Avaliação laboratorial e produtiva de bovinos confinados, alimentados com feno de Brachiaria sp. e suplementados com antioxidantes
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Data
2014-12-22
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Universidade Federal de Goiás
Resumo
The grass Brachiaria sp. brought to Brazil in the green revolution, came with the goal of
increasing the Brazilian livestock production. The introducing of the grass, starts emerging
problems such as leaf hopper pastures and hepatogenous photosensitization. The etiology of
photosensitization caused by Brachiaria sp. is still controversial. But not even knowing for
sure rightly if the cause is the steroidal saponins or the fungus Phytomices chartarium, it is
known that they occur and cause damage to livestock. The described laboratory
abnormalities are increased activity of enzymes aspartate aminotransferase (AST) and
gamma glutamyl transferase (GGT), bilerrubinemia and jaundice, and evidence of
insufficient functionof.liver. Histopathological examination can demonstrate a
cholangiohepatitis and presence of foamy macrophages. The presence of these cells is
important because its quantification was negatively correlated with the gain in cattle weight.
Thus this study evaluated 40 Nelore young bulls, with the Brachiaria sp hay consumption
adjusted to the maximum amount of forage (84%), with the goal of reproducing the hepatic
abnormalities described in cases of photosensitization. Therefore, the aim of this study was
to evaluate the possible liver changes, by the metabolic and histological profile of the liver
and lymph nodes, and also check if the offered antioxidants would be able to minimize these
changes, promoting greater weight gain and improving carcass characteristics of feedlot
cattle. As a result, the braquiaria hay with low amounts of saponin and fungal spores did not
induce clinical signs of liver damage in young bulls, but laboratory assessments indicate evidence of chronic inflammatory liver change with the presence of foamy macrophages.
The antioxidant supplementation did not alter the metabolic profile of the animals, but
reduced the amount of foamy macrophages in the liver. However this decrease did not
improve weight gain of cattle, carcass characteristics and the final quality of the meat.
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Palavras-chave
Estresse oxidativo , Selênio , Zinco , Vitamina E , α- tocoferol , Oxidative stress , Zinc , Selenium , Vitamin E , α- tocopherol
Citação
COSTA, G. L. Avaliação laboratorial e produtiva de bovinos confinados, alimentados com feno de Brachiaria sp. e suplementados com antioxidantes. 2014. 106 f. Tese (Doutorado em Ciência Animal) - Universidade Federal de Goiás, Goiânia, 2014.