Clinical and pathological assessment of the calystegines in Ipomoea carnea in a goat model.

The alkaloids swainsonine and calystegines are found in some Ipomoea species. Swainsonine is a potent cellular glycosidase inhibitor that often poisons livestock while the calystegines inhibit cellular glycosides and can cause cellular glycoside dysfunction. The role of the calystegines in a livestock model is lacking as no studies to date have experimentally dosed calystegines alone in livestock. The objective of this study was to directly compare goats dosed with Ipomoea carnea containing both swainsonine and calystegines and I. carnea containing only the calystegines. Three groups of four goats were treated with ground alfalfa (control), I. carnea containing both swainsonine and calystegines or I. carnea containing only the calystegines, for 45 days. Animals were observed daily; body weights, serum biochemistries, and serum swainsonine concentrations were determined weekly. On day 45, all animals were euthanized and necropsied. Goats treated with I. carnea containing only the calystegines showed no changes in clinical disease, serum biochemistries, and histologic lesions while goats treated with swainsonine and the calystegines developed clinical disease and showed changes in serum biochemistries and histologic lesions characteristic of animals poisoned by other plants containing swainsonine. The data suggests that the calystegines play no role in field cases or experimental studies for plants containing swainsonine and the calystegines. Swainsonine is the principal driver of toxicity in plants containing both these toxins.