References of "kestemont, Patrick"
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See detailEffects of low dose endosulfan exposure on brain neurotransmitter levels in the African clawed frog Xenopus laevis
Preud'Homme, Valérie; Milla, Sylvain; Gillardin, Virginie et al

in Chemosphere (2015), 120(2), 357-364

Understanding the impact of pesticides in amphibians is of growing concern to assess the causes of their decline. Among pesticides, endosulfan belongs to one of the potential sources of danger because of ... [more ▼]

Understanding the impact of pesticides in amphibians is of growing concern to assess the causes of their decline. Among pesticides, endosulfan belongs to one of the potential sources of danger because of its wide use and known effects, particularly neurotoxic, on a variety of organisms. However, the effect of endosulfan was not yet evaluated on amphibians at levels encompassing simultaneously brain neurotransmitters and behavioural endpoints. In this context, tadpoles of the African clawed frog Xenopus laevis were submitted to four treatments during 27 d: one control, one ethanol control, and two low environmental concentrations of endosulfan (0.1 and 1 μg L−1). Endosulfan induced a significant increase of brain serotonin level at both concentrations and a significant increase of brain dopamine and GABA levels at the lower exposure but acetylcholinesterase activity was not modified by the treatment. The gene coding for the GABA transporter 1 was up-regulated in endosulfan contaminated tadpoles while the expression of other genes coding for the neurotransmitter receptors or for the enzymes involved in their metabolic pathways was not significantly modified by endosulfan exposure. Endosulfan also affected foraging, and locomotion in links with the results of the physiological assays, but no effects were seen on growth. These results show that low environmental concentrations of endosulfan can induce adverse responses in X. laevis tadpoles. At a broader perspective, this suggests that more research using and linking multiple markers should be used to understand the complex mode of action of pollutants. [less ▲]

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See detailAssessment of the health status of wild fish inhabiting a cotton basin heavily impacted by pesticides in Benin (West Africa).
Agbohessi, Prudencio T.; Imorou Toko, Ibrahim; Ouedraogo, Alfred et al

in The Science of the total environment (2014)

To determine the impact of agricultural pesticides used in cotton cultivation on the health status of fish living in a Beninese cotton basin, we compared the reproductive and hepatic systems of fish ... [more ▼]

To determine the impact of agricultural pesticides used in cotton cultivation on the health status of fish living in a Beninese cotton basin, we compared the reproductive and hepatic systems of fish sampled from rivers located in both contaminated and pristine conditions. Different types of biomarkers, including biometric indices (a condition factor K, a gonadosomatic index GSI, and a hepatosomatic index HSI), plasma levels of sex steroids (11-ketotestosterone 11-KT, testosterone T and estradiol-17beta E2) and the histopathology of the gonads and liver, were investigated for two different trophic levels of the following two fish species: the Guinean tilapia Tilapia guineensis and the African catfish Clarias gariepinus. The fish were captured during both the rainy season (when there is heavy use of pesticides on cotton fields) and the dry season from one site, in Pendjari River (reference site), which is located outside the cotton-producing basin, and from three other sites on the Alibori River within the cotton-producing basin. Comparing fish that were sampled from contaminated (high levels of endosulfan, heptachlor and DDT and metabolites) and reference sites, the results clearly indicated that agricultural pesticides significantly decreased K and GSI while they increased HSI, regardless of the season, species and sex of the fish. These pesticides also induced a decrease in the plasma levels of 11-KT and T and increased those of E2. The histopathology of the testes revealed, in both species, a high rate of testicular oocytes, up to 50% in the African catfish, downstream of the Alibori River, which indicated estrogenic effects from the pesticides. The disruption of male spermatogenesis primarily included necrosis, fibrosis and the presence of foam cells in the lobular lumen. The histopathology of the ovaries revealed high levels of pre-ovulatory follicular atresia, impaired oogenesis, a decrease in the oocyte vitellogenic diameter and other lesions, such as fibrosis, vacuolation and melano-macrophagic centers. The histopathology of the liver revealed the presence of necrosis, hypertrophic hepatocytes, foci of vacuolation, glycogen depletion and hemosiderin. An assessment of the general health of the fish indicated that all of the sampled fish from the polluted sites were in poorer health compared with those from the reference site but that the African catfish appeared much more affected than the Guinean tilapia, regardless of the sex and season. In conclusion, the overall results indicated that agricultural pesticides significantly impair the endocrine regulation of fish living in the Beninese cotton basin and that this would most likely be one of the causes of the severe damage observed in the liver and gonads and the reduced health condition. [less ▲]

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See detailInfluence of domestication process on immune response to repeated emersion stressors in Eurasian perch (Perca fluviatilis L.)
Douxfils, Jessica; Lambert, S; Mathieu, Cédric et al

in Comparative Biochemistry and Physiology. A : Comparative Physiology (2014), 173

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See detailIMMUNE AND NEURO-ENDOCRINE RESPONSES OF GRAVID EURASIAN PERCH TO CHRONIC CONFINEMENT AND SOCIAL ISOLATION STRESS
Mandiki, SMN; Douxfils, Jessica; Massart, Sophie et al

Poster (2013, June)

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See detailDevelopment of an analytical method to detect metabolites of nitrofurans. Application to the study of furazolidone elimination in Vietnamese black tiger shrimp (Penaeus monodon)
Douny, Caroline ULg; Widart, Joëlle ULg; De Pauw, Edwin ULg et al

in Aquaculture (2013), 376-379

Nitrofurans, banned antibiotics in European Union (EU), have often been found in imported aquaculture products in the past and are still found nowadays according to the Rapid Alert System for Feed and ... [more ▼]

Nitrofurans, banned antibiotics in European Union (EU), have often been found in imported aquaculture products in the past and are still found nowadays according to the Rapid Alert System for Feed and Food (RASFF) of the European Commission. A quantitative method based on liquid chromatography coupled to isotopic dilution tandem mass spectrometry (LC–IDMS/MS) was developed for the determination of the residues of four nitrofuran antibiotic residues in shrimps. The experimental protocol consisted of an acid-catalysed release of protein-bound metabolites, followed by derivatisation with 2-nitrobenzaldehyde (NBA). Then, a double liquid–liquid extraction with ethyl acetate was performed before LC–IDMS/MS analysis by positive electrospray ionisation (ES+) with multiple reaction monitoring (MRM) of two transitions per compound. An “in-house” validation of the method for shrimp analysis was conducted according to the EU criteria for the analysis of veterinary drug residues in foods. The decision limits (CCalpha) were 0.08–0.36 µg kg -1 and the detection capabilities (CCbeta) were 0.12–0.61 µg kg-1, which are both below the minimum required performance limit (MRPL) set at 1 µg kg -1 by the EU. The developed method was applied to evaluate the elimination of furazolidone residues in shrimp muscles after a contamination experiment. After 28 days of decontamination, a concentration of 115 µg kg-1 of furazolidone metabolite 3-amino-2-oxazolidinone (AOZ) was still measured in shrimp muscle. [less ▲]

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See detailEffects of a sublethal pesticide exposure on locomotor behavior: A video-tracking analysis in larval amphibians
Denoël, Mathieu ULg; Libon, Sylvie; Kestemont, Patrick et al

in Chemosphere (2013), 90(3), 945-951

Organochlorine pesticides such as endosulfan have been shown to have both lethal and sublethal effects on amphibians. In this context, behavioral endpoints have proved their usefulness in evidencing ... [more ▼]

Organochlorine pesticides such as endosulfan have been shown to have both lethal and sublethal effects on amphibians. In this context, behavioral endpoints have proved their usefulness in evidencing impacts of such chemicals at environmental concentrations that do not necessarily cause mortality. The recent development of video-tracking technologies now offers the possibility of accurately quantifying locomotor behaviors. However, these techniques have not yet been applied to evaluating the toxicity of pesticides in amphibians. We therefore aimed at determining the potential toxicity of endosulfan on endpoints associated with locomotion after short-term environmental endosulfan exposure in Rana temporaria tadpoles and at using these data as warning systems for survival alterations after a longer exposure. To this end, we analyzed video-tracks of 64 tadpoles (two pesticide treatments: 5 and 50 μg L−1, one control and one solvent-control) with Ethovision XT 7 software. The highest endosulfan concentration had a significant effect on all four behavioral endpoints. Contaminated tadpoles traveled shorter distances, swam less often, at a lower mean speed, and occupied a less peripherical position than control tadpoles. The lowest endosulfan concentration had similar but lower effects, and did not affect mean speed during swimming. Survival was reduced only after a long-term exposure to endosulfan and was associated with short-term behavioral dysfunctions. These results show that endosulfan strongly affects the behavioral repertory of amphibian tadpoles, but in different ways depending on concentration, thus suggesting that the pesticide has complex modes of action. Given the importance of locomotion and space use in tadpole success in their aquatic environment, these results confirm the toxic action of endosulfan. By highlighting effects before mortality markers, video-tracking systems also show their potential as sentinels of sublethal effects of pesticides. [less ▲]

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See detailFirst evidence of the possible implication of the 11-deoxycorticosterone (DOC) in immune activity of Eurasian perch (Perca fluviatilis, L.): Comparison with cortisol
Mathieu, Cédric; Mila, Sylvain; Mandiki, Robert et al

in Comparative Biochemistry & Physiology Part A : Molecular & Integrative Physiology (2013), 165(2), 149-158

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See detailCortisol is responsible for positive and negative effects in the ovarian maturation induced by the exposure to acute stressors in Nile tilapia, Oreochromis niloticus
Gennotte, Vincent ULg; Sawadogo, Philippe; Milla, Sylvain et al

in Fish Physiology and Biochemistry (2012), 38

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See detailKINETICS OF QUINALPHOS RESIDUES ELIMINATION IN WATER AND FISH TISSUES FROM TANK CULTURED SILVER BARB (Barbonymus gonionotus)
Nguyen Quoc, Thinh; Tran Minh, Phu; Do Thi Thanh, Huong et al

Poster (2012)

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See detailUsing sets of behavioral biomarkers to assess short-term effects of pesticide: a study case with endosulfan on frog tadpoles
Denoël, Mathieu ULg; D'hooghe, Bastien; Ficetola, G. Francesco et al

in Ecotoxicology (2012), 21(4), 1240-1250

Pesticides and other chemicals often have detrimental effects at environmental concentrations. Many amphibian species are particularly threatened because of their susceptibility but also because wetlands ... [more ▼]

Pesticides and other chemicals often have detrimental effects at environmental concentrations. Many amphibian species are particularly threatened because of their susceptibility but also because wetlands are often polluted. Behavioral assessments of toxicity have the advantage of showing sublethal effects but quantitative measures at varied scales of integrations are rarely considered together. In this study, we aimed at showing that these behavioral endpoints could be differently affected across time and concentrations, and be biomarkers of toxicity. To this end, we tested the effects of an organochlorine pesticide (endosulfan) on amphibians during a standard 96 h test. We evaluated possible lag effects in continuing the analyses after removal of the pesticide. The study was based on 240 tadpoles (4 pesticide treatments: 0.4, 3, 22, and 282 lg/l, 1 control and 1 solvent-control). Abnormal behaviors such as lying and swirling rapidly were exhibited only in the presence of the pesticide. Essential functions such as breathing and feeding were deeply affected by the pesticide: contaminated tadpoles breathed and fed less than control tadpoles. They also moved less and occupied a more central position in the aquariums in the presence of the pesticide. A higher mortality was only found at the highest concentration. These results suggest that endosulfan is toxic to amphibians at environmental concentrations. Behavioral markers showed potential as early warning systems. They should thus be used in complement to other markers to detect sublethal effects only a few days after application of the pesticide and at concentrations where mortality does not occur. [less ▲]

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See detailDoes domestication process affect stress response in juvenile Eurasian perch Perca fluviatilis ?
Douxfils, Jessica; Mandiki, S. N. M.; Marotte, Grégory et al

in Comparative Biochemistry and Physiology. A : Comparative Physiology (2011), 159

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See detailEffect of Chronic confinement stress on growth, survival, blood cortisol and glucose of perch (Perca fluviatilis)
Rougeot, Carole ULg; Tomson, Thomas; Vandecan, Michaël et al

Poster (2011)

Detailed reference viewed: 57 (12 ULg)