Journal or Publishing Institution: Doctoral thesis
Author(s): Persch, T.S.P.
Article Type: Study
Record ID: 1883
Abstract: Agrochemicals are water contaminants, resulting from anthropogenic activities, having as main objective the elimination of some form of life and, therefore, being harmful even to non-target species. It is utmost importance the standardization and the use of bioindicators, especially of native organisms, besides the development of toxicity tests or bioassays to assess the impacts of the agro- industrial activities. Thus, it was sought to identify possible biochemical changes, to evaluate the oxidative balance and the survival of individuals of catfish Rhamdia quelen, in two aged groups, facing acute toxicity tests with different concentrations of Roundup® (glyphosate: 18, 36, 72 and 144μg/L), Primoleo® (atrazine: 2.5, 5, 10 and 15μg/L) and Facet® (quinclorac: 1.75, 3.5, 7 and 14μg/L). The procedures were performed with fingerlings (individuals with total length between 6 and 8 cm) and sexually newly matured individuals, called young-adult (with total length of more than 18 cm). All the animals were purchased from a farm and were kept for 7 days in a period called Acclimatization. After, agrochemicals were applied individually, at concentrations similar to those reported for the natural environment and allowed by law in our country. After 7 days of exposuring to the agrochemical, the animals were euthanized by cervical spinal cord section and the gill, liver, kidney and muscle tissues were separated and frozen at -20oC. In fingerlings, pools were performed, grouping the tissue from three individuals, due to their low weight; the tissues from young-adult were analyzed individually. It was estimated the effect of this agrochemicals on intermidiate metabolism, by determining the glycogen levels, total proteins, total lipids and triacylglycerols, on the two length ranges. It was also evaluated the effect of this agrochemicals on the oxidative status determining the activity of superoxide dismutase (SOD) and catalase (CAT), and levels of lipid peroxidation (TBARS) in all the tissues from the animals on the two length ranges. The experimental procedures and the biochemical readings were performed in triplicate. It was also observed the effect of this agrochemicals on the survival of the individuals in experimental culture conditions, in both aged groups, searching for confirmation of sublethallity of determined concentrations for testing. The results are organized into three articles. The first is entitled Metabolic parameters and oxidative balance Rhamdia quelen changed after exposure to herbicides of rice crops (Roundup , Primoleo and Facet ), for submission to the journal Archives of Environmental Contamination and Toxicology, which presents the results obtained for the metabolism and the oxidative balance of fingerlings, which seem to have been able to modulate their enzymes as not to suffer oxidative damage front to Roundup herbicide (by increasing CAT) and Primoleo (without changes in SOD and CAT). The Facet led to the increase of lipid peroxidation, especially in the gill, kidney and muscle tissues, despite the higher SOD, prejudicing the species significantly. The biochemical composition tissue of juveniles of R. quelen changed significantly, which may cause damages, mainly in the gill tissue, leading to a loss of homeostasis and it may result the death of the animals and/or the decrease of the reproductive success, when chronically exposed to these substances and concentrations. The second article entitled Metabolic changes in silver catfish exposed to herbicide of rice crop Roundup, Primoleo and Facet , is concerned to the young-adult metabolism, for submission to the journal Environmental Pollution. There were changes in the metabolic profile of all sampled tissues, showing a differentiated tissue responsiveness, being the gills and the kidneys the most affected organs by the exposure to agrochemicals. The herbicide Facet changed the gill tissue significantly, and it was suggested that the relevant Brazilian agencies regulate its use in protective standards for the environment. Finally, the third manuscript Article Oxidative status and lipid peroxidation determined by the exposure to agrochemicals Roundup, Primoleo and Facet in Rhamdia quelen approaches the oxidative stress suffered by young-adults to be submitted to the journal Ecotoxicology and Environmental Safety. In this work the liver and kidney tissues were the most affected, and it can be inferred that the Facet (quinclorac) was the most toxic herbicide to the sexually newly matured individuals, followed by Primoleo (atrazine) and after by Roundup (glyphosate). One can suggest, from this set of results, a review of the current legislation in our country, to include products with the quinclorac active principle into the toxic list to be controlled in the natural environment.
Keywords: fish, metabolism, oxidative stress, glyphosate, atrazine, quinclorac
Citation: Persch, T.S.P., 2015. The effect of herbicides Roundup, Primoleo and Facet on metabolism, the oxidative stress and the survival of silver catfish Rhamdia quelen at different stages of development. Doctoral thesis.
