Intoxicação experimental por Brachiaria decumbens em ovinos confinados

Outbreaks of Brachiaria ruziziensis and Brachiaria brizantha intoxications in Brazilian experienced cattle

Brachiaria species are some of the most used forage species for raising Brazilian cattle because of their great nutritional value and adaptability to the tropical climate. However, cases of animal intoxication have been described. Animal species, age, genetic resistance, and previous adaptation to the forage can influence the susceptibility to intoxication. Cattle (young or adults), other adult ruminants and animals adapted to consumption (experienced flocks) are considered more resistant. The main clinical presentation is that of hepatogenous photosensitization. Brachiaria brizantha and Brachiaria ruziziensis are considered less toxic. The aim of this study is to describe three outbreaks of intoxication by B. brizantha and B. ruziziensis in experienced cattle, as well as to compare the concentrations of protodioscin in paddocks with and without clinical cases. It was observed that the two forage species are toxic to all age groups of cattle adapted to their consumption, and the concentrations of protodioscin present in the plant cannot be used as the only criterion for determining the occurrence of intoxication.

Economic impact of poisoning by Brachiaria grass in lambs from birth to finishing receiving to different levels of supplementation

This study aims to evaluate the economic impact of poisoning by Brachiaria grass in lambs from birth to weaning (suckling) and from weaning to slaughter (finishing) different levels of energy protein supplementation (EPS). In addition, we estimated the economic efficiency of removing lambs from the pasture as a control measure to minimize the losses caused by Brachiaria grass poisoning. Seventy lambs were used in the suckling phase, distributed in two nutritional treatments (control and creep feeding). Hospitalization expenses were US$ 1580.80 for the control treatment and US$ 256.16 for the creep feeding treatment. In the finishing phase, 48 lambs were distributed in four nutritional treatments, which consisted of increasing levels of EPS (mineral salt, 0.8, 1.6 and 2.4% of LW). The largest difference in total revenue (US$) was observed between 2.4% of BW EPS and mineral salt (- 2300.28) treatments. Hospitalization expenses were similar between nutritional treatments, being higher in the treatment 1.6% of BW EPS (US$ 578.15). The biggest difference in gross income (US$) observed was between 2.4% of BW EPS and mineral salt (- 1439.43) treatments. The Brachiaria grass poisoning caused economic losses to the sheep farming system, due to the death of lambs, reduced weight gain and lower weights at weaning and in the finishing phase. Brachiaria grass poisoning caused economic damage to the production system. There were direct losses, with the death of the lambs without supplementation, in the suckling and finishing phases. The supplementation increases the performance and reduces the mortality. The supplementation in high levels is efficient in reducing the economic impact of poisoning by Brachiaria grass in both periods of suckling and finishing.

Protodioscin levels in Brachiaria spp. in a sheep production system and a brief review of the literature of Brachiaria spp. poisoning in ruminants

ABSTRACT: Plants of the genus Brachiaria, used in several countries as forage, are poisonous to some livestock species. Their toxic principle is protodioscin, and the main form of clinical presentation of the toxicosis is hepatogenous photosensitization. Here we compare protodioscin levels in B. decumbens and B. brizantha and review the literature on the concentrations and methodologies of collection and analysis of the toxic principle in Brachiaria spp. and the risk of contamination of pastures by more toxic species that may facilitate poisoning by plants of this genus in sheep. The experiment was conducted in pastures originally formed by B. brizantha, with many B. decumbens invasion points. The occurrence of cases of poisoning by Brachiaria spp. was the criterion for confirming pasture toxicity. The forage samples were collected at ten random points every 28 days through manual grazing simulation. The samples were analyzed for protodioscin by high-performance liquid chromatography (HPLC) with light scattering by evaporation (ELSD) after being dried and crushed. In the flock of 69 sheep, five poisoning cases occurred, three sheep died, and two recovered. The protodioscin levels found in the evaluated pastures ranged from 0.70 to 0.45%; higher levels appeared in B. decumbens (7.09%) compared to 1.04% in B. brizantha. We suggest that Brachiaria spp. should be avoided in pastures where sheep are grazing.

Intoxicação espontânea por Brachiaria híbrida cv mulato I em ovinos e caprinos e experimental por Brachiaria híbrida cv mulato II em ovinos

RESUMO: Descreve-se a epidemiologia, sinais clínicos e lesões de uma enfermidade em ovinos e caprinos que cursa com fotossensibilização e morte. A doença espontânea ocorreu no município de Abelardo Luz, SC. De um rebanho de 350 ovinos e 278 caprinos, de corte, mantidos em pastagem de Brachiaria híbrida cv mulato I, adoeceram 27 animais, dos quais, 17 morreram e 10 recuperaram-se após terem sido removidos do local. A enfermidade caracterizou-se por lacrimejamento, hiperemia, edema das faces, das orelhas e das pálpebras seguidas de formação de crostas, corrimento nasal seroso, ulcerações na córnea e esclera e conjuntiva levemente amarelada. Seis ovinos e onze caprinos foram necropsiados na propriedade. As lesões macroscópicas observadas foram fígado de coloração castanha, vesícula biliar com conteúdo aumentado e bile grumosa, rins acastanhados com pontos vermelhos na superfície. Na avaliação microscopia foram observadas no fígado, lesões de intensidade leve a moderada caracterizadas principalmente por tumefação e ou, vacuolização de hepatócitos, megalocitose, fibrose periportal, proliferação biliar, pequenos aglomerados de macrófagos, aleatórios e infiltrado de eosinófilos, neutrófilos e macrófagos na periferia do lóbulo. Na luz de ductos biliares encontravam-se imagens negativas de cristais. Nos rins havia dilatação de túbulos variando de leve a acentuada, contração de tufo glomerular e distensão do espaço de Bowman. Quatro ovinos receberam experimentalmente Brachiaria híbrida cv mulato II ad libitum pelo período de 90 dias e não manifestaram alterações clinicas.

Experimental poisoning by Enterolobium contortisiliquum in sheep

ABSTRACT: Ingestion of Enterolobium contortisiliquum pods causes digestive disturbances, secondary hepatogenous photosensitization and abortions in ruminants. Pods were administered to sheep via a ruminal cannula to characterize acute poisoning. In Experiment 1, a single dose of 12g/kg of body weight (BW) was administered to three sheep in one experiment. One sheep died, and the other two recovered after presenting clinical signs. In Experiment 2, 10g/kg BW were administered daily to 15 sheep until the onset of clinical signs or for three consecutive days. Fourteen sheep showed mild to severe signs after the ingestion of 1-3 doses. Two sheep died, and the others recovered. Clinical signs in both experiments were diarrhea, anorexia, rumen atony, apathy, dehydration and tachypnea. The main macroscopic findings were an orange, frothy ruminal content witch contained pods fragments. The intestinal content was liquid. Detachment of the mucosa from the submucosa and ballooning degeneration of mucosal cells were observed histologically in the forestomachs. Evaluation of ruminal contents revealed acute lactic ruminal acidosis (ALRA). Bromatological analysis of E. contortisiliquum pods revealed 537.8g/kg DM (dry matter) of non-fibrous carbohydrates, which is sufficient to cause ALRA. Only one sheep in Experiment 2 had liver failure, characterized by jaundice, elevated serum activity of liver enzymes and histological lesions in liver biopsies. It is concluded that the administration of E. contortisiliquum pods in forage-fed sheep at doses of 10g/kg BW or higher may cause ALRA. The induction of liver failure in one sheep suggests that liver damage may occur in those sheep that do not develop acidosis.

Ultrahigh-Performance Liquid Chromatography-High-Resolution Quadrupole Time-of-Flight Mass Spectrometry Based Metabolomics Reveals Key Differences between Brachiaria decumbens and B. brizantha, Two Similar Pastures with Different Toxicities

Several species of Brachiaria (Poaceae) currently cover extensive grazing areas in Brazil, providing valuable source of feed for a large cattle population. However, numerous cases of toxicity outbreaks in livestock have raised concerns on safety of using these plants, especially B. decumbens. In this study, chemometric analysis of ultrahigh-performance liquid chromatography-high-resolution quadrupole time-of-flight mass spectrometry (UHPLC-HR-QTOF-MS) data has for the first time uncovered qualitative and quantitative differences between metabolomes of toxic B. decumbens and nontoxic B. brizantha. The steroidal saponin protoneodioscin was established as the main biomarker for B. decumbens when compared to B. brizantha, and therefore the key explanation for their phytochemical differentiation. Quantification of protodioscin in both plants showed no significant differences; consequently, the idea that this compound is solely responsible for toxicity outbreaks must be discarded. Instead, we propose that the added occurrence of its stereoisomer, protoneodioscin, in B. decumbens, can be considered as the probable cause of these events. Interestingly, the greatest concentrations of saponins for both species were reached during winter (B. decumbens = 53.6 ± 5.1 mg·g(-1) dry weight (D.W.); B. brizantha = 25.0 ± 1.9 mg·g(-1) D.W.) and spring (B. decumbens = 49.4 ± 5.0 mg·g(-1) D.W.; B. brizantha = 27.9 ± 1.4 mg·g(-1) D.W.), although in the case of B. decumbens these values do not vary significantly among seasons.

Spontaneous poisoning by Brachiaria decumbens in goats

Abstract: An outbreak of Brachiaria decumbens poisoning in goats in the state of Mato Grosso do Sul, Brazil, is described. Out of a herd of about 1,000 goats, seven goats died after showing photosensitivity (3 out 7 goats) and icterus (4/7). Other clinical signs included lethargy, dehydration and weight loss (7/7). At necropsy there was either hepatomegaly or liver atrophy; orange, yellow or gray discoloration - were observed in the liver of six goats. Two had accentuation of lobular pattern and punctate, linear or stellar fibrous depressions were randomly distributedover the capsular surface. Macroscopic changesattributedto liver failure consisting of hydropericardium (2/7) and ascites (2/7) were observed. Histologically, there was accumulation of refringent crystals in the bile ducts and infiltration of foamy macrophages in the liver of all goats. Foamy macrophages were also present in the hepatic and mesenteric lymph nodes of two goats. The diagnosis of B. decumbens poisoning was based on epidemiology, clinical signs, necropsy findings and histopathology.

Identification of lamb flocks susceptible and resistant against Brachiaria poisoning

Abstract: This study was designed to assess the influence of genetic resistance against brachiaria poisoning in sheep. Two groups of sheep, one identified as susceptible (formed by two ewes and one ram) and the other as resistant against brachiaria poisoning (formed by three ewes and one ram) were selected. Sheep considered susceptible were those that presented clinical signs of brachiaria poisoning at any time of their life; resistant sheep were those that even raised on Brachiaria spp. pastures, did not developed any sign of the poisoning during their life. The offspring of the two flocks (15 lambs from the sensitive flock and 9 lambs from the resistant flock) were placed into brachiaria pasture (initially Brachiaria decumbens and B. brizantha,and only B. decumbens after weaning) and followed up during two years (2013-2014). The determination of protodioscin levels in B. decumbens pasture was performed only in 2014 and revealed significant amounts of the toxic principle. Eleven lambs of the susceptible group were affected to some degree of brachiaria poisoning and six died; no lamb of the resistant group was affected. Clinical signs consisted of varying degrees of subcutaneous edema of the face and, erythema and loss of hair of the ears, crusts on the skin of ears, around the eyes and on planum nasale, scar deformation of the ears, and bilateral ocular discharge; affected lambs also sought for shadowy shelters and they were poor doers. Several sheep recovered from the condition and then relapsed. Necropsy findings in six lambs included pale mucous membranes, emaciation, dermatitis, scar deformation of the ears, large yellow livers with marked lobular pattern, and moderate infestation by Haemonchus contortus. Histologically the liver lesions were similar in all necropsied lambs but with varying degrees of severity; they were consistent with brachiaria poisoning and included architectural disruption of hepatocellular trabecula, clusters of foamy macrophages occasionally forming multinucleated giant cells, swollen and vacuolated hepatocytes, crystals or negative images of crystals in the biliary system, bilestasis, bile duct proliferation and lymphoplasmacytic infiltrate in portal triads. The skin lesions were those of photodermatitis and included epidermal necrosis, hyperkeratosis and dermal neutrophilic infiltrate. The results of this study allow to conclude that there is a genetic related resistance to brachiaria poisoning in sheep since the progeny of resistant sheep did not manifest the poisoning. The use of resistant flocks in brachiaria pastures is suggested as a valuable option for the prevention of brachiaria poisoning in sheep.

Performance of sheep grazing in pastures of Brachiaria decumbens, Brachiaria brizantha, Panicum maximum, and Andropogon gayanus with different protodioscin concentrations

Brachiaria spp. are the most important grasses for ruminants in central-western Brazil. However, the use of these pastures is limited by their toxicity due to steroidal saponins. This experiment was conducted for 60 days to demonstrate the resistance of sheep raised on Brachiaria spp. pastures to steroidal saponin poisoning. The experiment was composed by 48 animals randomly divided into four groups (n = 12). Among them, 32 4- to 5-month-old castrated male crossbred Santa Inês sheep, originating from flocks that had been grazing on Brachiaria spp. for more than three consecutive years, and 16 were non-adapted (naïve) sheep from flocks that never had prior contact with pastures of Brachiaria spp. were randomly divided into four groups. Each of the four experimental groups was composed by eight adapted and four non-adapted animals. The four experimental groups were introduced into paddocks, each of which contained a single grass: either Brachiaria decumbens, Brachiaria brizantha, Panicum maximum, or Andropogon gayanus. The addition of the naïve sheep to the groups was designed to detect pastures' toxicity to naïve sheep and to adjust the stocking rate to optimize the use of forage. The weight gains of sheep grazing on B. decumbens, B. brizantha, and P. maximum were similar; however, the A. gayanus group showed lower weight gains compared with the other groups (P < 0.05). The mean serum activities of γ-glutamyltransferase in the sheep grazing on B. decumbens were higher than those in the sheep from the other groups. No significant differences among the groups were found in aspartate aminotransferase, creatinine, albumin, or total protein serum concentrations. No clinical signs were observed in the adapted sheep in any of the pastures. Of the four non-adapted sheep introduced into the B. decumbens pasture, two showed clinical signs of steroidal saponin poisoning, and one died. No clinical signs were observed in the non-adapted sheep in the other pastures. The saponin (protodioscin) concentrations in the pastures varied from 3.3 to 12.2 g/kg DM in B. decumbens, from 2.8 to 9.1 g/kg DM in B. brizantha, and from 1 to 1.5 g/kg DM in A. gayanus. No saponins were found in P. maximum. It is concluded that sheep from flocks reared in pastures of B. decumbens and B. brizantha were resistant to steroidal saponin poisoning and showed similar weight gains to those of sheep grazing in other tropical pastures.

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

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 animais que morreram foram submetidos a necropsia e em todos os ovinos sobreviventes foi realizada biópsia hepática no final do experimento. Três animais do grupo GS adoeceram e dois morreram. Um ovino do grupo GSB adoeceu e morreu. Não houve alterações clínicas nos ovinos controles. Os principais sinais clínicos observados nos animais que adoeceram foram apatia, emagrecimento, fotofobia, hiperemia e secreção ocular e icterícia. Nenhum animal apresentou lesões cutâneas de fotossensibilização. O grupo que permaneceu no sol apresentou atividades séricas médias de AST e GGT significativamente maiores que a dos demais grupos (p<0,05) e os animais que permaneceram na sombra apresentaram níveis maiores de GGT (p<0,05) em comparação ao grupo controle. A histopatologia das amostras de fígados dos ovinos com sinais clínicos demonstrou tumefação e vacuolização de hepatócitos, necrose individual de hepatócitos, macrófagos espumosos com cristais birrefringentes intracitoplasmáticos e dentro de ductos biliares e infiltrado mononuclear periportal. Amostras do capim fornecidas aos cordeiros evidenciaram níveis médios de 0,94±0,80% da saponina protodioscina. As observações do presente experimento sugerem que a não exposição ao sol não evita a presença de sinais clínicos da intoxicação, mas que a exposição solar exacerba os sinais clínicos.

Avaliação lectino-histoquímica de fígado e rim de ovinos com fotossensibilização causada por Brachiaria decumbens

Embora sejam as forrageiras mais importantes para a pecuária de corte (bovinocultura de corte) no Brasil, em certas épocas ou condições, Brachiaria spp. podem ser tóxicas e causar surtos de fotossensibilização hepatógena que determinam significativas perdas econômicas. Animais que se alimentam em pastos de Brachiaria spp. comumente apresentam macrófagos espumosos isolados ou agrupados, além de cristais no interior de ductos biliares. Saponinas esteroidais têm sido identificadas nestes cristais e são responsabilizadas por lesar o fígado levando ao acúmulo de filoeritrina. Por vezes, imagens negativas desses cristais podem estar presentes no citoplasma de macrófagos espumosos. A patogênese de formação e o tipo de material armazenado nas células espumosas ainda são desconhecidos. A técnica de lectino-histoquímica visa auxiliar na detecção desses macrófagos e, consequentemente, no diagnóstico, além de identificar quais os resíduos de açúcares específicos que estão presentes no citoplasma das células espumosas. Assim, este trabalho teve por objetivo identificar quais lectinas são mais indicadas na detecção de saponinas esteroidais no fígado e rim de ovinos com fotossensibilização causada por Brachiaria decumbens. Fragmentos de fígado e rim de quinze ovinos, de ambos os sexos e idade variável, oriundos de Conceição do Mato Dentro, Minas Gerais, e um ovino mantido em pastagem livre de Brachiaria spp. foram avaliados pela técnica de lectino-histoquímica. Quatorze lectinas foram utilizadas (Con-A, DBA, SBA, PNA, SJA, RCA-I, UEA-I, WGA, SWGA, GSL, PSA, PHA-L, PHA-E e LCA). Verificou-se que, no fígado de ovinos com fotossensibilização provocada pela ingestão de Brachiaria decumbens, a lectina PNA apresentou especificidade e acentuada reatividade aos macrófagos espumosos, bem como especificidade e leve reatividade aos hepatócitos; a lectina WGA teve especificidade e moderada reatividade aos macrófagos espumosos do fígado e especificidade e leve reatividade aos hepatócitos; e as lectinas SBA, GSL e LCA apresentaram especificidade e moderada reatividade aos macrófagos espumosos, entretanto, não foram específicas para hepatócitos. No rim dos ovinos, a lectina PNA foi a que apresentou maior reatividade. Avaliações lectino-histoquímicas ainda não haviam sido realizadas em fígado e rim de ovinos com fotossensibilização provocada por Brachiaria spp.

Doenças de ovinos diagnosticadas no Laboratório de Anatomia Patológica Animal da Universidade Federal de Mato Grosso do Sul (1996-2010)

Nas últimas décadas a pecuária ovina cresceu significativamente no Brasil. Concomitantemente, grupos de pesquisas e laboratórios de diagnósticos realizam estudos retrospectivos com a finalidade de fornecer subsídios técnico-científicos para os médicos veterinários. Desta forma, realizou-se um estudo de prevalência nos arquivos do Laboratório de Anatomia Patológica Animal (LAP) da Universidade Federal de Mato Grosso do Sul (UFMS) no período de Janeiro de 1996 a Dezembro de 2010. O Laboratório de Bacteriologia da UFMS e o Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul forneceram apoio diagnóstico nos casos de mannheimiose pulmonar e scrapie, respectivamente. Os laudos da espécie ovina foram revisados e agrupados em conclusivos e inconclusivos, dos quais foram excluídos os casos experimentais e de outros estados e países. Os casos conclusivos foram classificados de acordo com a etiologia da doença. Os exames da espécie ovina somaram 331 laudos (3,97 %) de um total de 8.333 casos diagnosticados no período. Destes, foram excluídos sessenta e quatro (19,3%) casos experimentais e materiais oriundos de outros estados ou países. Dos 267 casos remanescentes, 87 (32,6%) foram inconclusivos e 180 (67,4%) considerados conclusivos, sendo 60 (33,3%) doenças infecciosas e parasitárias; 45 (25%) intoxicações e toxi-infecções; 41 (22,8%) "lesões sem causa definida"; 22 (12,2%) doenças metabólicas e nutricionais; 10 (5,6%) foram classificadas como "outros distúrbios" e 2 (1,1%) neoplasmas. A hemoncose, intoxicação por Brachiaria spp., pleuropneumonias, broncopneumonias, pneumonias fibrinonecrosante ou fibrinossupurativa sem causa definida e a intoxicação por cobre foram as doenças mais prevalentes no período estudado. Dois casos de scrapie foram diagnosticados no período.

Brachiaria spp. poisoning of ruminants in Brazil

Brachiaria species are the most important grasses for cattle production in Brazil. However, a limiting factor for the use of Brachiaria spp. is their toxicity. Most outbreaks of hepatogenous photosensitization are caused by B. decumbens; however B. brizantha, B. humidicola and B. ruziziensis can also cause poisoning. The poisoning affects cattle, sheep, goats and buffalo. Sheep are more susceptible than other animal species and the young are more susceptible than adults. There are differences in susceptibility among animals of the same species and it has been suggested that this resistance is genetic. Also has been suggested that buffalo and probably some sheep are resilient, i.e. when poisoned these animals have histologic lesions and high GGT serum concentrations, but do not show clinical signs. In general, saponin concentrations are higher in growing plants, but outbreaks occur all over the year, probably due to unexplained rise in saponin concentration in the plant. A clinical syndrome of progressive weight loss and death, without photosensitization, has been reported in cattle poisoned by B. decumbens. Main preventive measures are based on the selection of resistant or resilient animals and on the development of Brachiaria species or varieties with low saponin concentration.