Exposure to different cobalt chloride levels produces oxidative stress and lipidomic changes and affects the liver structure of Cyprinus carpio juveniles.

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.

Dual oxidative stress and fatty acid profile impacts in Paracentrotus lividus exposed to lambda-cyhalothrin: biochemical and histopathological responses.

Lambda-cyhalothrin (λ-cyh) is a potential pyrethroid insecticide widely used in pest control. The presence of pyrethroids in the aquatic ecosystem may induce adverse effects on non-target organisms such as the sea urchin. This study was conducted to assess the toxic effects of λ-cyh on the fatty acid profiles, redox status, and histopathological aspects of Paracentrotus lividus gonads following exposure to three concentrations of λ-cyh (100, 250 and 500 µg/L) for 72 h. The results showed a significant decrease in saturated fatty acid (SFAs) with an increase in monounsaturated fatty acid (MUFAs) and polyunsaturated fatty acid (PUFAs) levels in λ-cyh treated sea urchins. The highest levels in PUFAs were recorded in the eicosapentaenoic acids (C20:5n-3), docosahexaenoic acids (C22:6n-3) and arachidonic acids (C20:4n-6) levels. The λ-cyh intoxication promoted oxidative stress with an increase in hydrogen peroxide (H2O2), malondialdehyde (MDA) and advanced oxidation protein products (AOPP) levels. Furthermore, the enzymatic activities and non-enzymatic antioxidants levels were enhanced in all exposed sea urchins, while the vitamin C levels were decreased in 100 and 500 µg/L treated groups. Our biochemical results have been confirmed by the histopathological observations. Collectively, our findings offered valuable insights into the importance of assessing fatty acids' profiles as a relevant tool in aquatic ecotoxicological studies.

New insight into the toxic effects of lithium in the ragworm Perinereis cultrifera as revealed by lipidomic biomarkers, redox status, and histopathological features.

Lithium (Li) is a toxic monovalent alkaline metal used in household items common to industrial applications. The present work was aimed at investigating the potential toxic effects of LiCl on the redox status, fatty acid composition, and histological aspects of the marine ragworm Perinereis cultrifera. Sea worms were exposed to LiCl graded doses (20, 40, and 80 mg/L) for 48 h. Compared with the control group, the saturated fatty acids (SFA) decreased while monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) increased upon exposure to LiCl. The increase in PUFA n-3 and PUFA n-6 was concomitant to an increase in docosahexaenoic (DHA: C22:6n-3), eicosapentaenoic (EPA: C20:5n-3), and docosapentaenoic acid (C22:5n-6) fatty acids. Results showed that LiCl-treated specimens accumulate lithium with increasing exposure gradient. Indeed, the exposure to LiCl doses promoted oxidative stress with an increase of the ferric reducing antioxidant power (FRAP), malondialdehyde (MDA), hydrogen peroxide (H2O2), advanced oxidation protein product (AOPP), and protein carbonyl (PCO) as well as the enzymatic and non-enzymatic antioxidants (non-protein thiols (NPSH), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione S-transferase (GST), and metallothionein (MT)) levels in all treated groups. Our biochemical findings have been affirmed by the histopathological observations showing hyperplasia and loss of the intestine structure in treated specimens. Overall, our findings give new insights on the toxic effect of LiCl on the redox status of P. cultrifera body tissue and highlighted the usefulness of the FA composition as an early sensitive bioindicators to better understand LiCl mechanism of toxicity in marine polychaetes.

Incorporation of ω3 fatty acids in the diets of Nile tilapia juvenile (Oreochromis niloticus L.): effects on growth performance, fatty acid composition, and tolerance to low temperature.

In order to increase the low-temperature resistance of Nile tilapia, the purpose of this study was to determine the potential effect of ω3 fatty acid incorporation in Oreochromis niloticus diet. To perform this, two experimental diets containing soybean oil (D1) and cod liver oil (D2) have been supplied to juvenile tilapia for 30 days. According to our results, similar improvements in the two diets have been recorded for growth performance of O. niloticus including the final body mass, specific growth rate, and feed conversion ratio. Our results showed that fish fed with diet D2 promoted high polyunsaturated fatty acids mainly n-3 series (PUFA (n-3)) percent, highlighting the increased levels of docosahexaenoic (DHA) and eicosapentaenoic (EPA) as well as the activation of their conversion enzyme ratios D5D and D6D desaturases. The second objective was to assess the effect of the two experimental diets on low water temperature tolerance. This was done by exposing juvenile fish at the end of the first experiment to 16, 14, 12, 10, and 8 °C for 12 h, 24 h, and 48 h. The sub-lethal LT50 of O. niloticus fed with diet D1 was 10.6, 11.4, and 13 °C respectively, after 12 h, 24 h, and 48 h. This pattern was commonly observed for O. niloticus fed with D2, showing that the subLT50 were 10.3, 11.1, and 12 °C during the same period. These results demonstrate that O. niloticus juveniles fed with diet D2 are more tolerant to low temperatures than those fed with diet D1.

Nutritional quality traits of raw and cooked Ark shell (Bivalvia: Arcidae): balancing the benefits and risks of seafood consumption.

Biochemical composition and fatty acid profile of raw Ark shells (RA) were compared to Ark shells submitted to three different cooking methods (BA: baking in the oven; PF: pan-frying in butter and MW: cooking in a microwave). Moisture (%) was significantly higher in RA (79.66) with respect to PF (65.09), BA (48.63) and MW (47.02). Protein (mg/g of flesh) decreased significantly from 18.62 in RA to 15.40 in MW, 13.76 in PF and 13.33 in BA. However, lipids significantly increased in MW (43.32 mg/g of flesh) and PF (63.63 mg/g of flesh) with respect to RA (35.05 mg/g of flesh). Pan-frying affected considerably triacylglycerol (TAG) and the fatty acid composition (FA) of Ark shell flesh. The most changes occurred in saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acid fractions after this process. The n-3 PUFA decreased significantly from RA (16.40 mg/g dry weight) to PF (10.02 mg/g DW). While, the opposite trend was observed for n-6 PUFA, revealing that this cooking method had considerable effects on the nutritional characteristics of this edible shellfish. The analysis of lipid peroxidation markers such as thiobarbituric acid reactive substances, free fatty acid and peroxide value confirmed that both heat treatment and time of cooking caused lipid degradation, which had been more accentuated during pan-frying treatment. For the populations who consume Ark shells occasionally or frequently, baking and microwave cooking could be then considered as wiser and healthier cooking methods since they conserve better the nutritional value of this marine product. The present study will be of practical value from a health perspective for Mediterranean populations.

Effect of storage temperature and time on the fatty acids and nutritional quality of the commercial mussel (Mytilus galloprovincialis).

The effect of storage time (5, 10 and 15 days) and temperature (- 20 °C and + 4 °C) on the biochemical composition of the Tunisian mussel (Mytilus galloprovincialis) was evaluated by investigating changes in proximate composition, fatty acids, minerals and nutritional quality indices. Lipid and protein degradations were also evaluated through several markers of oxidative damage. Results showed a significant decrease in the biochemical compounds in mussel tissues after both refrigeration and freezing processes (p < 0.01). As regards the fatty acid composition, saturated fatty acids increased significantly after both storage processes. However, polyunsaturated and monounsaturated decreased, especially after 10 and 15 days of storage. The reduction of nutritional quality and mineral contents were detected after both storage processes. Markers of oxidative damage varied remarkably between fresh and stored tissues, revealing that both processes greatly influenced the nutritional quality of mussels. Overall, it is well recommended to consume fresh and stored mussels for no more than 5 days in the refrigerator (+ 4 °C) in order to preserve the better quality of this product and provide more benefits for human health.

Trace elements and oxidative stress in the Ark shell Arca noae from a Mediterranean coastal lagoon (Bizerte lagoon, Tunisia): are there health risks associated with their consumption?

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.

Assessment of the biochemical and nutritional values of Venerupis decussata from Tunisian lagoons submitted to different anthropogenic ranks.

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.