Estudo do polimorfismo da kappa- caseína e alfa-lactoalbumina em bovinos Girolando, do Brasil e Siboney, de Cuba

Abstract

Milk is a food of nutritional and functional importance for all phases of life; however, of all constituents, the fat and protein components are considered to be the most economical value within milk quality payment programs. This fact suggests a greater importance given to these constituents by the main actors of the milk production chain within the economic scenario (MADALENA, 2000). Dürr (2004) reports that milk fat and protein concentrations vary mainly depending on the nutritional management and genetic potential of the animals. As a consequence of the genetic differences responsible for the variation of 25% of the total milk production and 50% in the variations of fat, protein and non-greasy solids (GONYON et al., 1987) ). According to Bonfatti et al. (2010), it is estimated that the additive genetic variance for milk composition characteristics is between 14 and 39% of the total variance. In relation to the polymorphisms of the genes coding for the main milk proteins, such as caseins, β-Lg and α-La, these became markers of interest in milk production, composition and processing. They are excellent models for understanding the behavior of the dairy raw material during the industrial process, since they are closely related to the milk casein fraction, the main protein portion involved with the high yield in the production of cheeses and other derivatives. In addition, genetic polymorphisms of milk proteins are frequently used for the characterization of several breeds of animal production (CAROLI et al., 2010). In order to promote improvements in the genetics of milk production, composition and processing characteristics, research in the field of molecular biology has made it possible to map and identify genomic, transcriptomic and proteomic levels of polymorphisms that contribute to variations in milk composition , In this way, the process of selection of animals in breeding programs. In view of the above, the objective of this research was to study the genetic polymorphisms of kappa-casein and alpha-lactalbumin in cattle of the Girolando and Siboney races