Efeito dos herbicidas Boral® 500 SC e Glifosato® isolados e em mistura sobre o balanço oxidativo, os níveis de glicose e de corticosterona de Rana catesbeiana Shaw, 1802

• Ano de defesa: 2017
• Autor(a) principal: Wilkens, Anike Liedtke Lauffer
• Orientador(a): Oliveira, Guendalina Turcato
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul
• Programa de Pós-Graduação: Programa de Pós-Graduação em Zoologia
• Departamento: Faculdade de Biociências
• País: Brasil
• Palavras-chave em Português: Anfíbios; Pesticidas
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS::ZOOLOGIA
• Link de acesso: http://tede2.pucrs.br/tede2/handle/tede/7716

Pesticides are widely used in agriculture, among them there are the triazines (atrazine, cyanazine, propazine, simazine, terbuthylazine, tetrazine), the phosphonated amino acids (glyphosate), the benzenamines (phenylamine, phenylenediamine, dinitroaniline, pedimetalin), organophosphates (fenitrothion), the phenyl pyrazoles (fipronil) e triazolones (sufentrazone). Therefore, they widely use of them is one of the factors which affects amphibians development, reproduction and survival. Among the pesticides most used worldwide, included in Brazil, are herbicides. However, its toxic effects in animals and plants have not been yet sufficiently study. This work aimed to study the effect of isolated and mixture of Boral ® and Glifosato ® herbicides on the biochemical composition and oxidative balance in the liver and muscle; levels of glucose, uric acid and corticosterone in plasma, and nutritional condition factors in tadpoles of bullfrogs ( Rana catesbeiana Shaw, 1802 ). Was used sixty tadpoles in prometamorphosis stage, no apparent members, acquired in a frog farm, and these, weighed, measured and distributed in tanks under controlled temperature (23°C), photoperiod (12h light: 12h dark) constant aeration, fed with commercial rations for seven days (C 7 ). After this, some animals continued under these conditions (C 14 ) e another it was divided into three groups which will be exposed to Boral ® 500 SC (sulfentrazone: 130μg/L), to Glifosato ® (glyphosate: 234μg/L) and to mixture Boral ® 500 SC and Glifosato ® (130μg/L + 234μg/L, respectively) for seven days. After the acclimation period (7 days) tadpoles of control 7 group had blood samples collected by cardiac puncture with heparinized syringe, then euthanized. They was weighed, measured and removed the liver, intestine (only to determinate an index), and muscle tissue. The tissues were immediately freeze in liquid nitrogen and homogenized for determination of activity of the enzymes Superoxide Dismutase, Catalase and Glutathione S-transferase, e TBARS levels, an indicator of Lipid Peroxidation (LPO, Lipid Peroxide Levels). The same procedures will used after the exposure period ending in animal control 14 days (C 14 ) and the exposed groups to herbicides (B, G and BG groups). We statistically compared the treatment groups C 7 e C 14 (Student T test for independent sample), as well as the control groups (C 14 e exposed). We observed on the three first acclimation days an animal mortality of 25%. We compared this percentage to major part of parameters analyzed, except glucose plasmatic and liver enzymes activity (SOD, CAT and GST) of groups acclimation control (C 7 ) and control 14 days (C 14 ) and this comparison was not different statistically. This difference in parameters can indicate that during the acclimation period the tadpoles showed a stress level, possibly because of adaptation process to culture conditions that justify the mortality percentage observed. We highlight that to scientific paper elaboration were used as control the animals of C 14 group, because this animals has the same time of life that the exposed animals and allied to answer to adaptation process reinforces this choice. We compared the C 14 group with exposed groups (B, G and BG groups) using Kolmogorov-Smirnov Test and we detected a non-parametric distribution to all parameters analyzed, so we used the Kruskal-Wallis Test and Student-Newman-Keuls Test a posteriori, to detect the differences between the groups to p<0,05. We verify a survey of 91.7%, those demonstrate that chosen herbicides concentrations was sub-lethal, Thus showing that the cultivation system was adequate to maintenance of animals. Even in low concentrations, similar of those found in natural environment, this herbicides induced changes in parameters analyzed, mainly in specific conduction level (K intestine ); in triglycerides levels, acid uric and corticosterone plasmatic, and in SOD CAT and GST antioxidants enzymes activity, primordially the GST modeling the lipid peroxidation levels in liver and muscle tissues. This alterations looks linked to an increment of energy demand in an attempt to maintain homeostasis and ensure the survival of the animals, decreasing the energy available for growth and metamorphosis, which may compromise the adult life cycle. We suggest that sulfentrazone and glyphosate mixture seems to be more harmful to animals, mainly by the maintenance and drastic reduction of the levels of Glutathione S-tansferase activity in the liver and caudal muscle, respectively.