Pulmonary and hepatic lesions caused by the dehydropyrrolizidine alkaloid-producing plants Crotalaria juncea and Crotalaria retusa in donkeys

Plants causing poisoning outbreaks of livestock in South America: A review

This paper reviews toxic plants for livestock in South America. We included 219 plants in this review, considering only the plants that caused at least one demonstrated outbreak of poisoning. Plants reported as toxic in other regions and present in South America, but with no confirmed outbreaks of poisoning in this region, are not included. We report the main aspects of the epidemiology, clinical signs, pathology and economical importance of the poisonings. Initially, the toxic plants are described based on their toxic compounds, but because the toxic compound is unknown in 92 (42%) of the plants we also classify them according to the affected system. This review highlights the great diversity of toxic plants capable of affecting livestock in South America, and for this reason studies in this regard should be intensified.

CHOP Regulates Endoplasmic Reticulum Stress-Mediated Hepatoxicity Induced by Monocrotaline

Monocrotaline (MCT), a pyrrolizidine alkaloid, is the major toxin in Crotalaria, which causes cell apoptosis in humans and animals. It has been reported that the liver is a vulnerable target of MCT. However, the exact molecular mechanism of the interaction between endoplasmic reticulum (ER) stress and liver injury induced by MCT is still unclear. In this study, the cytotoxicity of MCT on primary rat hepatocytes was analyzed by a CCK-8 assay and Annexin V-FITC/PI assay. Protein expression was detected by western blotting and immunofluorescence staining. As a result, MCT significantly decreased the cell viability and mediated the apoptosis of primary rat hepatocytes. Meanwhile, MCT could also induce ER stress in hepatocytes, indicated by the expression of ER stress-related proteins, including GRP78, p-IRE1α, ATF6, p-eIF2α, ATF4, and CHOP. Pretreatment with 4-PBA, an inhibitor of ER stress, or knockdown of CHOP by siRNA could partly enhance cell viability and relieve the apoptosis. Our findings indicate that ER stress is involved in the hepatotoxicity induced by MCT, and CHOP plays an important role in this process.

Crotalaria spectabilis poisoning in horses fed contaminating oats

The present report describes the clinical and pathological changes induced by the consumption of oats contaminated with Crotalaria spectabilis seeds by horses. Eighty horses were exposed to oats containing 10 g/kg of C. spectabilis seeds with 0.46% pyrrolizidine alkaloids, and 21 horses died within a 6-month period. Clinical signs included jaundice, apathy, a hypotonic tongue, ataxia, hyporexia, weight loss, aimless wandering, violent behavior, and proprioceptive deficits. Pathological findings were predominant in the liver and included periportal bridging fibrosis, megalocytosis, centrilobular necrosis, and bile stasis. Other findings were Alzheimer's type II astrocytes in the cortex, midbrain, basal nuclei, brainstem and pons; multifocal edema and hemorrhage in the lungs; and degeneration and necrosis of the tubular epithelium of kidneys. Horses are highly sensitive to pyrrolizidine alkaloid-containing plants, and the observed clinical and pathological findings are typical of this poisoning. The seeds were planted, and botanical identification of the adult plants confirmed the diagnosis of C. spectabilis poisoning.

Donkey Internal Medicine—Part I: Metabolic, Endocrine, and Alimentary Tract Disturbances

Metabolic and endocrine disturbances are common in donkeys. This species has an inherent ability to thrive with limited and poor-quality roughage. Donkeys are extremely efficient in energy storage and mobilization, which predisposes to hyperlipemia, obesity, and metabolic syndrome. The prevalence of dyslipidemias is higher in donkeys than other equids, which is more evident under stressful conditions. Diagnosis of endocrine and metabolic disorders in donkeys should be based on species-specific information considering that differences in a multitude of variables compared with horses have been demonstrated. Protocols to assess endocrine disorders (e.g., pituitary pars intermedia dysfunction, metabolic syndrome, and thyroid illness) are unavailable, and extrapolation from horse data can be misleading. Treatment guidelines for these conditions in donkeys are currently not reported. On the other hand, the typical stoic and hardy behavior of donkeys can hinder prompt diagnosis of gastrointestinal problems, specifically colic, which is commonly caused by dental issues in this species. Moreover, subclinical gastric ulcer syndrome appears to be a common pathology in this species, especially in working donkeys.

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Donkeys are different to horses.

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Numerous physiological and clinic-pathologic idiosyncrasies are reported in horses.

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Data published for horses should not be extrapolated for donkeys.

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Specific reference ranges, doses, and protocols have to be used for donkeys.