Performance,carcass characteristics, meat quality and fatty acids profile of Nelore cattle receiving diets with lipids sources rich in omega-3 and omega-6 fatty acids

Abstract

Beef cattle enterprise is very important in Brazil as a source of income. During the first two months of 2007, increases of 42,9 % in the export volume reaching the value of 690 millions dollars were observed. Besides the financial aspect, the social importance of livestock in the Brazilian economy is undeniable and helps to move industry and the distribution of a variable range of consumables used during production of the livestock chain which includes production, slaughter, transformation, transport and marketing of products and by-products, moving a large number of agents and structures, from the farm to industry, and so to the market, generating incomes and creating jobs in the different segments. In order to face the new world reality and one of the biggest economical transformations in the country, where the livestock activities margins of economic return are narrower all the time, the search for increased production efficiency becomes a matter of survival. Just the breeders who get adapt to this new situation, in large scale production with competitive costs and better product quality will continue in the activity. The country needs to develop strategies to attend the external market demands mainly regarding the sanitary aspects and the final product quality, as the only way to open new markets or keep those already conquered. Therefore, the adoption of management and feeding techniques which will guarantee the production of better quality meat becomes of greater importance to put the livestock sector in a similar situation as that of the major meat producing countries. As a consequence, the bovine meet production is moving towards the production of animals with better carcasses and superior meat quality. The aim of this study is to compare diets enriched with different oil sources on the performance, carcass characteristics and beef quality of Nellore cattle finished in feedlot. Thirty-five non-castrated males, finished in feedlot during 105 days, will be used to study five diets containing different sources of lipids: 1- linseed oil, rich in omega-3; 2-soybean oil, rich in omega-6; 3-MegalacE, rich in omega-6 and protected against rumen digestion; 4-protected linseed oil (OLIP) rich in omega-3 and protected from rumen degradation; and 5-traditional diet without any oil addition (control). All diets will be iso-proteic (equalized in protein content) and will contain sugar cane (IAC 86-2480) as the exclusive roughage component. The diets containing different oils will be iso-energetic (equalized in energy content). Animal performance (feed ingestion, weight gain and feeding efficiency); carcass characteristics using real time evaluation techniques (ultra-sound and body measurements) and after slaughter (gain, carcass length, primary cuts gain and viscera weight; meat quality (softness, collor and sensorial aspects); and the hump cover (Biceps femoris), and contra-filet (Longissimus lumborum ) meat fat-acid composition (conjugated linoleic acid, insaturated:saturated total fat acids rate, omega-6:omega-3 rate) and cholesterol content will be evaluated. The data were analized by a total randomized design, with 5 treatments and 7 replications, with the use of orthogonal contrasts to compare specific treatments. (AU)