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The genipap (Genipa americana L.) is a non-endemic species native to Brazil belonging to the family Rubiaceae. It is a species that unites socioeconomic and environmental pillars. The study objective was to establish the induction of indirect somatic embryogenesis in foliar explants of genipap genotypes. Leaf explants of UMB, SAL, JSA, SC, and CER accessions cultivated in half the salt concentration of Murashige & Skoog (MS), 30 g/L sucrose, and 3g/L PhytagelTM with the following combinations of NAA × BA regulators were used: M1: 4.0/4.0 mg/L NAA and BA, M2: 4.0/6.0 mg/L NAA and BA, and M3: 6.0/4.0 mg/L NAA and BA. At 60 days of culture, they were transferred to secondary embryogenic callus multiplication medium supplemented with 2.21 mg/L of 2,4-D. At 30 and 60 days, the increment (%) and fresh mass (g) of primary callus and at 120 days the presence of embryogenic callus were evaluated. The primary medium with 4.0 mg/L of NAA and 6.0 mg/L of BA induced embryogenic primary callus in leaf explants of the genipap accessions SAL, SC, and JSA. The secondary medium was promising for the multiplication of embryogenic callus. Cytochemical analysis confirmed the presence of embryogenic cells in SAL, SC, and JSA accessions.

O jenipapeiro (Genipa americana L.) é uma espécie nativa não endêmica do Brasil pertencente à família Rubiaceae. É considerada uma espécie que une os pilares socioeconômicos e ambientais. O objetivo deste trabalho foi estabelecer a indução da embriogênese somática indireta em genótipos de jenipapeiro. Foram utilizados explantes foliares dos acessos UMB, SAL, JSA, SC e CER cultivados em meio primário composto por ½ MS, 30 g/L de sacarose e 3g/L de Phytagel™ com as combinações dos reguladores de ANA x BAP M1: 4,0/4,0 mg/L de ANA e BAP, M2: 4,0/6,0 mg/L de ANA e BAP e M3: 6,0/4,0 mg/L de ANA e BAP. Aos 60 dias de cultura foram transferidas para meio secundário de multiplicação de calos embriogênicos suplementado com 2,21 mg/L de 2,4-D. Aos 30 e 60 dias foram avaliados o incremento (%) e a massa fresca (g) dos calos primários e aos 120 dias a presença de calos embriogênicos. O meio primário com 4,0 mg/L de ANA e 6,0 mg/L de BAP induziu calos primários embriogênicos em explantes foliares dos acessos SAL, SC e JSA de jenipapeiro. O meio secundário foi promissor para multiplicação de calos embriogênicos. A análise citoquímica confirmou a presença de células embriogênicas nos acessos SAL, SC e JSA.

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Abstract Ancylostoma spp. are found worldwide. Infected dog and cat feces can contaminate soil in public places. Despite prophylactic measures being available, studies on direct remediation of Ancylostoma-contaminated soils are scarce. This study aimed to determine the impact of heat treatment and liming on the viability of Ancylostoma spp. eggs in artificially contaminated sandy soil. Sterilized sand samples were contaminated with Ancylostoma spp. eggs extracted from infected dogs' feces. Samples were heated (trial I) to 70 °C or 80 °C, then sieved after 24 hours (212, 90, 38, and 25 µm). Larval cultures were assessed for larval development following heat treatment. Five quicklime concentrations (trial II; 50, 30, 20, 10 and 5%) were used to treat sand. The effect of liming on larval cultures was assessed by measuring embryonic development. Filariform larvae were exposed to 20% quicklime (25 °C and 37 °C, 20 min). Heat treatment destroys Ancylostoma spp. eggs and prevents in vitro larval development. Liming at 50, 30, and 20% concentrations made embryonic development impossible. However, filariform larvae treated with 20% lime solution retained their motility. Heating at 70 °C and liming at 20% were sufficient to make Ancylostoma spp. egg embryogenesis impossible in experimentally contaminated sand samples.

Resumo Ancylostoma spp. são nematódeos que infectam cães e gatos e podem contaminar locais públicos. Apesar da existência de medidas profiláticas, estudos sobre tratamento do solo são escassos. No presente estudo, foi avaliado o efeito do tratamento térmico e caleação na viabilidade de ovos de Ancylostoma spp., em solo arenoso estéril. Amostras de solo foram contaminadas com ovos de Ancylostoma spp. obtidos de fezes de cães naturalmente infectados, aquecidas a 70°C ou 80°C, e filtradas em tamises metálicas (212, 90, 38 e 25 µm) após 24 horas (Teste I). Cultivos de larvas foram realizadas para a avaliação do desenvolvimento larval. Na caleação (Teste II), cinco concentrações (50, 30, 20, 10 e 5%) de cal virgem foram utilizadas. O efeito da caleação foi avaliado com observação do desenvolvimento larval nos cultivos. Ainda, larvas foram expostas (20 minutos) ao leite de cal (20% a 25°C e 37°C). O tratamento térmico foi capaz de degenerar ovos de Ancylostoma spp. e impedir o desenvolvimento larval, enquanto a caleação (50, 30, e 20%) impossibilitou o desenvolvimento larval. Entretanto, as larvas filariformes, expostas ao leite de cal (20%) mantiveram motilidade. O aquecimento (70°C) e caleação (20%) impediram o embrionamento de ovos de Ancylostoma spp. em solo experimentalmente contaminado.

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Developmental plasticity of the planarians is well-illustrated by whole-body regeneration from any tissue fragments and body size scaling regulated by food intake. Here we report another form of developmental plasticity that appears to be shared by multiple planarian species. We have observed developmental defects at rates up to ~10% in batches of Schmidtea mediterranea (Benazzi, 1975) and Schmidtea polychroa (Schmidt, 1862) hatchlings. The most frequent defect is duplicated body parts which occurs in both two species, which can be corrected after amputation and regeneration, supporting that these developmental defects were not caused by genetic mutations. Taken together, our data described a new form of developmental plasticity and an interesting comparison between development and regeneration in the hatchlings of freshwater planarians, that the two processes can have different outcomes.

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Scientific research on passion fruit has been conducted in several institutions worldwide, and it is of interest to the productive sector, the scientific community, and science and technology managers to learn about current scientific advances and opportunities through metric studies of bibliographic information. A survey of publications indexed in the Web of Science and the Agricultural Research Database-BDPA, in European Patent Office - Espacenet, and Embrapa's technologies and projects were used as indicators to characterize research networks. This study analyzed the co-authorship and co-citation network of scientific production, the strength of connections among institutions, and a map of co-occurrence of keywords from 2001 to 2020. Brazil, the United States, Colombia, and France had the largest co-authorship networks for Passifloraceae. Brazilian institutions that are in a prominent position in the analysis of co-authorship networks and that produced the largest number of publications were Embrapa, University of São Paulo (USP), and State University of Campinas (Unicamp). The main themes studied were adsorption, antioxidant, clarification, evolution, flavonoid, flowering, growth, and somatic embryogenesis. Patents related to the use of passifloras were highest between 2015 and 2017 and were mainly focused on the production of food, beverages, cosmetics, and medicines. Brazil has relevant bibliographic production and technological development regarding passion fruit for the academic community and rural producers. These results integrated aspects of scientific activity that can help explore new research directions and explain the use and circulation of scientific production.

As pesquisas sobre o maracujá são realizadas em diversas instituições ao redor do mundo e é de interesse do setor produtivo, da comunidade científica e dos gestores de ciência e tecnologia, conhecer a dinâmica da ciência por meio de estudos métricos das informações bibliográficas. O levantamento das publicações indexadas na Web of Science e na Base de Dados de Pesquisa Agropecuária da Embrapa (BDPA), os registros no Escritório Europeu de Patentes - Espacenet, as tecnologias e os projetos da Embrapa foram utilizados como indicadores para caracterizar as redes de pesquisa sobre os maracujás. Este estudo analisou a rede de coautoria e cocitação da produção científica, a força de conexão entre as instituições e o mapa de coocorrência de palavras-chave entre 2001 e 2020. Brasil, Estados Unidos, Colômbia e França tiveram as maiores redes de coautoria em Passifloraceaes. As instituições brasileiras em posição de destaque na análise das redes de coautoria e que produziram o maior número de publicações foram Embrapa, USP e Unicamp. Os principais temas estudados foram adsorção, antioxidante, clarificação, evolução, flavonoide, floração, crescimento e embriogênese somática. As patentes relacionadas ao uso do maracujá tiveram destaque entre 2015 e 2017 com foco na produção de alimentos, bebidas, cosméticos e medicamentos. O Brasil possui relevante produção bibliográfica e desenvolvimento tecnológico sobre o maracujá tanto para a comunidade acadêmica quanto para os produtores rurais. Estes resultados integram aspectos da atividade científica que poderão prospectar novos direcionamentos de pesquisa e tornar conhecidos o uso e a circulação da produção científica.

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During oocyte meiosis resumption, a coordinated program of transcript translation and decay machinery promotes a remodeling of mRNA stores, which determines the success of the acquisition of competence and early embryo development. We investigated levels of two genes related to mRNA translation (CPEB1 and CPEB4) and two related to mRNA degradation (CNOT7 and ZFP36L2) machinery and found ZFP36L2 downregulated in in vitro-matured bovine oocytes compared to in vivo counterparts. Thereafter, we tested the effects of a pre-IVM step with NPPC and a modified IVM with AREG on the modulation of members of mRNA translation and degradation pathways in cumulus cells and oocytes. Our data showed a massive upregulation of genes associated with translational and decay processes in cumulus cells, promoted by NPPC and AREG supplementation, up to 9h of IVM. The oocytes were less affected by NPPC and AREG, and even though ZFP36L2 transcript and protein levels were downregulated at 9 and 19h of IVM, only one (KDM4C) from the ten target genes evaluated was differently expressed in these treatments. These data suggest that cumulus cells are more prone to respond to NPPC and AREG supplementation in vitro, regarding translational and mRNA decay programs. Given the important nursing role of these cells, further studies could contribute to a better understanding of the impact of these modulators in maternal mRNA modulation and improve IVM outcomes.(AU)

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Embryonic stem cells (ESCs) have proven to be a great in vitro model that faithfully recapitulates the events that occur during in vivo embryogenesis, making them a unique tool to study the cellular and molecular mechanisms that define tissue specification during embryonic development. Livestock ESCs are particularly attractive and have broad prospects including drug selection and human disease modeling, improvement of reproductive biotechniques and agriculture-related applications such as production of genetically modified animals. While mice and human ESCs have been established many years ago, no significant advances were made in livestock species until recently. Nowadays, livestock ESCs are available from cattle, pigs, sheep, horses and rabbits with different states of pluripotency. In this review, we summarize the current advances on livestock ESCs establishment and maintenance along with their present and future applications.(AU)

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With the development of in vitro technologies, embryos can be produced using oocytes retrieved directly from the ovaries, i.e., regardless of ovulation. This has allowed the use of different animal categories as oocyte donors, including prepubertal cattle. The advantages of using this strategy to shorten the generation interval and accelerate genetic gain over time were soon recognized, and the first offspring generated using oocytes collected from calves were born in the early 1990s. Nevertheless, embryo production from calves and prepubertal heifers remains a challenge. The oocytes collected before puberty present low in vitro developmental potential, and the subsequent blastocyst rates are consistently lower than those from pubertal females. The acquisition of developmental competence by the oocytes occurs progressively throughout the prepubertal period, which can be subdivided into an early, intermediate, and late prepubertal (or peripubertal) phases, each characterized by different physiological and endocrine features. Therefore, embryo yield increases with age but will only achieve its maximum after puberty. The most common strategy to improve oocyte developmental potential before puberty is the use of gonadotrophic stimulation prior to oocyte retrieval. The results with superstimulation, however, vary among studies, depending on the source, dose, and length of FSH treatment, as well as the age and breed of the donors. The use of calves and prepubertal heifers as oocyte donors should also consider the possible impacts of the oocyte retrieval technique (LOPU or OPU) and the use of exogenous hormones on their subsequent fertility and productive life.(AU)

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The oviduct and uterus provide an optimal environment for early embryo development, where effective communication between the embryo and the maternal reproductive tract is crucial for establishing and maintaining pregnancy. Oviductal and uterine-derived EVs play pivotal roles in this maternal-embryonic communication and in facilitating early embryo development. However, despite the ability of in vitro culture methods to produce viable embryos, the lack of exchange between the embryo and the mother often results in lower-quality embryos than those derived in vivo. Therefore, there is a pressing need to increase our understanding of the physiological mechanisms underlying embryo interaction with the oviduct and endometrium through EVs and to develop models capable of mimicking the in vivo environment. This review aims to provide up-to-date insights into the communication between the mother and pre-implantation bovine embryo, exploring their applications and perspectives in the field.(AU)

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Embryo transfer in cattle is an increasingly important technique for cattle production. Full attainment of the benefits of the technology will depend on overcoming hurdles to optimal performance using embryos produced in vitro. Given its importance, embryo technology research should become a global research priority for animal reproduction science. Among the goals of that research should be developing methods to increase the proportion of oocytes becoming embryos through optimization of in vitro oocyte maturation and in vitro fertilization, producing an embryo competent to establish and maintain pregnancy after transfer, and increasing recipient fertility through selection, management and pharmacological manipulation. The embryo produced in vitro is susceptible to epigenetic reprogramming and methods should be found to minimize deleterious epigenetic change while altering the developmental program of the resultant calf to increase its health and productivity. There are widening opportunities to rethink the technological basis for much of the current practices for production and transfer of embryos because of explosive advances in fields of bioengineering such as microfluidics, three-dimensional printing of cell culture materials, organoid culture, live-cell imaging, and cryopreservation.(AU)

Resumo

Ancylostoma spp. are found worldwide. Infected dog and cat feces can contaminate soil in public places. Despite prophylactic measures being available, studies on direct remediation of Ancylostoma-contaminated soils are scarce. This study aimed to determine the impact of heat treatment and liming on the viability of Ancylostoma spp. eggs in artificially contaminated sandy soil. Sterilized sand samples were contaminated with Ancylostoma spp. eggs extracted from infected dogs' feces. Samples were heated (trial I) to 70 °C or 80 °C, then sieved after 24 hours (212, 90, 38, and 25 µm). Larval cultures were assessed for larval development following heat treatment. Five quicklime concentrations (trial II; 50, 30, 20, 10 and 5%) were used to treat sand. The effect of liming on larval cultures was assessed by measuring embryonic development. Filariform larvae were exposed to 20% quicklime (25 °C and 37 °C, 20 min). Heat treatment destroys Ancylostoma spp. eggs and prevents in vitro larval development. Liming at 50, 30, and 20% concentrations made embryonic development impossible. However, filariform larvae treated with 20% lime solution retained their motility. Heating at 70 °C and liming at 20% were sufficient to make Ancylostoma spp. egg embryogenesis impossible in experimentally contaminated sand samples.(AU)

Ancylostoma spp. são nematódeos que infectam cães e gatos e podem contaminar locais públicos. Apesar da existência de medidas profiláticas, estudos sobre tratamento do solo são escassos. No presente estudo, foi avaliado o efeito do tratamento térmico e caleação na viabilidade de ovos de Ancylostoma spp., em solo arenoso estéril. Amostras de solo foram contaminadas com ovos de Ancylostoma spp. obtidos de fezes de cães naturalmente infectados, aquecidas a 70°C ou 80°C, e filtradas em tamises metálicas (212, 90, 38 e 25 µm) após 24 horas (Teste I). Cultivos de larvas foram realizadas para a avaliação do desenvolvimento larval. Na caleação (Teste II), cinco concentrações (50, 30, 20, 10 e 5%) de cal virgem foram utilizadas. O efeito da caleação foi avaliado com observação do desenvolvimento larval nos cultivos. Ainda, larvas foram expostas (20 minutos) ao leite de cal (20% a 25°C e 37°C). O tratamento térmico foi capaz de degenerar ovos de Ancylostoma spp. e impedir o desenvolvimento larval, enquanto a caleação (50, 30, e 20%) impossibilitou o desenvolvimento larval. Entretanto, as larvas filariformes, expostas ao leite de cal (20%) mantiveram motilidade. O aquecimento (70°C) e caleação (20%) impediram o embrionamento de ovos de Ancylostoma spp. em solo experimentalmente contaminado.(AU)

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The initial stages of early embryonic development were analyzed as a function of the incubation period and age of Japanese quail breeders. A total of 203 Japanese quails housed in 29 conventional laying cages with 5 females and 2 males at 31, 39, 48, and 59 weeks of age were used, and the fertile eggs from these breeders were selected and incubated. The eggs were opened, and the embryos were isolated, fixed in a glutaraldehyde solution, analyzed and classified according to the stage of development. For after laying and the incubation periods of 24, 48, and 72 hours, the embryos presented, on average, Hamburger-Hamilton stages XI, HH 6.1, HH 12.7, and HH 18.5, respectively, with no effect of breeder age. It was also observed that, between 31 and 59 weeks of age in Japanese quail breeders, the eggs become longer and wider, with greater weight, volume, and area. Therefore, it is concluded that the age of the Japanese quail mother influences the weight, length, width, volume, and area of the eggs but does not influence the embryonic development up to 72 hours.(AU)

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The physical parameters of eggs significantly impact embryo development and hatching success. This study aimed to examine the influence of the egg shape index (SI), specific gravity (SG), weight loss (WL), and area-volume ratio (AV) on hatching eggs from brown-layer hen grandparents. A total of 7,500 eggs were randomly selected from two batches of Lohmann Brown grandparents at various ages (39, 44, 50, 58, and 66 weeks). SG was determined by flotation (1,070 to 1,090 g/L), while egg length, width, and weight were measured digitally. Each egg was tracked to determine hatching success, with unhatched eggs collected for embryonic diagnosis. Physical parameters were categorized into minor, intermediate, and major groups, based on viability frequency; and embryonic mortality was analyzed using the chi-square test and odds ratio (OR). The study found a lower probability of embryo death in eggs with intermediate SI (75.1% to 79%) and AV (1.01 cm²/cm³ to 1.04 cm²/cm³). No significant differences were observed between SG and WL groups. SI proved to be a reliable parameter for assessing egg quality and predicting hatchability.(AU)

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)

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Goldfish or Kinguio is a widely marketed species worldwide due to the ornamental market. There is some lack of acknowledgment of the production of the species under specific climatic conditions. To evaluate the effect of temperature on embryonic development and the first exogenous feeding of goldfish, an experiment was proposed. Fifteen incubators, organized in five treatments (18, 22, 26, 30, and 34 °C) with three replications each, were used to keep the fertilized goldfish eggs until the first exogenous feeding of the larvae. The main development events were observed to understand the possible effects of these temperatures on embryos and larvae of the species. Temperature influences embryo development and the time of first exogenous feeding of goldfish. The temperature of 34 °C was lethal to the species causing 100% of anomalies in the embryos and larvae. The experiment data allow us to conclude that the species presents a maximum thermal limit during embryogenesis, and these data are important to the aquaculture industry and to understand the effect of climate changes on goldfish. The data obtained in this experiment will assist in the management of invasive species and production of the species (aquaculture).

O peixe dourado ou Kinguio é uma espécie amplamente comercializada em todo o mundo devido ao mercado ornamental. Existe alguma falta de conhecimento da produção da espécie em condições climáticas específicas. Para avaliar o efeito da temperatura no desenvolvimento embrionário e na primeira alimentação exógena do Kinguio, um experimento foi proposto. Quinze incubadoras, organizadas em cinco tratamentos (18, 22, 26, 30 e 34 °C) com três repetições cada, foram utilizadas para manter os ovos fertilizados de Kinguio até a primeira alimentação exógena das larvas. Os principais eventos do desenvolvimento foram observados para entender os possíveis efeitos dessas temperaturas em embriões e larvas da espécie. A temperatura influencia o desenvolvimento do embrião e o tempo da primeira alimentação exógena do Kinguio. A temperatura de 34°C foi letal para a espécie causando 100% de anomalias nos embriões e larvas. Os dados do experimento permitem concluir que a espécie apresenta um limite térmico máximo durante a embriogênese, sendo esses dados importantes para a indústria da aquicultura e para entender o efeito das mudanças climáticas no Kinguio. Os dados obtidos neste experimento auxiliarão no manejo de espécies invasoras e na produção da espécie (aquicultura).

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A espermatogênese é o processo fisiológico de formação dos gametas masculinos em que as células de linhagem germinativa, denominadas de espermátides, células haplóides originadas das espermatogônias através do processo de divisão celular e que possuem a porção específica de DNA para fins reprodutivos, passam por etapas de diferenciação celular, desde sua organização estrutural, morfológica e bioquímica, dando origem assim aos espermatozoides que serão liberados no lúmen dos túbulos seminíferos, com posterior embriogênese. As espermátides são células arredondadas, de núcleo central e envolto de citoplasma, em que durante o processo de maturação, ocorre a reorganização das organelas presentes nesta célula, moldando-a para uma forma alongada. Há também o desenvolvimento do acrossoma, migração das mitocôndrias para a porção caudal do espermatozoide para geração de energia que concomitantemente auxiliará na movimentação da célula juntamente com uma cauda, também desenvolvida, e que é de extrema importância no quesito reprodutivo. Desta forma, o objetivo desta revisão de literatura foi exemplificar como ocorre as etapas da espermatogênese de uma forma objetiva, cooperando para o entendimento desta fase da gametogênese que está associada a resultados reprodutivos.

Spermatogenesis is the physiological process of formation of male gametes in which germline cells, called spermatids, haploid cells originated from spermatogonia through the process of cell division and which have a specific portion of DNA for reproductive purposes, undergo stages of cell differentiation, from its structural, morphological and biochemical organization, thus giving rise to spermatozoa that will be released into the lumen of the seminiferous tubules, with later embryogenesis. Spermatids are rounded cells, with a central nucleus and surrounded by cytoplasm, in which, during the maturation process, the organelles present in this cell are reorganized, molding it to an elongated shape. There is also the development of the acrosome, migration of mitochondria to the caudal portion of the sperm to generate energy that will concomitantly assist in the movement of the cell along with a tail, also developed, and which is of extreme importance for reproduction. Thus, this literature review aimed to exemplify how the stages of spermatogenesis occur in an objective way, cooperating for the understanding of this phase of gametogenesis that is associated with reproductive outcomes.

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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)

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)

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A sazonalidade reprodutiva e a condição nutricional são os principais fatores que influenciam o desempenho reprodutivo em ovinos, principalmente em áreas onde a disponibilidade de alimentos é altamente sazonal. A desnutrição pode comprometer a competência folículo-oocitária, a função lútea e o desenvolvimento embrionário. Por outro lado, o tratamento com melatonina é um método eficaz para induzir ciclicidade, aumentando a ovulação e melhorando a viabilidade do embrião durante o anestro. Portanto, levantamos a hipótese de que a melatonina pode substituir os efeitos prejudiciais da desnutrição para melhorar o desempenho reprodutivo em ovelhas. A este respeito, esta revisão enfoca os efeitos da interação entre melatonina e nutrição na viabilidade do embrião e resume a informação disponível sobre o efeito da melatonina exógena na viabilidade do embrião em ovelhas desnutridas.(AU)

Reproductive seasonality and nutritional condition are the main factors that influence reproductive performance in sheep, particularly in the areas where the availability of food is highly seasonal. Undernutrition can compromise follicle-oocyte competence, luteal function and embryo development. On the other hand, melatonin treatment is an effective method for inducing estrous cycles, increasing ovulation and improving embryo viability during anestrus. Therefore, we hypothesized that melatonin can override the detrimental effects of undernutrition to improve reproductive performance in ewes. In this regard, this review focuses on the effects of the interaction between melatonin and nutrition on embryo viability and summarizes the available information about the effect of exogenous melatonin on embryo viability in undernourished ewes.(au)

Resumo

O objetivo deste artigo é revisar o efeito da melatonina na viabilidade embrionária e ambiente uterino em ovinos, tanto in vivo quanto in vitro, considerando as vias pelas quais esse hormônio pode ter influência no embrião ou o mecanismo de reconhecimento materno e estabelecimento de gravidez em ovelhas.(AU)

The aim of this article is to review the effect of melatonin on embryo viability and uterine environment in sheep, both in vivo and in vitro, considering the pathways by which this hormone could have influences at the embryo or the mechanism of maternal recognition and establishment of pregnancy in sheep.(AU)

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)