Avaliação da exposição solar na intoxicação experimental por Brachiaria decumbens em ovinos

Abstract

ABSTRACT.-Porto M.R., Saturnino K.C., Lima E.M.M., Lee S.T., Lemos R.A.A., Marcolongo--Pereira C., Riet-Correa F. & Castro M.B. 2013 Twenty-six five-month-old lambs originated from flocks with no previous contact with Brachiaria spp. pastures were divided into three groups. Two groups (GS and GSB) were fed daily with fresh harvested Brachiaria decumbens ad libitum. GS was kept in an area with solar exposure and GSB was kept in stalls sheltered from solar exposure. Control group (GC) was also kept under solar exposure, but fed with Cynodon dactylon grass hay and Pennisetum purpureum fresh grass. All sheep from the three groups were supplemented with 200g daily of a commercial concentrated food. Evaluation of clinical signs was carried out daily and blood samples were collected twice a week to determine AST and GGT serum activities. Three out of nine lambs of GS presented clinical signs of Brachiaria spp. poisoning, and two died. One animal showed clinical signs and died in GSB. The main clinical signs observed were apathy, weight loss, photophobia, conjunctivitis, ocular mucous discharge and jaundice. Dermatitis due to photosensitization was not observed. Mean serum AST and GGT activities were significantly higher (p≤0,05) in the group exposed to sun, than in the other two groups, and the GGT activities were significantly higher in the group sheltered than in the control group (p≤0,05). All animals at the end of the experiment were submitted to liver biopsy and died lambs were necropsied. Histopathological evaluation of liver samples from sheep with clinical signs evidenced swelling and vacuolization of hepatocytes, individual hepatocytes necrosis, presence of foamy macrophages, crystal negative images within bile ducts and foamy macrophages, biliary duct hyperplasia and periportal mononuclear infiltration. These results suggest that sun exposure does not define intoxication, but exacerbates the toxicity of the grass. RESUMO.-Foram utilizados 26 ovinos, entre 3 e 4 meses de idade, divididos em 3 grupos, provenientes de rebanhos que nunca tiveram contato com pastos de Brachiaria spp.. Dois grupos receberam Brachiaria decumbens no cocho diariamente ad libitum, sendo que um deles permaneceu em área com exposição solar (GS) e o outro foi mantido em baias cobertas protegidos do sol (GSB). O grupo controle (GC) foi também mantido em local com exposição solar e alimentado com feno de Cynodon dactylon e capim Pennisetum purpureum triturado. Todos os grupos receberam alimentação em cochos e foram suplementados com 200g/ dia/animal de ração comercial para ovinos. Foi realizada a avaliação clínica diária dos ovinos e colhidas amostras duas vezes por semana para dosagem sérica de AST e GGT. Os

Anti-nutritional potential of protodioscin and kinetics of degradation in Urochloa grasses

“…Brum et al (2007) ) did not display signs of intoxication. However, protodioscin concentrations of 9.4 g kg -1 were found in Urochloa decumbens pastures, and lambs approximately four months old presented clinical signs of photosensitivity (PORTO et al, 2013).…”

“…BRUM et al, 2007;MENDONÇA et al, 2008;SATURNINO et al, 2010;PORTO et al, 2013) is primarily responsible for poisoning. Brum et al (2007) ) did not display signs of intoxication.…”

Clinical and histopathological study of the phototoxic dermatitis in Zebu calves in grazing of Brachiaria decumbens

“…Ha sido reportada en diferentes especies; sin embargo, la mayor presentación de casuística se ha reportado en rumiantes, entre las cuales existen informes de presentación en ovinos (4)(5)(6), caprinos (7), bufalinos (8,9) y bovinos (2,10), de igual forma, se reporta mayor susceptibilidad en ovinos que en bovinos (7), así como la mayor presentación en animales jóvenes que en adultos (11).…”

“…It is known in Brazil as "requeima" (2) and in Colombia it is known on the Atlantic coast as "fiebre candela" and in the Andean region as "Brasa, lamparón or fiebrón" (3). It has been reported in different species; however, the largest presentation of casuistry has been reported in ruminants, including reports for sheep (4)(5)(6), goats (7), buffalo (8,9) and bovines (2.10). Also, greater susceptibility is reported in sheep than in cattle (7), and it mostly affects young animals rather than in adults (11).…”

“…Es importante la realización de pruebas sanguíneas, con el fin de evaluar la actividad catalítica de las enzimas hepáticas, en particular la GGT (Gamma Glutamil Transferasa) y la AST (Aspartato Amino Transaminasa), ya que un aumento considerable de las concentraciones séricas son indicadoras de alteración hepática, en especial la GGT que se ubica a nivel de los canalículos hepáticos (4)(5)(6).…”