Neurotoxicose em bovinos associada ao consumo de ?cevada? (baga?o de malte) contaminada por Aspergillus clavatus no Estado do Rio de Janeiro

• Autor(a) principal: Oliveira, Glenda Ribeiro de
• Data de Publicação: 2016
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/2032
• topic: Neurotoxicosis; Malted barley waste; Aspergillus clavatus; Neurotoxicose; Cevada; Aspergillus clavatus; Medicina Veterin?ria

Four outbreaks of a neurological disease affecting dairy cattle which consumed malted barley waste contaminated with Aspergillus clavatus in the municipalities of Valen?a, Paty do Alferes, and Barra Mansa, in the state of Rio de Janeiro, are described. In all farms, stored malted barley waste exhibited visible fungal contamination and only the animals that ingested the by-product got sick. Animals exhibited muscle tremors, hyperesthesia, ataxia, progressive paresis and paralysis, and marked weight loss. Affected animals were walking with knuckling of hindlimb fetlocks, and some would assume a sitting-dog position. When forced to move around, falls were frequent. There was marked decrease in milk production, even though appetite and thirst remained normal up to the moment of death or euthanasia. Clinical evolution varied from 1 to 16 days. From the animals that recovered, four remained with mild locomotor system sequelae. Morbidity varied between 41.42% and 73.08%, mortality between 33.33% and 69.23%, and lethality between 51.11% and 94.73%. Macroscopic alterations included focal pale areas on the myocardium, semitendinosus, semimembranosus, adductor, pectineus, and Longissimus dorsi muscles. Histopathology was characterized by degenerative-necrotic alterations, tumefaction, vacuolation, and chromatolysis of neurons of cerebellar peduncle nuclei, base of the brain, medulla oblongata, and grey matter of the medulla (the H shape). At histology, muscular lesions were characterized by degeneration and coagulative necrosis, at times with incipient mineralization. In one of the bovines, there was also coagulative necrosis of the myocardium , and presumably, myoglobinuric nephrosis. Fungal culture of samples of malted brewer waste resulted in isolation and identification of A. clavatus. The clinical pathological picture was reproduced experimentally in sheep which consumed 40g/kg of malted brewer waste per day, which was collected from the two investigated farms; these animals developed clinical signs and microscopic lesions similar to those observed in bovines. We conclude that even though brewery by-products have a reasonable cost/benefit ratio for bovine feeding, there is a need to observe steps to avoid eventual poisoning and consequent economical losses