2,4,6-Tribromophenol is toxic to Oreochromis niloticus (Linnaeus, 1758) after trophic and subchronic exposure

Comparative toxicity of trophic exposures to polybrominated compounds (2, 4, 6 - Tribromophenol and BDE-209) to Oreochromis niloticus (Linnaeus, 1758)

“…Overcompensation through de novo synthesis of AChE, following a prior inhibition, may explain the increase of AChE activity observed after exposure to TBP and BDE-209. Comparatively, TBP seems to present a more neurotoxic effect in O. niloticus, including here a decrease of AChE activity observed in the chronic exposure, also described by Folle et al (2021) for the same species. In Danio rerio, the cholinergic neurons are distributed in telencephalon, diencephalon, hypothalamus and mesencephalon (Clemente et al, 2004;Kaslin et al, 2004;Mueller et al, 2004), showing a high diversity of potential target regions of the brain sensitive to TBP and BDE-209 disturbs.…”

“…The occurrence of necrosis, a degenerative damage, was found in all studied groups including the control. This kind of effect reveals the failure of defense mechanisms in cells or tissues and represent a permanent effect that depending on the extension can decrease the liver function (Folle et al, 2021). Necrosis is more related with chronic exposure and in the current study individuals exposed to BDE-209 showed higher values comparatively with those exposed to TBP.…”

“…The effects of both brominated compounds in the liver were also in uenced by the duration of exposure, as the results showed a decrease in the activity of GST after acute exposure and an increase after chronic exposure, both at highest doses. The opposite effect was observed in C. auratus after acute exposure to higher doses of BDE-209 (Xie et al, 2014) and by Folle et al (2021) after chronic exposure. These ndings strongly suggest that the effects of the brominated compounds TBP and BDE-209 are highly in uenced by the exposure period under environmental doses, whereas the effects at short-term exposure are dose-dependent.…”

“…These ndings showed the importance to associate the acute and chronic studies to a better understanding of the toxic effects of chemicals, despite of these biological parameters being more useful for long-term of exposure. Recently, Folle et al (2021) described that HSI was not in uenced by sex in O. niloticus exposed to TBP at similar doses, but GSI were more affected in female sh. In general, according to the somatic indexes TBP seems to be more toxic to liver in a time-dependent way since the same effects were observed only at high doses for acute exposure and at lower doses under chronic exposure.…”