Polimorfismo em genes candidatos relacionados ao metabolismo de lip?dios e sua associa??o com caracter?sticas de qualidade do leite em caprinos

• Ano de defesa: 2017
• Autor(a) principal: Ferreira, Leonardo
• Orientador(a): Soares, Maria Am?lia Menck
• Banca de defesa: Soares, Maria Am?lia Menck, Gasparino, Eliane, Ara?jo, Jean Luiz Sim?es, Silva, Heriberto Dias da, Ribeiro, Marina Mortati Dias
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Zootecnia
• Departamento: Instituto de Zootecnia
• País: Brasil
• Palavras-chave em Português: express?o g?nica; marcadores moleculares; valor gen?tico
• Palavras-chave em Inglês: gene expression; genetic merit; molecular marker
• Área do conhecimento CNPq: Zootecnia
• Link de acesso: https://tede.ufrrj.br/jspui/handle/jspui/4584

In Brazil, as part of the goat milk produced is destined to the dairy industry, the evaluation of quality parameters, such as protein and fat content, is of great importance. Generally, breeding programs that aim an increase in milk quality, are based only on phenotype measurements, however, this process can be improved with the use of molecular markers. To search for new markers of this type in Saanem and Alpine goats, with this study we aimed to evaluate the association of polymorphisms in the UCP2, LPL, SCD and PPARG genes with dairy goats genetic value for milk production and quality characteristics. We also aimed to evaluate if polymorphisms described in the PPARG, UCP2 and GPAT4 genes results in alterations in its expression in milk mammary gland epithelial cells and if this expression changes during lactation. To search for polymorphisms, fragments of the UCP2, LPL, SCD and PPARG genes were amplified by the PCR technique and submitted to electrophoresis, sequencing and PCR-RFLP. After the identification and characterization of the polymorphisms, approximately 180 animals were genotyped for the polymorphisms found in the UCP2 and PPARG genes and the genetic values of these animals were estimated from milk production and composition data using the univariate model. The evaluation of the association of these polymorphisms with the genetic value of the animals was performed through analysis of variance followed by Tukey test with significance level of 5%. In order to evaluate whether polymorphisms in the PPARG, UCP2 and GPAT4 genes affect its expression in milk mammary gland epithelial cells and if its expression varies during lactation, collections of these cell types were performed in 50 Alpine animals at 35 days post-partum, and in 20 of these animals, samples were also collected at 10, 50 and 140 days post-partum. As RNA degradation occurred in these samples, it was not possible to perform the gene expression analyzes in this material, so we chose to use this primers to evaluate the expression of these genes in cDNA samples of Longissimus lumborum muscle from another experiment of this same team. In this experiment, it was also evaluated whether the expression of these genes correlates with the slaughter weight, carcass weight and shear force characteristics. This correlation was assessed using the Pearson correlation test followed by the T-test. Polymorphisms were identified in the PPARG, UCP2 and LPL genes. The polymorphism identified in the PPARG gene was associated with the genetic value of the animals for total milk production, fat production, protein production, dry extract production and lactose production. In the UCP2 gene, two polymorphisms, ?3708G/A and ?2569G/A, are associated with the genetic value of the animals for percentages of fat, protein and dry extract. In the Longissimus lumborum muscle, the expression of the PPARG gene showed a positive correlation with the expression of the GPAT4 gene. From these results, it can be concluded that, potential molecular markers for milk production and quality were identified, that the methodology used for collection and storage of milk mammary gland epithelial cells is not suitable for subsequent gene expression analysis and that the GPAT4 gene is a probable PPAR-? target gene in the caprine longisimus lumborum muscle.