[Selenium toxicity in domestic animals].

Area of Science:

• Environmental Toxicology
• Animal Science
• Chemistry

Context:

• Selenium (Se) poisoning, historically noted in 13th-century China, was recognized as a toxic principle in the 1930s.
• Toxicity is influenced by the chemical form of selenium, animal species, and route of administration.
• Different forms of selenium exhibit varying toxicity levels, with soluble salts being more potent than poorly soluble forms or those found naturally in grains.

Purpose:

• To detail the varying toxicity of different selenium compounds.
• To describe the clinical and pathological manifestations of acute, subacute, and chronic selenium poisoning (selenosis) in animals.
• To highlight factors influencing selenium toxicity, including chemical form, species, and administration route.

Summary:

• Soluble selenium salts (e.g., Na2SeO3) are highly toxic, while elemental selenium and selenides are less toxic.
• Acute selenosis presents with garlic breath, lethargy, and organ congestion; subacute (blind staggers) involves neurological signs; chronic (alkali disease) causes hair loss, hoof lesions, and emaciation.
• Oral administration of selenium is generally less toxic than parenteral routes. Sheep and poultry show varying degrees of tolerance or specific symptoms.

Impact:

• Provides a comprehensive overview of selenium toxicity, aiding in diagnosis and management of poisoning in veterinary medicine.
• Differentiates between various forms of selenosis, crucial for understanding disease progression and treatment strategies.
• Informs agricultural practices regarding safe selenium supplementation levels and potential risks associated with contaminated feed or environments.