|De Melo, Lucio|
Submitted to: Pesquisa Veterinaria Brasileira
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2007
Publication Date: 10/1/2007
Publication URL: http://www.pprl.ars.usda.gov
Citation: Barbosa, R.C., Riet-Correa, F., Lima, E.F., Medeiros, R.M., Guedes, K.M., Gardner, D.R., Molyneux, R.J., De Melo, L.E. 2007. Experimental swainsonine poisoning in goats ingesting Ipomoea sericophylla and Ipomoea riedelii (Convolvulaceae). Pesquisa Veterinaria Brasileira, 27(10):409-414. Interpretive Summary: Ipomoea seicophylla and Ipomoea riedelii are plants commonly found in the semiarid regions of Paraiba Brazil. These plants cause serious poisoning problems in goats. This study was completed to confirm the poisoning as a glycoprotein storage disease observed in the goats, define the dosage required to induce poisoning, describe the clinical signs of poisoning, describe the clinical and histological lesions of poisoning and measure the concentration of the toxin, swainsonine, in the plant material and the resulting dosage required to induce intoxication. Clinical signs of poisoning and histological lesions were consistent with other swainsonine containing plants. The minimum toxic dose of swainsonine was 60 mg/kg and being 0.0004% of the dry matter intake.
Technical Abstract: Ipomoea sericophylla and Ipomoea riedelii cause a glycoprotein storage disease in goats. This paper reports the experimental poisoning in goats by dried I. sericophylla and I. riedelii containing 0.05% and 0.01% swainsonine, respectively. Three groups with four animals each were used. Group 1 received daily doses of 2g/kg body weight (bw) of dried I. sericophylla (150mg of swainsonine/kg). Goats from this group had clinical signs 36-38 days after the start of ingestion. Group 2 received dried I. riedelii daily doses of 2g/kg of I. riedelii (30mg of swainsonine/kg) for 70 days. No clinical signs were observed, therefore the swainsonine dose was increased to 60mg/kg for another 70 days. Goats from Group 2 had clinical signs 26-65 days after increase in swainsonine dose to 60mg/kg. Group 3 was used as control. In these experiments the minimum toxic dose was 60mg/kg which represents 0.0004% of the dry matter in goats ingesting 1.5% bw of the dry matter. For goats ingesting 2%-2.5% bw of dry matter this dose would be 0.00024%-0.0003% of the dry matter. After the end of the experiment two goats were euthanized and another six were observed for recovery of clinical signs. Four goats that continued to consume swainsonine containing plant for 39-89 days after the first clinical signs had nonreversible signs, while two goats that ingested the plant for only 15 and 20 days after the first clinical signs recovered completely. These and previous results indicate that irreversible lesions due to neuronal loss occur in goats that continue to ingest the plants for about 30 days after the first clinical signs. Clinical signs and histological lesions were similar to those reported previously for goats poisoned by swainsonine containing plants. No significant alterations were found in packed cell volume, red and white blood cell counts, hemoglobin and mean corpuscular hemoglobin concentrations, mean corpuscular volume, and serum levels of glucose, total protein, and albumin, and the serum activities of gamma glutamyl transferase and aspartate aminotransferase. Swainsonine concentration of 0.05% in I. sericophylla and 0.01% in I. riedelii are different from samples of these plants used in previous experiments, which contained 0.14% and 0.5% swainsonine, respectively, demonstrating a wide variation in the toxicity of different samples.