Níveis de ractopamina nas dietas de suínos machos castrados na fase de terminação / Ractopamine levels in diet for finishing borrows

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The swine production in Brazil has become in recente years, a highly dynamic activity, because the consumer is getting increasingly demanding especially with rescpet to the product it consumes. This fact, coupled with the need for the producer to remain in business, have meant that people involved in the chain pig were in constant learning and the search for new technologies in several areas, mostly in animal nutrition. One of the objective pursued by both consumers as the producers, is to reduce the amount of fat produced in pig carcass and increase meat production, so there is improvement in profitability, reduction of production costs in addition to meet the demands of the market by a healthy product. Currently, the development of thin genetic lineages, fast and most efficient growing combined with the adoption of new technologies, especially those related to nutrition, has resulted in increase in slaughter weight without prejudice to the content of lean tissue in carcass and feed efficiency. The energy distribution beta-adrenergic such as ractopamine, are gaining prominence among large food additives used for this purpose. This additive has the ability to serve the changing patterns of deposition of muscle and adipose tissue without affect the deposition of other animal tissues. In addition to benefits associated with performance and carcass characteristics, the animal receiving ractopamine in diet did not show changes on meat quality and by products resulting. Although there are many studies evaluating the responses to the use of ractopamine to finishing animals, has been found that these studies are usually conducted in situation of termical comfort. However, it is know that the state of Mato Grosso do Sul are recorded high temperatures during almost the whole year, and is very important to assess the effects of ractopamine in animals subjected to such weather. In this context, this study was conducted to evaluate different ractopamine levels in diet of finishing pigs kept in different environments. Two experiments were carried out over a period of 28 days each. In both it was evaluated the same level for inclusion of ractopamine in diet (0, 5, 10 and 20 ppm), differing only with respect to the thermal environment. In the first experiment the animals were kept in comfort and it is linear effect of ractopamine levels on the daily weight gain and feed conversion. On quantitative carcass characteristics, was observed decreasing the fat thickness and increase depth of muscle and percentage of lean meat in the carcass in accordance with the increasing levels of ractopamine in diet. Thus, in situations of comfort, the optimum ractopamine level of inclusion in diet was 20 ppm. In the second experiment, the animals were kept in an heat stress environment and observed a linear reduction of feed conversion and linear increase in daily weight gain and final weight of animas fed. However, none of the carcass characteristics evaluated was influenced by ractopamine inclusion in diet. There was also increase in weight of the liver and kidneys in those animals that received the additive, not observing the effect on other organs. In the heat stress environment, for the variables of performance, the optimum level of inclusion was 20 ppm of ractopamine.

ASSUNTO(S)

suíno producao animal carcass ractopamine beta-agonistas swine beta-agonists carcaça ractopaminha

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