Effect of in-house cooking in Mytilus galloprovincialis and Trachurus trachurus: Lipid and fatty acids quality and polycyclic aromatic hydrocarbons formation

Cooking effect (grilling - barbecue, oven-cooking, frying, boiling and microwaving) on lipid and fatty acids (FAs) in mussel Mytilus galloprovincialis and fish Trachurus trachurus was investigated. The levels of priority PAHs were also evaluated as well as the potential risk associated with their consumption. Cooking increased lipid content, reaching the highest value in fried product with 13.2 and 5.6 g/100 g in mussel and fish, respectively. The n-3/n-6 ranged from 0.15 to 5.31 in mussel and from 0.29 to 5.35 in mackerel. In both species, frying and oven-cooking negatively affected FAs composition as shown by the lipid quality indices. However, FAs profile exhibited by species after cooking remained beneficial for human health. Concerning PAHs, levels ranged from 31 to 78 μg/kg in M. galloprovincialis, and from 8.4 to 25 μg/kg in T. trachurus. The minimum and maximum values were found, respectively, in the raw product and after barbecue cooking with charcoal placed at 4 cm away from the seafood. The carcinogenic benzo[a]pyrene was detected only in mussels after barbecue cooking. Risk assessment of dietary exposure to PAHs, calculated by the Hazard Quotient and Cancer Risk, showed that the consumption of cooked seafood should not be a concern for human health.

The genome sequence of the Atlantic horse mackerel, Trachurus trachurus (Linnaeus 1758)

We present a genome assembly from an individual Trachurus trachurus (the Atlantic horse mackerel; Chordata; Actinopteri; Carangiformes; Carangidae). The genome sequence is 801 megabases in span. The majority of the assembly, 98.68%, is scaffolded into 24 chromosomal pseudomolecules. Gene annotation of this assembly on Ensembl has identified 25,797 protein coding genes.

Lifelong mercury bioaccumulation in Atlantic horse mackerel (Trachurus trachurus) and the potential risks to human consumption

Atlantic horse mackerel is one of the most commercially important species in Europe. It can reach a longevity of 30 years, with potential implications in lifespan mercury contamination. This study conducted along the Portuguese coast aimed at evaluating the total Hg content and tissue distribution, to determine the annual mercury bioaccumulation patterns and the associated risk for consumption. The T-Hg accumulation patterns observed followed the order: muscle (0.34) > liver (0.28) > heart (0.19) > gills (0.11) > brain (0.041 mg kg^-1). Significant differences between tissues reflect the role of the different tissues in storage and redistribution. Significant relationships observed between age and T-Hg for all tissues highlight the continuous nature of the bioaccumulation process. European food safety guidelines signalled significant risk of consumption in about 30% of the samples. Still, there was an overall low risk from the consumption of this species, which can be further minimized through consumer options to avoid health issues.

Plastic ingestion by Atlantic horse mackerel (Trachurus trachurus) from central Mediterranean Sea: A potential cause for endocrine disruption

Plastics in the oceans can break up into smaller size and shape resembling prey or particles selected for ingestion by marine organisms. Plastic polymers may contain chemical additives and contaminants, including known endocrine disruptors that may be harmful for the marine organisms, in turn posing potential risks to marine ecosystems, biodiversity and food availability. This study assesses the presence of plastics in the contents of the gastrointestinal tract (GIT) of a commercial fish species, the Atlantic horse mackerel, Trachurus trachurus, sampled from two different fishing areas of central Mediterranean Sea. Adverse effect of plastics occurrence on T. Trachurus health were also assessed quantifying the liver expression of vitellogenin (VTG), a biomarker for endocrine disruption. A total of 92 specimens were collected and morphometric indices were analysed. A subgroup was examined for microplastics (MP < 1 mm) and macroplastics (MaP >1 cm) accumulation in the GIT and for VTG expression. Results indicated that specimens from the two locations are different in size and maturity but the ingestion of plastic is widespread, with microplastics (fragments and filaments) abundantly present in nearly all samples while macroplastics were found in the larger specimens, collected in one of the two locations. Spectroscopic analysis revealed that the most abundant polymers in MP fragments were polystyrene, polyethylene and polypropylene, whereas MP filaments were identified mainly as nylon 6, acrylic and polyester. MaP were composed mainly of weathered polyethylene or polypropylene. The expression of VTG was observed in the liver of 60% of all male specimens from both locations. The results of this study represent a first evidence that the ingestion of plastic pollution may alter endocrine system function in adult fish T. Trachurus and warrants further research.

Anisakid and Raphidascaridid parasites in Trachurus trachurus: infection drivers and possible effects on the host's condition

This study investigated the distribution of nematode larvae of Anisakidae and Raphidascarididae (genera Anisakis and Hysterothylacium) in Trachurus trachurus (Linnaeus, 1758) in the Ligurian and central-northern Tyrrhenian Seas. The relationship between the number of parasites and the length and weight parameters of the fish was assessed, and the possible effect of the parasites on the condition factor was evaluated. A total of 190 T. trachurus specimens were collected in July 2019. Parasites were found in 70 individuals. A total of 161 visible larvae were collected in the viscera. Morphological analysis revealed the presence of Anisakis spp. in 55 fish and Hysterothylacium spp. in 15 fish, while 5 fish showed coinfection with both genera. The specimens subjected to PCR (n = 67) showed that 85% of the Anisakis larvae analyzed belonged to the species A. pegreffii, while the remaining 15% belonged to hybrids of A. pegreffii-A. simplex (s.s.). A total of 58% (n = 7) of the Hysterothylacium larvae analyzed belonged to the species H. fabri, while 42% belonged to the species H. aduncum. Our results support the hypothesis that infection with these parasites does not affect the condition of the fish host analyzed, and that body size and depth are major drivers in determining infection levels with Anisakid and Raphidascaridid nematodes.

Inhibition effects of some pesticides and heavy metals on carbonic anhydrase enzyme activity purified from horse mackerel (Trachurus trachurus) gill tissues

The gill tissue is the main site of metabolic enzymes or compensation, with the kidney tissue playing a supporting role. At the gill tissue, carbonic anhydrase enzymes (CAs) catalyze the hydration of CO₂ to HCO₃^- and H⁺ for production to the H₂O. In this work, the CA enzyme was purified from horse mackerel (Trachurus trachurus) gill with a specific activity of 21,381.42 EU/mg, purification fold of 150.61, total activity of 2347.68 EU/mL, and a yield of 16.13% using sepharose 4B-L-tyrosine-sulfanilamide affinity gel chromatography. For recording the enzyme purity, gel electrophoresis was performed, and single band was seen. The molecular weight of this enzyme was found approximately 35 kDa. Also, the inhibitory effects of different pesticides such as thiram, clofentezine, propineb, deltamethrin, azoxystrobin, and thiophanate and heavy metal ions such as Fe²⁺, Cu²⁺, Co²⁺, Pb²⁺ Hg²⁺, and As³⁺ on horse mackerel gill tissue CA enzyme activities were investigated. Our results indicated that these pesticides and metal ions showed inhibitory effects at low nanomolar and millimolar concentrations for fish gill CA enzymes, respectively.

Purification and characterization of the carbonic anhydrase enzyme from horse mackerel (Trachurus trachurus) muscle and the impact of some metal ions and pesticides on enzyme activity

In this paper, the total carbonic anhydrase (CA) enzyme was purified from horse mackerel (Trachurus trachurus) muscle with a specific activity of 23,063.93 EU/mg, purification fold of 551.08, total activity of 1522.22 EU/mL and a yield of 18.50% using sulfanilamide affinity column chromatography. For obtaining the subunit molecular mass and enzyme purity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for this part was performed and a single band was clearly recorded. The molecular mass of this enzyme was found approximately 35 kDa. The optimum temperature and pH values were obtained from Arrhenius plot. In addition, the inhibitory effects of different heavy metal ions (Fe²⁺, Cu²⁺, Co²⁺, Pb²⁺ Hg²⁺ and As³⁺) and some pesticides (thiram, clofentezine, propineb, deltamethrin, azoxystrobin and thiophanate) on horse mackerel (Trachurus trachurus) muscle tissue CA enzyme activities were investigated by utilizing esterase assay activity. The used metal ions and pesticides had IC₅₀ values in the range of 0.21-13.84 mM and 3.78-70.58 mM, respectively.

Co-inertia multivariate approach for the evaluation of anthropogenic impact on two commercial fish along Tyrrhenian coasts

Aliphatic hydrocarbon levels were determined by the GC/MS technique in fish livers of Engraulis encrasicolus (Ee) and Trachurus trachurus (Tt), collected from a particular area of the Mediterranean Sea, called GSA 10, which is located exactly in Tyrrhenian Sea between Campania coast and North Sicily coast. The aim was to evaluate their potential use as specific bioindicators towards this class of contaminants. Both Tt and Ee are considered to be pollution monitoring bioindicators, due to their dominance in marine communities and economic fishing interest. Ee showed a higher tendency to bioaccumulate TAHs, due to the lower quantity of fatty acids in liver tissues with respect to Tt. The area under study has been characterised a) chemically with the acquisition of temperature, oxygen and salinity profiles along the water column, and b) ecologically with the determination of amino acid contents in fish eyes, in order to gain information on the adaptation to environmental changes. Moreover, specific activities of two hydrolytic enzymes, such as alkaline phosphatase and peroxidase in fish epidermal mucus, together with lactate in blood plasma and cortisol levels, have been investigated for the first time, in order to obtain insights into the effects of hydrocarbons on animal welfare. A multiple co-inertia analysis was also applied to chemical and environmental parameters, in order to explore any possible correlation between different variables. The multivariate approach showed a clear spatial distribution between environmental and chemical variables in Ee, whilst there was an absence of a spatial trend in Tt. Moreover, the chemometric analysis showed a very high correlation between amino acid profiles and environmental variables for both species, confirming the possibility of being used as ecological welfare indices for short-term environmental variations.

Bacteriophages against Serratia as Fish Spoilage Control Technology

Bacteria of the genus Serratia, mainly S. proteamaculans and S. fonticola, are important spoilage agents in Atlantic horse mackerel (Trachurus trachurus). In order to evaluate whether bacteriophages against Serratia could delay the spoilage process, 11 viral strains active against this genus were isolated from food and best candidate was applied to fresh mackerel filets. All the phages belong to the Siphoviridae and Podoviridae families and were active at multiplicity of infection (MOI) levels below 1:1 in Long & Hammer broth. The ability of phage AZT6 to control Serratia populations in real food was tested in Atlantic horse mackerel extract and applied to fresh mackerel filets. Treatment with high phage concentration (MOI 350:1, initial Serratia population 3.9 ± 0.3 Log cfu/g) can reduce the Serratia populations up to 90% during fish storage (a maximum of 6 days) at low temperatures (6°C). Bacterial inhibition was dependent on the bacteriophage dosage, and MOI of 10:1 or lower did not significantly affect the Serratia populations.