Location: Poisonous Plant ResearchTitle: Pulmonary and hepatic lesions caused by the dehydropyrrolizidine alkaloid-producing plants Crotalaria juncea and Crotalaria retusa in donkeys Author
Submitted to: Toxicon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2013
Publication Date: 9/1/2013
Citation: Pessoa, C.R., Pessoa, A.F., Maia, L.A., Medeiros, R.M., Colegate, S.M., Barros, S.S., Soares, M.P., Borges, A.S., Riet-Correa, F. 2013. Pulmonary and hepatic lesions caused by the dehydropyrrolizidine alkaloid-producing plants Crotalaria juncea and Crotalaria retusa in donkeys. Toxicon. 71:113-120. Interpretive Summary: In different parts of the world, livestock poisoning caused by dehdropyrrolizidine alkaloids (DHPAs) seems primarily restricted to consumption of species from three plant families: Asteraceae (eg. Senecio, Eupatorium, Gnura), Fabaceae (eg. Crotalaria) and Boraginaceae (eg. Amsinckia, Cynoglossum, Echium, Heliotropium and Trichodesma). This study aimed to determine the susceptibility of donkeys to poisoning following exposure to C. juncea and C. retusa seeds at high and low doses, and to establish if the occurence of lung or liver lesions occurrence of lung or liver lesions depends on the type of DHPAs present in those plants and/or on the level and length of time and exposure.
Technical Abstract: The effects and susceptibility of donkeys to Crotalaria juncea and Crotalaria retusa poisoning were determined at high and low doses. Seeds of C. juncea conaining 0.074% of dehyrdropyrrolizidine alkaloids (DHPAs) were administered to three donkeys at 0.3, 0.6 and 1 g/kg body weight daily for 365 days. No clinical signs were observed and, on liver and lung biopsies, the only lesion was a mild liver megalocytosis in the donkes ingesting 0.6 and 1 g/kg/day. Two other donkeys that received daily doses of 3 and 5 g seed/kg showed initial respiratory signs 70 and 40 days after the start of the administration, respectiveyly. The donkeys were euthanized following severe respiratory signs and the main lung lesions were proliferation of Clara cells and insterstitial fibrosis. Three donkeys ingesting seeds of C. retusa containing 5.99% of monocrotaline at daily doses of 0.025, 0.05 and 0.1 g/kg for 365 days. No clinical signs were observed and, on liver and lung biopsies, the only lesion was a moderate liver megalocytosis in each of the three donkeys. One donkey that received a single dose of 5 g/kg of C. retusa seeds and another that received 1 g/kg daily for 7 days both showed severe clinical signs and died with diffuse centrilobular liver necrosis. No lung lesions were observed. Another donkey that recived a single dose of 2.5 g/kg of C. retusa seeds showed no clinical signs. The hepatic and pneumotoxic effects observed are consistent with an etiology involving DHPAs. Furthermore, the occurrence of lung or liver lesions correlates with the type of DHPAs contained in the seeds. Similarly as has been reported for horses, the data herein suggest that in donkeys some DHPAs are metabolized in the liver causing liver disease, whereas others are metabolized in the lung by Clara cells causing lung disease.