Linking behavioural alterations with biomarkers responses in the European seabass Dicentrarchus labrax L. exposed to the organophosphate pesticide fenitrothion

Abstract

The acute effects of the organophosphate insecticide fenitrothion on Dicentrarchus labrax juveniles were investigated through a bioassay using biomarkers and swimming behaviour as effect criteria. After 96 h of exposure to sub-lethal concentrations of fenitrothion, the swimming velocity and several biomarkers were individually determined, namely: brain acetylcholinesterase (AChE) activity; muscle cholinesterases (ChE), lactate dehydrogenase and isocitrate dehydrogenase activities; liver ethoxyresorufin-O-deethylase (EROD), glutathione S-transferases, glutathione peroxidase, glutathione reductase, catalase and superoxide dismutase (SOD) activities and lipid peroxidation levels (LPO). A significant decrease of the swimming velocity (LOEC = 2 mg l(-1)), an inhibition of both AChE (LOEC = 0.06 mg l(-1)) and ChE activities (LOEC = 0.03 mg l(-1)), and a positive and significant correlation between the swimming velocity and AChE were found in exposed fish, suggesting an influence of the inhibition of these enzymes in the swimming velocity decrease. An increase of EROD activity (LOEC = 1 mg l(-1)), indicating the involvement of this enzyme in fenitrothion biotransformation, and a negative and significant correlation between EROD activity and swimming velocity were also found, suggesting that the two findings may somehow be related. Furthermore, results show a significant induction of SOD (LOEC = 0.13 mg l(-1)) without LPO increase, suggesting that the enzyme is preventing oxidative stress damage. No significant alterations were found in any of the other parameters tested. Thus, exposure of seabass to fenitrothion in the wild at concentrations similar to those tested here may have adverse consequences at population level as neurotransmission and swimming ability are essential for fish performance and survival.

Effects of Temperature in Juvenile Seabass (Dicentrarchus labrax L.) Biomarker Responses and Behaviour: Implications for Environmental Monitoring

“…Healthy fish are expected to instantly react to the water flow stimuli and swim fast, reaching the end of the track race (4 m) in few seconds. Fish subjected to any kind of stress show incapacity to normally react to the water flow stimuli, either by taking longer time to reach the end of the track or stop moving forward in some point of the track keeping in that same position (Gravato and Guilhermino 2009;Almeida et al 2010;Almeida et al 2012b). Each fish is individually subjected to just one swimming trial after which returns to the respective experimental tank.…”

“…After the swimming test, fish were allowed to rest for 2 h in their original experimental tanks to stabilize metabolic rates, preventing biomarker response interference (Almeida et al 2010;Almeida et al 2012a;Almeida et al 2012b). After 2 h, individual body weight (18°C: 5.55±0.6 g; 25°C: 6.16± 0.6 g) and standard length (18°C: 6.48±0.4 cm; 25°C: 7.07± 0.5 cm) were recorded, and fish were immediately euthanized by decapitation.…”

Acute toxicity and cholinesterase inhibition of the nematicide ethoprophos in larvae of gar <i>Atractosteus tropicus</i>(Semionotiformes: Lepisosteidae).

“…In the case of organophosphates, Almeida et al (2010) found no significant response of these biomarkers in Dicentrarchus labrax after exposure to fenitrothion (OP). On the other hand, inhibition of GST was observed in Pseudorasbora parva exposed to methomyl (carbamate) (Li et al 2008).…”

“…Biomarkers, such as the inhibition of cholinesterase (ChE) activity are popular and widely used tools in the field of environmental toxicology, mainly with the goal of estimating the effects of pollutants at the sub-individual level (Triebskorn et al 2001, Guilhermino 2006, Sanchez et al 2007, Almeida et al 2010. Inhibition of ChE activity is one of the best characterized biomarkers and has been intensively used in environmental studies, showing a specific response to organophosphate (OP) and carbamate pesticides (Gruber & Munn 1998, Thompson 1999, Pathiratne et al 2008, Mdegela et al 2010.…”

Changes in nutritional parameters in diploid and triploid African catfish Clarias gariepinus following chlorpyrifos exposure

“…Biochemical parameters such as protein and lipid concentrations in tissue are re garded as sensitive indicators in fish exposed to OP pesticides (Almeida et al 2010). However, limited information is available regarding the effects of environmental contaminants on levels of nutritional parameters such as AAs and FAs (Zuraini et al 2006).…”