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Year 2005 - Volume 25, Number 1
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Intoxicação experimental por Sida carpinifolia (Malvaceae) em ovinos, p.15-20
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Seitz A.L., Colodel E.M., Barros S.S. & Driemeier D. 2005. [Experimental poisoning by Sida carpinifolia (Malvaceae) in sheep.] Intoxicação experimental por Sida carpinifolia (Malvaceae) em ovinos. Pesquisa Veterinária Brasileira 25(1):15-20. Departamento de Patologia Clínica Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91540-000, Brazil. E-mail: alseitz@terra.com.br.
Seven sheep received dry crushed Sida carpinifolia L.f. One of them died at 18 and other at 53 days of the experiment. Four others were euthanatized and necropsied at 30, 45, 75 and 100 days. For one sheep the supply of S. carpinifolia was interrupted on the 80th day of the experiment, and 70 days later the animal was euthanized and necropsied. The minimal amount of the dry plant consumed was 11 g/kg and the maximum was 30 g/kg. The progression of clinical findings was similar in six animals with slight diarrhea at 20 days of experiment. Neurological signs were observed at 25 days and included ataxia with dysmetria, muscle tremors of the head, atypical postural reactions, frequent falls, sluggish of movements, difficulty in grazing and swallowing. These signs were enhanced when the animals were forced to walk. Four of the animals presented progressive emaciation. The sheep whose supply of the plant was interrupted recovered gradually, and 11 days after the animal returned to normal. During necropsy, only enlarged mesenteric lymph nodes were observed. The histological alterations were more significant in the central nervous system, with multiple and severe cytoplasmic distention and vacuolation which affects specially Purkinje cells of the cerebellum, neurons of cerebral cortex, thalamus, midbrain and the ventral horn of spinal cord. Axonal spheroids in the brain, more frequently in the granular layer of cerebellum were also observed. The cytoplasmic vacuolation was also found in pancreatic acinar cells, renal tubules, thyroid follicular epithelium, hepatocytes and macrophages of lymphoid organs. The ultrastructural lesions observed were cytoplasmic vacuolation, some surrounded by membranes in Purkinje cells of cerebellum and thyroid follicular cells. The sheep, which had S. carpinifolia withdrawn from its diet for 70 days, had no significant histological alterations. |
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