Intoxicação por Portulaca elatior (Portulacaceae) em caprinos

Abstract

An outbreak of poisoning by Portulaca elatior was diagnosed in the state of Paraíba, northeastern Brazil, during the rainy season. Between February and April, 16 out of 316 goats were affected and 13 died. Fifteen of the affected animals were from a flock of 16 goats introduced on the farm at the beginning of the rainy season. Clinical signs were intense salivation, reluctance to move, lip tremors, slight uncoordinated gait, diarrhea, bloat, abdominal pain, groans, dehydration and constant bellowing. The course of the disease ranged from 2 to 48 hours; 13 goats died and three recovered. Gross lesions were reddening of the mucosa of rumen and reticulum, hemorrhages in the ruminal serosa, ulcerations of the abomasal mucosa, and ecchymoses in the small intestinal mucosa. Histological examination revealed degeneration and necrosis of epithelial cells with vesicle formation in the fore stomachs associated with infiltration by neutrophils. Suspected to have caused the outbreak, Portulaca elatior was administered experimentally to three animals at doses of 40, 20 and 10 grams of the fresh plant per kg bodyweight, respectively. The goats that ingested 20 and 40g/kg died, and the one that ingested 10g/kg showed clinical signs but recovered. These animals showed similar clinical signs and histological lesions as those seen in the goats poisoned spontaneously, demonstrating that the disease was caused by the ingestion of Portulaca elatior. Oxalate concentration were determined in P. elatior and in another plant identified as Blutaparon vermiculare. P. elatior contained 6.37% of total oxalates and B. vermiculare 5.29%. B. vermiculare was administered experimentally to one goat at a dose of 40g/kg, without causing clinical signs. These results and the absence of oxalate crystals in the digestive system and kidneys of the goats necropsied suggest that poisoning by P. elatior is not caused by high oxalate concentration in the plant.