Semi-industrial development of nutritious and healthy seafood dishes from sustainable species

This study aimed to devise innovative, tailor-made, appealing, tasty and semi-industrialized dishes, using sustainable and under-utilized seafood species (bib, common dab, common carp, blue mussel and blue whiting), that can meet the specific nutritional and functional needs of children (8-10-years), pregnant women (20-40-years) and seniors (≥60-years). Hence, contests were organised among cooking schools from 6 European countries and the best recipes/dishes were reformulated, semi-industrially produced and chemically and microbiologically evaluated. The dishes intended for: (i) children and pregnant women had EPA + DHA and I levels that reached the target quantities, supporting the claim as “high in I”; and (ii) seniors were “high in protein” (24.8%-Soup_S and 34.0%-Balls_S of the energy was provided by proteins), “high in vitamin B12”, and had Na contents (≤0.4%) below the defined limit. All dishes reached the vitamin D target value. Sausages_C, Roulade_P, Fillet_P and Balls_S had a well-balanced protein/fat ratio. Roulade_P presented the highest n-3 PUFA/n-6 PUFA ratio (3.3), while Sausages_C the lowest SFA/UNS ratio (0.2). Dishes were considered safe based on different parameters (e.g. Hg-T, PBDEs, Escherichia coli). All represent dietary sources contributing to meet the reference intakes of target nutrients (33->100%), providing valuable options to overcome nutritional and functional imbalances of the three groups.This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement no. 773400 (SEAFOODTOMORROW). This work was also supported by the Spanish Ministry of Science and Innovation (Project CEX 2018-000794-S), the Generalitat de Catalunya (Consolidated Research Group Water and Soil Quality Unit 2017 SGR 1404) and Fundação para a Ciência e a Tecnologia (FCT)/Ministério da Ciência, Tecnologia e Ensino Superior (MCTES) through national funds (UID/QUI/50006/2019, UIDB/50006/2020, UIDP/50006/2020, UIDB/04423/2020 and UIDP/04423/2020). The authors also thank FCT and the European Union's H2020 Research and Innovation Programme for funding through the project Systemic - An integrated approach to the challenge of sustainable food systems: adaptive and mitigatory strategies to address climate change and malnutrition. Sara Cunha also acknowledges FCT for the IF/01616/2015 contract. Biotage is acknowledged for providing SPE cartridges and Bekolut for the QuEChERS kits. This output reflects the views only of the author(s), and the European Union cannot be held responsible for any use that may be made of the information contained therein

First record of the leopard pleco, Pterygoplichthys gibbiceps (Actinopterygii, Loricariidae) in the Brda River in the centre of Bydgoszcz (northern Poland)

Background. The presently reported finding of leopard pleco, Pterygoplichthys gibbiceps (Kner, 1854) (Loricariidae), in open waters of the Brda River in the centre of Bydgoszcz, constitutes the first record of a south-American loricariid fish species in Poland. The specimen found is described and illustrated. The finding is discussed in association with other alien species sightings in Poland. The described leopard pleco is possibly the next example of an emerging alien fish species in inland Polish waters

Species and sex-specific variation in the antioxidant status of tench, Tinca tinca; wels catfish, Silurus glanis; and sterlet, Acipenser ruthenus (Actinopterygii) reared in cage culture

Background. Oxidative stress poses a serious threat to farmed fish, exemplified by depressed growth, decreased disease resistance, and reduced flesh quality. Therefore, the aim of this study was to examine differences in activity of antioxidant enzymes and concentration of selected biochemical parameters between blood plasma of both sexes of three species important for sustainable development of aquaculture: tench, Tinca tinca (Linnaeus, 1758); wels catfish, Silurus glanis Linnaeus, 1758; and sterlet, Acipenser ruthenus Linnaeus, 1758. Materials and methods. Experimental fishes were fed ad libitum for 60 days with a formulated diet (45% proteins, 20% fat, 16% carbohydrates, 8% ash and 2% fibre). At the end of the study venous blood samples were collected and 11 biochemical parameters were assessed: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), total antioxidant capacity (FRAP), alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), bilirubin, albumin, and uric acid. Results. Comparison between species revealed that the most significant differences were observed for tench and sterlet (in FRAP, GPx, CAT, GST LDH, ALT, bilirubin, and uric acid), less significant—for sterlet and wels (in FRAP, GST, LDH, AST, bilirubin, uric acid), followed by tench and wels catfish (in FRAP, GPx, GST, AST, and uric acid). Moreover, significant variations in the level of biochemical markers were also detected between sexes within each species, where the highest number was observed for tench (in FRAP, GPx, albumin, and uric acid), next wells catfish (in SOD, albumin, and bilirubin), and the lowest in sterlet (in ALA). Additionally, numerous differences in antioxidant potential (FRAP), antioxidant defence indices, as well as in markers of liver function, heart dysfunction, and markers of nutritional status were observed as species-specific and sex-specific. Conclusion. Results obtained in this study for the first time demonstrated species- and sex-related differences in plasma activity of antioxidant enzymes and concentration of selected biochemical parameters between tench, wels catfish, and sterlet reared in cage culture. The presented findings provide significant contribution not only to the existing knowledge of fish physiology but will also help to design optimal feeding practices to achieve sustainable cage aquaculture

Genetic identifiability of selected populations of Indian mackerel, Rastrelliger kanagurta (Actinopterygii: Perciformes: Scombridae)—CELFISH Project—Part 1

Background. Genetic traceability of seafood as well as population identification using molecular methods provide useful information about the fish origin and are important for protection of overfished populations, as well as for monitoring illegal, unreported, and unregulated (IUU) fisheries. The presently reported study focused on Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816)—a pelagic species with a wide range of distribution—especially important for many tropical countries, such as India, Philippines, and Thailand. This paper is the first part of a larger project: ”Development of a genetic-based system for identification of food products from fisheries and aquaculture introduced to the European Union customs area”. Materials and methods. Samples consisting of fin fragments of Indian mackerel were obtained from local markets in Thailand (MTH), Vietnam (SVN), Cambodia (SKH), and Madagascar (SMG) within 2012–2013. Two genes were analysed: nuclear rhodopsin gene (RH1) and mitochondrial D-loop (D-loop) region through RFLP analysis simulation and sequencing. Additionally, the samples from Cambodia and Madagascar were analysed with eight microsatellite loci (SSR). The data processing was aided by GenAlEx 6.5 and GeneClass2 software. Results. A comparison of the RH1 gene section revealed a total homology among the studied samples. A comparative analysis of D-loop sequences in the studied groups revealed intrapopulational diversity for MTH-, SKH-, SMG-, and SVN samples, at the level of 1, 1, 0.5, and 0.6 percentage points, respectively. Furthermore, the D-loop sequences identified a characteristic restriction site for SMG population. Based on the allele frequencies, we randomly assigned selected individuals to their original populations. GeneClass2 software correctly assigned only 16 out of 21 individuals to either the Cambodian or the Madagascar population, which jointly constituted 76% of all samples. We demonstrated, using AMOVA and GenAlEx 6.5, that the highest level of variability occurred among individuals within the respective populations, while the lowest interpopulation diversity was between the SMG and SKH populations. Conclusion. Our results may help the relevant authorities in the countries of the European Union to identify Indian mackerel and especially its products and trace them to the respective locality. Our findings may also be used for species-specific conservation measures hopefully undertaken by fisheries authorities of the countries where we took our samples.  Results on other fish species, prepared in the frames of the same project, will be presented in other papers that will follow soon.

Molecular characterization of the noble crayfish ( Astacus astacus

The genetic variability between individuals from five crayfish (Astacus astacus L.) populations was determined. The analysis was based on sequences variations of mitochondrial DNA (cytochrome oxidase subunit I (COI) and 16S ribosomal DNA. Mitochondrial DNA sequences are widely used to detect genetic variation within and between populations. Data analysis revealed the existence of two COI haplotypes – most common haplotype Hap01 and one new haplotype, differed only in one substitution. Analysis of the 16S rDNA sequences obtained showed no differences in nucleotide composition. The results of the analysis are important part of project “Active protection of noble crayfish in lakes of Pomeranian Complex Landscape Parks” financed by Financial Mechanism of the European Economic Area 2014–2016

Microsatellite DNA-based genetic traceability of two populations of splendid alfonsino, Beryx splendens (Actinopterygii: Beryciformes: Berycidae)—Project CELFISH—Part 2

Background. The study is a contribution to Project CELFISH which involves genetic identification of populations of fish species presenting a particular economic importance or having a potential to be used in the so-called commercial substitutions. The EU fish trade has been showing a distinct trend of more and more fish species previously unknown to consumers being placed on the market. Molecular assays have become the only way with which to verify the reliability of exporters. This paper is aimed at pinpointing genetic markers with which to label and differentiate between two populations of splendid alfonsino, Beryx splendens Lowe, 1834, a species highly attractive to consumers in Asia and Oceania due to the meat taste and low fat content. Materials and methods. DNA was isolated from fragments of fins collected at local markets in Japan (MJ) (n = 10) and New Zealand (MNZ) (n = 18). The rhodopsin gene (RH1) fragment and 16 microsatellite DNA fragments (SSR) were analysed in all the individuals. The sequences obtained were processed using the BioEdit and BLAST software, whereas SSR data were processed with the GeAlEX analysis package. Results. The BioEdit software-aided comparison of MJ and MNZ nucleotide sequences of the rhodopsin gene fragments were identical and showed 100% agreement with the alfonsino sequence deposited under access number DQ197832. The preliminary analysis of SSR markers showed all the loci analysed in both populations to be polymorphic, and when randomly selected specimens were assigned to the original populations. The affinity test correctly identified the provenance of all those specimens. Conclusion. The results obtained constitute a tool for molecular differentiation between alfonsino populations collected in the FAO 81 (New Zealand) and FAO 71 (Japan) areas for the purpose of catch quota control and for checking the agreement between the label declaration and the actual product

Parasitic copepods (Crustacea: Copepoda) infecting muscles of a marine fish (Actinopterygii: Moridae)—A spectacular effect on a host fish and a case of seafood identity fraud

Background. Automated processing of the fish caught on board a ship can potentially lead to a quality control breach. Specimens visibly infected with parasites are processed, frozen, and directed to the market. On the other hand, the removal of the body elements of taxonomic importance (e.g., fins, head, skin) opens gates to variously motivated seafood frauds. We had been alerted by local veterinary authorities about a fish consignment from the Falklands with a substantial volume of muscles with black contents. Materials and methods. The material for the presently reported study were decapitated, finless, and gutted fish delivered to our lab by the County Veterinarian of Szczecin (Purchased by a local importer from a Spanish fish wholesaler). The fish were labeled as “Pseudophycis bachus (Forster, 1801)”, and allegedly came from the Falklands. After thawing, the fish muscles were dissected, focusing on the distinctly black areas, examined following methods commonly used in parasitology, and observed under a dissecting and a compound microscope. Samples were collected also for molecular studies aiming to disclose the fish taxonomic identity. DNA barcoding gene (cytochrome c oxidase subunit I, COX1) was used to perform the genetic characterization for the collected fish specimens. The degree of similarity between the new records (MT318699 and MT318700) and the other records of Moridae species in the GenBank was assessed by building COX1 gene phylogeny. Results. The muscles contained large galls filled with black fluid. The fluid stained the adjacent muscles. Inside each gall, we found a single female of Sarcotaces sp., several “dwarf” males, eggs, and newly hatched nauplius stages. Using the molecular methods, the fish were identified as Mora moro (Risso, 1810). Conclusion. A preliminary veterinary inspection of the catch on board of fishing vessels may help to avoid huge financial losses when a parasitized fish consignment is rejected by veterinary authorities on land. It is evident that the European regulation regarding fish parasites requires an urgent revision. Mora moro does not occur off the Falklands as declared by the wholesaler. This seafood fraud was probably motivated by the urge to conceal a catch from European waters and thus avoid exceeding national fishing quotas. Species of the genus Sarcotaces require a revision backed by molecular methods

Molecular characterization of the noble crayfish (Astacus astacus L.) population from Pomeranian lakes (north-western Poland) based on mitochondrial DNA

The genetic variability between individuals from five crayfish (Astacus astacus L.) populations was determined. The analysis was based on sequences variations of mitochondrial DNA (cytochrome oxidase subunit I (COI) and 16S ribosomal DNA. Mitochondrial DNA sequences are widely used to detect genetic variation within and between populations. Data analysis revealed the existence of two COI haplotypes – most common haplotype Hap01 and one new haplotype, differed only in one substitution. Analysis of the 16S rDNA sequences obtained showed no differences in nucleotide composition. The results of the analysis are important part of project “Active protection of noble crayfish in lakes of Pomeranian Complex Landscape Parks” financed by Financial Mechanism of the European Economic Area 2014–2016

Parasitological and molecular identification of cestode Bothriocephalus scorpii sensu stricto in the new host Chelidonichthys lucerna (L. 1758) (Triglidae, Scorpaenoidei) from the North Sea

AbstractA specimen of female tub gurnard (Chelidonichthys lucerna) caught as bycatch in commercial saithe, Pollachius virens, fisheries near the Shetland Islands was identified as a new definitive host for the cestode Bothriocephalus scorpii (Bothriocephalidea) sensu stricto. It was also the first Cestoda species recorded in tub gurnard. However, as shown in our study, the identification of complex species such as Bothriocephalus scorpii based only on external characteristics had to be supplemented with molecular marker analysis to determine the taxonomic status of the specimen. Therefore, to successfully identify the parasite specimen, DNA was extracted from it, and a partial sequence of lsrDNA was amplified and the PCR product was subjected to 2 × 300 bp PE sequencing with 10,000× coverage on MiSeq. A BLAST search using the 346 bp sequence showed 100% similarity to the lsrDNA sequence of B. scorpii deposited in GenBank under accession number AF286942. Relatedness between the sequence of B. scorpii found in our study and the 20 most similar records from GenBank was identified using a phylogenetic tree constructed under maximum likelihood. Our study proves that next-generation sequencing of partial lsrDNA supplemented the morphological identification of the parasite specimen and can be applied in future parasitological studies

Temperature influence on key players of the somatotropic axis of tench, Tinca tinca (Actinopterygii: Cypriniformes: Cyprinidae)

Background. Tench, Tinca tinca (Linnaeus, 1758), has been cultivated in Polish fish farms since centuries, due to its good quality meat. However, the most critical problem in tench culture is the slow growth, which makes farming of this species unprofitable. Growth rates of fish are influenced by numerous internal and external factors such as water temperature, food availability and quality, as well as photoperiod. In order to analyse and improve tench growth rate, the most important factors (GH, IGF-I) of the somatotropic axis should be analysed against selected culture factors. Key elements of the axis play a pivotal role in the coordination of protein and energy metabolism during postnatal growth. Therefore, the aim of this study was to assess effect of water temperature on the activity of somatotropic axis of tench. Obtained results can be useful in tench farming in order to deal with mass gain. Materials and methods. Forty tench, approximately 3+ years of age, were placed in eight 240 L tanks, five fish in each tank. There were four temperature regimes  (10°C, 15°C, 20°C, and 25°C) studied separately for males and females during a period of one week. At the end of the experiment, 2 mL of blood, the whole pituitary gland, 2 liver samples, and one muscle sample were collected from selected fish specimens.  Real-time PCR was used to assess the effect of water temperatures on the level of tench mRNA gh transcripts in pituitary-, liver-, and muscle samples. Also, the concentration of growth hormone (GH) protein was measured in relation to individual temperature treatments in blood plasma and liver samples using ELISA assay. Results. The highest cycle threshold (Ct) values of mRNA gh were detected in the pituitary samples. ELISA assays confirmed that water temperature affected GH and IGF-I concentrations in the blood and the liver samples. Additionally, results from ELISA assays confirmed sex size dimorphism (SSD) phenomenon in tench. Conclusion. Presented results shed new light on mechanisms of functioning of tench somatotropic axis and constitute benchmark information for future experiments on nutritional factors