Efeitos de herbicida à base de glifosato em aspectos reprodutivos de guppies (Poecilia reticulata)
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Data
2017-04-29
Autores
Gonçalves, Bruno Bastos [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A população humana cresce em proporções maiores que a produção de alimentos. Nesse cenário, a agricultura potencializa este cultivo por meio do uso de defensivos agrícolas, como por exemplo, herbicidas à base de glifosato (HBG). Entretanto, tais produtos possuem vários efeitos adversos em organismos não-alvos, como peixes. Estudos apontam danos em tecidos e em material genético de peixes, porém, não há estudos sobre o comportamento reprodutivo dessa espécie quando expostas a concentrações permitidas por lei. Assim, testamos os efeitos de HBG na seleção sexual de parceiros e na qualidade espermática de machos de Poecilia reticulata. Para isso, avaliamos o comportamento sexual, o interesse sexual, a qualidade espermática e a receptividade das fêmeas a machos expostos a 2 concentrações de HBG (50 e 100 μg/L) por 48 horas. Para avaliar a escolha de parceiros, utilizamos o método de escolhas dicotômicas e análise de múltiplas escolhas. Já para análise da qualidade espermática, avaliamos a morfologia, a viabilidade, a concentração e a motilidade dos espermatozoides. Nossos resultados indicam que machos não expostos ao HBG diminuem a exibição para fêmeas expostas ao HBG e evitam copular com fêmeas expostas à concentração de 100μg/L. Além disso, fêmeas expostas ao HBG são menos receptivas à cópula. O HBG afetou a morfologia dos espermatozoides, onde machos expostos a 50μg/L apresentaram maior quantidade de células com danos primários. Porém, não afetou a viabilidade, concentração e motilidade dos espermatozoides. Nossos dados indicam que concentrações ambientalmente relevantes de HBG podem afetar o comportamento reprodutivo e a qualidade espermática de peixes.
Human population grows in bigger proportions then food production worldwide. To solve this problem, increase food production is required. Agriculture has potentialized food production through pesticides usage. Besides that, GMO's increase production and usage of glyphosate based herbicide (HBG), since this product does not affect GMO’s. HBG's have many side effects on non-target animals, such as fishes. Many studies demonstrated damage in a lot of tissues and DNA. However, effects on behavior and even in concentrations allowed by law have not been studies. We aim to assess the effects of a GHB on physiological and behavioral reproductive features of Poecilia reticulata as male sexual behavior, sexual interest, sperm quality and female receptivity. We used dichotomous and multiple-choice arenas for mate choice and viability, concentration, motility and morphology to assess sperm quality. HBG decrease female receptivity, affects male interest on perform displays and mate attempt with females exposed to 100µg/L. HBG also affected sperm quality of males exposed to 50µg/L concentration. Despite this, we did not find any effect on viability, concentration and motility of sperm cells of exposed males to any concentration. We conclude that HBG affects female receptivity, and, in turn, it affects sexual male effort, reducing display and mate attempt rate. Our data shows that HBG, even in environment relevant concentrations, can affect reproductive behavior and sperm quality. We show here the necessity to assess with more caution the toxicology of pollutants and its effects, as the law that regulates it.
Human population grows in bigger proportions then food production worldwide. To solve this problem, increase food production is required. Agriculture has potentialized food production through pesticides usage. Besides that, GMO's increase production and usage of glyphosate based herbicide (HBG), since this product does not affect GMO’s. HBG's have many side effects on non-target animals, such as fishes. Many studies demonstrated damage in a lot of tissues and DNA. However, effects on behavior and even in concentrations allowed by law have not been studies. We aim to assess the effects of a GHB on physiological and behavioral reproductive features of Poecilia reticulata as male sexual behavior, sexual interest, sperm quality and female receptivity. We used dichotomous and multiple-choice arenas for mate choice and viability, concentration, motility and morphology to assess sperm quality. HBG decrease female receptivity, affects male interest on perform displays and mate attempt with females exposed to 100µg/L. HBG also affected sperm quality of males exposed to 50µg/L concentration. Despite this, we did not find any effect on viability, concentration and motility of sperm cells of exposed males to any concentration. We conclude that HBG affects female receptivity, and, in turn, it affects sexual male effort, reducing display and mate attempt rate. Our data shows that HBG, even in environment relevant concentrations, can affect reproductive behavior and sperm quality. We show here the necessity to assess with more caution the toxicology of pollutants and its effects, as the law that regulates it.
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Palavras-chave
Escolha sexual, Poecilia reticulata, Toxicologia, Roundup