Effect of seasonality on the quality of bovine oocytes selected by the brilliant cresyl blue method / Efecto de la estacionalidad en la calidad de los ovocitos seleccionados por el método de azul cresil brillante / Efeito da sazonalidade na qualidade dos ovócitos bovinos selecionados pelo método azul cresil brilhante

Abstract Background: The brilliant cresyl blue (BCB) staining is a non-invasive test to select the best-suited oocytes for embryonic development. This makes it a useful tool to select best-quality oocytes at the times of the year when there is forage restriction. Objective: To evaluate the effect of seasonality on the nuclear maturation and quality of oocytes selected by the BCB test. Methods: The cumulus-oophorus complexes (COCs) were obtained in summer and winter of 2010 and 2011. Selected COCs were maintained for 90 min at 38.5 °C in a CO2 incubator, in TCM 199 medium containing 10% fetal bovine serum and antibiotics, and supplemented with 26 µM brilliant cresyl blue. Afterwards, they were divided according to the ooplasm staining (BCB+ -blue; BCB− -unstained). Subsequently, COCs were matured for 22 h. Nuclear maturation was evaluated at 22 h of culture. Results: The proportion of BCB− oocytes was higher in the winter of 2010, but there was no increase in this group in the winter of 2011. The percentage of oocytes that reached metaphase II was higher in control and BCB+ groups in relation to oocytes from BCB− group. Conclusion: The season of the year influences the percentage of oocytes best suited for embryonic production in situations in which oocyte donors receive pasture-based feeding, since the method was effective in determining the effect of seasonality on the competence of bovine oocytes to reach nuclear maturation.

Resumen Antecedentes: La tinción con azul cresil brillante (BCB) es un método no invasivo para seleccionar ovocitos aptos para el desarrollo embrionario. Por tanto, es una herramienta útil para selecionar los ovocitos de mejor calidad en temporadas de restricción de forraje. Objetivo: Evaluar el efecto de la estacionalidad sobre la maduración nuclear y calidad de los ovocitos seleccionados por el test BCB. Métodos: Los complejos cumulus-oophorus (CCOs) fueron obtenidos durante el verano y el invierno de 2010 y 2011. Los CCOs seleccionados se mantuvieron durante 90 min a 38,5 oC en una incubadora de CO2 en un medio TCM 199 con 10% de suero fetal bovino y antibióticos, suplementado con 26 µM de azul cresil brillante. Luego se separaron según el color del citoplasma (BCB+ -azul y BCB− -incoloro). Posteriormente, los CCOs se maduraron durante 22 h. La evaluación de la maduración nuclear se realizó a las 22 h de cultivo. Resultados: La proporción de ovocitos BCB− fue mayor en el invierno de 2010, pero no hubo un aumento de ese grupo en el invierno de 2011. El porcentaje de ovocitos que alcanzaron la etapa de metafase II fue mayor en el grupo control y BCB+ con respecto al grupo BCB−. Conclusión: La estación del año influye en el porcentaje de ovocitos más aptos para la producción de embriones en situaciones donde las donadoras de ovocitos reciben alimentación a base de pastos, ya que este método fue eficaz para determinar el efecto de la estacionalidad en la competencia de ovocitos bovinos en alcanzar la maduración nuclear.

Resumo Antecedentes: O método do azul cresil brilhante (BCB) não é invasivo e seleciona ovócitos mais aptos ao desenvolvimento embrionário. Portanto é ferramenta útil para selecionar ovócitos de melhor qualidade em épocas do ano que ocorre restrição de pastagem. Objetivo: Avaliar o efeito da sazonalidade sobre a maturação nuclear e a qualidade dos ovócitos selecionados pelo teste BCB. Métodos: Os complexos cumulus oophorus (CCOs) foram obtidos no verão e inverno de 2010 e 2011. Os CCOs selecionados foram mantidos por 90 min, a 38,5 °C, em incubadora de CO2, em meio TCM 199 contendo 10% de soro fetal bovino e antibióticos, e suplementado com 26 µM de azul cresil brilhante. Em seguida, estes foram divididos de acordo com a coloração do citoplasma (BCB+ -azuis e BCB− -incolores). Então os CCOs foram maturados durante 22 h. A avaliação da maturação nuclear foi realizada às 22 h de cultivo. Resultados: A proporção dos ovócitos BCB− foi maior no inverno de 2010, mas não houve aumento desse grupo no inverno de 2011. O percentual de ovócitos que atingiu o estágio de metáfase II foi maior no controle e no grupo BCB+ em relação ao grupo BCB−. Conclusão: A estação do ano influencia o percentual de ovócitos mais aptos a produção de embriões, em situações onde as doadoras de ovócitos recebem alimentação baseada em pastagens, já que o método se mostrou efetivo para determinação do efeito da sazonalidade sobre a competência de ovócitos bovinos em atingirem a maturação nuclear.

Use of the male effect associated with different durations of mating season in goats in the semiarid of Pernambuco / Uso do efeito macho associado a diferentes durações de estação de monta em caprinos no semiárido pernambucano

Background: The goat rearing is practiced mainly in the Northeast region with semiarid climate, since climate conditionsand vegetation are extremely favorable to the species, but it has low productivity due to the low level of technology employed. Management alternatives aimed at maximizing productivity at low cost are essential tools for the reversal of thisframework. Aiming to focus the onset of estrus for females at low cost is common to use the male effect with the breedingseason, representing a practical, inexpensive and efficient methodology for the producer Thus, this study is to evaluate theeffect of different durations of mating season associated with the male effect on reproductive performance of multiparousAlpine goats during the dry and rainy seasons.Materials, Methods & Results: The survey was conducted in the municipality of Serra Talhada-PE from October 2011 toMay 2013. A total of 160 multiparous females aged between 22 and 74 months and four breeders aged between 24 and 38months were used. In the first step, we tested the mating season durations 25 (MS-25) and 45 days (MS-45). In the secondstep, the mating seasons were 25 (MS-25) and 15 days (MS-15) in different climate periods, each experimental groupconsisting of 20 females and one breeder that has been away from females for 15 days before starting the season in orderto stimulate the male effect and thus synchronizing the estrus. The lots were observed at 6:00 and 16:00 pm by qualifiedpersonnel to identify the mated females and after 45 days of the last mating, an ultrasound examination was performed todetect the matrices that had positive pregnancy, assessing the data by the Chi-square test at 5% significance. The estrusresults obtained during the first stage of...

Use of the male effect associated with different durations of mating season in goats in the semiarid of Pernambuco / Uso do efeito macho associado a diferentes durações de estação de monta em caprinos no semiárido pernambucano

Background: The goat rearing is practiced mainly in the Northeast region with semiarid climate, since climate conditionsand vegetation are extremely favorable to the species, but it has low productivity due to the low level of technology employed. Management alternatives aimed at maximizing productivity at low cost are essential tools for the reversal of thisframework. Aiming to focus the onset of estrus for females at low cost is common to use the male effect with the breedingseason, representing a practical, inexpensive and efficient methodology for the producer Thus, this study is to evaluate theeffect of different durations of mating season associated with the male effect on reproductive performance of multiparousAlpine goats during the dry and rainy seasons.Materials, Methods & Results: The survey was conducted in the municipality of Serra Talhada-PE from October 2011 toMay 2013. A total of 160 multiparous females aged between 22 and 74 months and four breeders aged between 24 and 38months were used. In the first step, we tested the mating season durations 25 (MS-25) and 45 days (MS-45). In the secondstep, the mating seasons were 25 (MS-25) and 15 days (MS-15) in different climate periods, each experimental groupconsisting of 20 females and one breeder that has been away from females for 15 days before starting the season in orderto stimulate the male effect and thus synchronizing the estrus. The lots were observed at 6:00 and 16:00 pm by qualifiedpersonnel to identify the mated females and after 45 days of the last mating, an ultrasound examination was performed todetect the matrices that had positive pregnancy, assessing the data by the Chi-square test at 5% significance. The estrusresults obtained during the first stage of...(AU)

Influência das estações seca e chuvosa na capacidade de desenvolvimento de oócitos e produção in vitro de embriões da espécie caprina / Influence of dry and rainy seasons on oocyte maturation and in vitro embryo production in goats

Objetivou-se com este estudo determinar a influência das estações seca e chuvosa na maturação de oócitos e produção in vitro (PIV) de embriões na espécie caprina. Os ovários das cabras nas estações seca (outubro a março) e chuvosa (abril a setembro) foram colhidos em abatedouro e transportados ao Laboratório de Biotécnicas da Reprodução da UFRPE. Os complexos cumulus oophorus (CCOs) foram colhidos pela técnica de "slicing" dos folículos entre 2 a 6 mm de diâmetro e selecionados com base na classificação morfológica. Foram realizadas 12 repetições, nas quais os CCOs foram submetidos à maturação, fertilização e cultivo in vitro dos embriões. A média e desvio padrão da taxa de clivagem foi determinada no dia 3 (D-3) e dos embriões que se desenvolveram aos estádios de 8-16 células, mórula e blastocisto foi determinada nos dias 4 (D-4), 5 (D-5) e 8 (D-8) após a fecundação, respectivamente. A quantidade de blastômeros foi determinada com o corante DAPI e os blastômeros positivos para apoptose por meio do teste de TUNEL. A produção de embriões no D-3 e mórulas foram inferiores ao obtido no período chuvoso (P < 0,05). Não apresentaram diferenças (P > 0,05) quanto às fases de maturação, fertilização, cultivo no D-4 e blastocisto. Os embriões produzidos na estação seca apresentaram maior incidência de apoptose (P < 0,05). Nas condições descritas neste estudo, os resultados permitem concluir que as fases iniciais do desenvolvimento embrionário sofrem maior impacto negativo durante a estação seca em protocolos de PIV na espécie caprina.(AU)

This study aimed to determine the influence of dry and rainy seasons on oocyte maturation and in vitro production (IVP) of embryos in goats. The ovaries of does in dry (October to March) and rainy season (April-September) were collected at a slaughterhouse and transported to the Laboratory of Biotechnical Reproduction of UFRPE. The cumulus oophorus complexes (COCs) were collected by the technique of slicing of the follicles from 2 to 6 mm in diameter, and selected based on morphologic classification. We used 12 replicates, in which the COCs were submitted to maturation, fertilization and in vitro culture. The cleavage rate was determined on day 3 (D-3) and embryos that developed to 8-16 cells (D-4), morulae (D-5) and blastocyst (D-8) stages after fertilization. The number of blastomeres was assessed with DAPI staining, and the determination of apoptotic blastomeres was performed by TUNEL assay. In the dry season, D-3 embryos and morulae development was lower than that obtained in the rainy season (P<0.05). However, no differences (P>0.05) were observed on oocyte maturation, fertilization, D-4 embryo yield and blastocyst development. Embryos produced during the dry season had a higher incidence of apoptosis on D- 3 and at the morulae stage (P<0.05). Under the conditions described in this study, the results suggest that the early stages of embryonic development suffer greater negative impact during the dry season in IVP protocols in goats.(AU)

Influência das estações seca e chuvosa na capacidade de desenvolvimento de oócitos e produção in vitro de embriões da espécie caprina / Influence of dry and rainy seasons on oocyte maturation and in vitro embryo production in goats

Objetivou-se com este estudo determinar a influência das estações seca e chuvosa na maturação de oócitos e produção in vitro (PIV) de embriões na espécie caprina. Os ovários das cabras nas estações seca (outubro a março) e chuvosa (abril a setembro) foram colhidos em abatedouro e transportados ao Laboratório de Biotécnicas da Reprodução da UFRPE. Os complexos cumulus oophorus (CCOs) foram colhidos pela técnica de "slicing" dos folículos entre 2 a 6 mm de diâmetro e selecionados com base na classificação morfológica. Foram realizadas 12 repetições, nas quais os CCOs foram submetidos à maturação, fertilização e cultivo in vitro dos embriões. A média e desvio padrão da taxa de clivagem foi determinada no dia 3 (D-3) e dos embriões que se desenvolveram aos estádios de 8-16 células, mórula e blastocisto foi determinada nos dias 4 (D-4), 5 (D-5) e 8 (D-8) após a fecundação, respectivamente. A quantidade de blastômeros foi determinada com o corante DAPI e os blastômeros positivos para apoptose por meio do teste de TUNEL. A produção de embriões no D-3 e mórulas foram inferiores ao obtido no período chuvoso (P 0,05) quanto às fases de maturação, fertilização, cultivo no D-4 e blastocisto. Os embriões produzidos na estação seca apresentaram maior incidência de apoptose (P < 0,05). Nas condições descritas neste estudo, os resultados permitem concluir que as fases iniciais do desenvolvimento embrionário sofrem maior impacto negativo durante a estação seca em protocolos de PIV na espécie caprina.

This study aimed to determine the influence of dry and rainy seasons on oocyte maturation and in vitro production (IVP) of embryos in goats. The ovaries of does in dry (October to March) and rainy season (April-September) were collected at a slaughterhouse and transported to the Laboratory of Biotechnical Reproduction of UFRPE. The cumulus oophorus complexes (COCs) were collected by the technique of slicing of the follicles from 2 to 6 mm in diameter, and selected based on morphologic classification. We used 12 replicates, in which the COCs were submitted to maturation, fertilization and in vitro culture. The cleavage rate was determined on day 3 (D-3) and embryos that developed to 8-16 cells (D-4), morulae (D-5) and blastocyst (D-8) stages after fertilization. The number of blastomeres was assessed with DAPI staining, and the determination of apoptotic blastomeres was performed by TUNEL assay. In the dry season, D-3 embryos and morulae development was lower than that obtained in the rainy season (P0.05) were observed on oocyte maturation, fertilization, D-4 embryo yield and blastocyst development. Embryos produced during the dry season had a higher incidence of apoptosis on D- 3 and at the morulae stage (P<0.05). Under the conditions described in this study, the results suggest that the early stages of embryonic development suffer greater negative impact during the dry season in IVP protocols in goats.

Avaliação de oócitos caprinos submetidos à estresse calórico induzido durante a maturação in vitro / Evaluation of Goat Oocytes Subjected to Heat Stress Induced During Maturation In Vitro

Background: The low productivity of Northeast goat herds has been circumvented by the importation of exotic species; however, caution is needed due to the susceptibility of these breeds to the high temperatures found in this region. It is now known that the oocyte and the embryo are the primary targets of the deleterious effects induced by heat stress, causing cellular damage that triggers the cascade of apoptosis. Therefore, the purpose of this study was to evaluate the effect of thermal heat stress during in vitro maturation of oocytes and its effects on embryo production in goats. Materials, Methods & Results: The ovaries were collected in a slaughterhouse and transported to the Laboratory of Biotechnical Reproduction of UFRPE. The cumulus oophorus complexes (COCs) were collected by the technique of slicing the follicles from 2 to 6 mm in diameter, selected based on morphology and placed in a basic medium for maturation. In 10 replications, the COCs were submitted to the thermal heat stress at 41°C for 0 (thermoneutrality at 39°C), 3, 6, 12, 18, and 24 h of maturation in vitro. The data was evaluated in maturation, fertilization, cleavage (D-3), stage of 8-16 cells (D4), morula (D-5), and blastocyst (D-8) after fertilization and blastocysts positive for apoptosis through the TUNEL test. For statistics, the results were expressed as mean and standard deviation. Also considering the measurements addressed in percentages, a comparison of variances was carried out, F-test for variances to the level of signifi cance 5% (P < 0.05). Then, a t-test to compare averages was conducted, to the significance level of 5%, for equivalent variances or distinct variances, according to what was observed in the F-test for variances. A signifi cant difference (P < 0.05) was observed during all time periods studied for heat stress on maturation, fertilization, D-3, D-4, and D-5. On D-8 no significant difference (P > 0.05) was observed between the periods of 3 vs 6 and 18 vs 24 h, and in the blastocysts positive by the TUNEL test for the periods of 0 vs 3, 3 vs 6, 12 vs 18, and 18 vs 24 h of heat stress. Discussion: When applying a thermal shock that produces damage to the oocyte maturation in vitro, the characteristic membrane, chromatin configuration, and meiotic spindles are changed, and thus, the developmental potential of oocytes after fertilization is compromised. It was observed in this study that there was a gradual reduction in the number of oocytes as the time of exposure to heat shock increased, reflecting directly on each stage of IVP embryos. These stages are most vulnerable during maturation in vivo (ovulation), fertilization, within two days after fertilization, and in the first division of cleavage, as evidenced in this study in vitro after heat stress, reducing the number of blastocysts. This suggests that apoptosis can be induced in pre-implantation of embryos exposed to maternal hyperthermia. Moreover, the degree of apoptosis experienced by IVP embryos generally reflects the severity of thermal shock. In this study, the percentage of cells that were TUNEL positive increased with the prolongation of thermal shock. Induction of apoptosis was time dependent and the number of apoptotic cells increased proportionally after 6, 12, 18, and 24 h of exposure. Under the conditions observed in this study, the results indicate that the time in which the oocyte is exposed to heat stress during maturation in vitro is of great importance for embryonic development and their level of apoptotic cells.

Evaluation of goat oocytes subjected to heat stress induced during maturation in vitro / Avaliação de oócitos caprinos submetidos à estresse calórico induzido durante a maturação in vitro

Background: The low productivity of Northeast goat herds has been circumvented by the importation of exotic species; however, caution is needed due to the susceptibility of these breeds to the high temperatures found in this region. It is now known that the oocyte and the embryo are the primary targets of the deleterious effects induced by heat stress, causing cellular damage that triggers the cascade of apoptosis. Therefore, the purpose of this study was to evaluate the effect of thermal heat stress during in vitro maturation of oocytes and its effects on embryo production in goats. Materials, Methods & Results: The ovaries were collected in a slaughterhouse and transported to the Laboratory of Biotechnical Reproduction of UFRPE. The cumulus oophorus complexes (COCs) were collected by the technique of slicing the follicles from 2 to 6 mm in diameter, selected based on morphology and placed in a basic medium for maturation. In 10 replications, the COCs were submitted to the thermal heat stress at 41C for 0 (thermoneutrality at 39C), 3, 6, 12, 18, and 24 h of maturation in vitro. The data was evaluated in maturation, fertilization, cleavage (D-3), stage of 8-16 cells (D- 4), morula (D-5), and blastocyst (D-8) after fertilization and blastocysts positive for apoptosis through the TUNEL test. For statistics, the results were expressed as mean and standard deviation. Also con

O rebanho caprino no país se concentra principalmente na região Nordeste com 9,3 milhões de cabeças, destacando-se os estados da Bahia (29,2%) e Pernambuco (20,5%). Apesar de deter praticamente todo o rebanho caprino, o Nordeste necessita de pesquisas e tecnologias para minimizar a relação custo/benefício do sistema de produção, estimulando o desenvolvimento e criando novas possibilidades de agronegócio. A baixa produtividade dos rebanhos locais tem sido contornada através da importação de raças exóticas para o Semiárido nordestino, porém, é preciso cautela devido à susceptibilidade destas raças às temperaturas elevadas encontrada nesta região. [...]

Evaluation of goat oocytes subjected to heat stress induced during maturation in vitro / Avaliação de oócitos caprinos submetidos à estresse calórico induzido durante a maturação in vitro

Background: The low productivity of Northeast goat herds has been circumvented by the importation of exotic species; however, caution is needed due to the susceptibility of these breeds to the high temperatures found in this region. It is now known that the oocyte and the embryo are the primary targets of the deleterious effects induced by heat stress, causing cellular damage that triggers the cascade of apoptosis. Therefore, the purpose of this study was to evaluate the effect of thermal heat stress during in vitro maturation of oocytes and its effects on embryo production in goats. Materials, Methods & Results: The ovaries were collected in a slaughterhouse and transported to the Laboratory of Biotechnical Reproduction of UFRPE. The cumulus oophorus complexes (COCs) were collected by the technique of slicing the follicles from 2 to 6 mm in diameter, selected based on morphology and placed in a basic medium for maturation. In 10 replications, the COCs were submitted to the thermal heat stress at 41C for 0 (thermoneutrality at 39C), 3, 6, 12, 18, and 24 h of maturation in vitro. The data was evaluated in maturation, fertilization, cleavage (D-3), stage of 8-16 cells (D- 4), morula (D-5), and blastocyst (D-8) after fertilization and blastocysts positive for apoptosis through the TUNEL test. For statistics, the results were expressed as mean and standard deviation. Also con

O rebanho caprino no país se concentra principalmente na região Nordeste com 9,3 milhões de cabeças, destacando-se os estados da Bahia (29,2%) e Pernambuco (20,5%). Apesar de deter praticamente todo o rebanho caprino, o Nordeste necessita de pesquisas e tecnologias para minimizar a relação custo/benefício do sistema de produção, estimulando o desenvolvimento e criando novas possibilidades de agronegócio. A baixa produtividade dos rebanhos locais tem sido contornada através da importação de raças exóticas para o Semiárido nordestino, porém, é preciso cautela devido à susceptibilidade destas raças às temperaturas elevadas encontrada nesta região. [...]