Influência da sazonalidade e da condição ovariana sobre a produção embrionária in vitro de gato doméstico (Felis catus, Linnaeus. 1758)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito da somatotrofina recombinante bovina (rbST) sobre a resposta superovulatória e recuperação embrionária em éguas tratadas com extrato de pituitária equina (EPE)

Pós-graduação em Medicina Veterinária - FMVZ

Efeito da densidade nutricional da dieta e suplementação com cromo nas concentrações séricas de glicose, insulina e ácidos graxos não esterificados em vacas de leite lactantes

Pós-graduação em Zootecnia - FMVZ

Expressão de fatores relacionados à morte celular programada em embriões bovinos infectados com BHV-5

Pós-graduação em Microbiologia - IBILCE

Produção in vitro de embriões de bovinos da raça Nelore oriundos de ovócitos de ovários com e sem corpo lúteo

Comparou-se a produção de embriões a partir de ovócitos oriundos de ovários com e sem corpo lúteo de vacas da raça Nelore, em relação à qualidade e quantidade de ovócitos obtidos, embriões produzidos, taxa de prenhez e proporção dos sexos. Foram realizadas aspirações foliculares dos dois ovários de 219 vacas em 250 seções, igualmente distribuídas em cinco grupos, sendo G1=fêmeas gestantes; G2=não gestantes, com CL e submetidas a tratamento hormonal com progestágeno+BE+PGF2∝; G3=não gestantes, sem CL e com o mesmo tratamento de G2; G4=não gestantes, com presença de CL e sem tratamento; G5=não gestantes, sem presença de CL e sem tratamento. Os resultados foram avaliados pela análise de variância (ANOVA) e aplicado o Teste de Tukey para comparação entre médias, a 5% de significância, pelo programa SISVAR. Já para comparação de proporção de sexos dentro e entre os grupos, foi utilizado o teste de comparação múltipla de proporções. O G4 produziu maior média de ovócitos totais aspirados que G2 e G3. Comparando-se os três grupos que apresentavam CL (G1, G2, G4), o G4 foi superior a G1 e G2 em ovócitos totais, no ovário com e sem CL. Em ovócitos viáveis, G2 foi superior a G1 no ovário com CL. Os ovócitos obtidos de ovários com CL é que resultaram em melhores índices de produção de embriões. As vacas gestantes produziram melhor nos ovários sem CL, com mais ovócitos viáveis (p<0,05) e iguais em embriões (p>0,05), em relação ao ovário com CL. As taxas de prenhez e proporção dos sexos foram semelhantes entre os grupos (p>0,05). A concentração de progesterona (P4) foi diferente entre os grupos, mas não influenciou as variáveis analisadas. A utilização do tratamento hormonal não melhorou os resultados de nenhuma variável. Portanto, o melhor critério de escolha de doadoras Nelore para programas de Produção in vitro (PIV) de embriões é o conhecimento individual de cada animal ao longo das seções de aspiração folicular.

A diet enriched in linoleic acid compromises the cryotolerance of embryos from superovulated beef heifers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Artificial activation of bovine and equine oocytes with cycloheximide, roscovitine, strontium, or 6-dimethylaminopurine in low or high calcium concentrations

Knowledge on parthenogenetic activation of oocytes is important to improve the efficiency of nuclear transfer (NT) and intracytoplasmic sperm injection (ICSI) because artificial activation of oocyte (AOA) is an essential step to achieve embryo production. Although different procedures for AOA have been established, the efficiency of in vitro production of embryos remains low, especially in equines and Bos taurus bovines. In an attempt to improve the techniques of NT and ICSI in bovine and equine species, we tested different combinations of drugs that had different mechanisms of action for the parthenogenetic activation of oocytes in these animals. The oocytes were collected, in vitro matured for 24 to 30 h and activated artificially, in the presence of low or high concentrations of calcium, with combinations of calcium ionophore (ionomycin) with cycloheximide, roscovitine, strontium, or 6-dimethylaminopurine (6-DMAP). For assessment of activation rates, oocytes were stained with Hoechst 33342 and observed under an inverted microscope. We showed that all combinations of drugs were equally efficient in activating bovine oocytes, with the best results obtained when high concentrations of calcium were adopted. For equine oocytes, high concentrations of calcium were not beneficial for the parthenogenetic activation and the combination of ionomycin with either 6-DMAP or roscovitine was effective in inducing artificial activation of oocytes. We believe that our preliminary findings provide some clues for the development of a better AOA protocol to be used with these species.

Assessment of the reproductive parameters, laparoscopic oocyte recovery and the first embryos produced in vitro from endangered Caninde goats (Capra hircus)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Forskolin effect on the cryosurvival of in vitro-produced bovine embryos in the presence or absence of fetal calf serum

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In vitro Maturation of Oocytes from Santa Ines Ewes Subjected to Consecutive Sessions of Follicular Aspiration by Laparoscopy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efficiency of OPU-IVEP-ET of Fresh and Vitrified Embryos in Buffaloes

The present study aims to report ovum pickup (OPU), in vitro embryo production (IVEP) and embryo transfer (ET) outcomes of fresh and vitrified buffalo embryos. For this purpose, 36 buffalo donors were submitted to 11 OPU sessions (n = 201). A total of 998 oocytes (5.0 +/- 0.5/donor/session) and 584 viable oocytes (2.9 +/- 0.3/donor/session) were recovered. Viable oocytes (grades 1, 2 and 3) were subjected to IVM, IVF (D0) and IVC. On D2, 54.5% of cleavage rate was obtained. Embryo yield on D7 was 44.9% (grade 1: 229 embryos, grade 2: 5 embryos and grade 3: 28 embryos). From this total, 115 fresh (grades 1 to 3) and 70 vitrified embryos (only grade 1) were transferred into recipients previously synchronized with fixed time embryo transfer (FTET) protocol. Vitrification was performed using the cryotop method. Pregnancy diagnosis in fresh and in vitrified groups were, respectively: 43.5% (50/115) and 37.1% (26/70) on 30 days after embryo transfer, and 41.7% (48/115) and 31.4% (22/70) on 60 days after embryo transfer. In conclusion, our results demonstrate the possibilities for commercial use of the techniques of OPU, IVEP and ET of fresh and vitrified embryos in buffaloes.

The role of chromosome variation in the speciation of the red brocket deer complex: the study of reproductive isolation in females

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito de dose reduzida de somatotropina bovina recombinante associada a protocolos de superovulação na fertilidade de embriões transferidos para receptoras em lactação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Control of oocyte maturation

Oocyte maturation is a complex process involving nuclear and cytoplasmic maturation. The nuclear maturation is a chromosomal segregation and the cytoplasmic maturation involves the reorganization of the cytoplasmic organelles, mRNA transcription and storage of proteins to be used during fertilization and early embryo development. The mechanism of oocyte maturation in vivo and in vitro still are not totally understood. However it is generally accepted that the second messenger cyclic adenosine monophosphate (cAMP) plays a critical role in the maintenance of meiotic blockage of mammalian oocytes. A relative increase in the level of cAMP within the oocyte is essential for maintaining meiosis block, while a decrease in cAMP oocyte concentration allows the resumption of meiosis. The oocyte cAMP concentration is regulated by a balance of two types of enzymes: adenylate cyclase (AC) and phosphodiesterases (PDEs), which are responsible for the synthesis and degradation of cAMP, respectively. After being synthesized by AC in cumulus cells, cAMP are transferred to the oocyte through gap junctions. Thus, specific subtypes PDEs are able to inhibit or attenuate the spontaneous meiotic maturation of oocytes with PDE4 primarily involved in the metabolism of cAMP in granulosa cells and PDE3 in the oocyte. Although the immature oocytes can resume meiosis in vitro, after being removed from antral follicles, cytoplasmic maturation seems to occur asynchronously with nuclear maturation. Therefore, knowledge of the oocyte maturation process is fundamental for the development of methodologies to increase the success of in vitro embryo production and to develop treatments for various forms of infertility. This review will present current knowledge about the maintenance of the oocyte in prophase arrest, and the resumption of meiosis during oocyte maturation, focusing mainly on the changes that take place in the oocyte.

Preservation of wild feline semen by freeze-drying: experimental model

According to the Convention on International Trade in Endangered Species, 36 wild feline species are threatened by extinction or severely endangered, and to save them is the target of several conservation programs. This study aimed to assess the viability of the freeze-drying technique for domestic cat sperm cells, with the ultimate goal of transferring this technology to the wild feline species. The domestic cat is an excellent experimental model for wild felids. It is in this scenario that the freeze-drying process (low-temperature vacuum dehydration) of sperm cells shows its value in preserving male cats' germplasm. Results from membrane and DNA integrity analysis are promising and validates the use of frozen-dried sperm samples in intracytoplasmic sperm injections (ICSIs). Further studies are still necessary to evaluate the ICSI embryo production using domestic cat frozen-dried sperm and the possibility of using such technology with wild felines.