Toxicity of the different vegetative stages of Amorimia pubiflora to sheep

Authors: LIMA, STEPHANIE - Universidade Federal De Mato Grosso; GODOY, KELLY - Universidade Federal De Mato Grosso; LEAL, PAULA - Universidade Federal De Mato Grosso; Lee, Stephen; Pfister, James; SOUZA, ALDA - Universidade Federal De Mato Grosso; DE BARROS, CLAUDIO - Universidade Federal De Mato Grosso; LEMOS, RICARDO - Universidade Federal De Mato Grosso

Submitted to: Toxicon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2018
Publication Date: 11/22/2018
Citation: Lima, S.C., Godoy, K.C., Leal, P.V., Lee, S.T., Pfister, J.A., Souza, A.I., De Barros, C.S., Lemos, R.A. 2018. Toxicity of the different vegetative stages of Amorimia pubiflora to sheep. Toxicon. 158:47-50. https://doi.org/10.1016/j.toxicon.2018.11.306.
DOI: https://doi.org/10.1016/j.toxicon.2018.11.306

Interpretive Summary: Toxic plants containing mono'uoroacetate (MFA) cause sudden death in livestock in Australia, South Africa and Brazil, causing economic losses to producers. The objective of this study was to determine the amount of MFA present in young leaves, mature leaves, senescent leaves, and seeds of Amorimia pubi'ora harvested at di'erent times of the year and to determine their toxic e'ect on sheep. Samples of Amorimia pubi'ora were collected during April, August and December of 2015 and March of 2016, separated according to the vegetative stage (young leaves, seeds, mature leaves, and senescent leaves), dried in an oven, and administered in daily doses of 5 g/kg/body weight (bw) of fresh leaves to sheep through ruminal cannulae. The experiment was divided into four stages according to the time of collection of the plant so that each sheep received a di'erent vegetative stage of the plant (young leaves, mature leaves, and senescent leaves). Only in the second stage of the experiment was it possible to collect A. pubi'ora seeds, which were administered using the same method used for the administration of the leaves. The sheep were dosed with the plant until they showed clinical signs of toxicosis or until the plant was no longer available. Aliquots of leaves and seeds of A. pubi'ora were analyzed for MFA concentration. The seeds and young leaves had higher concentrations of MFA than did the mature (harvested in August and December) and senescent (harvested in December) leaves. However, all vegetative stages of the plant were toxic and caused fatal poisoning in sheep. The results of our study showed that A. pubi'ora is toxic to sheep even when MFA concentrations are low, demonstrating that the presence of MFA is a risk factor for the occurrence of poisoning. Knowing the toxic principle and its variations allow us to determine the conditions for the occurrence of plant toxicosis as well as possible treatment, control, and prophylaxis methods, contributing signi'cantly to the reduction of economic losses by livestock producers from poisoning by MFA-containing plants.

Technical Abstract: Toxic plants containing mono'uoroacetate (MFA) cause sudden death in livestock in Australia, South Africa and Brazil, causing economic losses for livestock producers. The objective of this study was to determine the amount of MFA present in young leaves, mature leaves, senescent leaves, and seeds of Amorimia pubi'ora harvested at di'erent times of the year and to determine their toxic e'ect on sheep. Samples of Amorimia pubi'ora were collected during April, August and December, 2015 and March, 2016, separated according to the vegetative stage (young leaves, seeds, mature leaves, and senescent leaves), dried in an oven, and administered in daily doses of 5 g/kg/body weight (BW) of fresh leaves to sheep through ruminal cannulae. The experiment was divided into four stages according to the time of collection of the plant so that each sheep received a di'erent vegetative stage of the plant (young leaves, mature leaves, and senescent leaves). Only in the second stage of the experiment was it possible to collect A. pubi'ora seeds, which were administered using the same method used for the administration of the leaves. The sheep were dosed with the plant until they showed clinical signs of toxicosis or until the plant was no longer available. Aliquots of leaves and seeds of A. pubi'ora were analyzed for MFA concentration. The seeds and young leaves had higher concentrations of MFA than did the mature (harvested in August and December) and senescent (harvested in December) leaves. However, all vegetative stages of the plant were toxic and caused fatal poisoning. The results of our study showed that A. pubi'ora is toxic to sheep even when MFA concentrations are low, demonstrating that the presence of this compound is a risk factor for the occurrence of poisoning. Knowing the toxic principle and its variations allow livestock producers to determine the conditions for the occurrence of plant toxicosis as well as possible treatment, control, and prophylaxis methods, contributing signi'cantly to the reduction of economic losses on farms and ranches due to plant poisoning.