Protodioscin levels in Brachiaria spp. in a sheep production system and a brief review of the literature of Brachiaria spp. poisoning in ruminants

Authors: GASPAR, ALBERTO - Federal University Of Mato Grosso; GUIZELINI, CAROLINA - Universidade Federal De Mato Grosso; ROBERTO, FRANCISCA - Universidade Federal Da Paraiba (UFPB); DIFANTE, GELSON - Federal University Of Mato Grosso; BRUMATTI, RICARDO - Universidade Federal De Mato Grosso; ITAVO, CAMILA - Universidade Federal De Mato Grosso; LEMOS, RICARDO - Universidade Federal De Mato Grosso; Lee, Stephen

Submitted to: Pesquisa Veterinaria Brasileira
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2021
Publication Date: 7/23/2021
Citation: Gaspar, A.O., Guizelini, C.C., Roberto, F.C., Difante, G.S., Brumatti, R.C., Itavo, C.C., Lemos, R.A., Lee, S.T. 2021. Protodioscin levels in Brachiaria spp. in a sheep production system and a brief review of the literature of Brachiaria spp. poisoning in ruminants. Pesquisa Veterinaria Brasileira. 41. Article e06921. https://doi.org/10.1590/1678-5150-PVB-6921.
DOI: https://doi.org/10.1590/1678-5150-PVB-6921

Interpretive Summary: Plants belonging to the Brachiaria genus are used in several countries as forage and are poisonous to several livestock species. Their toxic principle is protodioscin and yhe main clinical presentation of poisoning photosensitization. This study compared protodioscin levels in B. decumbens and B. Brizantha and the literature is reviewed on the concentrations and methodologies of collection and analysis of protodioscin in Brachiaria spp. The risk of contamination of pastures by more toxic species that may facilitate poisoning by plants of this genus in sheep is also evaluated. The experiment was conducted in pastures of B. brizantha, with invasion by by B. decumbens. Occurrence of cases of intoxication by Brachiaria spp. was the criteria for confirming pasture toxicity. In a flock of 69 sheep, five poisoning cases occurred, three sheep died, and two recovered. The protodioscin levels found in the evaluated pastures ranged from 0.70 to 0.45%. We suggest that Brachiaria spp. should be avoided in the pasture of grazing sheep.

Technical Abstract: Plants of the genus Brachiaria used in several countries as forage are poisonous to several livestock species. Their toxic principle is protodioscin, and the main form of clinical presentation of the toxicosis is hepatogenous photosensitization. This study aimed to compare protodioscin levels in B. decumbens and B. Brizantha and to review the literature on the concentrations and methodologies of collection and analysis of the toxic principle in Brachiaria spp. and the risk of contamination of pastures by more toxic species that may facilitate poisoning by plants of this genus in sheep. The experiment was conducted in pastures originally formed by B. brizantha, with many invasion points by B. decumbens. Occurrence of cases of intoxication by Brachiaria spp. was the criterion for confirming pasture toxicity. The forage samples were collected at ten random points every 28 days through manual grazing simulation. The samples were analyzed for protodioscin by high-performance liquid chromatography (HPLC) with light scattering by evaporation (ELSD) after being dried and crushed. In the flock of 69 sheep, five poisoning cases occurred, three sheep died, and two recovered. The protodioscin levels found in the evaluated pastures ranged from 0.70 to 0.45%; higher levels appeared in B. decumbens (7.09%) compared 1.04% in B. Brizantha. We suggest that Brachiaria spp. should be avoided in the pasture of grazing sheep.