Ticktrefoil (Desmodium) species as a nutraceutical forage resource for animals

Ticktrefoil (Desmodium) species from the USDA, ARS, Plant Genetic Resources Conservation Unit (PGRCU) germplasm collection in Griffin, GA, were evaluated for their potential livestock nutraceutical (nutritional + pharmaceutical) value in a field small plot study at the Fort Valley State University (FVSU) Agricultural Research Station, Fort Valley, GA. Horse marmalade (Desmodium discolor Vogel), greenleaf ticktrefoil (Desmodium intortum [Mill.] Urb.), panicledleaf ticktrefoil (Desmodium paniculatum [L.] DC.), Hawaii ticktrefoil (Desmodium sandwicense E. May) and twisted ticktrefoil (Desmodium tortuosum [Sw.] DC.) were established in a greenhouse and transplanted to field plots, with plant material from each species harvested, freeze-dried, ground and analyzed for nutrient content and bioactivity. Crude protein (CP) levels in D. discolor and D. tortuosum averaged 233 g/kg, whereas CP in D. intortum, D. paniculatum and D. sandwicense ranged from 99 to 157 g/kg. The Desmodium species had in vitro true digestibility values of 755 to 878 g/kg. There were no detectable condensed tannins in D. discolor and D. tortuosum, whereas D. intortum, D. paniculatum and D. sandwicense averaged 88, 89 and 73 g/kg total condensed tannin, respectively. There were species differences in flavonoid content (p < .01), with the highest delphinidin and cyanidin concentrations in D. sandwicense and D. paniculatum, respectively. There were no detectable levels of delphinidin or cyanidin for D. discolor or D. tortuosum. Quercitin and kaempferol concentrations were highest in D. intortum and D. paniculatum, respectively, whereas D. discolor and D. tortuosum had the lowest values. The highest protein precipitable phenolics and total phenolic concentrations were for D. paniculatum. Desmodium species have potential as nutraceutical forage for livestock and warrant further investigation.