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In these days, the main barriers for production of transgenic animals are the identification of efficient systems of transgenic, such as different mechanisms on finding gene expression. Based on the idea of searching for different ways of developing transgenic animals, the objective of this research was to produce transgenic bovine embryos using the lentiviral vector of microinjection or nuclear transfers of genetically modified somatic cells, which have the finality of developing and quickly selecting animals from transgenic bovine embryos. This research was conducted in two different stages. Stage I consisted on establishing and producing a lentiviral vector which codified GFP protein. Stage II consisted on conducting three different experiments. On experiment I, a microinjection was developed on the lentiviral vector in the perivitelline space of the bovine ovocites before fecundation (T4), obtaining 5,26 percent of blastocites. When compared with the controle (T1) (complex ovoocites with cumulus-ovocites and without manipulation) the percetage was lower (P< 0,05), control without microinjection (T2), or a control with microinjections and Talp medium (T3). On all the microinjected embryos with the lentiviral vectors, a gene expression of GFP (Green Fluourocent Protein) was detected. On experiment II, a microinjection of the lentiveral vector on the perivitelline space of the of the bovine zygote was evaluated six hours after fecundation. The microinjected zygotes with the lentiveral vector (T4), on in vitro cultivars, blastocite rates day seven and day eight, 3,4% and 3,8% respectively. This values were below (P 0.05) in blastocyst rate of embryos treated with trichostatin (T1) (18.1%) when compared with untreated embryos (T2) (6.8%). When the rate was calculated from cleaved zygotes, production was higher (P 0,05) na taxa de blastocistos de embriões tratados com tricostatina (T1) (18,1%) quando comparada com embriões não tratados (T2) (6,8%). Quando a taxa foi calculada a partir de zigotos clivados, a produção foi superior (P

The competency of the cumulus-oocyte complex (COC) selected to the in vitro maturation systems (MIV) is directly related to the biotechnical success of embryo in vitro production. Because of that, associated to the morphological selection, the oocyte selection method of Brilliant Cresyl Blue (ACB) has been widely testes and appears as an additional tool to oocytary selection. The maintenance of the COC in specific media for the several hours right after the ovarian follicles can compromise the COC quality due to pH alterations, to temperature oscillations and even to the media used. The objective of this experiment was to investigate the in vitro nuclear maturation of stained (ACB+) and non-stained (ACB-) oocytes after kept for 5 hours in Talp Hepes. After the oocytes selection by ACB, five experimental treatments were submitted to MIV. At T1 (control), the oocytes were matures in vitro immediately after the manipulation. After the exposition time in ACB (1h) and 5 or 0 hours in Talp Hepes, the oocytes were separated in zero-hour stained (T2), zero-hour non-stained (T3), five-hour stained (T4) and five-hour (T5) and submitted in vitro maturation. There where differences between the treatments about the oocyte percentage that presented MI nuclear configuration after MIV. The T1 and T4 treatments were similar (p>0,05). The T3 and T5 treatments were equal, but presented higher MI oocyte percentage than T1, T2 and T4 (p0,05), but presented higher MII oocyte percentage then T3 and T5, the similar ones. Of all the oocytes submitted to MIV, T1 presented lower percentage of degenerated than T2, T3, T4 and T5, the ones that showed similar percentage of degenerated oocytes. Concluding, the oocyte staining capacity by ACB doesn t change after keeping the COCs for 5 hours in Talp Hepes media. The ACB+ oocyte competence to get MII stage in higher than ACB-, even after keeping the COCs in Talp Hepes media. A competência dos complexos cumulus ovócito (CCOs) selecionados para os sistemas de maturação in vitro (MIV) está diretamente relacionada ao sucesso da biotécnica de produção in vitro de embriões. Por tal razão, associado à seleção morfológica, o método de seleção de ovócitos através da coloração por Azul Cresil Brilhante (ACB) tem sido amplamente testado e surge como ferramenta adicional de seleção ovocitária. Também a manutenção por várias horas dos CCOs em meios específicos, logo após aspiração dos folículos ovarianos, pode comprometer o qualidade dos CCOs devido a alterações de pH, oscilações de temperatura e ao próprio meio utilizado. O presente experimento teve por objetivo investigar a competência de maturação nuclear in vitro dos ovócitos corados (ACB+) e incolores (ACB-) após manutenção por 5 horas em Talp Hepes. Após seleção dos ovócitos por ACB, cinco tratamentos experimentais foram submetidos a MIV. No T1 (testemunha), os ovócitos foram maturados in vitro imediatamente após a manipulação. Posteriormente ao tempo de exposição em ACB (1h) após 5 ou 0 horas em Talp Hepes, os ovócitos foram separados em corados zero hora (T2), não corados zero hora (T3), corados cinco horas (T4) e não corados cinco horas (T5) e submetidos à maturação in vitro. Houve diferença entre os tratamentos quanto ao percentual de ovócitos que apresentaram configuração nuclear de metáfase I (MI) ao término da MIV. Os tratamentos T1 e T4 foram semelhantes (p>0,05). O T2 foi semelhante (p>0,05) ao T4, mas inferior (p0,05) porém apresentaram maior (p0,05) entre si mas apresentaram maior (p