Plantas tóxicas para ruminantes no Agreste da Paraíba.

Abstract

Outbreaks of plant poisoning in ruminants in the Agreste of the State of Paraíba are described. This thesis is composed of three papers. In the first paper, accepted for publication in the Brazilian Journal of Veterinary Research, describes an outbreak of natural intoxication by Portulaca elatior (Portulacaceae) in cattle. Clinical signs included abdominal pain, muscle tremors, intense salivation, moderate bloat and dehydration. Macroscopic findings included dehydration, reddening of the mucosa of the pre-stomachs, abomasum and intestines, and ulceration of the ruminal mucosa. Histological lesions were degeneration and necrosis of the superficial layers of the pre-stomach epithelium, necrosis and inflammation of the intestinal mucosa and lymphoid necrosis. The second paper, accepted for publication in the journal Semina: Agrarian Sciences, describes the spontaneous and experimental intoxication of cattle by Cestrum laevigatum. The clinical signs observed in natural intoxications were respiratory distress, hypersalivation, jugular engorgement, muscle tremors, incoordination and recumbence. Experimental intoxication was performed in two cattle. Bovine 1 showed mild clinical signs after the ingestion of 35 g/kg body weight of the plant. After an intake of 50 g/kg, Bovine 2 showed apathy, stool dryness, hypersalivation, hyperexcitability, head pressure against objects, opisthotonous, nystagmus, miosis, jugular and episcleral vessel engorgement, ruminal atony, muscle tremors, falls, incoordination, convulsions, sternal decubitus and lateral decubitus followed by death. The main macroscopic changes observed in naturally intoxicated animals and experimental animals were found in the liver. The histopathological exam revealed diffuse centrilobular coagulation necrosis, associated with hemorrhage and congestion, with the presence of vacuolization of the hepatocytes of the midzonal regions. The third chapter, published in the journal Toxicon (v.135, p.12-16, 2017), reports an outbreak of natural intoxication of goats by Palicourea aenefusca. The clinical signs were characterized by motor incoordination, generalized muscle tremors, broad-based posture, tachypnea, tachycardia, vocalization and respiratory distress. Macroscopic and microscopic findings were characterized by hemorrhages and congestion of various organs. Pulmonary edema was also observed. The main microscopic findings consisted of cytoplasmic vacuolization and necrosis of the renal tubular epithelium.