Perfil da expressão de genes relacionados à resistência à mastite em bovinos leiteiros

• Autor(a) principal: Fonseca, Isabela
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5564
• topic: Interleucina; RT-PCR; Gir leiteiro; Gado holandês; Interleucin; RT-PCR; Dairy cattle; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::GENETICA E MELHORAMENTO DOS ANIMAIS DOMESTICOS

Among health problems in livestock production, infectious contagious diseases are those that stand out most being mastitis one of the main disease conditions. One of the most promising ways to reduce problems caused by infectious contagious diseases, besides sanitary control, is the selection of resistant animals, in order to incorporate this trait within the herd. The candidate gene strategy might be used as a tool for the selection of best adapted and more productive animals, whereas for the selection of the best animals, characterization of genetic expression from susceptible and resistant cows is important. Therefore, the objective of the present study was to characterize the expression of genes that can be related with mastitis resistance/susceptibility phenotype. Thus, an investigation was made on IL-2, IL-4, IL-6, IL-8, IL-10, IFN- g and TNF- a&#305; gene expression on milk cells from Dairy Gyr and Holstein black-white (BW) cows with and without clinical mastitis, throughout real-time quantitative PCR (qPCR) technique. Six animals from each breed were evaluated three with mastitis and three without it. The total RNA was extracted from milk cells in order to synthesize the cDNA s first strand. For qPCR reactions, the GAPDH gene was used as endogenous control. Five comparisons for each gene expression analysis were made: Non-mastitis cows vs Mastitis cows from both breeds; Non- mastitis Holstein cows vs Mastitis Holstein cows; Non-mastitis Dairy Gyr cows vs Mastitis Dairy Gyr cows; Non-mastitis Holstein cows vs Non-mastitis Dairy Gyr cows; Mastitis Holstein cows vs Mastitis Dairy Gyr cows. Within Dairy Holstein BW animals, the IL-10 gene had the highest expression in mastitis animals (p<0.001), and on both breeds the IL-10 also had a higher expression on mastitis animals (p<0.05). It was also possible to identify in the healthy group a higher expression of all genes on the Holstein breed (p>0.5), being the expression of the genes IL-2 and IFN-y significantly different (p<0.001). It was possible to verify a difference, between the two breeds, on the gene expression profile of mastitis resistance/susceptibility phenotype. However, mastitis is a multifatorial disease and is affected by a large number of genes, so more genes and animals under different infection stages must be used on further studies to a better understanding of the immune response mechanism and design of more efficient strategies for control and eradication of mastitis.