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United States Department of Agriculture

Agricultural Research Service

Research Project: Understanding and Mitigating the Adverse Effects of Poisonous Plants on Livestock Production Systems

Location: Poisonous Plant Research

Title: Weather and plant age affect the levels of steroidal saponin and Pithomyces chartarum spores in Brachiaria grass

Authors
item Lima, Flavia -
item Haraguchi, Mitsue -
item Pfister, James
item Guimaraes, Victor -
item Andrade, Diogo -
item Ribeiro, Carolina -
item Costa, Gustavo -
item Araujo, Ana -
item Fioravanti, Maria -

Submitted to: International Journal of Poisonous Plant Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 10, 2013
Publication Date: April 1, 2013
Citation: Lima, F.G., Haraguchi, M., Pfister, J.A., Guimaraes, V.Y., Andrade, D.D., Ribeiro, C.S., Costa, G.L., Araujo, A.L., Fioravanti, M.C. 2013. Weather and plant age affect the levels of steroidal saponin and Pithomyces chartarum spores in Brachiaria grass. International Journal of Poisonous Plant Research. 2:45-53.

Interpretive Summary: Brachiaria species are cultivated worldwide in tropical and subtropical climates as the main forage source for ruminants. Numerous tropical and warm-season grasses cause photosensitization via liver toxicity, among them several species of Brachiaria. Steroidal saponins present in these plants may be responsible for liver damage. However, sporidesmin and other mycotoxins (types of fungus growing on plants) are likely to produce synergistic effects, which could explain the sporadic incidence of poisoning. The objective of this study was to evaluate the relation between steroidal saponins, fungal spores present in Brachiaria, and the possible influence of weather factors on saponin and spore levels. The saponin detected in B. brizantha and B. decumbens was protodioscin. The saponin concentration was higher in immature plants during early growth; further, B. decumbens had a higher amount of saponin than found in B. brizantha. The level of saponin concentration was moderately influenced by weather variables; the two main variables were the maximum sunshine duration and total cumulative precipitation. P. chartarum spore count was higher in older plants and did not differ between B. brizantha and B. decumbens. Spore counts were mainly influenced by maximum precipitation and average evaporation

Technical Abstract: Brachiaria species are cultivated worldwide in tropical and subtropical climates as the main forage source for ruminants. Numerous tropical and warm-season grasses cause hepatogenous photosensitization, among them several species of Brachiaria. Steroidal saponins present in these plants may be responsible for liver damage. However, sporidesmin and other hepatotoxic mycotoxins are likely to produce synergistic effects, which could explain the sporadic incidence of poisoning. The objective of this study was to evaluate the relation between steroidal saponin, Pithomyces chartarum spores present in Brachiaria, and the possible influence of meteorological factors on saponin and spore levels. The saponin detected in B. brizantha and B. decumbens was protodioscin. The saponin concentration was higher in immature plants during early growth; further, B. decumbens had a higher amount of saponin than found in B. brizantha. The level of saponin concentration was moderately influenced by weather variables; the two main variables were the maximum sunshine duration and total cumulative precipitation. P. chartarum spore count was higher in older plants and did not differ between B. brizantha and B. decumbens. Spore counts were influenced by maximum precipitation and average evaporation.

Last Modified: 10/24/2014
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