Intoxicação experimental por Passiflora foetida (Passifloraceae) em caprinos

Abstract

Passiflora foetida is mentioned as a toxic plant by farmers in northeastern Brazil. This research aimed to establish the toxicity of P. foetida for goats, in different seasons of the year, and to determine its toxic compound. Initially, the plant collected two days before administration was non toxic at the daily dose of 40g per kg of body weight (g/kg) given during two days. Furthermore, the plant was administered immediately after collection at a dose of 4-8g/kg to four goats. The animal that ingested 8g/kg showed severe clinical signs, but recovered after treatment with sodium thiosulfate. The other three goats showed mild signs of poisoning and recovered spontaneously. The plant was then administered during different seasons to 23 goats at the dose of 10g/kg. The plant was significantly (P<0.05) more toxic during the dry season than during the rainy season; 11 out of 14 goats that received the plant in the dry season showed clinical signs, but only 3 out of 13 goats that ingested the plant during the rainy season had signs. All goats with clinical signs recovered after the administration of sodium thiosulfate. Clinical signs were apathy, tachycardia and tachypnea, jugular venous pulse, incoordination, bellowing, mydriasis, and sternal recumbence followed by lateral recumbence. Before each administration the plant was tested for cyanide by the picric acid paper test to estimate the cyanide concentration in the plant, which was defined as slight, moderate, high, and very high. Samples with slight reaction were not toxic, those with moderate reaction induced mild signs of poisoning, and those with high reaction induced severe clinical signs. Samples with very high concentrations of cyanide were not observed. The results demonstrated that P. foetida is a cyanogenic plant, which causes poisoning after the ingestion of fresh leaves, mainly during the dry period.