Epi-Sarsasapogenin and epi-smilagenin: two sapogenins isolated from the rumen content of sheep intoxicated by Brachiaria decumbens

Lajis, Nordin H.; Abdullah, Ahmad Fikri; Salim, Sabiha; Bremmer, John B.; Khan, M. Niyaz

doi:10.1016/0039-128x(93)90043-m

Cited by 29 publications

(20 citation statements)

References 9 publications

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“…As saponinas esteroidais litogêncicas presentes na forrageira causam, entre outras alterações, formação de material cristalóide em ductos biliares e interferência no metabolismo de hepatócitos (Graydon et al 1991. Essas alterações promovem a obstrução dos ductos biliares, seguida de acúmulo de filoeritrina na circulação e nos tecidos, causando fotossensibilização (Abdhullah et al 1992, Lajis et al 1993, Cheeke 1995, Cruz et al 2001, Stegelmeier 2002.…”

Section: Introductionunclassified

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

et al. 2013

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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

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Section: Introductionunclassified

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

et al. 2013

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“…A intoxicação por B. decumbens é descrita em bovinos (Nobre & Andrade 1976, Opasina 1985, Abdullah et al 1989, Rowe 1989, Lemos et al 1996a, Lemos et al 1996c, Lemos et al 1997, Driemeier et al 1998, Driemeier et al 1999, ovinos (Graydon et al 1991, Abdullah et al 1992, Lajis et al 1993, Lemos et al 1996b, Abdullah & Rajion 1997, Lemos et al 2008, Cruz et al 2000, Driemeier et al 2002, Brum et al 2007, caprinos (Opasina 1985, Lemos et al 1998, bubalinos (Rozza et al 2004, RietCorrea et al 2007) e eqüinos (Barbosa et al 2006).…”

Section: Introductionunclassified

Intoxicação experimental por Brachiaria decumbens em ovinos confinados

et al. 2010

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Brachiaria decumbens was fed as exclusive source of food to feedlot sheep. Sheep were evaluated in three periods of the year, of 60 days each, regarding their clinical status and was performed collection of blood samples to measure enzymatic activity of gamma glutamyltransferase and aspartate aminotransferase to evaluate their diagnostic importance and usefulness besides the clinical signs, necropsy and histopathology finds in hepatogenous photosensitization Brachiaria related. Out of 24 feedlot sheep, five died in the first period (February-April), four in the second (June-August) and two in the third (October-December). Main clinical signs were anorexia, jaundice, photophobia and two cases of slight dermatitis, besides dehydration, apathy and corneal opacity. Necropsy revealed generalized jaundice, distended gall bladder and liver with evident lobular pattern. The histological changes varied in severity according the time after the beginning of the plant ingestion; they were more significant in the liver and included bilestasis, swelling and vacuolation of hepatocytes, foammy macrophages, bile duct proliferation and mononuclear inflammatory cell infiltration, further crystal negative images were found within cytoplasm of macrophages present inside of hepatic sinusoid and in the periportal space and also optically active refringent crystal in the lumen of bile tubules. These finds are characteristic of hepatogenous photosensitization, mainly by presence of photophobia, even when the sheep did not present photodermatitis. The results of serum biochemistry activity, during the course of poisoning with strong relation between increased gamma glutamyltransferase activity, and lethality. Onset of arising gama glutamyltransferase activity was 11 days, in average, before beginning of clinical signs. Aspartate aminotransferase had increased activity only close to the beginning of clinical signs. Serum biochemistry results of GGT suggest that they are useful for a precocious diagnosis preventing deaths caused by ingestion of B. decumbens. Thirteen sheep didn't show clinical signs despite significant increases on serum enzyme activity, suggesting the existence of tolerant/resistant individuals. The experimental model of feedlot was adequate to study B. decumbens toxicosis in sheep.INDEX TERMS: Brachiaria decumbens, photosensitization, sheep, pathology, feedlot.

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“…Steroidal sapogenins, derived from the parent plant tissue saponins, have been isolated from rumen contents [125,126] and from bile in affected animals and identified primarily as metabolic derivatives of diosgenin [109,127] and yamogenin (the 25 S isomer of diosgenin) [93,108,109,126,128]. Lambs dosed with extracts from B. decumbens plant material developed liver lesions, bile duct proliferation with birefringent crystals found in the bile ducts [88,89,126].…”

Section: Identification and Metabolism Of Toxic Compoundsmentioning

confidence: 99%

Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants

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2015

Agriculture

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Signal grass (Brachiaria decumbens) is a highly productive tropical grass that is widespread through South America, Australia, Indonesia, Vanuatu and Malaysia due to its adaptation to a wide range of soil types and environments. Animal production from these B. decumbens pastures is highly variable due to sporadic outbreaks of photosensitisation associated with low growth rates of young animals, anorexia and wasting. The identification of B. decumbens toxicity through clinical signs may grossly underestimate the impact and severity of the disease. Affected animals without clinical signs have elevated serum liver enzyme concentrations resulting from blockage of the bile ducts by birefringent crystals, identified as calcium salts of steroidal saponins found in leaves and stems. The concentrations of the steroidal saponins vary through the year and within the plant. Young, green leaves contain 5-10 times the saponin concentration of mature leaves indicating that B. decumbens pastures are likely to be more toxic during sprouting and early growth. Previous exposure, selective grazing, and avoiding toxic leaves may partly explain apparent resistance of some animals to B. decumbens toxicity. Further research is needed to define growing conditions that produce elevated saponin levels and to investigate the impact of B. decumbens on rumen function.

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Epi-Sarsasapogenin and epi-smilagenin: two sapogenins isolated from the rumen content of sheep intoxicated by Brachiaria decumbens

Cited by 29 publications

References 9 publications

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

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

Intoxicação experimental por Brachiaria decumbens em ovinos confinados

Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants

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