Lead, Mercury and Cadmium in Fish and Shellfish from the Indian Ocean and Red Sea (African Countries): Public Health Challenges

Differential Cellular Response to Mercury in Non-Farmed Fish Species Based on Mitochondrial DNA Copy Number Variation Analysis

Mercury (Hg) pro-oxidant role on biological systems and its biogeochemical cycle represent a serious threat due to its persistence in marine environment. As the mitochondrial genome is exposed to reactive oxygen species (ROS), the aim of the present study is the validation of the variation in the number of mitochondrial DNA copies (mtDNAcn) as biomarker of oxidative stress in aquatic environment. During summer 2021, three selected fish species (Mullus barbatus, Diplodus annularis and Pagellus erythrinus) were collected in Augusta Bay, one of the most Mediterranean contaminated areas remarkable by past Hg inputs, and in a control area, both in the south-east of Sicily. The relative mtDNAcn was evaluated by qPCR on specimens of each species from both sites, characterized respectively by higher and lower Hg bioaccumulation. M. barbatus and P. erythrinus collected in Augusta showed a dramatic mtDNAcn reduction compared to their control groups while D. annularis showed an incredible mtDNAcn rising suggesting a higher resilience of this species. These results align with the mitochondrial dynamics of fission and fusion triggered by environmental toxicants. In conclusion, we suggest the implementation of the mtDNAcn variation as a valid tool for the early warning stress-related impacts in aquatic system.

Physiological and transcriptomic responses of seawater halobios to micro/nano-scale polystyrene-cadmium exposure in a marine food web

Micro/nano-plastics (MPs/NPs) represent an emerging contaminant, posing a significant threat to oceanic halobios. While the adverse effects of joint pollutants on marine organisms are well-documented, the potential biological impacts on the food chain transmission resulting from combinations of MPs/NPs and heavy metals (HMs) remain largely unexplored. This study exposed the microbial loop to combined contaminants (MPs/NPs + HMs) for 48h, bacteria and contaminants are washed away before feeding to the traditional food chain, employing microscopic observation, biochemical detection, and transcriptome analysis to elucidate the toxicological mechanisms of the top predator. The findings revealed that MPs/NPs combined with Cd2+ could traverse both the microbial loop and classical food chain. Acute exposure significantly affected the carbon biomass of the top predator Tigriopus japonicus (75.8% lower). Elevated antioxidant enzyme activity led to lipid peroxidation, manifesting in increased malondialdehyde levels. Transcriptome sequencing showed substantial differential gene expression levels in T. japonicus under various treatments. The upregulation of genes associated with apoptosis and inflammatory responses, highlighting the impact of co-exposure on oxidative damage and necroptosis within cells. Notably, NPs-Cd exhibited stronger toxicity than MPs-Cd. NPs-Cd led to a greater decrease in the biomass of top predators, accompanied by lower activities of GSH, SOD, CAT, and GSH-PX, resulting in increased production of lipid peroxidation product MDA and higher oxidative stress levels. This investigation provides novel insights into the potential threats of MPs/NPs combined with Cd2+ on the microbial loop across traditional food chain, contributing to a more comprehensive assessment of the ecological risks associated with micro/nano-plastics and heavy metals.

An integrative data-centric approach to derivation and characterization of an adverse outcome pathway network for cadmium-induced toxicity

Cadmium is a prominent toxic heavy metal that contaminates both terrestrial and aquatic environments. Owing to its high biological half-life and low excretion rates, cadmium causes a variety of adverse biological outcomes. Adverse outcome pathway (AOP) networks were envisioned to systematically capture toxicological information to enable risk assessment and chemical regulation. Here, we leveraged AOP-Wiki and integrated heterogeneous data from four other exposome-relevant resources to build the first AOP network relevant for inorganic cadmium-induced toxicity. From AOP-Wiki, we filtered 309 high confidence AOPs, identified 312 key events (KEs) associated with inorganic cadmium from five exposome-relevant databases using a data-centric approach, and thereafter, curated 30 cadmium relevant AOPs (cadmium-AOPs). By constructing the undirected AOP network, we identified a large connected component of 18 cadmium-AOPs. Further, we analyzed the directed network of 59 KEs and 82 key event relationships (KERs) in the largest component using graph-theoretic approaches. Subsequently, we mined published literature using artificial intelligence-based tools to provide auxiliary evidence of cadmium association for all KEs in the largest component. Finally, we performed case studies to verify the rationality of cadmium-induced toxicity in humans and aquatic species. Overall, cadmium-AOP network constructed in this study will aid ongoing research in systems toxicology and chemical exposome.

Heavy metals contamination of seafood from the crude oil-impacted Niger Delta Region of Nigeria: A systematic review and meta-analysis

This study aims at computing the pooled mean estimate (PME) and health risks of heavy metals in seafood obtained from the Niger Delta Region of Nigeria (NDRN), using data from existing literatures. Pubmed, Scopus and Google Scholar were searched to retrieve articles that investigated the heavy metal contents of edible seafood from the NDRN. Search hits were screened against predetermined criteria following which relevant data were extracted from eligible articles. The PME for each metal was computed by performing a maximum likelihood random effect model meta-analysis using the R Studio Software. Outcome from the meta-analysis involving 58 studies and a total of 2983 seafood samples revealed the following PMEs (mg/kg dry wt seafood) for the investigated heavy metals: As (0.777), Cd (0.985), Co (4.039), Cr (2.26), Cu (11.45), Fe (143.39), Hg (0.0058), Mn (13.56), Ni (5.26), Pb (4.35), and Zn (29.32). The health risk assessment suggests that seafood from this region poses considerable carcinogenic and non-carcinogenic risks to human consumers. Our finding calls for urgent actions aimed at identifying and eliminating point sources of heavy metals pollution of the NDRN marine environment. Inhabitants of NDRN are encouraged to reduce seafood consumption while diversifying their protein sources to include non-seafood options.

Evaluation of cadmium and mercury on cardiovascular and neurological systems: Effects on humans and fish

Chemicals are at the top of public health concerns and metals have received much attention in terms of toxicological studies. Cadmium (Cd) and mercury (Hg) are among the most toxic heavy metals and are widely distributed in the environment. They are considered important factors involved in several organ disturbances. Heart and brain tissues are not among the first exposure sites to Cd and Hg but they are directly affected and may manifest intoxication reactions leading to death. Many cases of human intoxication with Cd and Hg showed that these metals have potential cardiotoxic and neurotoxic effects. Human exposure to heavy metals is through fish consumption which is considered as an excellent source of human nutrients. In the current review, we will summarize the most known cases of human intoxication with Cd and Hg, highlight their toxic effects on fish, and investigate the common signal pathways of both Cd and Hg to affect heart and brain tissues. Also, we will present the most common biomarkers used in the assessment of cardiotoxicity and neurotoxicity using Zebrafish model.

Sample Preparation and Analytical Techniques in the Determination of Trace Elements in Food: A Review

Every human being needs around 20 essential elements to maintain proper physiological processes. However, trace elements are classified as beneficial, essential, or toxic for living organisms. Some trace elements are considered essential elements for the human body in adequate quantities (dietary reference intakes, DRIs), while others have undetermined biological functions and are considered undesirable substances or contaminants. Pollution with trace elements is becoming a great concern since they can affect biological functions or accumulate in organs, causing adverse effects and illnesses such as cancer. These pollutants are being discarded in our soils, waters, and the food supply chain due to several anthropogenic factors. This review mainly aims to provide a clear overview of the commonly used methods and techniques in the trace element analysis of food from sample preparations, namely, ashing techniques, separation/extraction methods, and analytical techniques. Ashing is the first step in trace element analysis. Dry ashing or wet digestion using strong acids at high pressure in closed vessels are used to eliminate the organic matter. Separation and pre-concentration of elements is usually needed before proceeding with the analytical techniques to eliminate the interferences and ameliorate the detection limits.

Redox Status, Immune Alterations, Histopathology, and Micronuclei Induction in Labeo rohita Dwelling in Polluted River Water

In this study, we measured various parameters of oxidative stress, immune response, and abnormalities in the erythrocyte nucleus of Labeo rohita inhabiting the polluted Kshipra River, India. The river water contains heavy metals in this order: Ni > Fe > Cd > Cr > Mn > Zn > Cu. Fe showed the highest accumulation in gills, liver, and gut, whereas Ni (gills and gut) and Cd (liver) were lowest accumulated. The superoxide dismutase (SOD) and catalase (CAT) were found to be increased significantly (p < 0.05) in the gills (SOD: 211%; CAT: 150%), liver (SOD: 447%; CAT: 304%), and gut (SOD: 98.11%; CAT: 58.69%) in comparison with the reference fish. However, glutathione S transferase (GST) showed significantly (p < 0.05) higher activity in the gills (25.5%) but lower activity in the liver (- 49.22%) and the gut (- 30.57%). Moreover, reduced glutathione (GSH) decreased significantly (p < 0.05) in the gills (- 46.66%), liver (- 33.20%), and gut (- 39.87%). Despite the active response of the antioxidant enzymes, the highest lipid peroxidation was observed in the liver (463%). The effect of heavy metals was also observed on the immunity of the fish, causing immunosuppression as evident by significantly (p < 0.05) lower values of acid phosphatase (- 50%), myeloperoxidase (- 48.33%), and nitric oxide synthase (- 50%) in serum. Histopathological findings showed gill lamellae shortening, hyperplasia, club-shaped lamellar tip in exposed gills and necrosis, vacuolization, and pyknosis in the exposed liver. Furthermore, polluted river water was also found to induce micronuclei (2.1%) and lobed nuclei (0.72%) in erythrocytes (0.65%). These results indicate the potential of heavy metal-induced oxidative stress and other forms of stress in inhabiting fish, highlighting the need to control the pollution of this river water.

Bivalve Shellfish Safety in Portugal: Variability of Faecal Levels, Metal Contaminants and Marine Biotoxins during the Last Decade (2011-2020)

Bivalves are a high-value product whose production has markedly increased, reaching 9863 tonnes in Portugal in 2021. Bivalves' habitats-lagoons, estuaries and coastal waters-are exposed to biological and anthropogenic contaminants, which can bioaccumulate in these organisms and pose a significant public health risk. The need to obtain a safe product for human consumption led to the implementation of standardised hygiene regulations for harvesting and marketing bivalve molluscs, resulting in routine monitoring of bivalve production areas for microbial quality, metal contaminants, and marine biotoxins. While excessive levels of biotoxins and metal contamination lead to temporary harvesting bans, high faecal contamination leads to area reclassification and impose post-harvest treatments. In this study, the seasonal and temporal variability of these parameters were analysed using historical data generated by the monitoring programme during the last decade. Moreover, the impact of the monitoring program on bivalve harvesting from 2011 to 2020 was assessed. This program presented a considerable improvement over time, with an increase in the sampling effort and the overall program representativeness. Finally, contamination risk, revising control measures, and defining recommendations for risk mitigation measures are given in the light of ten years' monitoring.

Environmental monitoring of trace metal pollutants using cellulosic-paper incorporating color change of azo-chromophore

An essential requirement for colorimetric paper-sensor is to allow the target analytes (heavy metal ions) to access the chromophore while maintaining strong chromophore immobilization on the porous substrate surface. This work evaluates the selection of sensitive chromophores (dithizone, 1-(2-pyridylazo) 2-naphthol and 4-(2-pyridylazo)-resorcinol) and their immobilization strategies on paper sensors. Dithizone (DTz) are capable of producing a significant color transition at unadjusted pH, observed by UV-Vis absorption spectroscopy and visible recognition. After immobilizing DTz on a paper substrate (cellulose acetate/chitosan substrate), the DTz-paper sensor showed a distinctive color change from blue-green to peach-pink upon reaction with Pb²⁺ ions, and the color intensity was proportional to the metal concentration. Quantitative analysis using RGB (R:Red; G:Green; B:Blue) plots showed that increasing DTz concentration on the CA/CS paper sensor increases the difference in total color intensity (∆I_T) and the difference in red code intensity (∆I_R). This is due to the formation of more DTz-Pb²⁺ complexes on the CA/CS paper substrate. The CA/CS paper strips immobilized with 100 ppm DTz showed practical potential for rapid detection of heavy metal ions. The DTz-CA/CS paper sensor showed significant color change when detecting spiked heavy metals ions (0.1 ppm Pb²⁺, 2.0 ppm Zn²⁺, and 0.2 ppm Cu²⁺) in river water samples that prepared at the maximum permissible limit for industrial effluent in Malaysia.

Assessment of trace metal concentrations in Indian Ocean silky sharks Carcharhinus falciformis and their toxicological concerns

This study assessed the concentrations of nine trace metals from juvenile C. falciformis caught from Indian Ocean. This study also discussed the metal pollution index (MPI) and bioconcentration factor (BCF) of each element, and their correlations. Further, the potential health risks of consuming shark muscles (THI) were evaluated. Results showed the mean concentrations of 9 elements as follows: Cu (0.36 ± 0.17), Zn (5.19 ± 16.6), Pb (0.12 ± 0.23), Cd (0.17 ± 0.21), Cr (0.57 ± 1.61), Ni (0.086 ± 0.51), As (1.36 ± 0.83), Co (0.000073 ± 0.0074), and V (0.0024 ± 0.0094) mg/kg ww. The BCF values of the elements were higher than 1, with Co and V being the lowest indicating their bioaccumulative behavior. Correlation analysis showed MPI to be highly correlated with Cu, indicating its greater contributions to the total pollution load. Principal components analysis explained 81.0% of the variability in biometric characteristics and metal concentrations. Health risk assessment for consuming shark muscle in Taiwanese male and female adults suggests potential chronic non-carcinogenic health hazards.

Industrialization and food safety for the Tsleil-Waututh Nation: An analysis of chemical levels in shellfish in Burrard Inlet

While Indigenous food systems remain critical for community well-being, traditionally harvested foods are a potential source of toxic exposures. The Tsleil-Waututh Nation (TWN) is seeking to restore shellfish harvesting in Burrard Inlet (British Columbia [BC], Canada), where the cumulative effects of industrial activity have nearly eliminated safe harvesting. The Trans Mountain Expansion project would triple the capacity to transport oil through the inlet, threatening TWN's progress to restore shellfish harvesting. To inform ongoing efforts we assessed contamination by heavy metals (arsenic, cadmium, lead, and mercury) and 48 polycyclic aromatic hydrocarbons (PAHs) congeners in different shellfish species (Softshell clams, Varnish clams, and Dungeness crab) in three areas. We compared our results against local screening values (SVs) established by the TWN and BC Ministry of Environment and Climate Change Strategy, as well as provincial and national benchmarks. In total, we analyzed 18 composite samples of Softshell clams and Varnish clams (5 individuals per sample), as well as 17 individual crabs. We found chemical contamination in all species at all sites. PAHs were most frequently detected in Softshell clams, highest in the site closest to the pipeline terminus. Clams presented higher levels of contamination than crabs for PAHs, but not for heavy metals. For Softshell and Varnish clams, all heavy metals across study sites exceeded at least one of the population-specific SVs. Of the 14 PAHs detected, benzo(a)pyrene presented a median concentration in Softshell clams of 3.25 μ/kg, exceeding local SV for subsistence fisher. Our results call for further assessment of human health impacts related to food harvesting within Burrard Inlet and establishing a long-term coordinated program co-led by the TWN to monitor contamination and inform future harvesting programs. The study draws attention to the need to consider locally-relevant toxicity benchmarks, and include potential health impacts of food contamination in appraising development project proposals.

A Simplified Approach to Modeling the Dispersion of Mercury from Precipitation to Surface Waters—The Bay of Kaštela Case Study

Wet deposition is the main source of mercury (Hg) from the atmosphere to the Earth’s surface. However, the processes that govern the dispersion of deposited Hg in seawater are currently not well understood. To address this issue, total mercury (THg) concentrations in surface seawaters and precipitation were determined on a monthly basis in the Bay of Kaštela (Central Adriatic Sea). Following the assumption that deposited THg is diluted in the seawater bulk due to mixing processes, an exponential decay-like model was developed and the wet deposition of THg was normalized based on periods between precipitation events and seawater sampling. Normalized wet deposition of THg showed significant correlation with the THg gradient in surface seawater after removal of an outlier. To explain the observed outlier, further data normalization included wind data to account for enhanced seawater mixing due to strong winds. Wind-normalized THg deposition of all datapoints showed significant correlation with the THg gradient in surface seawater. The correlation showed that the THg gradient in surface seawater of 0.378 pg L−1 m−1 corresponds to THg wet deposition of 1 ng m−2 after including the influence of wind speed on seawater mixing.

Protective efficacy of naringenin against cadmium-induced redox imbalance in Labeo rohita: an integrated biomarker approach

The protective efficacy of dietary naringenin (NG) has been investigated against the toxicity caused by cadmium chloride (CdCl₂) using biomarkers of oxidative stress in the liver, gills and kidney of Labeo rohita. The fish were exposed to environmentally relevant concentrations of CdCl₂ (0.37 and 0.62 mg/L) and simultaneously orally administered with NG (50 mg/kg bw/day) for 60 days. Tissue (gills, liver and kidney) samples were collected on days 15, 30 and 60 of the experiment and analysed for endogenous antioxidants and oxidative stress biomarkers. CdCl₂ exposure for 15 and 30 days induced the development of adaptive mechanism as demonstrated by the enhanced activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase in all three tissues. However, on the 60th day, CdCl₂-induced oxidative damage was stipulated by a decline in the enzyme activities and reduced glutathione (GSH) content significantly (p < 0.05) below control levels along with enhanced levels of lipid peroxidation. Oral administration of NG in toxicant exposed fish significantly restored the altered levels of antioxidants, oxidative enzymes and lipid peroxidation. Besides, integrated biomarker response (IBR) analysis was applied by combining all the biomarkers to indicate the overall stress response index. IBR analysis confirmed the altered levels of biomarkers, the oxidative stress induced by CdCl₂ exposure and the ameliorative potential of NG. The present study suggested that NG might have protective role against Cd-induced oxidative insult which might be ascribed to the ability of NG to chelate metals and scavenge free radicals.

Comparison of Growth Performance, Pigment Synthesis, and Esterase Activity of Synechococcus sp. HS01 and Limnothrix sp. KO01 in Response to Cadmium Toxicity

Various studies have been conducted to understand the impact of environmental pollutants on cyanobacteria due to their abundant presence in aquatic and terrestrial environments, specific morphological and physiological characteristics, and high ecological flexibility in response to environmental changes. Here, the effect of different concentrations of cadmium on two native strains of cyanobacteria, namely Synechococcus sp. HS01 and Limnothrix sp. KO01 was studied and compared with each other. In this regard, the cyanobacterial growth, pigment contents, and esterase enzyme activity were evaluated after exposure of the cells to different concentrations of cadmium (II). The toxic effects of Cd(II) on the growth rate of Limnothrix sp. KO01, even at low concentrations, tended to be higher than those for Synechococcus sp. HS01. The content of pigments decreased by an increase in Cd(II) concentration. In compliance with the cell growth, the changes occurred in pigment contents of Limnothrix sp. KO01 was more sensitive than Synechococcus sp. HS01 in the presence of different concentrations of cadmium. Flow cytometry analysis of Cd(II) effects on esterase activity of both strains after 6, 24, 48, and 72 h of exposure to Cd(II) concentrations of 9, 27, 63, and 90 μM showed that tolerance to Cd(II) toxicity in Limnothrix sp. KO01 is less than Synechococcus sp. HS01. The results obtained in this study suggest high potentials of Synechococcus sp. HS01 for heavy metal bioaccumulation due to its considerable tolerance to cadmium.

Aquatic food animals in the United States: Status quo and challenges

This review summarizes (1) the U.S. status quo for aquatic food animal production and marketing; (2) major food safety and quality issues/concerns for aquatic food animals in the United States, including fish misbranding, finfish/shellfish allergies, pathogens, toxins and harmful residues, microplastics, and genetically engineered salmon; and (3) various U.S. regulations, guidances, and detection methods for the surveillance of fishery products. Overall, fish misbranding is the biggest challenge in the United States due to the relatively low inspection rate. In addition, due to the regulatory differences among countries, illegal animal drugs and/or pesticide residues might also be identified in imported aquatic food animals. Future regulatory and research directions could focus on further strengthening international cooperation, enhancing aquatic food animal inspection, and developing reliable, sensitive, and highly efficient detection methods.

Sustainable mitigation of heavy metals from effluents: Toxicity and fate with recent technological advancements

Increase in anthropogenic activities due to rapid industrialization had caused an elevation in heavy metal contamination of aquatic and terrestrial ecosystems. These pollutants have detrimental effects on human and environmental health. The majority of these pollutants are carcinogenic, neurotoxic, and are very poisonous even at very low concentrations. Contamination caused by heavy metals has become a global concern for which the traditional treatment approaches lack in providing a cost-effective and eco-friendly solution. Therefore, the use of microorganisms and plants to reduce the free available heavy metal present in the environment has become the most acceptable method by researchers. Also, in microbial- and phyto-remediation the redox reaction shifts the valence which makes these metals less toxic. In addition to this, the use of biochar as a remediation tool has provided a sustainable solution that needs further investigations toward its implementation on a larger scale. Enzymes secreted by microbes and whole microbial cell are considered an eco-efficient biocatalyst for mitigation of heavy metals from contaminated sites. To the best of our knowledge there is very less literature available covering remediation of heavy metals aspect along with the sensors used for detection of heavy metals. Systematic management should be implemented to overcome the technical and practical limitations in the use of these bioremediation techniques. The knowledge gaps have been identified in terms of its limitation and possible future directions have been discussed.

Heavy metals in processed seafood products from Turkey: risk assessment for the consumers

In this study, concentrations of 6 different elements (copper (Cu), tin (Sn), zinc (Zn), iron (Fe), cadmium (Cd) and lead (Pb)) in 9 different processed seafood (marinated and smoked mackerel, smoked mackerel, marinated octopus tentacles, marinated octopus salad, marinated squid salad, salted and dried mackerel, marinated and smoked anchovy, smoked salmon and smoked bonito) randomly taken from markets in Mugla province (West Anatolia, Turkey) were determined with the method of inductively coupled plasma mass spectroscopy (ICP-MS) after microwave wet digestion process. In addition, risk assessment for consumer health was conducted by the determination of estimated daily intake (EDI), target hazard quotient (THQ), total target hazard quotient (TTHQ) and carcinogenic risk (CR). According to the obtained results, the seafood product samples with the highest concentrations of each metal were marinated and smoked anchovy for Fe (65.85 ± 16.03 mg kg^-1), marinated and smoked anchovy for Zn (64.58 ± 25.16 mg kg^-1), marinated octopus salad for Cu (26.33 ± 17.76 mg kg^-1), smoked mackerel for Sn (0.42 ± 0.18 mg kg^-1), smoked mackerel for Pb (0.28 ± 0.18 mg kg^-1) and marinated squid salad for Cd (0.31 ± 0.12 mg kg^-1). According to risk assessment for consumer health, it was found that EDI results did not exceed the tolerable daily intake (TDI) values. As a conclusion, any risk for consumer health in terms of CR, THQ and TTHQ values was not detected in the examined samples.

Health risk estimation of metals bioaccumulated in commercial fish from coastal areas and rivers in Bangladesh

Metal contaminations in commercial fish have become a great public health concern worldwide including Bangladesh. The current study was conducted to provide preliminary evidence of nine metals in three commercially significant fish namely Pampus argenteus, Sardinella longiceps and Tenualosa ilisha collected from four coastal stations- Kuakata, Pathorghata, Cox's Bazar, and Pirojpur, and eight stations of five rivers- Padma, Meghna, Jamuna, Katcha, and Nobogonga in Bangladesh. High magnitudes of Pb (0.74-4.59 mg/kg ww), Cd (0.07-0.24 mg/kg ww), and Mn (0.45-2.03 mg/kg ww) were recorded in the sampling stations that exceeded the maximum permissible limits (MPL) proposed by different recognized organizations. Significant mean differences of metal concentrations were observed (p < 0.05) between species and stations. In fish samples, excessive metals accumulations were recorded from Kuakata (St.1) at the coastal area, and Nobogonga (St. 12) among the rivers. The health risk assessment (HRA) was carried out comprehensively via the estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TR) calculations. The outcomes of EDI, THQ, and HI suggest that chronic exposure to towering Pb content might pose potential health threats to inhabitants particularly living in highly polluted stations of the coastal area. In addition, the massive TR values of Cd intake through fish consumption from the coastal area might create cancer risks. Accordingly, the ingestion of metals contaminated fish portends chronic as well as acute health risks to Bangladeshi people living both at home and abroad.

Impact on Fertility Rate and Embryo-Larval Development Due to the Association Acidification, Ocean Warming and Lead Contamination of a Sea Urchin Echinometra lucunter (Echinodermata: Echinoidea)

Ocean warming and acidification can cause deleterious effects on marine biota, which may be potentialized when associated with metal pollution. Thus, the aim of this work was to evaluate the effects of pH decrease, temperature increase and lead contamination on fertility rate and embryo-larval development of Echinometra lucunter. Gametes and embryos were exposed at pH 8.2 (control) and 7.5; at 26°C (control) and 28°C; and at lead concentrations of 0 (control), 125, 250 and 500 μg/L. These conditions were tested individually and in combination. The fertilization rate of E. lucunter was only significantly reduced in the treatments where temperature was increased and in the treatment where pH decreased. However, the development rate of the pluteus larvae was significantly affected in the majority of treatments: metal contamination in the higher concentration; decreased pH in all metal concentrations; increased temperature in the highest metal concentration; decreased pH and increased temperature and all variables combined, which is decreased pH, increased temperature and metal contamination in relation to the control group (C). The development test was shown to be more sensitive than the fertilization test in all the studied scenarios. In general, the present study suggests that pH decrease, temperature increase and metal pollution may have a significant impact on E. lucunter reproductive cycle.

Black Soldier Fly Larvae Meal as Alternative to Fish Meal for Aquaculture Feed

Hermetia illucens meal (HIM) as ingredient in feed represents a way to achieve more sustainable food production. The aim was to characterize the chemical, microbiological and organoleptic characteristics of four diets for Sparus aurata, isoenergetic and isoproteic, containing 0%, 25%, 35% and 50% of HIM in substitution of fish meal (FM). Analyses were carried out using gas chromatography for fatty acids and amino acids, ICP-OES for minerals and liquid chromatography for aflatoxins and following International Organization for Standardization methods for microbial flora. E-sensing analysis of the diets was evaluated using an artificial sensory platform (E-eye, E-nose and E-tongue). The chemical results were submitted to a one-way ANOVA while Principal Component Analysis (PCA) of the e-sensing data was performed. No significant differences were observed for polyunsaturated fatty acids, thrombogenic and peroxidation indices among the diets. The replacement of FM with HIM increased the content of lysine, methionine, isoleucine, leucine, threonine and valine, while phosphorus, calcium and sodium content decreased (p < 0.01) as the percentage of HIM increased. Lead was significantly below the maximum level set by the EU regulation. The diets showed good hygienic and sanitary quality. The artificial senses permitted distinguishing color, odor and taste among the diets. Data allow considering Hermetia illucens as alternative protein source in fish nutrition.

Enhanced Cytotoxicity of Cadmium by a Sulfated Polysaccharide from Abalone

Consumption of seafood is a common route of cadmium ion (Cd²⁺) exposure to consumers. The seafood matrices may alter the toxicity profile of Cd²⁺ due to the interaction between Cd²⁺ and biomacromolecules in seafood. In this study, enhanced cytotoxicity of Cd²⁺ was found in the presence of an abalone gonad sulfated polysaccharide (AGSP) and the mechanism was investigated at a metabolic level. The formation of the AGSP-Cd²⁺ complex was demonstrated by isothermal titration calorimetry. The level of reactive oxygen species (ROS) increased and mitochondrial membrane potential reduced upon exposure to the AGSP-Cd²⁺ complex as compared with those of Cd²⁺ exposure. The decreased cell viability after incubation with the AGSP-Cd²⁺ complex also suggested enhanced Cd²⁺ toxicity induced by AGSP. The metabolomics and lipidomics analysis revealed that, compared with the Cd²⁺ group, the AGSP-Cd²⁺ downregulated the phospholipid metabolism and resulted in more serious damage in the cellular membrane. The lipid metabolism disorder, in turn, amplified the generation of ROS, leading to a decrease in cell viability. These results provided new evidence of the enhanced Cd²⁺ toxicity upon interaction with seafood polysaccharides, and much attention should be paid to the effect of food ingredients on heavy metal ion toxicity.