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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 current study examined the concentrations of ten trace elements (TE) (nickel, chromium, cadmium, iron, zinc, manganese, aluminum, copper, selenium and lead) in the edible tissue of the Ark shell Arca noae (L. 1758) from a Mediterranean coastal lagoon, the Bizerte lagoon during 2013–2014. The analysis of several redox status biomarkers, metallothioneins (MTs), malondialdehyde (MDA), glutathione peroxidase (GPx), reduced glutathione (GSH) and acetylcholinesterase (AChE), was monitored as a response to TE bioaccumulation and environmental parameters variability. Significant differences (p < 0.05) were observed between mean seasonal TE concentrations in A. noae soft tissue. The highest TE concentrations in A. noae soft tissues were recorded during summer, which coincided with the increase of body dry weight (BDW) and the gonad index (GI). During this season, biomarker responses were enhanced, revealing significant increases of MTs, MDA and GSH levels as well as GPx activity in A. noae tissues, while a decrease of AChE activity was observed. The levels of TE analyzed in A. noae and several parameters used to assess the potential human risk (estimated weekly intake, target hazard quotient and target hazard risk) were lower than the permissible limits for safe seafood consumption. Consequently, this shellfish can be considered safe for human consumption. This preliminary study presents prospects for the valorization of this seafood product in Tunisia's food sector. It also gives basal information for future environmental assessment studies in which A. noae could be used as early warning tools in the field of biomonitoring programs and confirms the usefulness of biomarkers to monitor the health status of aquatic organisms. [ABSTRACT FROM AUTHOR]

The invasive Portunus segnis, an atlantic species, was recently recorded in Tunisian waters. Since its record in the Gulf of Gabes, no studies have been carried out about the biochemical analysis of this alien species. In this context, our study aims to evaluate the fatty acid profile, lipid classes (neutral and polar), and nutritional value of breast of this invasive species. Specimens sampled from the gulf of Gabes were found to be rich in protein and oil, with significant differences between sexes. The level of saturated, monounsaturated, and polyunsaturated fatty acids in neutral and polar showed a significant difference between sexes. Saturated fatty acids were significantly higher in male P. segnis compared to the female. Docosahexaenoic (DHA), eicosapentaenoic (EPA), and arachidonic (ARA) were the most predominate polyunsaturated fatty acids (PUFA) in all oil classes. Oleic (C18:1) and Palmitoleic (C16:1) were the most abundant in monounsaturated. Palmitic (C16:0) and Stearic (C18:0) were the major saturated fatty acids. Consequently, the breast of P. segnis was a valuable source of high oil quality: It is rich in essential fatty acids and has an important n-3/n-6 ratio in both male and female blue crab. Therefore, the atherogenicity and the thrombogenicity were also evaluated, showing that P. segnis is a shellfish of greater value for human consumption in Tunisia. [ABSTRACT FROM AUTHOR]

The current study aims to examine the concentrations of eight trace elements (TE) (nickel, aluminum, copper, cadmium, lead, cobalt, chromium, and zinc) in the edible tissue of the invasive blue crab Portunus segnis in two southern Mediterranean lagoons (i.e., Bizerte Lagoon (BL) and Ghar El-Melh Lagoon (GML)) between 2020 and 2021. The samples were analyzed for TE using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the mean concentrations in P. segnis muscles were significantly lower in Ghar El-Melh (0.183 mg/kg DW, 1.887 mg/kg DW, and 0.986 mg/kg DW for Cd, Cu, and Al, respectively) compared to Bizerte Lagoon (0.227 mg/kg DW, 8.016 mg/kg DW, and 3.658 mg/kg DW for Cd, Cu, and Al respectively), except for Zn which exhibited similar concentrations in crabs harvested from both lagoons. The recorded concentrations of all TE measured in both lagoons were within acceptable limits per the recommended standards. The highest TE concentrations in P. segnis muscle tissue of crabs from both lagoons were recorded during the summer. The analysis of trace element (TE) levels in P. segnis and the assessment parameters, including estimated daily intake (EDI), target hazard quotient (THQ), and target cancer risk (TCr), revealed values below the acceptable limits for human health. THQ and TCr are commonly utilized in environmental and health risk assessments to gauge the potential impact of contaminants on human health. As a result, we can affirm that the invasive crab P. segnis figures as a secure shellfish product suitable for human consumption in Tunisia. This study provides an opportunity to assess the health risks of consuming blue crabs, with the toxicity risk index aiding decision-making for consumers, policymakers, and stakeholders focused on safety and sustainability. Additionally, it offers fundamental insights to lay the groundwork for forthcoming studies on environmental assessments., Competing Interests: Declarations. Ethical approval: The animals received humane care under the International Guidelines for Animal Care with strict adherence to the Ethical Committee of Faculty of Sciences, Sfax, Tunisia, under the ethical approval no. 1204. Consent to participate: Not applicable. Consent to publish: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The present study aimed to evaluate the biochemical status of Venerupis decussata collected seasonally from two Tunisian coastline lagoons (Ghar El Melh and Boughrara) submitted to different anthropogenic levels. Trace elements were significantly higher in clams from Boughrara, especially during the warm season. Fatty acids, proximate compositions, and nutritional value of both clam populations were higher, appearing to be the best for human consumption principally during the spring season. The principal component analysis was determined, including phospholipids and reserve lipids, revealing a great variation with the exogenous and endogenous factors. Generally, clams from Boughrara had a significant alteration in biochemical composition principally due to the anthropogenic levels and physicochemical fluctuation of this lagoon. Our results reflected the healthy benefit of clam consumption and the use of energy reserves and essential fatty acids as a great biomarker to assess ecological risk in lagoons and other coastal ecosystems.

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.)