Abstract It is well known that several of the swainsonine-containing plant species found widespread around the world have a negative economic impact in each country. In Argentina, most of the information on the poisonous plant species that produce α-mannosidosis is published in Spanish and thus not available to most English-speaking researchers interested in toxic plants. Therefore, the aim of this review is to summarize the information about swainsonine-containing plants in Argentina, which are extensively distributed throughout different ecoregions of the country. To date, five species from three genera have been shown to induce α-mannosidosis in livestock in Argentina: Ipomoea carnea subsp. fistulosa, Ipomoea hieronymi subsp. calchaquina (Convolvulaceae), Astragalus garbancillo, Astragalus pehuenches (Fabaceae), and Sida rodrigoi (Malvaceae). These species contain the indolizidine alkaloid swainsonine, which inhibits the lysosomal enzyme α-mannosidase and consequently affects glycoprotein metabolism, resulting in partially metabolized sugars. The prolonged consumption of these poisonous plants produces progressive weight loss and clinical signs related to a nervous disorder, characterized by tremors of head and neck, abnormalities of gait, difficulty in standing, ataxia and wide-based stance. Histological lesions are mainly characterized by vacuolation of different cells, especially neurons of the central nervous system. The main animal model used to study α-mannosidosis is the guinea pig because, when experimentally poisoned, it exhibits many of the characteristics of naturally intoxicated livestock.

The clinical and pathological findings of the experimental poisoning by Senna occidentalis in pigs are described. Six pigs were distributed into two groups, one of which was fed a ration containing 10% pods and seeds of S. occidentalis for 30 days and the other group remained as a control group. The intoxicated animals showed lethargy, ataxia, muscular tremors, emaciation and recumbency. The enzyme creatine phosphokinase increased significantly in pigs intoxicated with S. occidentalis (p<0.05). The histopathology revealed that the intoxicated pigs mainly had degeneration of the muscle fibres and fibrosis in the skeletal muscles. Electron microscopy revealed mitochondrial lesions. The results confirm the myotoxic effect of chronic poisoning by S. occidentalis in pigs.

Se describen los hallazgos clínicos y patológicos del envenenamiento experimental por Senna occidentalis en cerdos. Seis cerdos se distribuyeron en dos grupos, uno de los cuales se alimentó con una ración que contenía 10% de vainas y semillas de S. occidentalis por 30 días y el otro grupo permaneció como grupo control. Los animales intoxicados mostraron letargia, ataxia, temblores musculares, emaciación y recumbencia. La enzima creatina fosfoquinasa aumentó significativamente en los cerdos intoxicados con S. occidentalis (p<0.05). La histopatología reveló que los cerdos intoxicados mostraron principalmente degeneración de las fibras musculares y fibrosis en los músculos esqueléticos. La microscopía electrónica reveló lesiones mitocondriales. Los resultados confirman el efecto miotóxico de la intoxicación crónica por S. occidentalis en cerdos.

Ipomoea carnea subsp. fistulosa, aguapeí ou mandiyura, causa uma doença de depósito lisossomal em caprinos. A planta contém vários alcalóides, principalmente swansonine, que inibe uma α-mannosidase lisossomal e uma mannosidase II do Golgi. A intoxicação ocorre pela inibição dessas hidrolases. Há vacuolização neuronal, disfunção endócrina, lesões cardiovasculares e gastrointestinais e distúrbios imunológicos. No presente trabalho é descrita a intoxicação experimental por Ipomoea carnea subsp. fistulosa em caprinos da Argentina. Cinco cabras receberam folhas frescas e ramos de Ipomoea. No começo eles não consumiram a planta, mas depois ela foi preferida a qualquer outras forrageiras. Altas doses induziram uma intoxicação rápida, enquanto que com doses baixas demora mais tempo. As cabras foram sacrificadas quando ficavam em decúbito. Cérebro, cerebelo, medula oblonga, ponte e colículos foram processados rotineiramente para histologia. Aos nove dias, encontramos: fascie anormal, narinas dilatadas, posturas anormais da cabeça, tremores cefálicos e nistagmo, dificuldade para permanecer na estação. Posteriormente, presentearam a tendência de queda, sempre à esquerda, com convulsões espásticas. Os neurônios de Purkinje e os os núcleos profundos foram danificados. Como conseqüência, emergiu a falta de coordenação de movimentos voluntários. A hiper-reflexo coclear originou postura anormal, movimentos de cabeça e tremores. A retirada produz reflexos hipersensibilidade nos flexores dos quatro membros, depois depressão e letargia. As respostas anormais estão ligadas a lesões do colículo. Injurias no tálamo alteram o reflexo de retirada, mostrando uma reação incompleta. Os pelos eriçados da região cervical podem representar uma resposta nociceptiva também regulada pelo tálamo. A depressão pode estar associada com agonistas do ácido lisérgico presentes na Ipomoea. Esses sintomas estão relacionados com lesões em diferentes partes do SNC.

Ipomoea carnea subsp. fistulosa, aguapei or mandiyura, is responsible for lysosomal storage in goats. The shrub contains several alkaloids, mainly swansonine which inhibits lysosomal α-mannosidase and Golgi mannosidase II. Poisoning occurs by inhibition of these hydrolases. There is neuronal vacuolation, endocrine dysfunction, cardiovascular and gastrointestinal injury, and immune disorders. Clinical signs and pathology of the experimental poisoning of goats by Ipomoea carnea in Argentina are here described. Five goats received fresh leaves and stems of Ipomoea. At the beginning, the goats did not consume the plant, but later, it was preferred over any other forage. High dose induced rapid intoxication, whereas with low doses, the course of the toxicosis was more protracted. The goats were euthanized when they were recumbent. Cerebrum, cerebellum, medulla oblongata, pons and colliculi, were routinely processed for histology. In nine days, the following clinical signs developed: abnormal fascies, dilated nostrils and abnormal postures of the head, cephalic tremors and nystagmus, difficulty in standing. Subsequently, the goats had a tendency to fall, always to the left, with spastic convulsions. There was lack in coordination of voluntary movements due to Purkinje and deep nuclei neurons damage. The cochlear reflex originated hyperreflexia, abnormal posture, head movements and tremors. The withdrawal reflex produced flexor muscles hypersensitivity at the four legs, later depression and stupor. Abnormal responses to sounds were related to collicular lesions. Thalamic damage altered the withdrawal reflex, showing incomplete reaction. The observed cervical hair bristling was attributed to a thalamic regulated nociceptive response. Depression may be associated with agonists of lysergic acid contained in Ipomoea. These clinical signs were correlated with lesions in different parts of the CNS.