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1.
Ars vet ; 39(2): 29-33, 2023. ilus, tab
Artigo em Inglês | VETINDEX | ID: biblio-1438472

Resumo

A ultrassonografia é um dos principais métodos de diagnóstico gestacional, no qual se realiza: biometria, monitoramento de batimentos e organogênese, detecção de anormalidades e avaliação da circulação sanguínea materno-fetal. Nesse quesito, o diagnóstico ultrassonográfico intrauterino de anormalidades fetais vem adquirindo espaço com o desenvolvimento de equipamentos mais avançados, tendo potencial para se tornar uma ferramenta de triagem para tal. Baseado na escassez observada nesse aspecto, visa-se relatar o diagnóstico ultrassonográfico intrauterino de uma alteração fetal em uma felina gestante. Foi atendida uma felina da raça persa, 3 anos, com histórico de monta natural há 40 dias. Na ultrassonografia visibilizou-se quatro fetos vivos com aproximadamente 38 dias. Uma segunda avaliação ultrassonográfica ocorreu após 12 dias, notando-se um feto com cardiomegalia, oscilação da frequência cardíaca e sofrimento fetal, enquanto os demais fetos apresentavam-se dentro da normalidade. O terceiro exame foi feito após quatro dias, visibilizando ausência de batimento cardíaco e presença de líquido em espaço pleural no feto em questão, confirmando o óbito. O parto natural ocorreu após uma semana, com nascimento de três filhotes vivos e um natimorto. Ao exame necroscópico do natimorto, confirmou-se cardiomegalia generalizada. Conclui-se que a ultrassonografia é um método padrão-ouro para diagnóstico de anormalidades fetais, permitindo planejar o parto e interceder de maneira precoce conforme a situação. Assim, esse trabalho enriquece a literatura com maiores informações relacionadas a malformações fetais observadas antes do parto, contribuindo assim com as condutas obstétricas em pequenos animais.(AU)


Ultrasonography is one of the main methods of gestational diagnosis, in which it performs: biometry, monitoring of beats and organogenesis, detection of abnormalities and evaluation of maternal-fetal blood circulation. In this regard, intrauterine sonographic diagnosis of fetal abnormalities has been gaining space with the development of more advanced equipment, and has the potential to become a screening tool for this purpose. Based on the scarcity observed in this aspect, this study aimsto report the intrauterine ultrasound diagnosis of a fetal abnormality in a pregnant feline. The patient was a 3-year-old Persian female with a history of natural mounting for 40 days. At ultrasonography, four live fetuses were visualized at approximately38 days of age. Asecond ultrasonographic evaluation was performed after 12 days, and one fetus with cardiomegaly, heart rate oscillation and fetal distress was observed, while the other fetuses were within normal limits. The third scan was performed after four days, showing absence of heartbeat and presence of fluid in the pleural space in the fetus in question, confirming the death. Natural delivery occurred after one week, with the birth of three live pups and one stillborn. At necroscopic examination of the stillborn, generalized cardiomegaly was confirmed. We conclude that ultrasonography is a gold standard method for diagnosing fetal abnormalities, allowing birth planning and early intervention according to the situation. Thus, this study enriches theliterature with more information related to fetal malformations observed before delivery, thus contributing to obstetric management in small animals.(AU)


Assuntos
Animais , Feminino , Gravidez , Diagnóstico Pré-Natal/veterinária , Gatos , Ultrassonografia Pré-Natal/métodos , Cardiomegalia Induzida por Exercícios/fisiologia , Anormalidades Congênitas/veterinária
2.
Anim. Reprod. (Online) ; 20(1): e20230006, 2023. graf, tab, ilus
Artigo em Inglês | VETINDEX | ID: biblio-1427296

Resumo

The aim of this study was to evaluate and correlate modifications of vaginal mucous impedance, vulvar temperature and ultrasonographic measurements (echobiometric parameters) to parturition in pregnant Saanen does. 30 does were selected for the study and submitted to an estrus synchronization protocol and natural mating. The females were evaluated daily from Day 143 of pregnancy to parturition. For the sonographic evaluations, the following structures were measured: biparietal diameter, thoracic diameter, abdominal diameter, ocular orbit, kidney length, kidney height, cardiac area, placentome length, cervical measurement and fetal heart rate; by means of two different approaches: transrectal and transabdominal, using a 7.5 MHz linear transducer. The vaginal mucous impedance was assessed using an electric estrous detector and vulvar temperature was measured using a non-contact infrared thermometer. Statistical analysis was performed using the R-project software and the significance level was set at 5% for all tests. 25 Saanen does became pregnant, resulting in 80.33% pregnancy rate. Fetal heart rate was negatively correlated to the hours to parturition (p<0,001; r-Pearson= -0,451), as well as vaginal temperature (p= 0,001; r-Pearson= -0,275), while cervical thickness was positively correlated to hours to parturition (p<0,001; r-Pearson= 0,490). The echobiometric parameters (biparietal diameter, thoracic diameter, abdominal diameter, ocular orbit, kidney length and height, cardiac area, placentome length), as well as vaginal mucous impedance did not vary throughout the timepoints of evaluation and did not correlate to the moment of parturition. It was concluded that the parameters of fetal heartbeat, vaginal temperature and cervical effacement in the last week of pregnancy provide valuable information regarding the proximity of parturition.(AU)


Assuntos
Animais , Feminino , Gravidez , Prenhez , Cabras/fisiologia , Impedância Elétrica , Composição Corporal/fisiologia , Biometria/métodos , Ultrassonografia Pré-Natal/veterinária
3.
Anim. Reprod. (Online) ; 20(2): e20230069, 2023. ilus
Artigo em Inglês | VETINDEX | ID: biblio-1452376

Resumo

Advancements in assisted reproduction (AR) methodologies have allowed significant improvements in live birth rates of women who otherwise would not be able to conceive. One of the tools that allowed this improvement is the possibility of embryo selection based on genetic status, performed via preimplantation genetic testing (PGT). Even though the widespread use of PGT from TE biopsy helped to decrease the interval from the beginning of the AR intervention to pregnancy, especially in older patients, in AR, there are still many concerns about the application of this invasive methodology in all cycles. Therefore, recently, researchers started to study the use of cell free DNA (cfDNA) released by the blastocyst in its culture medium to perform PGT, in a method called non-invasive PGT (niPGT). The development of a niPGT would bring the diagnostics power of conventional PGT, but with the advantage of being potentially less harmful to the embryo. Its implementation in clinical practice, however, is under heavy discussion since there are many unknowns about the technique, such as the origin of the cfDNA or if this genetic material is a true representative of the actual ploidy status of the embryo. Available data indicates that there is high correspondence between results observed in TE biopsies and the ones observed from cfDNA, but these results are still contradictory and highly debatable. In the present review, the advantages and disadvantages of niPGT are presented and discussed in relation to tradition TE biopsy-based PGT. Furthermore, there are also presented some other possible non-invasive tools that could be applied in the selection of the best embryo, such as quantification of other molecules as quality biomarkers, or the use artificial intelligence (AI) to identify the best embryos based on morphological and/or morphokitetic parameters.(AU)


Assuntos
Animais , Técnicas de Reprodução Assistida/veterinária , Teste Pré-Natal não Invasivo/veterinária , Inteligência Artificial , Desenvolvimento Embrionário
4.
Rev. bras. reprod. anim ; 47(3): 536-543, jul.-set. 2023. ilus, tab
Artigo em Português | VETINDEX | ID: biblio-1436726

Resumo

Na prática, compreender a anatomia reprodutiva, a fisiologia e o comportamento do macho, da espécie selvagem com a qual se está trabalhando, é essencial para a avaliação andrológica e para a reprodução bem sucedida. Neste artigo damos especial ênfase à andrologia de felídeos selvagens. O profissional pode ser chamado para solucionar problemas quando a espécie apresenta dificuldade de reprodução em cativeiro e/ou encontra-se ameaçada de extinção. Baixas taxas de fertilidade e de prenhez podem estar associadas ao macho, com influências do estresse pelo cativeiro, nutrição inadequada e erros de manejo reprodutivo. E também, as instituições que mantêm essas espécies sob cuidado humano poderão ser auxiliadas no manejo reprodutivo com o exame andrológico periódico, que pode ser acompanhado de criopreservação de sêmen para formação ou manutenção de um banco de reserva genômica. Como componente de um programa holístico de conservação, incluindo os estudos de ecologia de campo, esta estratégia fortalece ainda mais o vínculo entre as populações ex situ e in situ.(AU)


In practice, understanding the male reproductive anatomy, physiology and the behavior, of the wild species that you are working, is essential for andrological assessment and successful reproduction. In this article we give special emphasis to the andrology of wild felids. The professional can be called to solve problems when the species has difficulty reproducing in captivity and/or is threatened with extinction. Low fertility and pregnancy rates may be associated with the male, with influences from stress in captivity, inadequate nutrition and reproductive management errors. Also, the institutions that keep these species under human care can be assisted in reproductive management with periodic andrological examination, which can be accompanied by semen cryopreservation for the formation or maintenance of a genome resource bank. As a component of a holistic conservation program, including field ecology studies, this strategy further strengthens the link between ex situ and in situ populations.(AU)


Assuntos
Animais , Felidae/embriologia , Animais Selvagens/embriologia , Andrologia/tendências
5.
Rev. bras. reprod. anim ; 47(2): 76-80, abr.-jun. 2023.
Artigo em Inglês | VETINDEX | ID: biblio-1434952

Resumo

The follicular growth waves are directly linked to the fluctuations in plasma gonadotrophins, which are controlled by the hypothalamic GnRH release pattern. Therefore, if the actions of the GnRH are inhibited or blocked, the final stages of the antral follicle growth are suppressed, resulting in an induced anestrus (a.k.a. waveless model). In the human medicine, GnRH agonists or antagonists are broadly used in the control of ovarian disfunctions, as well as in the preparation of women for assisted reproductive cycles. In cattle, a similar effect can be obtained by active immunization against GnRH. This was shown to be a viable strategy, for example, for the control of chronic cases of cystic ovarian disease in oocyte donors. However, on shall take into account the substantial individual variation on the immune response and, consequently, the lack of control of the duration of the anestrus induced. The waveless model is also very useful as a research model, once it controls the potential interference of the endogenous FSH and LH, improving the sensitivity of essays with exogenous hormones and consequently reducing the required number of replicas within studies.(AU)


O padrão de crescimento folicular em ondas está diretamente associado às flutuações nas concentrações plasmáticas de gonadotrofinas, controladas por sua vez pelo padrão de liberação de GnRH hipotalâmico. Desta forma, a inibição ou bloqueio da ação do GnRH suprime as etapas finais do crescimento folicular, resultando em anestro induzido (também chamado modelo waveless). Na medicina humana, agonistas ou antagonistas de GnRH são utilizados tanto no controle de disfunções ovarianas quanto na preparação de pacientes para procedimentos de reprodução assistida. Em bovinos, este efeito pode ser obtido pela imunização ativa contra GnRH, e mostrou-se estratégia viável, por exemplo, no controle de casos crônicos de doença ovariana cística em doadoras de oócitos. Contudo, é importante considerar a grande variação individual na resposta à imunização e consequente impossibilidade de controlar a duração do anestro induzido. O modelo waveless também é de grande utilidade na pesquisa, uma vez que elimina a potencial interferência do FSH e LH endógenos, aumentando a sensibilidade nos ensaios com hormônios exógenos e consequentemente reduzindo o número de réplicas necessárias nos estudos.(AU)


Assuntos
Animais , Bovinos/embriologia , Estruturas Embrionárias/crescimento & desenvolvimento , Fase Folicular , Gonadotropinas/análise
6.
Rev. bras. reprod. anim ; 47(2): 113-115, abr.-jun. 2023.
Artigo em Espanhol | VETINDEX | ID: biblio-1435052

Resumo

El primer punto a tener en cuenta es determinar si el estado de salud de la gata permite incluirla en un plan reproductivo y de ser así cuál es su probabilidad de distocia. Es así que se planifican 3 consultas: la primera durante el celo previo al servicio, la segunda 20 días después del día de los servicios momento en el que se realiza el diagnóstico de gestación y se evalúa el desarrollo de los conceptos gestados si la gata quedó preñada, y la tercera al día 50 de gestación en la cual se realiza un examen de salud y el control del número de fetos gestados mediante Rx. La evaluación del estado de salud de la madre y de los conceptos gestados, así como el desarrollo de los mismos permitirá estimar la fecha probable de parto, y programar la asistencia al parto o una cesárea con mínimos riesgos según sea el caso.(AU)


Assuntos
Animais , Feminino , Prenhez/fisiologia , Gatos/embriologia
7.
Rev. bras. reprod. anim ; 47(2): 159-163, abr.-jun. 2023.
Artigo em Português | VETINDEX | ID: biblio-1435138

Resumo

A transferência de embriões equinos é uma biotecnologia que traz inúmeros benefícios reprodutivos para um haras. Entretanto, os índices reprodutivos obtidos numa estação de monta podem ser afetados por diversos fatores que interferem tanto na recuperação embrionária que normalmente são relacionados à doadora de embriões, quanto na taxa de gestação na receptora de embriões. O objetivo do presente artigo foi revisar os fatores relacionados à receptora de embriões em programas de transferência de embriões equinos.(AU)


Equine embryo transfer is a biotechnology that brings reproductive benefits to a stud farm. However, the reproductive rates obtained in a breeding season can be affected by several factors that interfere both in the embryonic recovery that are normally related to the embryo donor, and in the pregnancy rate in the embryo recipient. The aim of this article was to review the factors related to the recipient of embryos in equine embryo transfer programs.(AU)


Assuntos
Animais , Feminino , Gravidez , Transferência Embrionária/veterinária , Cavalos/embriologia , Taxa de Fecundidade
8.
Anim. Reprod. (Online) ; 20(1): e20220076, 2023. tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1418557

Resumo

The establishment of epigenetic marks during the reprogramming window is susceptible to environmental influences, and stimuli during this critical stage can cause altered DNA methylation in offspring. In a previous study, we found that low levels of sulphur and cobalt (low S/Co) in the diet offered to oocyte donors altered the DNA methylome of bovine embryos. However, due to the extensive epigenetic reprogramming that occurs during embryogenesis, we hypothesized that the different methylation regions (DMRs) identified in the blastocysts may not maintain in adulthood. Here, we aimed to characterize DMRs previously identified in embryos, in the blood and sperm of adult progenies of two groups of heifers (low S/Co and control). We used six bulls and characterized the DNA methylation levels of KDM2A, KDM5A, KMT2D, and DOT1L genes. Our results showed that all DMRs analysed in both groups and tissues were hypermethylated unlike that noticed in the embryonic methylome profiles. These results suggest that embryo DMRs were reprogrammed during the final stages of de novo methylation during embryogenesis or later in development. Therefore, due to the highly dynamic epigenetic state during early embryonic development, we suggest that is essential to validate the DMRs found in embryos in adult individuals.(AU)


Assuntos
Animais , Bovinos/embriologia , Epigenômica
9.
Anim. Reprod. (Online) ; 20(2): e20230085, 2023. ilus
Artigo em Inglês | VETINDEX | ID: biblio-1452316

Resumo

The establishment and maintenance of a pregnancy that goes to term is sine qua non for the long-term sustainability of dairy and beef cattle operations. The oocyte plays a critical role in providing the factors necessary for preimplantation embryonic development. Furthermore, the female, or maternal, environment where oocytes and embryos develop is crucial for the establishment and maintenance of a pregnancy to term. During folliculogenesis, the oocyte must sequentially acquire meiotic and developmental competence, which are the results of a series of molecular events preparing the highly specialized gamete to return to totipotency after fertilization. Given that folliculogenesis is a lengthy process in the cow, the occurrence of disease, metabolic imbalances, heat stress, or other adverse events can make it challenging to maintain oocyte quality. Following fertilization, the newly formed embryo must execute a tightly planned program that includes global DNA remodeling, activation of the embryonic genome, and cell fate decisions to form a blastocyst within a few days and cell divisions. The increasing use of assisted reproductive technologies creates an additional layer of complexity to ensure the highest oocyte and embryo quality given that in vitro systems do not faithfully recreate the physiological maternal environment. In this review, we discuss cellular and molecular factors and events known to be crucial for proper oocyte development and maturation, as well as adverse events that may negatively affect the oocyte; and the importance of the uterine environment, including signaling proteins in the maternal-embryonic interactions that ensure proper embryo development. We also discuss the impact of assisted reproductive technologies in oocyte and embryo quality and developmental potential, and considerations when looking into the prospects for developing systems that allow for in vitro gametogenesis as a tool for assisted reproduction in cattle.(AU)


Assuntos
Animais , Feminino , Gravidez , Bovinos/embriologia , Colo do Útero/embriologia , Células Germinativas/citologia , Técnicas de Reprodução Assistida/veterinária , Desenvolvimento Embrionário
10.
Anim. Reprod. (Online) ; 20(2): e20230064, 2023.
Artigo em Inglês | VETINDEX | ID: biblio-1444264

Resumo

Genomic selection has transformed the livestock industry, enabling early-life selection of animals. Biopsy sampling of pre-implantation embryos has been described since 1968. However, it was only after 2010, with the advancement of molecular biology techniques such as whole genomic amplification and SNP Chips, that next-generation sequencing became commercially available for bovine embryos. It is now possible to make decisions about which embryos to transfer not only based on recipients' availability or embryo morphology but also on genomic estimates. This technology can be implemented for a wide spectrum of applications in livestock. In this review, we discuss the use of embryo biopsy for genomic selection and share our experience with Gir and Girolando Brazilian breeding programs, as well as future goals for implementing it in Brazilian bovine in vitro embryo production practices.(AU)


Assuntos
Animais , Feminino , Biópsia/veterinária , Bovinos/embriologia , Seleção Genética , Melhoramento Genético/métodos
11.
Rev. bras. reprod. anim ; 47(2): 148-153, abr.-jun. 2023. tab
Artigo em Português | VETINDEX | ID: biblio-1435103

Resumo

A biodiversidade das abelhas africanizadas (Apis melífera) encontra-se sob grande ameaça e, neste cenário as investigações acerca da biologia reprodutiva, alguns aspectos ainda incipientes, bem como métodos aprimorados para a inseminação instrumental e criopreservação de gametas podem ser ferramentas preciosas para a conservação in situ e ex situ de subespécies e ecótipos. O entendimento e adoção de ferramentas como estas mencionadas, podem auxiliar na seleção de características de interesse para os criadores, assim como, nos esforços para a conservação de populações de abelhas ameaçadas.(AU)


The biodiversity of Africanized bees (Apis mellifera) is under great threat and, in this scenario, investigations about reproductive biology, some aspects are still incipient, as well as improved methods for instrumental insemination and cryopreservation of gametes can be precious tools for ex situ and in conservation. situ of subspecies and ecotypes can be contemplated. The understanding and adoption of tools such as those mentioned can help in the selection of characteristics of interest to breeders, as well as those committed to the conservation of endangered bee populations.(AU)


Assuntos
Animais , Abelhas/embriologia , Biotecnologia/métodos , Criopreservação/veterinária , Fenômenos Reprodutivos Fisiológicos
12.
Anim. Reprod. (Online) ; 20(2): e20230034, 2023.
Artigo em Inglês | VETINDEX | ID: biblio-1452377

Resumo

It can be assumed that the natural processes of selection and developmental condition in the animal provide the best prerequisites for embryogenesis resulting in pregnancy and subsequent birth of a healthy neonate. In contrast, circumventing the natural selection mechanisms and all developmental conditions in a healthy animal harbors the risk of counteracting, preventing or reducing the formation of embryos or substantially restricting their genesis. Considering these facts, it seems to be obvious that assisted reproductive techniques focusing on early embryonic stages serve an expanded and unselected germ cell pool of oocytes and sperm cells, and include the culture of embryos outside their natural habitat during and after fertilization for manipulation and diagnostic purposes, and for storage. A significant influence on the early embryonic development is seen in the extracorporeal culture of bovine embryos (in vitro) or stress on the animal organism (in vivo). The in vitro production per se and metabolic as well as endocrine changes in the natural environment of embryos represent adequate models and serve for a better understanding. The purpose of this review is to give a brief presentation of recent techniques aimed at focusing more on the complex processes in the Fallopian tube to contrast in vivo and in vitro prerequisites and abnormalities in early embryonic development and serve to identify potential new ways to make the use of ARTs more feasible.(AU)


Assuntos
Animais , Feminino , Bovinos/embriologia , Técnicas Reprodutivas/veterinária , Interação Gene-Ambiente , Desenvolvimento Embrionário , Meio Ambiente
13.
Rev. bras. reprod. anim ; 47(2): 154-158, abr.-jun. 2023.
Artigo em Português | VETINDEX | ID: biblio-1435109

Resumo

Inúmeras são as vantagens da utilização da técnica de transferência de embriões (TE) em equinos. No entanto, alguns fatores podem afetar a taxa de recuperação embrionária: dia da colheita do embrião; condição uterina e idade da doadora; manejos reprodutivo, sanitário e nutricional; garanhão/qualidade do sêmen; habilidade do técnico; condições climáticas, número de ovulações e adaptação da doadora. O objetivo deste artigo é revisar os fatores que podem exercer influência sobre a taxa de recuperação embrionária tendo impacto direto nos índices reprodutivos de um programa de TE.(AU)


There are countless advantages of using the embryo transfer (ET) technique in horses. However, some factors may affect the embryonic recovery rate: day of embryo collection; uterine condition and donor age; reproductive, health and nutritional management; stallion/semen quality; skill of the technician; climatic conditions, number of ovulations and adaptation of the donor. The objective of this article is to review those factors that can influence the embryonic recovery rate, having a direct impact on the reproductive rates of an ET program.(AU)


Assuntos
Animais , Feminino , Desenvolvimento Embrionário , Cavalos/embriologia , Coeficiente de Natalidade , Transferência Embrionária/veterinária
14.
Rev. bras. reprod. anim ; 47(3): 574-578, jul.-set. 2023. graf, tab
Artigo em Português | VETINDEX | ID: biblio-1436749

Resumo

A importância da qualidade do sêmen no processo comercial de produção in vitro de embriões (PIVE) é bem conhecida, ainda que não devidamente relatada na literatura. Existe não apenas uma significativa diferença entre touros nas taxas de clivagem e de blastocistos, mas também nas taxas de prenhezes subsequentes. Adicionalmente, há evidências de interação entre touro e tecnologia de processamento do sêmen (particularmente na separação de espermatozoides por sexo), entre touro e protocolo de preparação do sêmen para fertilização in vitro, e ainda entre touro e doadora. Controlar estes efeitos em uma rotina comercial tem sido um desafio crescente para os laboratórios, particularmente com a alta oferta de novos touros decorrente da recente adoção da seleção genômica. O presente trabalho aborda algumas destas questões, com base na experiência da Bio Biotecnologia da Reprodução Animal nesta área.(AU)


The importance of semen quality in a commercial in vitro embryo production (IVEP) routine is well-known, although underreported in the literature. There is not only a significant difference among sires on cleavage and blastocyst rates, but also on subsequent pregnancy rates. Moreover, there are evidences of interaction between sire and sperm processing technology (particularly in the case of sex-sorted semen), between sire and the protocol for sperm preparation for in vitro fertilization, and between sire and donor. Controlling such effects in a commercial routine has been a growing challenge for the laboratories, especially due to the high turnover of sires caused by the recent adoption of genomic selection in most breeds. The current study discusses some of these aspects, from the perspective of the experience of Bio Biotecnologia da Reprodução Animal in this field.(AU)


Assuntos
Animais , Masculino , Bovinos/embriologia , Desenvolvimento Embrionário , Análise do Sêmen/veterinária , Técnicas In Vitro
15.
Anim. Reprod. (Online) ; 20(1): e20220079, 2023. tab
Artigo em Inglês | VETINDEX | ID: biblio-1418572

Resumo

Logistic and economical limitations are often the causes of dog owners not accurately monitoring the estrous cycle and the optimal insemination time. The aim of this study was to evaluate in vivo early embryonic development in bitches, after the analysis of sequential vaginal cytologies associated to single progesterone measurement and single laparoscopic insemination with high quality semen (fresh and with high spermatozoa concentration) or low-quality semen (frozen/thawed and with low spermatozoa concentration) at 48 h post- ovulation time predicted on a single progesterone measurement. Ten bitches were inseminated with 250 x 106 fresh spermatozoa (80% motility), and ten with 80 x 106 frozen/thawed spermatozoa (60% motility) in the cranial part of each uterine horn. Seven days later, ovariohysterectomy was performed and the oviducts and uterine horns and body were flushed to recover embryos and unfertilized oocytes. In 80% of the bitches inseminated with fresh and 50% of bitches inseminated with frozen/thawed semen, embryos at 2 to 8 cells stage were recovered mostly from the, oviducts. This study indicates that pregnancies can be obtained with a single laparoscopic intrauterine insemination after single serum progesterone measurement, although with a low number of embryos. This result should be taken into account in case economic or logistic restrictions that affect the possibility of owners to plan an accurate monitoring of the optimal breeding time using fresh and frozen semen.(AU)


Assuntos
Animais , Feminino , Progesterona/administração & dosagem , Laparoscopia/métodos , Cães/embriologia , Desenvolvimento Embrionário , Inseminação
16.
Anim. Reprod. (Online) ; 20(2): e20230049, 2023.
Artigo em Inglês | VETINDEX | ID: biblio-1444315

Resumo

The present review addresses the oocyte and the preimplantation embryo, and is intended to highlight the underlying principle of the "nature versus/and nurture" question. Given the diversity in mammalian oocyte maturation, this review will not be comprehensive but instead will focus on the porcine oocyte. Historically, oogenesis was seen as the development of a passive cell nursed and determined by its somatic compartment. Currently, the advanced analysis of the cross-talk between the maternal environment and the oocyte shows a more balanced relationship: Granulosa cells nurse the oocyte, whereas the latter secretes diffusible factors that regulate proliferation and differentiation of the granulosa cells. Signal molecules of the granulosa cells either prevent the precocious initiation of meiotic maturation or enable oocyte maturation following hormonal stimulation. A similar question emerges in research on monozygotic twins or multiples: In Greek and medieval times, twins were not seen as the result of the common course of nature but were classified as faults. This seems still valid today for the rare and until now mainly unknown genesis of facultative monozygotic twins in mammals. Monozygotic twins are unique subjects for studies of the conceptus-maternal dialogue, the intra-pair similarity and dissimilarity, and the elucidation of the interplay between nature and nurture. In the course of in vivo collections of preimplantation sheep embryos and experiments on embryo splitting and other microsurgical interventions we recorded observations on double blastocysts within a single zona pellucida, double inner cell masses in zona-enclosed blastocysts and double germinal discs in elongating embryos. On the basis of these observations we add some pieces to the puzzle of the post-zygotic genesis of monozygotic twins and on maternal influences on the developing conceptus.(AU)


Assuntos
Animais , Suínos/embriologia , Desenvolvimento Embrionário/fisiologia , Gêmeos Monozigóticos
17.
Anim. Reprod. (Online) ; 20(2): e20230076, 2023. tab
Artigo em Inglês | VETINDEX | ID: biblio-1452334

Resumo

Paternal programming is the concept that the environmental signals from the sire's experiences leading up to mating can alter semen and ultimately affect the phenotype of resulting offspring. Potential mechanisms carrying the paternal effects to offspring can be associated with epigenetic signatures (DNA methylation, histone modification and non-coding RNAs), oxidative stress, cytokines, and the seminal microbiome. Several opportunities exist for sperm/semen to be influenced during development; these opportunities are within the testicle, the epididymis, or accessory sex glands. Epigenetic signatures of sperm can be impacted during the pre-natal and pre-pubertal periods, during sexual maturity and with advancing sire age. Sperm are susceptible to alterations as dictated by their developmental stage at the time of the perturbation, and sperm and seminal plasma likely have both dependent and independent effects on offspring. Research using rodent models has revealed that many factors including over/under nutrition, dietary fat, protein, and ingredient composition (e.g., macro- or micronutrients), stress, exercise, and exposure to drugs, alcohol, and endocrine disruptors all elicit paternal programming responses that are evident in offspring phenotype. Research using livestock species has also revealed that sire age, fertility level, plane of nutrition, and heat stress can induce alterations in the epigenetic, oxidative stress, cytokine, and microbiome profiles of sperm and/or seminal plasma. In addition, recent findings in pigs, sheep, and cattle have indicated programming effects in blastocysts post-fertilization with some continuing into post-natal life of the offspring. Our research group is focused on understanding the effects of common management scenarios of plane of nutrition and growth rates in bulls and rams on mechanisms resulting in paternal programming and subsequent offspring outcomes. Understanding the implication of paternal programming is imperative as short-term feeding and management decisions have the potential to impact productivity and profitability of our herds for generations to come.(AU)


Assuntos
Animais , Feminino , Gravidez , Ruminantes/embriologia , Desenvolvimento Fetal/fisiologia , Herança Paterna/genética , Epigenômica/métodos
18.
Anim. Reprod. (Online) ; 20(2): e20230092, 2023.
Artigo em Inglês | VETINDEX | ID: biblio-1452378

Resumo

Currently, gonadotropin products (follicle stimulating hormone, FSH, and luteinizing hormone, LH) used in animal reproduction are produced by extraction and purification from abattoir-derived pituitary glands. This method, relying on animal-derived materials, carries the potential risk of hormone contamination and pathogen transmission. Additionally, chorionic gonadotropins are extracted from the blood of pregnant mares (equine chorionic gonadotropin; eCG) or the urine of pregnant women (human chorionic gonadotropin; hCG). However, recent advancements have introduced recombinant gonadotropins for assisted animal reproduction therapies. The traditional use of FSH for superovulation has limitations, including labor requirements and variability in superovulation response, affecting the success of in vivo (SOV) and in vitro (OPU/IVEP) embryo production. FSH treatment for superstimulation before OPU can promote the growth of a homogenous follicular population and the recovery of competent oocytes suitable for IVEP procedures. At present, a single injection of a preparation of long-acting bovine recombinant FSH (rFSH) produced similar superovulation responses resulting in the production of good-quality in vivo and in vitro embryos. Furthermore, the treatment with eCG at FTAI protocol has demonstrated its efficacy in promoting follicular growth, ovulation, and P/AI, mainly in heifers and anestrous cows. Currently, treatment with recombinant glycoproteins with eCG-like activity (r-eCG) have shown promising results in increasing follicular growth, ovulation, and P/AI in cows submitted to P4/E2 -based protocols. Bovine somatotropin (bST) is a naturally occurring hormone found in cows. Recombinant bovine somatotropin (rbST), produced through genetic engineering techniques, has shown potential in enhancing reproductive outcomes in ruminants. Treatment with rbST has been found to improve P/IA, increase donor embryo production, and enhance P/ET in recipients. The use of recombinant hormones allows to produce non-animal-derived products, offering several advantages in assisted reproductive technologies for ruminants. This advancement opens up new possibilities for improving reproductive efficiency and success rates in the field of animal reproduction.(AU)


Assuntos
Animais , Feminino , Indução da Ovulação/métodos , Ruminantes/embriologia , Proteínas Recombinantes/farmacologia
19.
Anim. Reprod. (Online) ; 20(1): e20220103, 2023. ilus, tab, graf
Artigo em Inglês | VETINDEX | ID: biblio-1433932

Resumo

Carotenoids are determinants of reproductive fitness and egg quality. Here we studied the accumulation of astaxanthin (AX), canthaxanthin (CA) zeaxanthin (ZX), lutein (LU), retinol (RX) and dehydroretinol (DR) during vitellogenesis comparing previtellogenic and vitellogenic pikeperch (Sander lucioperca) eggs (n = 5 each), as well as selected tissues (liver, fat and muscles) in first süawning females (1176-1450 g). Futhermore, we compared egg batches with high (88­99% hatching rate, n = 5) or low (40­67% hatching rate, n= 5) egg quality. Vitellogenic follicles revealed higher concentrations of DR, RX, ZX and LU compared to previtellogenic follicles. Neither CA nor AX was detectable. In parallel, DR and RX were mobilized in the liver. In adipose and muscle tissue, comparing previtellogenic and vitellogenic females, no significant differences in carotenoid/retinoid content were observed. In high quality egg batches, both DR and RX were increased. LU was lower in high quality than in low quality eggs. In a conclusion, the amount of retinoids seems suboptimal in low quality egg batches and increased DR and RX are desirable in pikeperch. Since hypervitaminosis of retinoids can be problematic though, supplementation of the food with carotenoids, which can serve as precursors for retinoids, has to be carried out carefully.(AU)


Assuntos
Animais , Retinoides/efeitos adversos , Perciformes/embriologia , Carotenoides/efeitos adversos , Ovos/análise , Vitelogênese/fisiologia , Hormônios Gonadais
20.
Rev. bras. reprod. anim ; 47(1): 56-61, jan.-mar. 2023. graf, ilus
Artigo em Português | VETINDEX | ID: biblio-1434943

Resumo

A espermiogênese é o processo final da espermatogênese no qual a espermátide se transforma em espermatozoide. Durante esse processo podem ocorrer alterações espermáticas, especialmente no acrossoma, na morfologia da cabeça, na condensação da cromatina e na formação dos vacúolos nucleares. A diferenciação entre os quadros clínicos é feita com repetições dos exames andrológicos. A avaliação morfológica indica a situação da espermiogênese nas 4 semanas anteriores a coleta do sêmen. Com os resultados do exame andrológico é possível identificar a qualidade seminal naquele período. O presente artigo é o relato de caso de um touro jovem doador de sêmen com 26 meses de idade, no início do regime de coletas de sêmen em um Centro de Coleta e Processamento de Sêmen no Sul do Brasil. A produção espermática deste animal foi avaliada durante 12 meses de coleta, apresentando sempre morfologia espermática muito alterada e motilidade média de 54% no exame imediato. Em 13 coletas seminais, o ejaculado deste animal apresentou em média 86% de defeitos maiores, 10% de defeitos menores e 96% de defeitos totais. Os defeitos maiores, que são os que possuem maior efeito na fertilidade, estão diretamente ligados a espermiogênese e os defeitos menores, que possuem menor efeito na fertilidade, são ocasionados principalmente durante o trânsito pelo epidídimo. O quadro clínico desse animal demonstrou a importância do exame morfológico para avaliar a espermatogênese e principalmente o processo de diferenciação final da espermátide em espermatozoide. Casos como este devem ser descritos como espermiogênese alterada e o reprodutor deve ser afastado da reprodução, após descartar alterações morfológicas devido a degeneração testicular grave.(AU)


Spermiogenesis is the final process of spermatogenesis in which the spermatid transforms into sperm. During this process, sperm alterations may occur, especially in the acrosome, head morphology, chromatin condensation and formation of nuclear vacuoles. Differentiation between clinical conditions is made with repetitions of andrological exams. The morphological evaluation indicates the status of spermiogenesis in the 4 weeks prior to semen collection. With the results of the breeding soundness examination, it is possible to identify the seminal quality in that period. The present article is a case report of a young 26-month-old semen donor bull, that started semen collection routines at a Semen Collection and Processing Center in southern Brazil. The sperm production of this animal was evaluated during 12 months of collection, always showing very altered sperm morphology and average motility of 54% in the immediate examination. In 13 seminal collections, the ejaculate of this animal presented an average of 86% of major defects, 10% of minor defects and 96% of total defects. Major defects, which have the greatest impact on fertility, are directly linked to spermiogenesis and minor defects, which have less effect on fertility, are mainly caused during transit through the epididymis. The clinical conditions of this animal demonstrated the importance of the morphological examination to evaluate spermatogenesis and especially the process of final differentiation of the spermatid into spermatozoa. Cases like this should be described as altered spermiogenesis and the bull should be withdrawn from breeding, after ruling out morphological changes due to severe testicular degeneration.(AU)


Assuntos
Animais , Masculino , Espermatogênese/fisiologia , Bovinos/embriologia , Análise do Sêmen/veterinária
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