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- Title
Intoxicação crônica por cobre em ovinos alimentados com bagaço de uva.
- Authors
de Oliveira Reis, Matheus; Mello, Lauren Santos; da Cruz, Raquel Aparecida Sales; Guimarães, Lorena Lima; de Oliveira, Luiz Gustavo Schneider; Lorenzett, Marina Paula; Pavarini, Saulo Petinatti; Driemeier, David
- Abstract
Background: Sheep are very sensitive to excess copper, and therefore, cases of poisoning are frequently seen in this species. The chronic form of poisoning is the most often reported in this species, and is characterized by a subclinical stage, in which copper accumulates in the liver for weeks or even months, and an acute phase, which progresses with the release of hepatic copper in the bloodstream, culminating in intravascular hemolysis, anemia, jaundice and hemoglobinuria. The aim of this paper is to describe an outbreak of chronic copper poisoning in Texel sheep, fed grape marc. Case: A visit to a farm located in Westfalia, Rio Grande do Sul was performed in order to investigate the cause of the death of 15 Texel sheep of different ages, out of a flock of 75 animals, in the interval of one month. The sheep were fed on grape marc, native grass and corn bran. Clinical signs of hemoglobinuria and apathy were recorded in the affected sheep. Two sheep were necropsied (Sheep 1 and 2), and fragments of tissues were collected in 10% formalin solution and processed in routine histological techniques. The slides were stained with hematoxylin and eosin technique, and additionally, the liver slides were stained with rubeanic acid and Prussian blue. Fragments of the liver of the sheep submitted to necropsy, as well as samples of grape marc that the sheep were consuming were taken to determine the concentrations of copper by atomic absorption spectrophotometry method. Discussion: The diagnosis of chronic copper poisoning in sheep in this study was based on epidemiology, clinical and pathological findings, associated with high levels of copper in the sheep liver samples as well as in the grape marc they were consuming. The major cause of this type of poisoning is associated with the intake of feed and / or mineral salt with high copper levels, normally formulated for cattle. In this case, the grape marc used to feed the sheep was possibly the cause of the outbreak, since the sheep had no access to any other source of copper, and given the high contents of the metal detected in the marc. Grape marc is a by-product of the wine industry, and has been fed to sheep as a sustainable way to increase the profitability in agriculture. Copper poisoning due to grape marc ingestion results from the high contents of the metal in vineyards sprayed with copper-based fungicides. It was already reported the death of eight sheep by copper poisoning which were fed on grape marc and mineral salt formulated for cattle, and kept in a vine orchard, which has been annually sprayed with copper sulfate and fertilized with poultry litter, both containing high concentrations of copper. The clinicopathological picture observed in the outbreak described in this paper is similar to what is described by other authors, and is due to hemolytic crisis occurring in the acute phase of the intoxication. This type of poisoning is important to sheep, due to the high sensitivity of the species to copper, derived from its low capability to conjugate copper to metallothionein, reducing the metal excretion via bile, and consequently, leading to hepatic accumulation of copper. The most sensitive method of diagnosis is the determination of the copper levels in liver or kidney samples, in which values above 500 mg/g and 80 g/g, respectively, are considered toxic. In this report, the copper values found in the liver samples were above 1000 mg/g, proving that copper poisoning was the cause of the sheep mortality. The diagnosis of chronic copper poisoning was based on the epidemiology, clinicopathological features, confirmed by rubeanic acid staining of the liver in association with the dosage of copper in the tissue and grape marc samples. The results found here show that grape marc can contain high levels of copper, and so, should be avoided as sheep food.
- Publication
Acta Scientiae Veterinariae, 2015, Vol 43, p1
- ISSN
1678-0345
- Publication type
Article