Location: Poisonous Plant ResearchTitle: Senecio grisebachii Baker: Pyrrolizidine alkaloids and experimental poisoning in calves
|PRELIASCO, MARCELA - Ministerio De Ganadería, Agricultura Y Pesca (MGAP)|
|MORAES, JORGE - Universidad De La República|
|GONZALEZ, ANA - Universidad De La República|
|URIARTE, GONZALO - Ministerio De Ganadería, Agricultura Y Pesca (MGAP)|
|RIVERO, RODOLFO - Ministerio De Ganadería, Agricultura Y Pesca (MGAP)|
Submitted to: Toxicon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2017
Publication Date: 5/3/2017
Citation: Preliasco, M., Gardner, D.R., Moraes, J., Gonzalez, A.C., Uriarte, G., Rivero, R. 2017. Senecio grisebachii Baker: Pyrrolizidine alkaloids and experimental poisoning in calves. Toxicon. 133:68-73. https://doi.org/10.1016/j.toxicon.2017.05.004.
Interpretive Summary: Senecio grisebachii is one of several of the Senecio genera found in South America. In Uruguay it is considered to be one of the major causes of hepatotoxic diseases in cattle. In order to further understand the effects of this poisonous plant on cattle plant material was collected, the toxin (pyrrolizidine alkaloids) concentration in the plant was determined and then the plant material was experimentally administered to a group of calves. The treated animals were evaluated clinically, blood samples taken for analysis of liver enzymes and after death animals were necropsied and tissues taken for histopathological examination. Intoxicated animals were clinically characterized with depression, anorexia, emaciation, colic and dehydration leading to death in some of the animals. The gross and histological lesions observed where consistent with pyrrolizidine alkaloid induced hepatic disease and are fully described in the manuscript. The results of this study are conclusive that Senecio grisebachii is a hepatotoxic plant of agricultural interest and which indicates the importance of implementing measures to control this weed.
Technical Abstract: The main objectives of this study were to determine the 1,2-dehydropyrrolizidine alkaloid (DHPA) content in Senecio grisebachii Baker (Compositae), to experimentally demonstrate its toxicity in calves and to describe the main clinical and pathological findings of this toxicity. S. grisebachii plants were collected in Paysandú, Uruguay. The concentration and identification of DHPA and associated N-oxides were determined using liquid chromatography-mass spectrometry. Three calves weighing 85–89 kg received doses of 15, 24 or 45 g of dry S. grisebachii per kg of body weight for 6, 10 or 20 days of treatment, respectively. Two animals received no treatment and served as controls. The animals were clinically evaluated, and blood samples were taken to study the serum levels of gamma glutamyltransferase (GGT), aspartate aminotransferase (AST) and alkaline phosphatase (FAS). After death, necropsy was performed and organ samples were taken for histopathological examination. The concentration of DHPA in S. grisebachii was found to be 0.29% (dry weight basis) as free base and 0.08% as N-oxide for a total DHPA concentration of 0.37%. Individual alkaloids identified included seneciophylline, senecionine and retrorsine. The disease was clinically characterized by depression, anorexia, emaciation, colic, dehydration and death in the three animals. Serum concentrations of GGT, AST and FAS were higher than normal beginning on day 7 after start of treatments. Necropsy findings included generalized edema, hemorrhage, ascites and a grayish liver with increased consistency. The main histological lesions were hepatic necrosis, fibrosis, hepatomegalocytosis and bile duct proliferation. The control calves showed no clinical signs of disease.