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The aim of the present study was to investigate the combined effects of seasonality and anthropogenic pressure on a battery of oxidative stress, lipid peroxidation, protein oxidation, DNA damage and histological alterations in the native clam Ruditapes decussatus collected from a less contaminated area (LCA), Ghar El Melh, a moderately contaminated area (MCA), the North Lake, and a highly contaminated area (HCA), the South Lake, all located in the southern Mediterranean Sea. The accumulation of cadmium, lead, copper, iron and zinc was higher in the digestive glandsof clams collected from the MCA and the HCAthan in those from the LCA, particularly during the warm season. Our results reveal that metallothionein, lipid peroxidation, protein oxidation levels and antioxidant defence systems were higher, while acetylcholinesterase activity was lower, in clams from the MCAand HCAthan in those from the LCA. The results also indicate that clams from the MCA and the HCAare characterized by histological alterations and DNA damage. In conclusion, the evident changes of antioxidant defence systems and macromolecules between the studied lagoons reveal the perturbation of the physiological states of clams from polluted sites thatcope with seasonal changes and trace element accumulations., El objetivo del presente estudio es investigar los efectos combinados de la estacionalidad y la presión antropogénica en una batería de estrés oxidativo, peroxidación lipídica, oxidación de proteínas, daños en el DNA y alteraciones histológicas en la almeja nativa Ruditapes decussata recolectada de un área menos contaminada (Ghar El Melh «LCA») y de dos sitios con diferentes niveles de contaminación (la laguna norte «MCA» y la laguna sur «HCA» de Túnez) en el sur del mar Mediterráneo. La acumulación de cadmio, plomo, cobre, hierro y zinc fue mayor en la glándula digestiva de las almejas recolectadas de la MCA y la HCA en comparación con las de la LCA, particularmente durante la estación cálida. Nuestros resultados revelan que la metalotioneína, la peroxidación lipídica, los niveles de oxidación de proteínas y los sistemas de defensa antioxidante aumentaron, mientras que la actividad de la acetilcolinesterasa disminuyó en las almejas del área moderadamente y altamente contaminada en comparación con la menos contaminada. Los resultados también indican que las almejas del MCA y el HCA se caracterizan por varias alteraciones histológicas y daños en el ADN. En conclusión, los cambios evidentes de los sistemas de defensa antioxidante y las macromoléculas entre las lagunas estudiadas revelan la perturbación de los estados fisiológicos de las almejas de los sitios contaminados que hacen frente a los cambios estacionales y las acumulaciones de metales.

Acrylamide (ACR) is among the most deleterious pollutants in the environment and presents a serious risk to humans and ecosystems. The purpose of this study was to assess its effects when administered at different concentrations (5, 10 and 20 mg L–1) to evaluate antioxidant status in the gills of Mactra stultorum. Our results showed, after five days of treat­ment, an increase in malondialdehyde (MDA), lipid hydroperoxides (LOOH), advanced oxidation protein products (AOPP), reduced glutathione (GSH), ascorbic acid (Vit C) and metallothionein (MDA) levels in gills of treated clams compared with controls. Moreover, an increase in superoxide dismutase (SOD) and a significant decrease in glutathione peroxidase (GPx) activities were also observed. Acrylamide induced neurotoxicity, as evidenced by the inhibition of acetylcholinesterase (AChE) activity in a dose-dependent manner. Overall, our results indicated that oxidative stress may be considered one of the mechanisms behind acrylamide toxicity in bivalves, although the subject requires more research., La acrilamida (ACR) es uno de los contaminantes más perjudiciales en el medio ambiente y presenta un grave riesgo para los seres humanos y los ecosistemas. El objetivo de este estudio es evaluar los efectos del ACR administrado a diferentes concentraciones (5, 10 y 20 mg L–1) con el fin de evaluar el estado antioxidante en las branquias de Mactra stulto­rum. Nuestros resultados mostraron, después de 5 días de tratamiento, un aumento en los niveles de malondialdehído (MDA), hidroperóxidos lipídicos (LOOH), proteínas de oxidación avanzada (AOPP), glutatión reducido (GSH), ácido ascórbico (vit C) y metalotioneínas (MTs) en las branquias de las almejas tratadas en comparación con los controles. Además, también se observó un aumento en la superóxidodismutasa (SOD) y una disminución significativa en las actividades de glutatión pero­xidasa (GPx). La acrilamida indujo neurotoxicidad como lo demuestra la inhibición de la actividad de la acetilcolinesterasa (AChE) de una manera dependiente de la dosis. En general, nuestros resultados indicaron que el estrés oxidativo puede con­siderarse como uno de los mecanismos detrás de la toxicidad por ACR en los bivalvos, aunque el tópico debería beneficiarse de más investigaciones.

The present study aims to investigate the effects of pollution on the oxidative status of the natural species Venerupis decussata in the southern coast of Tunisia coast. Clams were collected each month during summer 2014 from two contrasting sites (S1: Zarrat coast region and S2: Boughrara lagoon). The concentration of copper (Cu), lead (Pb) and cadmium (Cd) in digestive gland of clams collected from the S2 was significantly higher from those of S1. We found an increase in malondialdehyde and advanced oxidation protein products levels in digestive gland homogenates of clams from S2 compared to S1. An increase in glutathione, non-protein thiol, metallothionein and vitamin C levels was also observed. Alteration of the antioxidant system in clams sampled from S2 was also confirmed by the significant increase of catalase and glutathione peroxidase activities. Further, a decrease of neurotoxicity biomarker, acetylcholinesterase activity, was also observed in clams collected from Boughrara lagoon. The principal component analysis of biomarker responses made a distinction between clams deployed in S2 and those from the reference site S1. These spatial differentiations were confirmed by histopathological observations and DNA damage variations. We can consider these parameters as the appropriate responses to evaluate the effects of pollutants on clams, in particular V. decussata, which can be used for the bio-surveillance in the coastal and lagoon regions.

[EN] Permethrin (PER) is a pyrethroid insecticide widely used in agriculture. Dumped into the sea, this pollutant causes considerable harm to living organisms. The present study was undertaken to evaluate the toxic effects of PER, on the commercial clam Donax trunculus, largely distributed along the sandy beaches of the Gulf of Tunis. A toxicity assay (72 hours) using different PER concentrations (0, 50, 100 and 150 µg.L-1) was carried out to study the effects of the pesticide on lipid class and fatty acid composition of mantle and siphons of D. trunculus. Results showed a significant decrease in total lipid content with exposure to PER. An increase in the percentage of neutral lipids driven by a concomitant increase of triacylglycerols (TAG) was found after exposure. On the other hand, polar lipids decreased following mainly the fall of phosphatidylethanolamine (PE) and phosphatidylinositol (PI). The fatty acid content was also significantly altered in exposed D. trunculus. Saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA) and especially PUFA (n3) decreased significantly with PER exposure, while, monounsaturated fatty acids (MUFAs) showed significant decrease with 50 µg.L-1 and no significant difference between control (0 µg.L-1 PER) clams and those exposed to 100 and 150 µg.L-1., [FR] L’exposition de courte durée à la perméthrine altère les différentes classes de lipides ainsi que la composition en acides gras chez le mollusque Donax trunculus des côtes tunisiennes (Méditerranée méridionale). La perméthrine (PER), insecticide pyréthrinoïde, est un ingrédient actif synthétique qui a été largement utilisé dans l’agriculture. L’utilisation de ce polluant au voisinage des plans d’eau menace l’état de santé de ces écosystèmes. La présente étude avait comme objectif d’évaluer les effets toxiques de la PER sur le bivalve marin Donax trunculus, fréquemment rencontré sur les côtes sablonneuses du Golfe de Tunis. Un essai de toxicité à court terme (72 heures) a été réalisé. Trois doses de concentrations croissantes en PER (50, 100 et 150 µg.L-1) ont été utilisées pour voir leurs effets sur la composition en acides gras et en lipides de D. trunculus. Les résultats ont montré une importante diminution des teneurs en lipides totaux chez les spécimens exposés à la PER. En outre, une variation importante des pourcentages des différentes classes lipidiques a été également signalée après l’exposition. Cette variation consistait à une augmentation des pourcentages de lipides neutres, due principalement à celle des triacylglycérols (TAG), parallèlement à une diminution de ceux des lipides polaires représentés essentiellement par les phosphatidyléthanolamines (PE) et les phosphatidylinositoles (PI). Le profil des acides gras a été également modifié de façon significative chez D. trunculus après l’exposition à la PER. Les teneurs en acides gras saturés (AGS), en acides gras polyinsaturés (AGPI) et surtout en AGPI (n-3) ont diminué de manière significative avec l’exposition, tandis que, celles des acides gras mono-insaturés (AGMI) ont chuté seulement après l’exposition à 50 µg.L-1, This study was supported by the Tunis University of Sciences, the Biology Department, the research Unit of Physiology and aquatic environment and the institute of aquaculture of Torre de la Sal, Spain

Trabajo presentado en el 41 Congrès de la Commission Internationale pour l'Exploration Scientifique de la mer Méditerranée (CIESM), celebrado en Kiel (Alemania) del 12 al16 septiembre de 2016, A short term exposure experiment (72 h) to permethrin (PER) of the clam Donax trunculus from the Tunisian coast was carried out. Changes in the lipid classes, fatty acid (FA) composition and lipid peroxidation were determined in the gills of adults and juveniles. A significant decrease of total lipid content was followed by a decrease in polar lipids (PL) and polyunsaturated fatty acids (PUFAs) especially n-3 and n-6. As, for the oxidative stress response, a significant elevation in lipid peroxidation (LPO) was found after the exposure of both adults and juveniles.

In Tunisia the commercial exploitation of Donax trunculus is limited to the unregulated catches which threaten the biological sustainability of this species. Knowledge of the gametogenic development of a species is a prerequisite for proper management and sustainable exploitation of this fishery. The reproductive cycle of D. trunculus from the Bay of Tunis was carried out between November 2006 and January 2008, using the dry weight changes, the histological examination of the gonad and the measurement of oocyte size. Results showed that, sex ratio were in favor of males without any hermaphroditism. The gametogenesis activity of both sexes, started with decreasing seawater temperature during late autumn and the main spawning event took place from June to October when temperatures rose. During this time, clams loose, gradually, their weights and condition and maturity indices reached their lowest values immediately after spawning period. The mean oocyte diameter varied significantly between 12.1 ± 9.8 urn in early gametogenesis and 45.9 ±13.6 um during maturity. Considering these data, a closed season from May to July coinciding with the most intensive gamete release should be considered for the preservation and the management of the natural stock of D. trunculus from the Bay of Tunis.

Les réponses de certains paramètres hématologiques et plasmatiques ont été suivies pour l’anguille européenne de stade jaune [Anguilla anguilla (Linnaeus, 1758)] maintenue à jeun et acclimatée en eau douce et en eau de mer à trois températures : basse (4°C), ambiante (16 à 18°C) et élevée (28°C), des conditions subies par l’anguille jaune pendant sa phase continentale. Le nombre d’érythrocytes, le taux d’hématocrite, la concentration en hémoglobine et l’osmolalité plasmatique ont été déterminés, et les constantes érythrocytaires (volume globulaire moyen, teneur globulaire moyenne en hémoglobine et concentration corpusculaire moyenne en hémoglobine) ont été calculées. Les paramètres hématologiques étudiés restent constants sous l’effet de la salinité en état de jeûne. A température élevée, le nombre d’érythrocytes augmente significativement, indépendamment de la salinité, sans pour autant influencer les valeurs des constantes érythrocytaires qui témoignent d’une stabilité de l’état physiologique des anguilles jaunes sous l’effet des trois températures étudiées. L’osmolalité plasmatique des anguilles acclimatées en eau de mer est plus élevée que celle des anguilles acclimatées en eau douce pour toutes les conditions étudiées. La variation thermique à 4°C ou à 28°C augmente l’osmolalité plasmatique en eau douce et en eau de mer chez l’anguille jaune par rapport à la température ambiante.

10 p., 3 tables, 3 figures and bibliography. Texto de las tablas y figuras en inglés y francés., The condition index, the lipid content and the fatty acid composition of the coquina clam Donax trunculus (Mollusca: Bivalvia) sampled from three stations of the North Eastern coast of Tunisia: Borj Cedria (BC), Rades (R) and Kalaat El Andalous (KA), were analysed. Total lipid content in dry weight ranged from 4.8 to 7.3%, from 5.9 to 8.1% and from 5.5 to 10.8% respectively in BC, R and KA specimens. The analysis of the fatty acid composition showed that the major fatty acids in D. trunculus tissues were palmitic C16:0, stearic C18:0, eicosapentaenoic (EPA) C20:5n-3 and docosa-hexaenoic (DHA) C22:6n-3 acids. In comparison with saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) constituted the highest proportion in D. trunculus from different sites. SFA varied during the year inversely to the variation of PUFA which were higher in winter and spring than in summer and autumn. A negative correlation between water temperature and (n-3) PUFA was observed, whereas the (n-6) PUFAs showed a positive correlation with this variable., This work was supported by a financial aid (grant) from the "Agencia Española de Cooperación Internacional (AECI)".

Total fatty acids (TFA) and different fatty acids contents of the gonads, liver and muscles in male and female Diplodus annularis were studied. The gonadosomatic (GSI) and hepatosomatic index (HIS) present a maximum value in female specimens, respectively 8.48 ± 0.80 and 1.86 ± 0.11. Our results show that TFA are accumulated in female liver (5.41 ± 0.66 mg.g-1 WM). It was noted that among all the samples studied for saturated (SFA) and monounsaturated fatty acids (MUFA) in male and female samples, palmitic acid C16:0 (18.00 ± 0.57 - 26.48 ± 0.99%TFA) and oleic acid C18:1 (11.79 ± 0.98 - 22.55 ± 0.37%TFA) were the predominant saturated and monounsaturated fatty acids respectively. All differences between male and female are statistically significant (p < 0.05) except these between the oleic acid (C18:1) values in gonads. Other more, docosahexaenoic acid (DHA) C22:6 (4.24 ± 0.72 -27.38 ± 2.97%) and eicosapentaenoic acid (EPA) C20:5 (4.55 ± 0.88 - 5.73 ± 0.68%) are the major PUFA. All differences between DHA values in male and female are statistically significant (p < 0.05). However, the EPA reveals a significant difference only between values obtained in male and female gonads. Our results suggest higher ω3 PUFA/ω6 PUFA and DHA/EPA ratios in male liver.

Nous nous sommes proposés dans ce travail d’étudier la variation saisonnière des acides gras de la chair du muscle blanc dorsal chez trois espèces de sparidés immatures du golfe de Tunis : le sparaillon commun, Diplodus annularis, le sar commun, D. sargus, et le sar à tête noire, D. vulgaris. Les résultats obtenus par chromatographie en phase gazeuse révèlent que les acides gras totaux exprimés en mg/g matière fraîche (MF) présentent les teneurs les plus élevées pendant l’hiver pour les trois espèces étudiées : 2,9 ± 0,2; 1,6 ± 0,3 et 2,5 ± 0,4 mg/g MF du muscle blanc dorsal respectivement chez D. annularis, D. sargus et D. vulgaris. L’étude des différentes familles d’acides gras exprimées en pourcentages des acides gras totaux (%AGT) montre que les acides gras saturés (AGS) et monoinsaturés (AGMI) présentent des teneurs maximales au printemps et en hiver chez l’espèce D. sargus respectivement égales à 65,7 ± 4,6% et 38 ± 8,7%. Pour la famille des acides gras polyinsaturés (AGPI) c’est l’espèce Diplodus annularis qui présente le maximum en été, égal à 49 ± 1%. L’étude détaillée des différents groupes d’acides gras saturés et monoinsaturés indique chez l’espèce Diplodus sargus des teneurs les plus élevées pour les deux acides palmitique (C16 : 0) et oleïque (C18 : 1) respectivement au printemps et en hiver égales à 43,6 ± 3 et 31,9 ± 6%. Par ailleurs, parmi les AGPI, l’acide docosahexaénoïque (C22 : 6) est le plus abondant chez les trois espèces étudiées avec des valeurs maximales observées en été chez les deux espèces D. annularis et D. vulgaris, égales à 22 ± 0,7% et 21,1 ± 1,9%. L’étude statistique de nos résultats montre des différences intersaisonnières significatives entre les différentes valeurs obtenues (p < 0,05).