Identification of a New Locoweed (Oxytropis serioopetala) and Its Clinical and Pathological Features in Poisoned Rabbits

Abstract

By a series of experiments, we identified a new member of locoweed family, Oxytropis serioopetala, which produces swainsonine, a phytotoxin harmful to livestock. In order to evaluate the toxicity of Oxytropis serioopetala, its extract was administered to ten rabbits by gavage at a dose of 1.5 mg/kg body weight as swainsonine once daily. After the 20th day, the rabbits appeared depressive and anorexia. Besides, intention tremors were apparent upon move. Their eyes were dull. The rear limbs were severely weak and even progressed to partial paresis. Activities of serum aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (AKP) and urea nitrogen (BUN) levels in the poisoned rabbits increased significantly. Serum α-mannosidase (AMA) activity decreased markedly. Pathomorphological lesions in the locoweed-poisoned rabbits developed severe microvacuolation of visceral and neurological tissue. The extensive vacuolation was observed in liver, kidney and brain. These clinical and pathological features are similar to the symptoms of locoism.