|Support type:||Scholarships in Brazil - Scientific Initiation|
|Effective date (Start):||May 01, 2012|
|Effective date (End):||April 30, 2013|
|Field of knowledge:||Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding|
|Principal Investigator:||Francisco Palma Rennó|
|Grantee:||Mariana Fragoso Rentas|
|Home Institution:||Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil|
The use of fat sources in diets of dairy cows has been common practice in the farms, especially for allowing improving the energy status of these animals. However, when evaluating the supplementation of fat sources in diets of ruminants, all the physiological processes must be taken into consideration because ruminal metabolism, intestinal absorption, transport and systemic metabolism, secretion and deposition of fat in the body are aspects directly related to lipid metabolism and may influence the physiological responses of animals receiving fat in diets. The process biohydrogenation in the rumen is in important part in the metabolism of fatty acids and can be considered a process self defense of the rumen microorganisms, which convert unsaturated fatty acids into saturated fatty acids, less toxic to the rumen microbial population. Additionally, this process increases the intestinal flow of polyunsaturated fatty acids to the duodenum and increases the isomers of CLA, cis and trans derived from ruminants depending on the source of fat used. These CLA isomers have been evaluates and found in products derived from ruminants on pasture or fed diets rich in linoleic and linolenic acids, presents in seeds with soybean oil and sunflower oil. While most of the fatty acids is modified through the rumen metabolism, the biohydrogenation is usually not complete, resulting in a variety of fatty acids. When the biohydrogenation of polyunsaturated fatty acids, occur of incomplete form increase of the duodenal flow of trans fatty acids - C18: 1 and conjugated linoleic acid cis-9, trans-11-CLA and trans-10, cis -12 - CLA with proven effect nutraceutical and effect on the synthesis of milk fat, by reducing the expression of genes lipogenics. Thus, the inclusion of fatty acids in diets of ruminants, to be considered source of energy and also used as moderator's of metabolism and physiology. Thus, the scientific hypothesis to be evaluated in this experiment suggests that, depending of the fat source used can occur changes and its components. This experiment will be conducted to evaluate the effects of the inclusion of fat sources in diets of dairy cows in lactation on milk production and composition, and fatty acid profile of milk.