Abstract

ESCOBAR, Arturo et al. Study of the acute pulmonary toxicity/pathogenicity in rats treated with Metarrhizium anisopliae. Rev Salud Anim. [online]. 2015, vol.37, n.1, pp.27-38. ISSN 0253-570X.

Metarhizium anisopliae, a fungus belonging to the family Moniliaceae, is a microbial pesticide effectively used to control coleopterans of the families Elateridae and Curculionidae. The acute pulmonary toxicity/pathogenicity of the product Metarhizium PM (M. anisopliae) was evaluated in rats. The animals were anesthetized and intratracheally inoculated with 10⁸ conidia per animal of the viable and inactivated microorganism and compared with the control groups (vehicles and untreated animals). Clinical observations and evaluation of food and water intake were carried out daily. The microbiological analysis of organs and the macro and histopathological studies were carried out at days 3, 7 14 and 21. At the end of the study, the groups did not differ in their weights at each sacrifice time; no animal died during the test or showed evident disease clinical symptoms. The histopathological examination showed an acute inflammatory response of the lung in the three groups where the intratracheal application was carried out, which was more severe in the group with the viable microorganism and decreased in severity in the control group The severe lesions decreased during the test and, at day 21, the tissue recovery, with only focal accumulations of lymphocytes, was observed. No fungal germination was found on any of the organs examined at the end of the experiment. The results showed no pathogenicity or severe toxicity of the Metarhizium-based product when administered in a single dose to rats intratracheally.

Keywords : Metarhizium anisopliae; rats; intratracheal; toxicity.

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