the embryo production. The aim of the present research was to study effects of fibroblast growth factor 2 (FGF2) and insulin-like growth factor 1 (IGF1) during IVM of bovine oocytes on their developmental potential after parthenogenetic activation. Bovine cumulus-oocyte complexes (COC; n = 1176) were cultured for 22h in either standard maturation medium (TCM-199 supplemented with 10% fetal calf serum (FCS), 0.2 mM sodium pyruvate, 10 μg/ml FSH and 10 μg/ml LH; Control) or maturation medium supplemented with different concentrations (5–160 ng/ml) of FGF2 and IGF1. After IVM, matured oocytes activated by sequential treatment with ionomycin followed by DMAP and cyclohexamide and then cultured up to the blastocyst stage. The obtained blastocysts were fixed, and the total cell number and the level of apoptosis were determined using DAPI and TUNEL staining. The data from 4 replicates (77–91 oocytes per treatment) were analyzed by ANOVA. Cleavage rates of activated oocytes did not differ between groups and ranged from 63.7 to 68.1%. The addition of 10, 20 and 40 ng/ml of FGF2 to the IVM medium led to an increase in the yield of blastocysts [from 19.6±1.8% (Control) to 35.2±3.4, 29.8±1.9 and 31.1±2.1%, respectively (P&lt;0.05)] and in the total cell number in embryos that developed to the blastocyst stage (P&lt;0.05). Meanwhile, the blastocyst yield and the total cell number in blastocysts in the IGF1-treated groups were similar to that in the control group. No effects of both growth factors on the proportion of apoptotic nuclei in blastocysts (5.3–7.1%) were observed. Thus, FGF2 (but not IGF1) are able to maintain competence for parthenogenetic development of bovine COC during their maturation invitro. Supported by RFBR (18-29-07089) and the Ministry of Science and Higher Education of Russia.

PSX-A-23 Late-Breaking: Supplementation of Nerve Growth Factor (β-NGF) in the maturation medium and efficiency of in vitro embryo production in cattle

The aim of this study was to evaluate the supplementation of Nerve Growth Factor (β-NGF) in the maturation medium in in vitro embryo production routines. Antral follicles were aspirated from ovaries of cows obtained from slaughterhouses and then oocytes were selected for quality (grades I and II) for in vitro maturation and subjected to 4 successive in vitro embryo production routines (IVEP). Supplementation of 100 ng of β-NGF was performed in the oocyte maturation medium 22 hours before in vitro fertilization. 48 hours after fertilization of the oocytes, an analysis was made of their cleavage rate by counting blastomeres with the aid of a stereoscopic microscope (cleavage rate = number of embryos / number of initial oocytes). Seven days after fertilization, the blastocyst rate was determined through the relation to the number of oocytes that started cleavage and reached this stage of development (blastocyst rate = number of blastocyst / number of oocytes that started cleavage). To verify the existence of a difference between the supplemented and the non-supplemented groups, the paired T test was applied, using the Excel / Action software (Microsoft). In vitro embryo production routines supplemented with β-NGF in the maturation medium had, on average, a higher cleavage rate (P = 0.0072) and a higher blastocyst rate (P = 0.0033) compared to non-supplemented routines with β-NGF. In this study was demonstrated that Nerve Growth Factor supplementation in the maturation medium improves the efficiency of in vitro embryo production in cattle, and this protein has a probable action in the oocyte maturation process.

Somatic embryogenesis in mature zygotic embryos of Picea pungens

This study developed somatic embryogenesis protocols for Picea pungens (Engelm), an important ornamental species, including initiation, proliferation, maturation, germination, and acclimation. Somatic embryogenic tissues were induced from mature zygotic embryos of five families, with a frequency of $$\ge $$ ≥ 22% for each. Embryogenic tissues (ET) from 13 clones of three families were proliferated for one week, achieving an average rate of 179.1%. The ET of 38 clones of three families were cultured in maturation medium for six weeks; 188 mature embryos on average were counted per gram ET cultured, of which $$\ge $$ ≥ 81.1% appeared normal, and each clone developed at least 28 normally matured embryos. A total of 69.9% or more of cotyledonary somatic embryos germinated normally and developed into normal emblings. The experiment of transplanting the emblings into a greenhouse had an average survival rate of 68.5%. Considerable variation among and within families during initiation and proliferation was observed, but this variation decreased in the maturation and germination. Changing the concentration of plant growth regulator of the initiation medium did not significantly change the initiation frequency. We recommend incorporating these protocols into the current Picea pungens practical programs, although further research is essential to increase efficiencies and reduce cost.

Pengaruh urea dalam media maturasi in vitro terhadap tingkat maturasi oosit sapi

This study was aimed to determine the effect of urea in maturation medium on in vitro oocyte maturation rate. The medium used was TCM-199 added with Hepes, NaHCO3, Kanamycin 0.15 IU/mL, PMSG, 0.15 IU/mL hCG, and 10% FBS. Cumulus oocyte complexes (COCs) of cows derived from follicle aspiration were divided into three groups. In control group (P0), the COCs were matured in vitro in a maturation medium without urea addition, meanwhile in the P1 and P2 groups, the medium was added with urea 20 and 40 mg/dL, respectively. Each petri dish contained three drops of maturation medium (300 µl/drops) according to the groups. Microdrops were coated with mineral oil and then incubated in a 5% CO2 incubator, at 39 ˚C with maximum humidity. Aceto-orcein staining was conducted to evaluate the maturation of oocytes based on the achievement of metaphase II phase that is indicated by the presence of metaphase plate and/or first polar body. The result showed that the oocyte maturation rates of P0, P1, and P2 were 51.25, 52.43 (p >0.05), and 46.88 % (p <0.05) respectively. It could be concluded that the presence of urea at 40 mg/dL in maturation medium reduced the percentage of bovine oocyte maturation in vitro.

EFFECT OF THE USE OF TWO SPERM SELECTION TECHNIQUES FOR IN VITRO PRODUCTION OF ALPACA EMBRYOS

The objective of this research was to evaluate the effect of the use of two sperm selection techniques for in vitro production of alpaca embryos. The ovaries and testis were collected from the local slaughterhouse and transport to 37 ° C in saline solution (0.9%) supplemented with gentamicin. Quality I, II and II oocytes were incubated in a maturation medium for 32 h at 38.5 ° C and 5% O2 and 5% CO2. For in vitro fertilization, sperm from the epididymis were selected using the Percoll gradient and Swim up technique. 18h after the oocytes were incubated with the sperm, these were denuded from the cumulus cells and cultured in SOFaa culture medium for 7 days. Morula and blastocyst rate and their morphological quality are evaluated at day 7 of culture. From a total of 370 ovaries, 1,137 oocytes were recovered, making an average of 3.6 oocytes / ovary. After the maturation and fertilization process and in vitro culture, the blastocyst rate was 8.43 ± 6.04% and 3.89 ± 1.75%, for oocytes fertilized with sperm selected with Percoll gradient and Swim up, respectively, not finding significant statistical differences (p> 0.05), between the groups. In conclusion, the in vitro fertilization of alpaca oocytes with spermatozoa selected with two selection techniques (percoll and swim up) did not significantly influence the quantity and quality of morulae and blastocysts at day 7 of embryo culture.

Effect of FSH and eCG on Alpaca (Vicugna pacos) Oocyte Maturation in vitro

This study evaluated alpaca oocytes that developed to metaphase II (MII), using different concentrations of follicle stimulating hormone (FSH) with and without equine chorionic gonadotropin (eCG) during in vitro maturation. Oocytes were obtained from ovaries of slaughtered alpacas. Oocytes were matured in vitro for 36h in TCM-99 and supplemented in groups with different doses of FSH: 0.5, 0.25, 0μg.mL-1 and eCG: 15, 5, 0IU.mL-1. Oocytes were stained with 2% lacmoid, and examined for their nuclear status. The parameter for comparisons between groups was the percentage of oocytes in MII. There was an interaction between FSH and eCG (P<0.05). A higher percentage of oocytes in MII were obtained when using 0.5µg.mL-1 of FSH with any concentration of 15, 5 or 0IU.mL-1 of eCG [58.4±1.94% (n=78); 59.5±1.94% (n=85); 54.3±0.56% (n=81); P<0.05]. A similar percentage was also found using 0.25µg.mL-1 of FSH plus 15IU.mL-1 of eCG [52.3±1.66% (n=86); P>0.05] followed by 0.25µg.mL-1 of FSH with 5 or 0IU.mL-1 of eCG [47.3±1.94% (n=82); 45.3±1.94% (n=86); P<0.05]. The lowest maturation percentages were found using any concentration of eCG without FSH [8.2±0.73% (n=84); 8.0±0.66% (n=74); 11.4±1.23% (n=71); P<0.05]. In conclusion, the addition of eCG to the maturation medium would reduce the amount of FSH required in the in vitro maturation of alpaca oocytes.