Técnicas para controle e prevenção da intoxicação em ruminantes por plantas que contém monofluoroacetato de sódio.

Abstract

Plants containing sodium monofluoroacetate (MFA) cause acute heart failure in ruminants, which is usually associated with exercise. The control of this type of poisoning based on the placement of fences in areas infested by these plants, the use of herbicides and the removal of them, most of the time has limited success. With the objective of studying and developing new techniques for the control and prevention of intoxications in ruminants by plants containing MFA, this thesis is composed of three chapters. In Chapter I, a bibliographic review was carried out with the new techniques that can be used to help in the control and prevention of intoxications in ruminants by plants containing MFA. In Chapter II, it was evaluated whether the resistance to intoxication by Amorimia septentrionalis in goats, obtained by the administration of MFA degrading bacteria (Ralstonia sp., Burkolderia sp., Paenibacillus sp. and Cupriavidus sp.), persisted under field conditions. It was observed that the goats that received the bacteria were able to ingest the plant in the field for up to 55 consecutive days without clinical signs of intoxication or death, whereas the control goats ingested the plant for a period of 25 days until the development clinical signs of intoxication or death. These results suggest the need to maintain the protection against plant poisoning containing MFA it is necessary to administer the bacteria that hydrolyze this compound continuously, probably in the form of probiotics. In Chapter III, the ability of Herbaspirillum seropedicae, a bacterium capable of degrading various toxic compounds, inducing resistance to A. septentrionalis intoxication in goats and degrading the MFA present in A. septentrionalis was evaluated. It was found that the goats that received the bacteria were able to ingest a larger amount of plant and consequently of MFA, and took more days to develop clinical signs of intoxication, when compared with the goats that did not receive the bacterium. It can also be observed that when H. seropedicae is placed on the surface of A. septentrionalis it is able to significantly reduce the MFA indices in the plant. So much so that eight days after spraying with the bacteria the amount of MFA in the plants reduced from 1.21 ± 0.53 μg / mg to 0.24 ± 0.05 μg / mg. It can be concluded that there are new techniques that were experimentally efficient in the control and prevention of intoxications in ruminants by plants that contain MFA, however, most of them have limitations for application in commercial properties, mainly in properties with a large number of animals. And new experiments should be conducted to study the possibility of using endophytic bacteria, which degrade MFA, in reducing the toxicity of plants containing that compound.