Comparative toxicity of selenium from seleno-DL-methionine, sodium selenate, and Astragalus bisulcatus in pigs

Selenium is an essential micronutrient, although ingestion in excess in pigs can cause disease conditions including neurological dysfunction and chronic skin and hoof lesions. Controlled feeding trials in growing swine, using the same Se content in feed sources, resulted in higher concentrations (p 0.05) of Se in blood and organs of pigs fed seleno-DL-methionine compared with those receiving Astragalus bisulcatus or sodium selenate. Clinical signs of Se toxicity including neurological signs of paralysis were more severe and occurred sooner in the A. bisulcatus group than in the sodium selenate or seleno-DL-methionine groups. All five pigs fed A. bisulcatus developed neurological signs of paralysis, and in four the signs occurred within 5 days of the start of treatment. Four of five pigs fed sodium selenate also developed paralysis, but this occurred 4 to 21 days after treatment began. The fifth pig in the group developed signs of chronic selenosis. Two of five pigs fed seleno-DL-methionine developed paralysis on 9 and 24 days, respectively, and the remaining three developed chronic selenosis. Selenium fed to pigs in three forms [plant (A. bisulcatus), sodium selenate, or seleno-DL-methionine] resulted in neurological dysfunction and lesions of symmetrical poliomyelomalacia. These were most severe in the A. bisulcatus group, which also had polioencephalomalacia. Although seleno-m-methionine caused the greater increase in tissue and blood Se concentrations, this did not correlate with severity of pathological changes, since animals fed A. bisulcatus developed more severe and disseminated lesions

Selenium poisoning in cattle (Chapter 74)

Selenium is readily absorbed by all plants. However certain soils contain selenium in amounts and forms that render some plants toxic to animals, plants have been divided into two groups according to their ability to accumulate selenium: (i) primary selenium-accumulators or indicator plants, which include species of the Astragalus, Haplopappus and Stanleya genera. These plants accumulate low molecular weight, water soluble organic compounds and selenate (Anon., 1980) to give selenium levels of 50 to several thousand mg kg-1; and (ii) non-accumulator plants which include grasses, shrubs, small grains, alfalfa and some forbs. These plants usually accumulate less than 50mg kg-1 (generally 5-12mg kg-1) selenium as organic forms in plant proteins. Selenium poisoning in livestock most frequently involves these non-accumulator plants

Larkspur Poisoning of Cattle: Plant and Animal Factors that Influence Plant Toxicity

Toxic larkspurs (Delphinium species) cause large economic losses from cattle deaths, increased management costs, and reduced utilization of pastures and rangelands. Larkspur toxicity to cattle can vary by geographic location due to toxic alkaloid content. Larkspur alkaloid chemistry can be used to predict plant toxicity. Cattle breeds differ in their susceptibility to larkspur poisoning. As cattle age from yearlings to two-year olds, they become less susceptible to larkspur. Heifers are three times more likely to be poisoned at the same dose of larkspur alkaloids than either bulls or steers, suggesting that they must be managed differently on rangelands where larkspur is present. © 2020The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

Rats offspring exposed to Ipomoea Carnea and handling during gestation: neurochemical evaluation

The present study evaluated the central monoamine levels of male and female adult rat offspring exposed orally by gavage to 0.0, 0.7, 3.0 and 15.0 mg/kg I. carnea aqueous extract daily, from gestation day (GD) 5 to GD 21. Several alterations in the monoamine activity systems were observed. However, the major differences were noted between the 0.0 mg/kg and the no gavage control groups, showing that alterations showing that alterations were not due to the alterations to the aqueous extract. The control data showed that gavage and handling of dams were stressful enough to produce a significant decline in 3,4-dihydroxyphenylacetic acid (DOPAC) and an increase in vanilmandelic acid (VMA), indicating decreased dopamine (DA) and enhanced norepinephrine (NE) activity, respectively.<br>Estudo anterior realizado em filhotes de ratas tratadas diariamente por gavage com 0,0, 0,7, 3,0 e 15,0 mg/kg de uma solução aquosa obtida de folhas frescas da Ipomoea carnea, do dia 5 ao dia 21 da gestação, mostrou poucas alterações comportamentais na prole em vida adulta. O presente estudo teve como objetivo avaliar a atividade e níveis das monoaminas cerebrais nas proles masculina e feminina expostas ao mesmo tratamento acima descrito. As maiores alterações encontradas, entretanto, foram entre os grupos 0,0 mg/kg e controle negativo (no gavage), impedindo a atribuição das alterações encontradas à solução aquosa. O dados resultantes do grupo controle sugerem que o estresse provocado pela gavage e pelo manuseio das fêmeas enquanto prenhes é suficiente para produzir um importante declínio nos níveis do ácido 3,4 dihidroxifenilacético (DOPAC) e um não menos importante aumento nos níveis do ácido vanilmandélico (VMA), promovendo maior atividade do sistema noradrenérgico (NE)

Encefalopatia hereditária em bovinos no estado do Espírito Santo

Descrevem-se os aspectos epidemiológicos e clínico-necroscópicos de uma doença neurológica hereditária observada em bovinos no município de Ecoporanga, norte do Estado do Espírito Santo. Trata-se de enfermidade do sistema nervoso central verificada exclusivamente em fêmeas, filhas de touro reprodutor de 5 anos de idade da raça Nelore, oriundo do município de Curvelo, Minas Gerais, com vacas mestiças Nelore x Quianini; bezerros machos oriundos deste cruzamento não demonstraram quaisquer sinais relacionados à enfermidade. Os sinais clínicos, presentes ao nascimento ou detectáveis nas primeiras semanas de vida, caracterizam-se por ataxia, perda do equilíbrio, instabilidade, andar em círculos, posicionamento incorreto dos membros no animal em estação ou em marcha (afastamento e/ou desvio de membros da posição normal) e desvio lateral da coluna (eixo principal do corpo em diagonal). De animal para animal, há marcada variação na intensidade das manifestações clínicas. Os bovinos mais afetados morrem devido à incapacidade de se alimentar. O exame macroscópico evidenciou, em grau variável de intensidade, áreas de depressão assimétrica setorial, sobretudo nos lobos frontal e temporal do córtex telencefálico e no córtex cerebelar. Em adição observou-se atrofia de grupos musculares de membros correspondentes às porções defeituosas no sistema nervoso central. O estudo histológico inicial revelou que as áreas deprimidas devem-se à redução setorial de populações neuronais (provavelmente abiotrofia/atrofia) principalmente nos lobos cerebrais frontal e temporal e nas camadas granular e molecular do córtex cerebelar. Estudos morfométrico, imunohistoquímico e ultraestrutural estão sendo realizados e devem trazer mais informações sobre os aspectos microscópicos e patogenéticos. Os achados epidemiológicos indicam que a enfermidade está diretamente ligada ao cromossoma X, com penetrância completa e expressividade variável