Indirect and direct impact of permethrin on the reproduction of killifish Nothobranchius furzeri

Details

Supervisors

Donnay, Isabelle ; Page, Melissa

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences agronomiques, à finalité spécialisée

Abstract

Permethrin is an insecticide belonging to the pyrethroid family, which is widely used in various fields such as crop protection, mosquito control for malaria prevention, and wood preservation against rot. One significant advantage of permethrin is its non-persistence in the environment and low toxicity to mammals. However, permethrin is toxic to fish, primarily due to its lipophilic nature. Numerous studies have highlighted the endocrine-disrupting and potential transgenerational effects of pyrethroids. The aim of this thesis was to assess the impact of permethrin exposure on Nothobranchius furzeri during the first seven days of larval life at a concentration of 100 µg/L. To achieve this, two generations were studied: the first generation (P1), which was directly exposed, and the second generation (F1), which was not exposed. For each generation, larvae that died during the first seven days were collected and sexed by PCR. The age and the sex ratio at puberty were recorded. Subsequently, breeding groups were formed to record the number of eggs laid, as well as egg viability, fertility, and development rates. Part of the eggs were used to produce the F1. Finally, several individuals of both sexes were euthanized to collect and measure their reproductive organs. The experiment revealed a higher sensitivity in P1 males during the exposure phase, with a greater number of male larvae dying in the exposed group compared to the control group. Surviving males exhibited delayed development and tended to have smaller testicular volumes. This developmental delay in males was also observed in the F1, along with a lower fertilization rate at the beginning of the breeding period. Despite the need for further improvements, particularly to reduce intra-group variability, this study using N. furzeri highlighted the potential impact of permethrin on male survival during the larval stage and suggested the possible transmission of epigenetic modifications induced during the exposure period.