RESUMO

One of the main factors that influences the fertility of cattle in grazing systems in hot tropical climates is heat stress. The objective of this study was to evaluate the effect of season, breed, hormonal and physiological condition on the quantity and quality of cumulus-oocyte complexes (COCs) and embryos produced in vitro, from Romosinuano (RM) and Tropical Milking (TM) donors. Three ovum pick-up and in vitro fertilization (OPU-IVF) were performed, one per season: hot dry (HD; 10, 10), hot humid (HH; 9, 9) and fresh dry (FD; 7, 10) in RM and LT donors. Serum levels of cortisol, insulin and glucose were measured, in addition to heart rate (HR), respiratory rate (RR) and rectal temperature (RT). Effect of season x genotype interaction (p ≤ 0.05) was observed in all COC variables and only in cleavage embryos (CLI) (p ≤ 0.05). Body weight (BW) affected all COC variables (p ≤ 0.01), except unviable (UNV) although affected degenerated embryos (DEG) (p ≤ 0.01) and total blastocysts (BLAST) (p ≤ 0.01). Cow age only affected viable COCs (VIAB) (p ≤ 0.05), code one blastocysts (BC1) and BLAST (p ≤ 0.01). Cortisol affected total COCs (COCsT), VIAB and total matured in vitro (TMIV) (p ≤ 0.01), as well as CLI, BC1 (p ≤ 0.01) and BLAST (p ≤ 0.05). Insulin affected COCsT (p ≤ 0.01), UNV (p ≤ 0.05), denuded oocytes (DE) (p ≤ 0.01), BC1 and code two blastocysts (BC2) (p ≤ 0.01). Glucose affected all COC variables (p ≤ 0.01), except UNV and all embryo variables except BC2. HR affected COCsT, DE, TMIV (p ≤ 0.01), CLI, BLAST and DEG (p ≤ 0.05). RR affected COCsT, UNV, VIAB, CLI (p ≤ 0.05), BC1, BLAST and DEG (p ≤ 0.01). RT only affected DE, VIAB (p ≤ 0.01) and BLAST (p ≤ 0.05). The seasonal climatic year variation of Veracruz and changes in physiological and hormonal variables have diverse effects on the cumulus-oocyte complexes and embryos produced by RM and TM donors.

RESUMO

The aim of this study was to evaluate follicular dynamics and ovum pick-up (OPU) efficacy in untreated mares or mares treated with an intravaginal progesterone (P4) device during seasonal anestrus (acyclic) and during the breeding season (cyclic). Six mares (mean age = 5 years), were recruited into an ovum pick-up scheme that was performed every 14 days with and without the P4 device, during the acyclic and cyclic phases. Aspirations amounted to seven procedures with or without the P4 device during each phase. Five ultrasound assessments were performed at each interval between the OPUs. Data on follicular number and diameter as well as the numbers of recovered and the percentage of recovered oocytes were also collected. The number of follicles from mares in the acyclic phase was higher (P < .005) regardless of the treatment. However, the follicular diameter was smaller for the P4 group (P < .005) from the 2nd to the 5th evaluation post-OPU procedure. The percentage of oocytes recovered during the acyclic phase was higher for mares treated with the P4 device (P < .005). The P4 device resulted in follicles with smaller diameters and facilitated OPU efficacy.

Assuntos

RESUMO

Transvaginal ultrasound-guided oocyte retrieval (commonly called OPU) and in vitro embryo production (IVP) in cattle has shown significant progress in recent years, in part, as a result of a better understanding of the full potential of these tools by end users. The combination of OPU and IVP (OPU-IVP) has been successfully and widely commercially used worldwide. The main advantages are a greater number of embryos and pregnancies per unit of time, faster genetic progress due to donor quick turn around and more elite sires mating combinations, larger spectrum of female age (calves, prepuberal, heifer, cow) and condition (open, pregnant) from which to retrieve oocytes, a reduced number of sperm (even sexed) required to fertilize the oocytes, among other benefits. OPU-IVP requires significant less donor preparation in comparison to conventional embryo transfer (<50% of usual FSH injections needed) to the extent of no stimulating hormones (FSH) are necessary. Donor synchronization, stimulation, OPU technique, oocyte competence, embryo performance, and its impact on cryopreservation and pregnancy are discussed.

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Under natural and well-managed conditions, the buffalo has good reproductive and productive indices. However, in vitro embryo production (IVEP) has been used commercially to maximise the number of elite animals. In this species, several factors (donor management, in vitro culture medium, semen, in vitro conditions, embryo transfer) still affect the IVEP results. In addition, the cost of this technique is very high for this purpose. Therefore, more studies, as well as adequate plans, are needed to achieve this objective efficiently. In this review, we discussed the current commercial status, influencing factors (in vivo and in vitro), and the progress and future challenges of IVEP in buffalo. A total of 81 references were used from 1979 to 2022. The relevant data or literature were searched using the following databases: Google, ResearchGate, Science Alert, Science Direct and PubMed, using the following keywords: buffalo oocytes/COCs, buffalo embryos, pregnancy and calving or live birth rate after embryo transfer. The best maturation, cleavage and blastocyst rates in the in vitro production of buffalo embryos were 95.8, 75.2 and 33.4%, respectively. The pregnancy and live birth rates ranged from 22.2% to 43.5% and from 15.3% to 36.5%, respectively, after the transfer of fresh embryos produced in vitro to the recipients. This review will help to contextualise IVEP in buffaloes, as well as create an adequate plan for implementing IVEP in buffaloes.

RESUMO

Here we report a case of peri-ovarian hematoma following ovum pick-up in a patient in a pooling cycle IVF (in vitro fertilization). We have attempted to discuss the possible mechanisms for the development of hematoma in such patients, the common clinical presentation, monitoring, and management of these cases. The decision to operate or to manage conservatively forms an important aspect of managing such patients. This case report can help to keep the clinicians alert while managing this subgroup of patients.

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Field collection of oocytes in mares using transvaginal follicular aspiration (TVA) for embryo production has the potential to revolutionate the equine industry. Protocols for TVA in specialized laboratory settings have been described in the scientific literature since the early 1980s. The objective of this study was to determine the success rate of TVA oocytes recovery under ambulatory conditions. A secondary goal of this study was to determine if TVA is associated with any health complications when performed by recently trained practitioners in the field. Follicles (n = 296) from 66 adult clinically healthy mares were aspirated over a period of 6 days. TVAs were performed by 22 veterinarians with 5-20 years of experience in equine and bovine reproductive medicine, but no previous experience in TVA. Oocytes (n = 145) were recovered. No short- or long-term systemic or local complications were observed following TVA in any of the mares used in this study. Fifty-six out of 66 mares became pregnant within 3 months following TVA. This study shows that with proper training, TVA can be successfully used to obtain equine oocytes with no health complications under field conditions in nonspecialized laboratory settings.

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In vitro embryo production and embryo transfer (ET) in buffaloes has been developed for decades. However, most studies are focused on the donor or laboratory improvements, and there is a lack of reports regarding the recipients. Therefore, our aim was to investigate factors associated to pregnancy (P/ET), pregnancy loss (PL), and calving rates in buffalo recipients. The studied factors were season, recipient parity, the synchronization protocol, the CL diameter, asynchrony between the embryo and the recipient, the day of the recipient estrous cycle, the embryo (fresh vs. vitrified), the day of embryo development, and the embryo stage. These retrospective data, from a program of in vitro produced embryos, were analyzed by logistic regression, and the odds ratio was also estimated. Two factors were related to P/ET and the calving rate: (1) progesterone associated to estradiol plus eCG protocol for fixed time ET tended to affect positively P/ET on day 30 (41.9 vs. 36.1%, respectively; P = 0.07; AOR = 1.28) and P/ET on day 60 (37.8 vs. 36.1%, respectively; P = 0.09; AOR = 1.08) compared to the Ovsynch protocol; and (2) the CL diameter (≥14.5 mm) at transfer increased P/ET on day 30 (47.4 vs. 32.5%; P < 0.01; AOR = 1.87) and on day 60 (45.3 vs. 27.7%; P < 0.01; AOR = 2.16), and also the calving rate (37.9 vs. 21.7%; P < 0.01; AOR = 2.20). PL was greater when ET was done in the nonbreeding season compared to the breeding season (PL 30-60: 12.8 vs. 0.0%, P = 0.01; AOR > 999.99; PL 60-calving: 26.8 vs. 3.6%, P = 0.03; AOR = 9.90; and PL 30-calving: 36.2 vs. 3.6%, P = 0.01; AOR = 15.30). In conclusion, the data of our study indicated that the synchronization protocol, the CL diameter, and ET during the breeding season impacted the reproductive efficiency of buffalo recipients.

RESUMO

A fim de avaliar o efeito de diferentes doses da rbST sobre a dinâmica folicular, a produção e a maturação in vitro de oócitos, 20 vacas Sindi, divididas em três grupos, receberam um dispositivo de progesterona intravaginal, estradiol e PGF2α, além de 2mL de solução salina (grupo controle), 250 (grupo rbST 250) ou 500mg de rbST (grupo rbST 500). Cinco dias depois, realizou-se a ovum pick up, e os complexos cumulus-oócitos (CCOs) recuperados foram selecionados, classificados e maturados in vitro. Os dados de contagem foram comparados pelo procedimento glht (General Linear Hypothesis Test), e os dados em porcentagem foram submetidos ao qui-quadrado, no programa estatístico R, onde as diferenças foram consideradas significativas quando P<0,05. Não houve diferença (P>0,05) entre os grupos quanto à quantidade de folículos e à taxa de maturação. Os grupos rbST 250 e rbST 500 foram significativamente superiores (P<0,05) ao grupo controle em relação ao número de folículos grandes (0,42±0,20 vs. 0). O grupo rbST 500 apresentou maior (P<0,05) porcentagem de oócitos viáveis (91,52%) do que os grupos controle (67,85%) e rbST 250 (53,33%). A rbST aumenta o número de folículos grandes, e 500mg de rbST aumentam a porcentagem de oócitos viáveis em vacas Sindi.(AU)

In order to evaluate the effect of different doses of rbST on the follicular dynamics, production, and in vitro maturation of oocytes, 20 Sindhi cows were divided into three groups, receiving an intravaginal progesterone device, estradiol and PGF2α, and 2mL of solution saline (Control Group), 250 (rbST 250 Group) or 500mg rbST (rbST 500 Group). Five days later, the ovum pick up was performed, and the cumulus-oocyte (CCO) complexes recovered were selected, classified, and matured in vitro. The counting data were compared by the glht (General Linear Hypothesis Test) procedure, and the percentage data were submitted to Qui- square, in the statistical program R, where differences were considered significant when P< 0.05. There was no difference (P> 0.05) between the groups regarding follicle quantity and maturation rate. The rbST 250 and rbST 500 groups were significantly higher (P< 0.05) than the Control group in relation to the number of large follicles (0.42±0.20 versus 0). The rbST 500 group presented higher (P< 0.05) percentage of viable oocytes (91.52%) than the Control (67.85%) and rbST 250 (53.33%) groups. rbST increases the number of large follicles and 500mg rbST increases the percentage of viable oocytes in Sindhi cows.(AU)

Assuntos

RESUMO

A fim de avaliar o efeito de diferentes doses da rbST sobre a dinâmica folicular, a produção e a maturação in vitro de oócitos, 20 vacas Sindi, divididas em três grupos, receberam um dispositivo de progesterona intravaginal, estradiol e PGF2α, além de 2mL de solução salina (grupo controle), 250 (grupo rbST 250) ou 500mg de rbST (grupo rbST 500). Cinco dias depois, realizou-se a ovum pick up, e os complexos cumulus-oócitos (CCOs) recuperados foram selecionados, classificados e maturados in vitro. Os dados de contagem foram comparados pelo procedimento glht (General Linear Hypothesis Test), e os dados em porcentagem foram submetidos ao qui-quadrado, no programa estatístico R, onde as diferenças foram consideradas significativas quando P<0,05. Não houve diferença (P>0,05) entre os grupos quanto à quantidade de folículos e à taxa de maturação. Os grupos rbST 250 e rbST 500 foram significativamente superiores (P<0,05) ao grupo controle em relação ao número de folículos grandes (0,42±0,20 vs. 0). O grupo rbST 500 apresentou maior (P<0,05) porcentagem de oócitos viáveis (91,52%) do que os grupos controle (67,85%) e rbST 250 (53,33%). A rbST aumenta o número de folículos grandes, e 500mg de rbST aumentam a porcentagem de oócitos viáveis em vacas Sindi.(AU)

In order to evaluate the effect of different doses of rbST on the follicular dynamics, production, and in vitro maturation of oocytes, 20 Sindhi cows were divided into three groups, receiving an intravaginal progesterone device, estradiol and PGF2α, and 2mL of solution saline (Control Group), 250 (rbST 250 Group) or 500mg rbST (rbST 500 Group). Five days later, the ovum pick up was performed, and the cumulus-oocyte (CCO) complexes recovered were selected, classified, and matured in vitro. The counting data were compared by the glht (General Linear Hypothesis Test) procedure, and the percentage data were submitted to Qui- square, in the statistical program R, where differences were considered significant when P< 0.05. There was no difference (P> 0.05) between the groups regarding follicle quantity and maturation rate. The rbST 250 and rbST 500 groups were significantly higher (P< 0.05) than the Control group in relation to the number of large follicles (0.42±0.20 versus 0). The rbST 500 group presented higher (P< 0.05) percentage of viable oocytes (91.52%) than the Control (67.85%) and rbST 250 (53.33%) groups. rbST increases the number of large follicles and 500mg rbST increases the percentage of viable oocytes in Sindhi cows.(AU)

Assuntos

RESUMO

The objective of this study was to evaluate the fertility of buffalo semen for in vitro embryo production (IVEP) by comparing the effectiveness of refrigerated versus frozen semen. Three OPU sessions were held at 30-day intervals. For oocyte fertilization three buffalo bulls were used, one per session. At each OPU-IVEP session, one ejaculate was collected and divided into two equal aliquots. Each aliquot was either refrigerated at 5ºC/24 hours or frozen. A TRIS extender containing 10% low density lipoproteins, 0.5% lecithin and 10 mM acetylcysteine was used adding 7% glycerol for freezing. Sperm motility/kinetic was evaluated by CASA and sperm membrane integrity by the hypoosmotic swelling test. The evaluations were performed at 0 h (post final dilution at 37ºC), at 4 and 24 hs post-incubation at 5ºC and post-thaw. At 24 hs incubation and immediately post thaw sperm cells were used for in vitro fertilization of buffalo oocytes equally distributed between both groups. Cleavage rates and embryo development were followed. The embryo/matured and embryo/cultured rates were 25.4 x 14.0% and 29.4 x 18.5% (P<0.05), for chilled and frozen semen, respectively. It is concluded that cooled semen can be used for in vitro embryo production in buffalo and that a better efficiency may be expected for cooled compared to frozen semen.

RESUMO

This study aimed to evaluate the potential of Girolando (Bos taurus × Bos indicus) cows with high and low antral follicle counts (AFC) for the in vitro production of bovine embryos (IVEP), as well as the pregnancy rates of the recipients of these embryos. Girolando cows (Bos taurus × Bos indicus) were classified as high and low AFC when they had 35-52 (n = 13) and 11-17 follicles (n = 15), respectively. All animals were subjected to repeated follicular aspiration [Ovum pick-up (OPU)] and subsequent IVEP sessions. The synchronization protocol of the recipients was performed on a random day of the estrous cycle (Day 0) with the implantation of progesterone, estradiol benzoate, and prostaglandin. The high AFC group had higher aspirated oocyte/OPU (42.6 ± 5.2 vs. 14.6 ± 1.9; p < 0.01) and cultured oocyte/OPU (38.1 ± 6.6 vs. 12.3 ± 2.8; p < 0.01) averages as well as a higher blastocyst percentage on D7 (23.0 ± 1.0% vs. 18.4 ± 1.5%; p < 0.05) and higher pregnancy rate (42.7 ± 2.7% vs. 39.7 ± 4.6%; p< 0.05) than the low AFC group. Thus, we can conclude that animals with high AFC had better IVEP success rates than animals with low AFC.(AU)

Este estudo teve como objetivo avaliar o potencial de produção in vitro de embriões (PIVE) bovinos de vacas da raça Girolando (Bos taurus x Bos indicus) com alta e baixa contagem de folículos antrais (CFA), bem como a taxa de prenhez nas receptoras destes embriões. As vacas da raça Girolando (Bos taurus x Bos indicus) foram classificadas como de alta CFA quando apresentavam de 35 a 52 folículos(n = 13) e baixa CFA, quando apresentavam de 11 a 17 folículos (n = 15). Todos os animais foram submetidos a repetidas sessões de aspiração folicular (OPU) e subsequente PIVE. O protocolo de sincronização das receptoras foi realizado em um dia aleatório do ciclo estral (Dia 0) com implante de progesterona, benzoato de estradiol e prostaglandina. O grupo de alta CFA obteve uma maior média de oócitos aspirados / OPU (42,6 ± 5,2 vs. 14,6 ± 1,9; p < 0,01); oócitos cultivados / OPU (38,1 ± 6,6 vs.12,3 ± 2,8; p < 0,01); porcentagem de blastocistos em D7 (23,0 ± 1,0% vs. 18,4 ± 1,5%; p < 0,05) e taxa de prenhez (42,7 ± 2,7% vs. 39,7 ± 4,6%; p < 0,05) maiores quando comparado ao grupo de baixa CFA. Desta maneira, podemos concluir que os animais de alta CFA apresentaram melhores taxas de PIVE que os animais de baixa CFA.

Assuntos

RESUMO

The objective of this study was to evaluate the fertility of buffalo semen for in vitro embryo production (IVEP) by comparing the effectiveness of refrigerated versus frozen semen. Three OPU sessions were held at 30-day intervals. For oocyte fertilization three buffalo bulls were used, one per session. At each OPU-IVEP session, one ejaculate was collected and divided into two equal aliquots. Each aliquot was either refrigerated at 5ºC/24 hours or frozen. A TRIS extender containing 10% low density lipoproteins, 0.5% lecithin and 10 mM acetylcysteine was used adding 7% glycerol for freezing. Sperm motility/kinetic was evaluated by CASA and sperm membrane integrity by the hypoosmotic swelling test. The evaluations were performed at 0 h (post final dilution at 37ºC), at 4 and 24 hs post-incubation at 5ºC and post-thaw. At 24 hs incubation and immediately post thaw sperm cells were used for in vitro fertilization of buffalo oocytes equally distributed between both groups. Cleavage rates and embryo development were followed. The embryo/matured and embryo/cultured rates were 25.4 x 14.0% and 29.4 x 18.5% (P 0.05), for chilled and frozen semen, respectively. It is concluded that cooled semen can be used for in vitro embryo production in buffalo and that a better efficiency may be expected for cooled compared to frozen semen.(AU)

Assuntos

RESUMO

This study aimed to evaluate the potential of Girolando (Bos taurus × Bos indicus) cows with high and low antral follicle counts (AFC) for the in vitro production of bovine embryos (IVEP), as well as the pregnancy rates of the recipients of these embryos. Girolando cows (Bos taurus × Bos indicus) were classified as high and low AFC when they had 35-52 (n = 13) and 11-17 follicles (n = 15), respectively. All animals were subjected to repeated follicular aspiration [Ovum pick-up (OPU)] and subsequent IVEP sessions. The synchronization protocol of the recipients was performed on a random day of the estrous cycle (Day 0) with the implantation of progesterone, estradiol benzoate, and prostaglandin. The high AFC group had higher aspirated oocyte/OPU (42.6 ± 5.2 vs. 14.6 ± 1.9; p < 0.01) and cultured oocyte/OPU (38.1 ± 6.6 vs. 12.3 ± 2.8; p < 0.01) averages as well as a higher blastocyst percentage on D7 (23.0 ± 1.0% vs. 18.4 ± 1.5%; p < 0.05) and higher pregnancy rate (42.7 ± 2.7% vs. 39.7 ± 4.6%; p< 0.05) than the low AFC group. Thus, we can conclude that animals with high AFC had better IVEP success rates than animals with low AFC.

Este estudo teve como objetivo avaliar o potencial de produção in vitro de embriões (PIVE) bovinos de vacas da raça Girolando (Bos taurus x Bos indicus) com alta e baixa contagem de folículos antrais (CFA), bem como a taxa de prenhez nas receptoras destes embriões. As vacas da raça Girolando (Bos taurus x Bos indicus) foram classificadas como de alta CFA quando apresentavam de 35 a 52 folículos(n = 13) e baixa CFA, quando apresentavam de 11 a 17 folículos (n = 15). Todos os animais foram submetidos a repetidas sessões de aspiração folicular (OPU) e subsequente PIVE. O protocolo de sincronização das receptoras foi realizado em um dia aleatório do ciclo estral (Dia 0) com implante de progesterona, benzoato de estradiol e prostaglandina. O grupo de alta CFA obteve uma maior média de oócitos aspirados / OPU (42,6 ± 5,2 vs. 14,6 ± 1,9; p < 0,01); oócitos cultivados / OPU (38,1 ± 6,6 vs.12,3 ± 2,8; p < 0,01); porcentagem de blastocistos em D7 (23,0 ± 1,0% vs. 18,4 ± 1,5%; p < 0,05) e taxa de prenhez (42,7 ± 2,7% vs. 39,7 ± 4,6%; p < 0,05) maiores quando comparado ao grupo de baixa CFA. Desta maneira, podemos concluir que os animais de alta CFA apresentaram melhores taxas de PIVE que os animais de baixa CFA.

Assuntos

RESUMO

The objective of this study was to evaluate the fertility of buffalo semen for in vitro embryo production (IVEP) by comparing the effectiveness of refrigerated versus frozen semen. Three OPU sessions were held at 30-day intervals. For oocyte fertilization three buffalo bulls were used, one per session. At each OPU-IVEP session, one ejaculate was collected and divided into two equal aliquots. Each aliquot was either refrigerated at 5ºC/24 hours or frozen. A TRIS extender containing 10% low density lipoproteins, 0.5% lecithin and 10 mM acetylcysteine was used adding 7% glycerol for freezing. Sperm motility/kinetic was evaluated by CASA and sperm membrane integrity by the hypoosmotic swelling test. The evaluations were performed at 0 h (post final dilution at 37ºC), at 4 and 24 hs post-incubation at 5ºC and post-thaw. At 24 hs incubation and immediately post thaw sperm cells were used for in vitro fertilization of buffalo oocytes equally distributed between both groups. Cleavage rates and embryo development were followed. The embryo/matured and embryo/cultured rates were 25.4 x 14.0% and 29.4 x 18.5% (P 0.05), for chilled and frozen semen, respectively. It is concluded that cooled semen can be used for in vitro embryo production in buffalo and that a better efficiency may be expected for cooled compared to frozen semen.

Assuntos

RESUMO

A high oocyte quality is the prerequisite for in vitro embryo production. Goat cumulus-oocyte complexes (COC) are mainly collected from slaughterhouse ovaries or by laparoscopic ovum pickup (LOPU) from live animals. Several features can influence the availability of good quality oocytes recovered by the LOPU technique. Interestingly, slaughterhouse and LOPU oocytes have different in vitro maturation kinetics and requirements, and thus, the IVP system must be adapted regarding the oocyte origin. Overall, the use of undefined media in the different steps makes interpretation of results more difficult, hampers their reproducibility, and introduces a sanitary risk. Thus, there is an effort worldwide to use simpler conditions for goat IVP. Although the success of IVP rates is relatively high, in vitro embryos differ from in vivo-derived ones in many aspects, resulting in lower viability. Therefore, strategies to improve in vitro embryo quality are crucial, such as the use of oviductal epithelium cells for coculture. Here we describe the main steps and culture media which can be utilized to produce embryos in vitro from LOPU or slaughterhouse oocytes in goats.

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RESUMO

As biotecnologias para produção de embriões in vivo e in vitro são de grande importância para acelerar o ganho genético dos rebanhos de corte e de leite. No entanto, o sucesso desses processos depende diretamente da quantidade e da qualidade dos oócitos da doadora de embrião. Diversos fatores influenciam a produção de embriões como a população folicular, a idade da doadora, o estresse térmico, o status metabólico e o status reprodutivo. Na atualidade, vários estudos têm sido desenvolvidos para elaborar estratégias que contornem estes desafios e aumentem a eficiência das técnicas de produção de embriões. Dentre os tratamentos estabelecidos para melhorar a produção de embriões das doadoras destacam-se a utilização de FSH, rBST, propilenoglicol e células tronco mesenquimais.

Biotechnologies for producing in vivo and in vitro embryos are very important to accelerate the genetic gain of beef and dairy herds. However, the success of these processes depend directly on the quantity and quality of the donors oocytes. Many factors influence the embryo production, such as follicle population, age, heat stress, metabolic status and reproductive status. Recently, many studies have been conducted to elaborate strategies that can overcome these issues and increase the efficiency of the embryo production techniques. Among the treatments developed to improve the embryo production, the use of FSH, rBST, propylene glycol and mesenchymal stem cells stand out.

Assuntos

RESUMO

As biotecnologias para produção de embriões in vivo e in vitro são de grande importância para acelerar o ganho genético dos rebanhos de corte e de leite. No entanto, o sucesso desses processos depende diretamente da quantidade e da qualidade dos oócitos da doadora de embrião. Diversos fatores influenciam a produção de embriões como a população folicular, a idade da doadora, o estresse térmico, o status metabólico e o status reprodutivo. Na atualidade, vários estudos têm sido desenvolvidos para elaborar estratégias que contornem estes desafios e aumentem a eficiência das técnicas de produção de embriões. Dentre os tratamentos estabelecidos para melhorar a produção de embriões das doadoras destacam-se a utilização de FSH, rBST, propilenoglicol e células tronco mesenquimais.(AU)

Biotechnologies for producing in vivo and in vitro embryos are very important to accelerate the genetic gain of beef and dairy herds. However, the success of these processes depend directly on the quantity and quality of the donors oocytes. Many factors influence the embryo production, such as follicle population, age, heat stress, metabolic status and reproductive status. Recently, many studies have been conducted to elaborate strategies that can overcome these issues and increase the efficiency of the embryo production techniques. Among the treatments developed to improve the embryo production, the use of FSH, rBST, propylene glycol and mesenchymal stem cells stand out.(AU)

Assuntos

RESUMO

This study aimed to evaluate the effect of equine chorionic gonadotrophin (eCG) stimulation prior to ovum pick-up (OPU) on follicular development, number and quality of recovered oocytes, fertilization rate, and early embryo development in vitro. There were four OPU sessions (cross over) conducted on 16 Braford cows to evaluate the effect of various eCG doses. The timing of the wave of ovarian follicular development was synchronized, and three days after, the respective eCG dose was administrated (0, 200, 400, or 800 IU). The OPU was performed on Day 6, and viable oocytes were used for IVM and IVF according to the respective treatment. After IVF treatment, the fertilization and cleavage rates, time of cleavage, and the cell number at 48 h were evaluated. There was no difference in the number of follicles, oocyte quantity, and morphological quality of oocytes among treatments (P > 0.05). The oocyte recovery rate was similar among the eCG-treated groups, but was less than in the control group (P < 0.01). The eCG800 group, however, had a greater recovery rate of follicles >6 mm in diameter (P < 0.01). In addition, the eCG800 group had a greater rate of normal fertilization (P < 0.01) and lesser rate of polyspermy (P < 0.02). The cleavage rate of the eCG800 group was greater than the other treatment groups but similar to that of the control. In conclusion, the use of eCG800 increased the proportion of follicles > 6 mm, with improved rate of normal fertilization and reduced occurrence of polyspermy, without affecting early embryonic development in vitro.

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Holstein-Gyr crossbred cattle are strategic for dairy systems in tropical countries, since they combine milk yield genetics with adaptability to tropical climate. However, Holstein (Bos taurus) and Gyr (Bos indicus) breeds present remarkable differences regarding reproductive physiology. Brazil stands out as the worlds largest user of embryo in vitro production (IVP) in bovine, and the use of this technique is increasing in dairy systems. As Holstein-Gyr crossbreds are important oocyte donors for IVP, the present work aimed at investigating whether increased Gyr or Holstein breed composition influences donors performance. Sixteen Holstein-Gyr crossbred females presenting increased (HG, 71.4 to 87.5% Holstein; n = 9) or decreased (GH, 40.2 to 46.6% Holstein; n = 7) Holstein composition were submitted to three ovum pick up (OPU) sessions. We observed similar (P = 0.2946) antral follicle count between HG and GH donors (24.8 ± 3.2 vs 29.4 ± 2.8 respectively; mean ± SEM). Groups also display similar morphological oocyte grading (Grade I: 0.1 ± 0.1 vs 0.1 ± 0.1 P = 0.9680; Grade II: 0.9 ± 0.5 vs 1.9 ± 0.5 P = 0.1942; Grade III, 4.0 ± 1.2 vs 7.2 ± 1.4 P = 0.1047, HG vs GH respectively; mean ± SEM). Additionally, the proportion of viable oocyte was similar between HG and GH groups (27.8% vs 31.9%, respectively, P = 0.3500) and oocyte lipid area fraction (6.8% vs 9.5%, respectively; P = 0.1539). Our results indicate that the individual variation has more influence than breed composition of crossbred oocyte donors.(AU)

Assuntos

RESUMO

Holstein-Gyr crossbred cattle are strategic for dairy systems in tropical countries, since they combine milk yield genetics with adaptability to tropical climate. However, Holstein (Bos taurus) and Gyr (Bos indicus) breeds present remarkable differences regarding reproductive physiology. Brazil stands out as the world’s largest user of embryo in vitro production (IVP) in bovine, and the use of this technique is increasing in dairy systems. As Holstein-Gyr crossbreds are important oocyte donors for IVP, the present work aimed at investigating whether increased Gyr or Holstein breed composition influences donor’s performance. Sixteen Holstein-Gyr crossbred females presenting increased (HG, 71.4 to 87.5% Holstein; n = 9) or decreased (GH, 40.2 to 46.6% Holstein; n = 7) Holstein composition were submitted to three ovum pick up (OPU) sessions. We observed similar (P = 0.2946) antral follicle count between HG and GH donors (24.8 ± 3.2 vs 29.4 ± 2.8 respectively; mean ± SEM). Groups also display similar morphological oocyte grading (Grade I: 0.1 ± 0.1 vs 0.1 ± 0.1 – P = 0.9680; Grade II: 0.9 ± 0.5 vs 1.9 ± 0.5 – P = 0.1942; Grade III, 4.0 ± 1.2 vs 7.2 ± 1.4 – P = 0.1047, HG vs GH respectively; mean ± SEM). Additionally, the proportion of viable oocyte was similar between HG and GH groups (27.8% vs 31.9%, respectively, P = 0.3500) and oocyte lipid area fraction (6.8% vs 9.5%, respectively; P = 0.1539). Our results indicate that the individual variation has more influence than breed composition of crossbred oocyte donors.

Assuntos