Intoxica??o experimental por monofluoroacetato de s?dio em bovinos: aspectos cl?nicos e patol?gicos

• Ano de defesa: 2009
• Autor(a) principal: Nogueira, Vivian de Assun??o
• Orientador(a): Peixoto, Paulo Fernando de Vargas
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Ci?ncias Veterin?rias
• Departamento: Instituto de Veterin?ria
• País: Brasil
• Palavras-chave em Português: monofluoroacetato de s?dio; patologia; bovino.
• Palavras-chave em Inglês: sodium monofluoroacetate; pathology; cattle
• Área do conhecimento CNPq: Medicina Veterin?ria
• Link de acesso: https://tede.ufrrj.br/jspui/handle/tede/844

Sodium monofluoracetate (MF) was identified, by cromatography, in three of the 12 plants that cause "sudden death" in cattle in Brazil. Among these, Palicourea marcgravii is the most important due to its high toxicity (0.6g/kg), wide distribution, good palatability and cummulative effect. In 1959, D?bereiner & Tokarnia detected in the kidney of cattle poisoned by that plant, hydropic-vacuolar degeneration (HVD) of the distal convoluted uriniferous tubules, a lesion they considered typical for the poisoning. MF inhibits the citrate aconitase enzyme, resulting in blockage of the Krebs Cycle and the production of ATP. The objective of this study was to verify if the ingestion of MF causes the same lesions in the kidney of cattle poisoned by the plants which cause sudden death . This would prove that this substance is responsible for the deaths of animals which ingest these plants. Six cows received orally 0.5 and 1 mg/kg of MF (Sigma Aldrich Co) diluted in 50 mL of distilled water. Clinically the animals presented palpitation, replete jugular vein with positive pulse, abdominal breathing, slight balance loss with sometimes swaying gait, the animals laid down and placed the head on their flank. In the dramatic phase , all the animals fell into lateral decubitus, stretched out the legs, made peddling movements, presented opistotonus, nistagmus, and died. The dramatic phase lasted from 3 to 14 minutes. At postmortem examination, the heart auricles, jugulars and pulmonary veins were moderately ingurgitated. Slight to moderate edema of the subserosa was seen in places of fixation of the gall bladder to the liver, besides slight edema around the duodenum in contact with the pancreas. Histopathology revealed HVD of the epithelial cells of the distal convoluted uriniferous tubules associated with nuclear picnosis in all cows. Coagulation necrosis of individual or groups of hepatocytes and slight hepatic congestion secondary to the venous stasis were also observed. Hydropic-vacuolar degeneration has been observed in cases of poisoning by many substances, which cause acute tubular nephrosis, however not restricted to the distal renal tubules and without nuclear picnosis. This study demonstrates that this peculiar kind of HVD in the kidney can be caused by MF and, in analogy, the compound should be considered responsible for the death of cattle that ingest toxic plants which cause "sudden death" in Brazil. For the first time it has now been proved that MF causes HVD of the distal convoluted uriniferous tubules, what indicates that studies of possible degradation of MF by rumen bacteria could have economic importance, as there die annually at least 600.000 cattle by sudden death causing toxic plants.