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The aim of this study was to analyze the biochemical alterations in the gills of Venus verrucosa under exposure for 6 days to three doses of lambda-cyhalothrin (λ-cyh) (100, 250, and 500 µg L -1 ). Malondialdehyde, lipid hydroperoxide, and hydrogen peroxide levels in the gills of treated groups increased. λ-Cyh exposure significantly increased the protein carbonyl and reduced glutathione levels in the gills of all treated groups. Moreover, the activities of superoxide dismutase and glutathione peroxidase were increased. In our study, the polyunsaturated fatty acid (FA), omega-6, eicosapentaenoic acid (C20:5n-3), and docosahexaenoic acid (C22:6n-3) were increased in the treated groups. A significant decrease in the saturated FAs, omega-3, and arachidonic acid (C20:4n-6) levels was observed. The content of monounsaturated FA was changed in the groups treated with 100 and 250 µg L -1 of λ-cyh. As a corollary, desaturase and elongase activities were significantly increased. Our study provides evidence of the underlying toxic mechanism of λ-cyh and its capacity to create oxidative stress and revealed that FA profiling is a new approach for elucidating the λ-cyh toxicity.

Hexavalent chromium (chromium (VI)), a highly toxic heavy metal, is a common pollutant of aquatic ecosystems. The present study aimed to elucidate the potential toxic effects of chromium (VI) on oxidative stress biomarkers and fatty acids profile in the gills and digestive gland of Venus verrucosa, an ecologically and economically important bivalve species. Three doses of chromium (VI) (1, 10 and 100 μg.L -1 ) were chosen for V. verrucosa exposure during 7 days under controlled conditions. A significant increase in the levels of malondialdehyde, lipid hydroperoxides and hydrogen peroxide was observed in the gills and digestive gland of chromium (VI)-exposed V. verrucosa as compared to the control group. Furthermore, an induction of enzymatic antioxidant activities (superoxide dismutase, glutathione peroxidase and glutathione S-transferase) and an enhancement of non-enzymatic antioxidant levels (non-protein thiols, glutathione and vitamin C) were marked. An alteration of fatty acids composition was also noted following chromium (VI) exposure. The obtained results highlighted the importance of assessing oxidative damage biomarkers and fatty acids profile in the study of chromium (VI)-induced toxicity in V. verrucosa., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Acrylamide (ACR), a ubiquitous agent, has various chemical and industrial applications, and it is found in backed or fried carbohydrate-rich food. It has been related to multiple toxicological effects, and it causes high cytotoxicity through oxidative stress. The present study aimed to investigate the potential effect of ACR toxicity administered at different concentrations (5, 10, and 20 mg/L), during 5 days, in order to evaluate the fatty acid (FA) composition and redox state in the digestive gland of Mactra corallina. The results showed, in ACR-treated clams, a significant increase in malondialdehyde, hydrogen peroxide, protein carbonyl, and metallothionein levels, as well as an alteration of the enzymatic (superoxide dismutase, glutathione peroxidase, and catalase) and non-enzymatic (reduced glutathione and ascorbic acid) antioxidant status. However, acetylcholinesterase activity was inhibited in a concentration-dependent manner. In our experiment, the n-3 (Omega-3) and n-6 (Omega-6) polyunsaturated fatty acid levels were significantly changed in all ACR-treated groups. A decrease in eicosapentaenoic acid (C20:5n-3, EPA) and docosahexaenoic acid (C22:6n-3, DHA) was observed in 10-mg/L and 20-mg/L ACR-treated groups. Nevertheless, arachidonic acid (C20:4n-6, ARA) and its precursor linoleic acid (C18:2n-6, LA) were increased. Besides oxidative stress parameters, FA composition may be an additional tool for assessing ACR contamination.

Mercury is one of the most harmful pollutant that threat marine biota. This study assessed the Hg impact on the fatty acid (FA) composition and the antioxidant statues in Holothuria forskali body wall tissue. Specimens were exposed to HgCl 2 graded doses (40, 80 and 160 μg L -1 ) for 96 h. A decrease in linoleic, arachidonic and eicosapentaenoic acid levels and an increase of docosahexaenoic acid were mainly observed at the nominal tested dose. The exposure to the upper dose promoted oxidative stress with an increase of malondialdehyde, hydrogen peroxide, advanced oxidation protein product, glutathione and non-protein thiols levels. Moreover, a decrease in catalase and an increase in superoxide dismutase and glutathione peroxidase activities were observed. Yet, an increase of the metallothionein level was registered in all treated groups. This study confirmed the Hg toxicity on the redox statue of H. forskali and highlighted the usefulness of the FA composition as an early sensitive bioindicators., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Teleost fish are ectothermic vertebrates. Their metabolism, physiology and behavior rely on the external temperature. This study, on the retina of the sea bass Dicentrarchus labrax, reports on the impact of temperature on the fatty acid composition and mRNA abundance of key enzymes of lipid metabolism: fatty acid desaturase-2 (FADS2), fatty acid elongase-5 (ELOVL5), sterol regulatory element-binding protein-1 (SREBP-1), triglyceride lipase and phospholipase A2 (PLA2). We also report on the effects on the photopigment molecule rhodopsin and on enzymes of the melatonin synthesis pathway, namely arylalkylamine N-acetyltransferases 1a and 1b and acetylserotonin methyltransferase. Juvenile fish were placed for 30 days at 18, 23 or 28 °C. At 23 °C, the fatty acid composition of D. labrax retina showed, as generally reported for the retina of other fish species, particularly high amounts of docosahexaenoic (DHA), palmitic and oleic acids. The fatty acids composition was not significantly (P > 0.05) altered between 23 and 28 °C, but did increase at 18 °C compared to 23 and 28 °C. At 18 °C there were noticeable increases in total DHA, ecosapentaenoic, arachidonic, oleic, linoleic, palmitoleic and stearic acids. A negative correlation was found in the abundance of neutral (NL) vs. polar (PL) lipids: 18 °C induced an increase in NL and a decrease in PL, while 28 °C induced higher PL with decreased NL. In NL the changes affected mainly triglycerides. FADS2 and ELOVL5 mRNA abundance decreased from 18° to 28 °C while SREBP-1 and triglyceride lipase mRNA remained stable. Conversely PLA2 mRNA was more abundant at 23 than at 18 and 28 °C. Temperature increased and decreased rhodopsin mRNA abundance, at 28 °C and 18 °C respectively, while there was no effect on mRNA from the melatonin synthesis enzymes. In conclusion the data indicate a temperature induced redistribution of fatty acids among the lipid classes that might affect the physical properties of the plasma membranes as well as functions associated with photoreception or generation of intracellular second messengers. In addition, the results suggest that temperature targets only the proteins and activities of retinal melatonin production. This study opens new lines of investigation related to the role temperature and fatty acids play in fish visual perception. They are relevant in the context of the global warming of seas affecting both the wild and the aquaculture species., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The present investigation was undertaken to evaluate the toxic effects of CoCl2-induced hepatotoxicity and fatty acid changes in juvenile Cyprinus carpio. Fish were divided into six experimental groups in duplicate. The first group served as controls. The second group received the lowest exposure dose at 2.5 µg/L. In the third group, fish were exposed to 25 µg/L of CoCl2. The fourth group was exposed to 50 µg/L of CoCl2. The last two groups were exposed to the highest doses, 100 and 500 µg/L of CoCl2. Total antioxidant activities were estimated using a colorimetric method. Liver fatty acid compositions were analyzed by high-performance gas chromatography (GC). Hepatopathy was identified through microscopic analysis. Exposure of C. carpio to CoCl2 resulted in hepatotoxicity, indicated by increased levels of malondialdehyde (MDA), hydrogen peroxide (H2O2), protein carbonyls (PCO), and alterations in the ferric reducing antioxidant power system (FRAP). Superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GPx), reduced glutathione (GSH), metallothioneins (MTs), and low thiol levels (L-SH) significantly increased, particularly under exposure to the highest CoCl2 doses (100 and 500 µg/L). Acetylcholinesterase activity decreased significantly in C. carpio exposed to graded CoCl2 doses. Additionally, there was a decrease in polyunsaturated fatty acids (PUFA), primarily n-3 PUFA, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), while an increase in monounsaturated (MUFA) and saturated fatty acids (SFA), including palmitic (C16:0), stearic (C18:0), palmitoleic (C16:1), and oleic (C18:1) acids, was observed. Histopathological examination of the liver confirmed hepatopathy revealing characteristic tissue changes such as leucocyte infiltration, hepatic cell membrane degradation, vacuolization, and lipid inclusions. The study provided ethnophysiology insights into the responses of C. carpio to CoCl2-induced oxidative stress and lipidomic alteration, underscoring its potential as a bioindicator for assessing environmental impacts and metal contamination. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the seasonal evolution of lipid classes (polar (PL) and neutral lipids (NL)) in the gonad–visceral mass (GV) and adductor muscle (AM) of Mactra stultorum collected from the northern coast of Tunisia. Our results have shown that NL was the major lipids in GV. However, the PL characterizes the AM. Significant decreases in the PL contents of both tissues were recorded during the summer season. Besides, NL was accumulated mostly in GV during winter and spring seasons, which correspond to the gametogenetic and ripe stages. The related fatty acid composition of NL and PL changed significantly between seasons. Our data demonstrated that PUFAs and SFA were the major FA's in PL and NL fractions, respectively. The seasonal fluctuation of PUFA-PL levels in GV was highly during spring as compared to summer. The percent of NL and PUFA-NL levels of GV appeared to be relate to the food availability which was confirmed by a positive correlation with chlorophyll a content. Specific variations were noted in GV as evidence by higher significant levels of DHA-PL and EPA-PL during autumn. Inversely, AM exhibited lower levels of DHA-PL during spring that could be explained by the probably transfer of fatty acids from AM to the GV to sustain the gametogenesis process. [ABSTRACT FROM AUTHOR]

The effect of frozen storage at a commercial temperature (−30°C) on the nutritional characteristics of the blue swimming crab Portunus segnis for a period of 120 days was investigated. Lipid and protein oxidation was investigated by analyses of peroxide value, thiobarbituric acid reactive substances, free fatty acids, and advanced oxidation protein products. Results showed significant lipid deterioration with extended storage time and changes in fatty acids composition and lipid classes. From a nutritional standpoint, it would be preferable for human consumption to eat frozen crabs for no more than 30 days as they retain a higher nutritional value. [ABSTRACT FROM AUTHOR]

The seasonal changes in biochemical composition of the edible bivalve Arca noae harvested from a Mediterranean coastal lagoon (Bizerte lagoon, Tunisia) were investigated from October 2013 to September 2014. Potential food sources and nutritional quality indices (NQI) were determined by analyzing the fatty acid profiles of their tissues during an annual reproductive cycle. Results showed that A. noae had moisture (73.8–82%) and protein (24.1–58.6% dry weight) as major components, followed by lipid (10.4–28.8% dry weight) and glycogen (4.05–14.6% dry weight). A. noae accumulated lipid and glycogen for gonadal development during both maturation periods (late autumn/late spring–summer) to be used during spawning periods (winter/late summer–early autumn). However, proteins were mainly used to support reproductive allocation and played an important role on the energetic maintenance. Lipid and glycogen were found to be significantly related to temperature, salinity and chlorophyll a (p

This investigation was aimed to assess and evaluate the effect of frying process with three different oils (corn, olive and margarine) on fatty acids and lipid classes' composition of clam and their impact on the nutritional value and tissues quality. The results indicated that the contents of saturated, monounsaturated and polyunsaturated fatty acids varied significantly in fried clams and frying oil. Our data demonstrated that all lipid classes' contents increased significantly after all frying processes. It was concluded that the frying process decreased the n-3/n-6 and DHA+EPA and increased the levels of atherogenic; thrombogenic indices. Additionally, these culinary processes promoted lipid peroxidation through the enhancement of TBARs, PV and FFA. These changes were more significant and intensive after frying with margarine and corn oils followed by virgin olive oil. These results suggest that clam fried with olive oil can be classified as highly nutritive in regard to its lipid content, major fatty acid profile; and nutritional value. [ABSTRACT FROM AUTHOR]

The aim of this study is to elucidate the toxicity induced by PbCl2, administered in graded doses (1; 2.5; 5 mg/L), in the redox state, in the fatty acid composition and in the histological structure of Mactra corallina digestive glands. Our findings showed a progressive accumulation of Pb in the M. corallina digestive glands in all treated groups. After 5 days of treatment with PbCl2, an increase in H2O2, MDA, PCO, GSH, NPSH and MT levels was observed in the digestive glands of treated groups. Moreover, activities of antioxidant enzymes, such as GPx and CAT, increased while SOD activity decreased in all treated groups, indicating a failure of the antioxidant defense system. Furthermore, the cholinergic function was evaluated by assessing the acetylcholinesterase activity, which was inhibited in all the treated digestive glands compared to the control group. In our experiment, the levels of n-3 (Omega-3) and n-6 (Omega-6) polyunsaturated fatty acids were greatly altered in the groups treated with 5 mg/L of PbCl2 (p < 0.001). Indeed, DHA and EPA decreased significantly in the digestive glands treated with 2.5 and 5 mg/L of PbCl2, respectively. On the other hand, under exposure to the medium and high doses (2.5 and 5 mg/L), arachidonic acid (ARA) and linoleic acid (LA) significantly increased (p < 0.001). These changes in PUFA were confirmed by significant modifications in the polyene and peroxidation indices. The histological findings confirmed the biochemical results. Integrated parameters were used to explore the toxic effect of PbCl2 graded doses in Mactra corallina digestive gland. Metals accumulation in digestive glands of M. corallina was greatly dependent to dose of PbCl2. Metabolic and macromolecules damaging of clams digestive glands were more sensitive at higher PbCl2 doses. Fatty acids composition especially polyunsaturated fatty acids (PUFA) and essentials fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in clams digestive glands were intensively altered at higher PbCl2 doses. Inflammation responses revealed in studied tissue. [ABSTRACT FROM AUTHOR]

Dimethoate is a broad-spectrum organophosphate insecticide and acaricide. Through various pathways, such as runoff and drift, dimethoate can reach marine environment, and easily impact common organisms in coastal areas, close to agriculture lands, namely crustaceans. The purpose of this study was to investigate the potential effects of dimethoate exposure (50, 100, and 200 μg/l), for 1 day, on a wide range of markers of oxidative stress and neurotransmission impairment, as well as fatty acids composition and histopathological aspect in the gills of the green crab Carcinus aestuarii. A significant increase in n-3 polyunsaturated fatty acids series, namely the eicosapentaenoic acid (C20: 5n3) and its precursor alpha-linolenic acid (C 18: 3n3) in dimethoate-treated crabs was recorded. Concerning n-6 polyunsaturated fatty acids, we noted a high reduction in arachidonic acid (C20:4n-6) levels. Dimethoate exposure increased the levels of hydrogen peroxide, malondialdehyde, lipid hydroperoxides, protein carbonyl, and caused the advanced oxidation of protein products along with enzymatic and non-enzymatic antioxidant-related markers. Acetylcholinesterase activity was highly inhibited following exposure to dimethoate in a concentration-dependent manner. Finally, deleterious histopathological changes with several abnormalities were noted in exposed animals confirming our biochemical findings. The present study offered unique insights to establish a relationship between redox status and alterations in fatty acid composition, allowing a better understanding of dimethoate-triggered toxicity. [Display omitted] • C.aestuarii can be used as bioindicators for exposure to potential toxic Dimethoate. • Dimethoate has high redox statuts responses and neurobehavioral toxicity to C.aestuarii. • 24H of Dimethoate exposure induce oxidative stress in crab's gills. • Dimethoate graded doses has the highest histopathological changes in C.aestuarii. • Chromatography identifies change of fatty acids following Dimethoate-exposure. [ABSTRACT FROM AUTHOR]

Bivalves are known for their high nutritional value and are considered a healthy food for human consumption. The effect of different cooking methods (steaming, boiling, grilling, and frying) on proximate and fatty acid composition ofArca noae(Bivalvia: Linnaeus 1758) were determined. The comparison of raw and cooked Ark shell showed that the cooking had considerable effects on the nutritional quality of this species. Significant changes in moisture (%), protein (mg/g of flesh), total lipid (mg/g of flesh), and fatty acid composition (mg/g dry weight) were observed after cooking as compared to fresh Ark shell (p < 0.05). However, the analysis of malondialdehyde (MDA) and peroxide value (PV) showed that all cooking treatments led to lipid oxidation. Steaming, boiling, and grilling were found to be a suitable and healthier cooking processes forA. noae, since they conserve the amount of n-3 PUFA better as compared to frying. [ABSTRACT FROM PUBLISHER]

• Risks associated to mercury chloride toxicity were evaluated in the detoxifying organs of Cerastoderma edule. • Increasing exposure concentrations altered the redox status of Cerastoderma edule gills and digestive gland. • Fatty acids modification could be a useful indicator of mercury chloride contamination. • Cerastoderma edule tissues contaminated with mercury chloride exhibited several histomorphological anomalies. • Damages were more pronounced in the gills than the digestive gland. Mercury chloride (HgCl 2) is a highly toxic compound which provokes a wide range of complicated disorders. The present work aimed to investigate the potential effects of HgCl 2 toxicity on the redox state, fatty acids composition and histomorphological aspect of Cerastoderma edule (C. edule) gills and digestive gland. To this end, C. edule were exposed to HgCl 2 graded concentrations (1, 10 and 100 µg.L−1) for 6 days. Results showed that HgCl 2 exposure caused a significant increase in the levels of hydrogen peroxidase (H 2 O 2) and malondialdehyde (MDA). Fatty acids (FA) analysis in the treated gills and digestive glands indicated an increase in saturated and monounsaturated fatty acids and a decrease in polyunsaturated fatty acids, mainly eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. However, the levels of arachidonic (ARA) and linoleic (C18:2n-6) acids were enhanced especially at the sharpest concentration (100 µg/L). In our investigation, we noticed a significant alteration in the estimated desaturases and elongases' activities in the treated gills as compared to the digestive glands. A concentration-dependent increase in the enzymatic (superoxide dismutase, glutathione peroxidase and catalase) and non-enzymatic (metallothionein, reduced glutathione and vitamin C) antioxidants was also observed in all treated C. edule. The histopathological changes detected in HgCl 2 -treated gills and digestive glands varied in a concentration-dependent manner. Overall, this work presented novel evidences about the mechanisms of HgCl 2 -induced toxicity in bivalves. [ABSTRACT FROM AUTHOR]

• Exposure to λ-cyh changed the ω-3 and ω-6 PUFA composition of V. verrucosa digestive gland. • FA profile serves as a sensitive tool to assess λ-cyh intoxication in V. verrucosa. • Exposure to λ-cyh disrupted antioxidant status. • λ-cyh induced neurotoxicity in treated bivalves. • Histopathology changes was observed in treated groups. Lambda-cyhalothrin (λ-cyh), a synthetic pyrethroid type II, is one of the most toxic xenobiotics to aquatic organisms, which leads to a number of complex toxicological syndromes. The present study aimed to assess the adverse effects of λ-cyh, on fatty acid (FA) composition, redox status, and the histopathology aspect of Venus verrucosa digestive gland under an exposure to a series of concentrations (100, 250 and 500 µg/L). An increase of saturated fatty acid (SFAs) levels and a decrease of polyunsaturated fatty acids (PUFAs) content, mainly eicosapentaenoic (C20: 5n − 3, EPA) and docosahexaenoic (C22: 6n − 3, DHA) acids, were observed in λ-cyh-treated digestive gland. Moreover, our data indicated an alteration in arachidonic acid (C20:4n − 6, ARA) level. The exposure to the highest dose of λ-cyh promoted oxidative stress with an increase of malondialdehyde (MDA), advanced oxidation protein product (AOPP), metallothionein (MT) and hydrogen peroxide (H 2 O 2) levels. A significant decrease in enzymatic (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)) and non-enzymatic (reduced glutathione (GSH), vitamin C and non-protein-SH (NPSH)) antioxidants was showed in treated groups. Moreover, acetylcholinesterase (AChE) activity was inhibited with the increase in λ-cyh concentration. Our biochemicals results have been confirmed by the histopathological observations. Overall, our results indicated the toxic effect of λ-cyh on the redox status of V. verrucosa digestive gland and highlighted the usefulness of determining FA composition in the better understanding of λ-cyh toxicity. [ABSTRACT FROM AUTHOR]