Behavioral and mutagenic biomarkers in tadpoles exposed to different abamectin concentrations

Abstract

It is known that pesticides such as abamectin (ABA) present cytotoxic effects on target organisms; however, the effects from ABA on non-target organisms such as amphibians are poorly understood. The aim of the current study is to investigate whether the exposure of Lithobates catesbeianus tadpoles to different abamectin concentrations [12.5, 25, and 50% of the median lethal concentration (LC)] leads to behavioral and morphological changes and/or generates possible cytotoxic effects. The aggregation test showed that tadpoles exposed to the highest ABA concentrations did not respond to the stimulus from non-familial and unrelated co-specific species. On the other hand, there was no difference in the total number of crossings in the central line of the herein adopted apparatus between groups; it suggests that ABA did not affect animal locomotion in the aforementioned test, although changes in the normal swimming pattern of tadpoles exposed to the pesticide were recorded in the swimming activity test. In addition, the herein exposed animals did not respond to the predatory stimulus in the antipredator response test; this result suggests defensive response deficit caused by the pesticide. With respect to their oral morphology, tadpoles exposed to ABA presented the lowest scores for mandibular pigmentation and structures, as well as for dentition condition. Finally, it was possible seeing that the exposure to ABA, even at the lowest concentration (12.5% of the LC), resulted in nuclear changes in the erythrocytes of the animals; these changes became evident in the increased number of micronuclei and in other nuclear abnormalities. Thus, besides confirming the cytotoxic potential of ABA in amphibians, the current study corroborates the hypothesis that the exposure to the herein investigated pesticide leads to behavioral and morphological changes in tadpoles, fact that may negatively reflect on the survival, as well as on natural populations of these individuals.

Acute toxicity, biochemical and transcriptomic analysis of Procambarus clarkii exposed to avermectin

“…The unintended effects of agrochemicals on non‐targeted organisms in fresh water have been investigated for decades 32–34 . AVMs are key insecticides used in pest management, 35–39 and show both acute and sublethal toxicities to few non‐target organisms 40,41 . The exposure routes of AVMs to non‐target organisms in aquatic systems could be run‐offs from land application into freshwater habitats 42 .…”

Abamectin induces apoptosis and autophagy by inhibiting reactive oxygen species‐mediated PI3K/AKT signaling in MGC803 cells

“…Previous studies showed that ABA has cytotoxic potential in amphibians, such as leading to behavioral and morphological changes in tadpoles . Moreover, ABA can induce apoptosis in King pigeon brain neurons and pigeon liver and inhibit the goat liver carbonic anhydrase enzyme .…”

The Toxic Effects of Glyphosate, Chlorpyrifos, Abamectin, and 2,4‐D on Animal Models: A Systematic Review of Brazilian Studies

“…Interestingly, the main models evaluated for abamectin were amphibians, birds, and fish that are part of very different groups. Nevertheless, the most striking effects were quite similar, for example, the blood abnormalities in L. catesbeianus and C. japonica (Montalvão and Malafaia 2017; Faria et al 2018b); developmental defects in L. catesbeianus (Vasconcelos et al 2017; Amaral et al 2018) and eggs hatching delay in zebrafish (Sanches et al 2018); and behavior impairment, with a decrease in the escape, low activity, low equilibrium and agitation, and change in the body posture (Vasconcelos et al 2016; Amaral et al 2018; Faria et al 2018a; Sanches et al 2018).…”