Novel Angiotensin-Converting Enzyme-Inhibitory Peptides Obtained from Trichiurus lepturus: Preparation, Identification and Potential Antihypertensive Mechanism.

Peptides possessing antihypertensive attributes via inhibiting the angiotensin-converting enzyme (ACE) were derived through the enzymatic degradation of Trichiurus lepturus (ribbonfish) using alkaline protease. The resulting mixture underwent filtration using centrifugation, ultrafiltration tubes, and Sephadex G-25 gels. Peptides exhibiting ACE-inhibitory properties and DPPH free-radical-scavenging abilities were isolated and subsequently purified via LC/MS-MS, leading to the identification of over 100 peptide components. In silico screening yielded five ACE inhibitory peptides: FAGDDAPR, QGPIGPR, IFPRNPP, AGFAGDDAPR, and GPTGPAGPR. Among these, IFPRNPP and AGFAGDDAPR were found to be allergenic, while FAGDDAPRR, QGPIGPR, and GPTGPAGP showed good ACE-inhibitory effects. IC50 values for the latter peptides were obtained from HUVEC cells: FAGDDAPRR (IC50 = 262.98 µM), QGPIGPR (IC50 = 81.09 µM), and GPTGPAGP (IC50 = 168.11 µM). Peptide constituents derived from ribbonfish proteins effectively modulated ACE activity, thus underscoring their therapeutic potential. Molecular docking and modeling corroborated these findings, emphasizing the utility of functional foods as a promising avenue for the treatment and prevention of hypertension, with potential ancillary health benefits and applications as substitutes for synthetic drugs.

Anatomical oropharyngeal cavity specialisations in the cutlassfish (Trichiurus lepturus, Linnaeus, 1758).

Trichiurus lepturus is a carnivorous fish, and most of the previous anatomical research has focused on computed tomography imaging and histology of their teeth and fangs, while the remaining structures of pharyngeal cavity remain unexplored. The present research is the first to use anatomical examinations alongside scanning electron microscopy to investigate the T. lepturus oral cavity. The oropharyngeal roof included teeth, upper lip, rostral and caudal velum and the palate. The middle of the palate showed a median groove flanked by two folds, followed by a median band flanked by micro-folds, thereafter the palate became crescent shaped. The lateral regions of the palate exhibited longitudinal folds that extended rostrally towards the fangs. The oropharyngeal floor had two cavities which acted as a scabbard for the premaxillary fangs and upper velum, while the caudal sublingual cavity contained two oyster-shaped structures on the outer surface plus sublingual ridges and sublingual clefts. The tongue apex exhibited a spoon-like shape, its body demonstrated a median elevation and the root with two lateral branches contained only dome-shaped papillae. Taste buds were located on the upper velum, lower lip and the caudal part of the interbranchial septum. Images and descriptions of T. lepturus tooth structure are also provided. The present research, using anatomical dissection and morphological observation using scanning electron microscopy, has identified the structures of the dentition system, a variety in shapes of the folds and microridges, and identified the taste buds and mucous pores in the T. lepturus oropharyngeal cavity.

Dried fish more prone to microplastics contamination over fresh fish - Higher potential of trophic transfer to human body.

Globally, microplastics (MPs) contamination in aquatic organisms is emerging as an alarming phenomenon. In the present study, we investigated MPs in three commercially important fishes (Bombay duck Harpadon nehereus, ribbon fish Trichiurus lepturus and hairfin anchovy Setipinna phasa) in fresh and dried conditions collected from two sites (Chattogram and Kuakata) of the Bay of Bengal. It was evident that fresh T. lepturus ingested highest amount of MPs through the gills (6.41 mps/g) from Chattogram followed by in the gastrointestinal tract, GIT (6.20 mps/g) and in the muscle (1.20 mps/g) from Kuakata. Among the fresh fishes, H. nehereus from Kuakata accumulated highest amount of MPs (0.21 mps/g), while S. phasa from Kuakata contained the least amount of MPs (0.06 mps/g). On the other hand, among the dried fishes, T. lepturus from Kuakata contained highest amount of MPs (46.00 mps/g), while S. phasa from Kuakata retained lowest amount of MPs (2.17 mps/g). Strangely, all the dried fishes showed significantly higher amount of MPs compared to fresh fishes from both the locations. Fiber was the most dominant type of shape of MPs which accounted 66 %, followed by fragment (27.38 %), microbeads (3.59 %), film (1.48 %), foam (1.31 %) and pellet (0.25 %). Size-wise, the major portion (39.66 %) of MPs was present to be in size range less than 0.5 mm followed by 37.67 % in the size range of 0.5-1.0 mm group and rest 22.67 % within 1.0-5.0 mm. Red (41.55 %) colored MPs was the most prominent, followed by brown (22.11 %), blue (16.32 %), pink (11.69 %), purple (5.10 %), and green (2.25 %). Among polymer types, low-density polyethylene (LDPE) was the most common (38 %), followed by polystyrene (PS-22 %), polyvinyl chloride (PVC-16 %), polyamide (PA-13 %) and ethylene-vinyl acetate (EVA-9 %). The present study confirms high occurrence of MPs in the dried fishes over the fresh fishes from the Bay of Bengal, with high potential of trophic transfer to the human body.

Study on the physicochemical indexes, nutritional quality, and flavor compounds of Trichiurus lepturus from three representative origins for geographical traceability.

Trichiurus lepturus (hairtail) is an important economic component of China's marine fishing industry. However, due to the difficulty in identifying the appearance of hairtail from different geographical distributions, hairtails with geographical indication trademarks were imitated by general varieties. In this study, the texture characteristics, color, basic nutrients, amino acids, mineral, fatty acids, and volatile flavor substances were used as indicators for multivariate statistical analysis to determine whether three origins of hairtails from the habitats of Zhoushan (East China Sea, T.Z), Hainan (South China Sea, T.N), and Qingdao (Yellow Sea, T.Q) in the market could be distinguished. The findings revealed that there were significant differences in amino acids composition, mineral composition, fatty acid composition in lipids, and volatile flavor substances among the hairtails of three origins (P < 0.05), but no differences in color, texture, protein content. T.Z had moisture, crude fat, essential amino acids (EAA), flavor amino acids (FAA), unsaturated fatty acids (UFA), and docosahexaenoic acids and dicosapentaenoic acids (ΣEPA + DHA) contents of 74.33, 5.4%, 58.25 mg⋅g-1, 46.20 mg⋅g-1, 66.84 and 19.38%, respectively, and the contents of volatile alcohols, aldehydes and ketones were 7.44, 5.30, and 5.38%, respectively. T.N contains moisture, crude fat, EAA, FAA, UFA and ΣEPA + DHA as 77.69, 2.38%, 64.76 mg⋅g-1, 52.44 mg⋅g-1, 65.52 and 29.45%, respectively, and the contents of volatile alcohols, aldehydes and ketones as 3.21, 8.92, and 10.98%, respectively. T.Q had the contents of moisture, crude fat, EAA, FAA, UFA, and ΣEPA + DHA 79.69, 1.43%, 60.9 mg⋅g-1, and 49.42 mg⋅g-1, respectively. The contents of unsaturated fatty acid and ΣEPA + DHA were 63.75 and 26.12%, respectively, while the volatile alcohols, aldehydes, and ketones were 5.14, 5.99, and 7.85%, respectively. Partial least squares-discriminant analysis (PLS-DA) multivariate statistical analysis showed that volatile flavor compounds could be used as the most ideal indicators for tracing the source of hairtail. In conclusion, the findings of this study can distinguish the three hairtail origins using some basic indicators, providing ideas for hairtail geographical identification.

Anisakid nematodes in Trichiurus lepturus and Saurida undosquamis (Teleostea) from the South-West Indian Ocean: Genetic evidence for the existence of sister species within Anisakis typica (s.l.), and food-safety considerations.

Nematode parasites of the genus Anisakis (Nematoda, Anisakidae) are considered among the most important biological hazards in seafood products worldwide. In temperate and tropical waters, the most common species appears to be Anisakis typica, generally found around the viscera and sporadically in the flesh of various fish host species. This study investigated the infection sites and genetic diversity of A. typica infecting commercial fishes from the South-West Indian Ocean. Largehead hairtail (N = 20) and brushtooth lizardfish (N = 72) fished off Tanzania were inspected for anisakid nematodes by UV-press. A subsample of 168 nematodes were identified by sequence analyses of the cox2 mtDNA gene and ITS region of rDNA. The species A. typica (s.l.) (N = 166), Pseudoterranova ceticola (N = 1) and Anisakis paggiae (N = 1) were molecularly identified. Phylogenetic analysis of A. typica (s.l.) sequences based on both genes, indicated the existence of two distinct phylogenetic lineages forming two well-supported clades. The first clade comprised 12 A. typica specimens including individuals from its type locality (central Atlantic Ocean). The second clade comprising 154 specimens, clustered with reference sequences retrieved from GenBank including one apparently undescribed taxon, i.e., Anisakis sp. 1, and A. typica var. indonesiensis. The two reciprocally monophyletic clades are closely related and correspond to two distinct sister species within A. typica (s.l.), presently indicated as A. typica sp. A and A. typica sp. B. Two and four fixed alternative nucleotide substitutions (SNPs), i.e., diagnostic positions, between the two taxa, respectively, were found at the mtDNA cox2 and the ITS region of rDNA. The genetic data, as well as their occurrence in sympatry, strengthens the hypothesis that the actual specimens represent two distinct gene pools. The occurrence of both A. typica sp. A and A. typica sp. B in the musculature of freshly examined T. lepturus and S. undosquamis, suggests that both species can migrate intra-vitam into the flesh. Although the zoonotic potential of A. typica s.l. is still unclear, the presence of these parasites in the musculature, edible part of the fish, raises health concerns for consumers.

Atmospheric cold plasma: a new approach to modify protein and lipid properties of myofibrillar protein isolate from hairtail (Trichiurus lepturus) fish.

BACKGROUND: Quite recently, considerable attention has been paid to atmospheric cold plasma (ACP) as an eco-friendly and highly efficient technology to modify the functional properties of foods. This study focuses on the effect of ACP on the myofibril protein and lipid quality of hairtail (Trichiurus lepturus) fish. In achieving this, the samples were treated with ACP at 50 kV for different times (30, 60, 120, 180, 240, 300 s). RESULTS: The findings indicated slight changes in peroxide value and thiobarbituric acid reactive substances in the samples treated with ACP. A significant increase (P < 0.05) in the surface hydrophobicity (from 131.71 ± 0.81 µg to 146. 34 ± 0.81 µg), turbidity (from 0.13 ± 0.001 to 0.27 ± 0.01), and water-holding capacity (from 61.63% ± 5.7% to 64.86% ± 1.5%) were detected with treated samples. CONCLUSIONS: We conclude that ACP treatment induces marked changes in the protein and lipid properties of myofibril protein isolated from hairtail fish, which strengthen the gel formation of hairtail fish. © 2021 Society of Chemical Industry.

Characterization of the Whole Mitogenome of Largehead Hairtail Trichiurus lepturus (Trichiuridae): Insights into Special Characteristics.

Mitochondrial genomes are valuable for making inferences regarding population genetics, phylogenetics and recently in understanding adaptive variation in OXPHOS genes. Ribbon fish, Trichiurus lepturus is distributed in the Indian Ocean and contributes to a major share of pelagic fish landings. Considering the importance, we characterized the complete mitogenome of large head hairtail T. lepturus from Indian waters by PCR amplification and sequencing. The entire mitogenome is 16,840 bp in length, with 13 protein coding genes, 2 subunit ribosomal RNA genes, and 1 control region similar to other vertebrates. Genome contains only 21 tRNAs (tRNAPro is absent) as against 22 tRNAs reported in other vertebrates. The putative origin of L-strand replication (OL) was located in a cluster of five tRNA genes (WANCY region) and may not be functional due to the variation of conserved motif (5'-GCCGG-3') and loop. These two unusual features are common for Trichiurus mitogenomes. Phylogenetic analysis supported the monophyly of Trichiuridae. This study will provide information for further studies on taxonomy, phylogeny and patterns of adaptive evolution in the mitogenome of Trichiurus species.

Multidisciplinary approach in study of the zoonotic Anisakis larval infection in the blue mackerel (Scomber australasicus) and the largehead hairtail (Trichiurus lepturus) in Northern Taiwan.

BACKGROUND: Anisakid larvae are the food-borne pathogen highly prevalent among numerous marine fishes. Accidental consumption of infected raw or poorly cooked fish fillets may cause anisakiasis. METHODS: This study used the multidisciplinary approach to investigate the occurrence of Anisakis nematodes in commonly consumed fish species, Scomber australasicus and Trichiurus lepturus purchased in Taipei Xinyi traditional fish market. RESULTS: All the Anisakis larvae collected herein were identified morphologically as Anisakis type I or Anisakis type II. The prevalence and the mean intensity of Anisakis larvae collected from S. australasicus was 80.77%, 26.8 (10-32) and 100%, 49.0 (27-70) for T. lepturus. Using molecular analysis, 83.33% (180/216) were identified as Anisakis pegreffii, 6.05% (13/216) as Ascaris typica, 1.85% (4/216) as Ascaris physeteris and 8.80% (19/216) as hybrid genotype (A. pegreffii + Anisakis simplex) in S. australasicus. In T. lepturus, 86.31% (290/336) were identified as A. pegreffii, 2.38% (8/336) as A. typica, and 11.31% (38/336) as hybrid genotype (A. pegreffii + A. simplex [s.s]). The molecular phylogenetic analysis shows two cluster clades, one group includes A. pegreffii complex and the other include Ascaris paggiae, Ascaris brevispiculata, and A. physeteris. CONCLUSION: Thus, A. pegreffii is the most abundant species and may be the potential causes of human infection.

Comparison of the Changes in Fatty Acids and Triacylglycerols between Decapterus maruadsi and Trichiurus lepturus during Salt-dried Process.

In order to reveal changes in fatty acids and triglycerides during the pickling process of white-fleshed and dark-fleshed fish with high-fat, to compare the changes of triacylglycerols (TAGs) and fatty acids (FAs) in round scad (Decapterus maruadsi, dark-fleshed) and hairtail (Trichiurus lepturus, white-fleshed) during salt-dried processing, ESI-MS/MS and GC-MS techniques were used to quantify. Lipid oxidation was evaluated via peroxide values (POVs), and thiobarbituric reactive substances (TBARS). A total of 31 and 27 FAs, 45 and 44 TAGs were quantified in round scad and hairtail, respectively. DHA (C22:6n3), palmitic acid (C16:0), stearic acid (C18:0), and oleic acid (C18:1n9) were the main FAs in round scad. POO (16:0/18:1/18:1), PPO (16:0/16:0/18:1), POD (16:0/18:1/22:6), and PPaO (16:0/16:1/18:1) were dominant TAGs in both species. Salt-dried processing significantly affected (p < 0.001) 7/5 FAs and 24/29 TAGs in round scad/hairtail. MUFAs changed significantly (p < 0.05) in dark-fleshed round scad; only SFAs and PUFAs changed in white-fleshed hairtail. Both species exhibited near-identical TAG compositions with different variation trends. More significant changes were observed in FAs at the half-dried stages and in TAGs (p < 0.05) at the salted stage. This coincided with the changing stages of POV and TBARS values that also increased significantly (p < 0.05) at the salted stages but peaked at the half-dried stages of both species.

Effect of Opuntia dillenii polysaccharide on gelling properties of Trichiurus lepturus myobrilar protein.

In this study, the effects of Opuntia dillenii polysaccharide (ODP) at different concentrations (1%, 3% and 5% wet materials) on the gel properties of Trichiurus lepturus myofibrillar proteins were investigated. ODP was prepared by hot water extraction, consisted of arabinose, xylose, fructose, glucose, galacturonic acid and rhamnose and its molecular weight was 106 kDa. The addition of ODP increased the water holding capacity, sulfhydryl content adhesiveness, cohesiveness, elasticity and overall likeness of T. lepturus myofibrillar proteins gel. However, a high dose (5% wet materials) of ODP could not further increase or decrease its efficiency compared with moderate dose (3% wet materials). Consequently, the addition of ODP increased the gel properties of T. lepturus myofibrillar protein gel and could be used as a myofibrillar protein gel supplement.

Changes of water state and gel characteristics of Hairtail (Trichiurus lepturus) surimi during thermal processing.

This study examined the changes of water state and gel characteristics of Hairtail surimi during thermal processing including two steps. The results showed that there were four content of water in Hairtail surimi gels. Water-holding capacity (WHC) and T23 relaxation time of water and gel strength increased from 47.01 to 78.97% and from 64.23 to 51.52 ms, respectively, and whiteness decreased from 63.87 to 55.22 during the entire thermal processing. Meanwhile, the texture properties including hardness, gumminess, and chewiness declined from 402.42 to 130.41 g, from 294.39 to103.70 g, and from 233.68 to 43.60 g, respectively, during the first step, and then increased markedly during the second step from 130.41 to 2,301.87 g, from 103.70 to 1,250.99 g, and from 43.60 to 978.51 g, respectively. Furthermore, the WHC and textural profile had positive correlation, and changes in protein secondary structure were interesting, with the α-helices decreasing significantly from 26.40 to 14.12%, while the ß-sheet and the random coil structure increasing significantly from 36.28 to 44.03%, and from 10.89 to 14.31%, respectively, and ß-turn structure increasing form 26.44 to 27.98% during the first step and then declining markedly during the second step, moreover ß-sheet had a fine positive correlation with WHC hardness and chewiness. Overall, dense, porous and compact three-dimensional network gel structure gradually formed. In a word, during thermal processing. WHC of Hairtail surimi increased, and protein secondary structure of protein became orderly, and a fine, dense gel formed during thermal processing. Water is considered as the highest and most important chemical constituent in surimi products. During surimi gelation, water molecules exist as bulk water and motionally restricted water on the protein surface. In order to gain more insights into the surimi heating-induced gelation processing, and improve the surimi gel properties, and give same advice to manufacturing enterprise, this work was conducted to study the structural changes of protein and water state during surimi gelation processing and performed along with the monitoring of the texture, WHC and other physical characteristics of surimi gel, as well as the microstructure of surimi gel.

Mesopredatory fishes from the subtropical upwelling region off NW-Africa characterised by their parasite fauna.

Eastern boundary upwelling provides the conditions for high marine productivity in the Canary Current System off NW-Africa. Despite its considerable importance to fisheries, knowledge on this marine ecosystem is only limited. Here, parasites were used as indicators to gain insight into the host ecology and food web of two pelagic fish species, the commercially important species Trichiurus lepturus Linnaeus, 1758, and Nealotus tripes Johnson, 1865. Fish specimens of T. lepturus (n = 104) and N. tripes (n = 91), sampled from the Canary Current System off the Senegalese coast and Cape Verde Islands, were examined, collecting data on their biometrics, diet and parasitisation. In this study, the first parasitological data on N. tripes are presented. T. lepturus mainly preyed on small pelagic Crustacea and the diet of N. tripes was dominated by small mesopelagic Teleostei. Both host species were infested by mostly generalist parasites. The parasite fauna of T. lepturus consisted of at least nine different species belonging to six taxonomic groups, with a less diverse fauna of ectoparasites and cestodes in comparison to studies in other coastal ecosystems (Brazil Current and Kuriosho Current). The zoonotic nematode Anisakis pegreffii occurred in 23% of the samples and could pose a risk regarding food safety. The parasite fauna of N. tripes was composed of at least thirteen species from seven different taxonomic groups. Its most common parasites were digenean ovigerous metacercariae, larval cestodes and a monogenean species (Diclidophoridae). The observed patterns of parasitisation in both host species indicate their trophic relationships and are typical for mesopredators from the subtropical epi- and mesopelagic. The parasite fauna, containing few dominant species with a high abundance, represents the typical species composition of an eastern boundary upwelling ecosystem.

Heavy Metal Concentration in Largehead Hairtail (Trichiurus lepturus Linneaus, 1758) and Savalai Hairtail (Lepturacanthus savala (Cuvier, 1829)) Obtained from Karachi Fish Harbour, Pakistan.

In this study, muscle samples gathered from Largehead hairtail (Trichiurus lepturus Linneaus, 1758) and Savali hairtail [Lepturacanthus savala (Cuvier, 1829)] from the Karachi Fish Harbour, Pakistan were analyzed to determine heavy metal concentrations (iron [Fe], zinc [Zn], copper [Cu], manganese [Mn], lead [Pb] and cadmium [Cd]) between January and December 2016. All samples were analyzed using the AAnalyst 700 Flame Atomic Absorption Spectrophotometer. It was observed that the average measured level of Fe, Zn, Cu, Mn, Pb and Cd in muscle were 77.72 ± 47.84 µg/g, 20.34 ± 8.49 µg/g, 2.23 ± 1.16 µg/g, 0.57 ± 0.36 µg/g, 0.20 ± 0.16 µg/g and 0.42 ± 0.19 µg/g for T. lepturus, respectively. Besides, the average level of the same metal concentrations in muscle for L. savala were 85.11 ± 57.64 µg/g, 16.63 ± 9.25 µg/g, 2.53 ± 1.90 µg/g, 0.47 ± 0.27 µg/g, 0.23 ± 0.18 µg/g and 0.47 ± 0.20 µg/g, respectively. The correlation between size groups and metal accumulation in muscle tissues were investigated for both fish. In terms of public risk assessment, the provisional tolerable weekly intake's of various heavy metals were compared with the consumption of both fish. As a result of the analysis, Fe, Zn, Cu, Mn, Pb and Cd accumulations in muscle tissues of T. lepturus and L. savala collected from Karachi Fish Harbour Pakistan did not exceed limit values.

Mitochondrial DNA sequence-based phylogenetic relationship of Trichiurus lepturus (Perciformes: Trichiuridae) from the Persian Gulf.

In this study, mitochondrial DNA analysis using 16S ribosomal DNA (rDNA) was performed to investigate the phylogeny relationship of Trichiurus lepturus in the Persian Gulf compared to the other investigated area. The amplification of 16S rDNA resulted in a product of 600 bp in all samples. The results showed that the isolated strain belongs to T. lepturus showing 42 divergence sites among the same reported partial sequences of 16S rRNA gene from the other area (West Atlantic and Indo-Pacific area). Phylogeny results showed that all 18 haplotypes of the species clustered into five clades with reasonably high bootstrap support of values (>64%). Overall, the tree topology for both phylogenetic and phenetic trees for 16S rDNA was similar. Both trees exposed two major clusters, one wholly containing the haplotypes of the T. lepturus species belonging to Indo-Pacific area with two major sister groups including Persian Gulf specimen and the other cleared the Western Atlantic and Japan individuals clustered in another distinct clade supporting the differentiation between the two areas. Phylogenic relationship observed between the Persian Gulf and the other Indo-Pacific Individuals suggested homogeneity between two mentioned areas.

Genetic distances and variations of three geographic hairtail populations identified by PCR analysis.

In the present study, muscle tissues were obtained separately from individuals from Atlantic hairtail population (AHP), Gunsan hairtail population (GHP) and Chinese hairtail population (CHP), respectively. The seven decamer primers were used to generate the shared loci, specific, unique shared loci to each population and shared loci by the three hairtail populations. Here, averagely, a decamer primer generated 64.7 amplified products per primer in the AHP population, 55.7 in GHP population and 56.4 in CHP population. The number of unique shared loci to each population and number of shared loci by the three populations generated by genetic analysis using 7 decamer primers in AHP, GHP and CHP population. 119 unique shared loci to each population, with an average of 17 per primer, were observed in the AHP population, and 28 loci, with an average of 4 per primer, were observed in the CHP population. The hierarchical dendrogram point out three main branches: cluster 1 (ATLANTIC 01 ~ ATLANTIC 07), cluster 2 (GUNSAN 08 ~ GUNSAN 14) and cluster 3 (CHINESE 15 ~ CHINESE 21). The shortest genetic distance displaying significant molecular difference was between individuals' CHINESE no. 16 and CHINESE no. 18 (0.045). In the long run, individual no. 01 of the AHP population was most distantly related to CHINESE no. 19 (genetic distance = 0.430). Consequently, PCR analysis generated on the genetic data displayed that the geographic AHP population was widely separated from CHP population, while individuals of CHP population were fairly closely related to those of GHP population.

Mercury and stable isotopes (delta-15N and delta-13C) as tracers during the ontogeny of Trichiurus lepturus

This study applies total mercury (THg) concentration and stable isotope signature (δ15N and δ13C) to evaluate the trophic status and feeding ground of Trichiurus lepturus during its ontogeny in northern Rio de Janeiro, south-eastern Brazil. The trophic position of T. lepturus is detected well by THg and δ15N as the sub-adult planktivorous specimens are distinct from the adult carnivorous specimens. The δ13C signatures suggest a feeding ground associated with marine coastal waters that are shared by fish in different ontogenetic phases. The diet tracers indicated that the fish feeding habits do not vary along seasons of the year, probably reflecting the prey availability in the study area. This fish has economic importance and the concentration of THg was compared to World Health Organization limit, showing that the adult specimens of T. lepturus are very close to the tolerable limit for safe regular ingestion. .

Este estudo utilizou a concentração de mercúrio total (THg) e a assinatura isotópica (δ15N e δ13C) para avaliar a posição trófica e a área de alimentação de Trichiurus lepturus durante sua ontogenia no norte do Rio de Janeiro, sudeste do Brasil. A posição trófica de T. lepturus foi bem detectada pelo THg e δ15N com os espécimes sub-adultos planctívoros distintos dos espécimes adultos carnívoros. As assinaturas de δ13C sugerem uma área de alimentação associada a águas marinhas costeiras que são compartilhadas por peixes em diferentes fases ontogenéticas. Os traçadores de dieta indicaram que os hábitos alimentares desse peixe não variam ao longo das estações do ano, refletindo provavelmente a disponibilidade de presas na área de estudo. Esse peixe tem importância econômica e a concentração de THg foi comparada com o limite estabelecido pela Organização Mundial de Saúde, demonstrando que os espécimes adultos de T. lepturus estão bem próximos do limite tolerável para uma ingestão regular segura.

Genetic Variations between Hairtail (Trichiurus lepturus) Populations from Korea and China.

PCR analysis generated on the genetic data showed that the geographic hairtail (Trichiurus lepturus) population from Korea in the Yellow Sea was more or less separated from geographic hairtail population from China in the South Sea. The average bandsharing value (mean±SD) within hairtail population from Korea showed 0.859±0.031, whereas 0.752±0.039 within population from China. Also, bandsharing values between two hairtail populations ranged from 0.470 to 0.611, with an average of 0.542±0.059. As compared separately, the bandsharing values of individuals within hairtail population from Korea were comparatively higher than those of individuals within population from China. The hierarchical dendevrepogram resulted from reliable oligonucleotides primers, indicating two genetic clusters composed of cluster 1 (KOREANHAIR1~KOREANHAIR11) and cluster 2 (CHINESEHAI12~CHINESEHAI22). The genetic distances between two geographic populations ranged from 0.038 to 0.476. Individual No. 11 within hairtail population from Korea was genetically closely related with No. 10 (genetic distance=0.038). The longest genetic distance (0.476) displaying significant molecular difference was also between individual No. 01 within hairtail population from Korea and No. 22 from Chinese. In the present study, PCR analysis has revealed significant genetic distances between two hairtail population pairs (P<0.05).

Ocorrência de Neobenedenia melleni (Monogenea; Capsalidae) em Trichiurus lepturus (Perciformes; Trichiuridae), naturalmente infestados, no litoral do Rio de Janeiro, Brasil / Occurrence of Neobenedenia melleni (Monogenea: Capsalidae) in Trichiurus lepturus (Perciformes: Trichiuridae), naturally infested off coastal zone of Rio de Janeiro, Brazil

Neobenedenia melleni (MacCallum, 1927) é um conhecido patógeno de teleósteos confinados que exibe baixo grau de especificidade ao hospedeiro. Entre julho de 2006 a junho de 2007, 120 espécimes de Trichiurus lepturus Linnaeus, 1.758 foram adquiridos de pescadores locais na Baia de Guanabara (22º 57' S e 42º 41' O), Estado do Rio de Janeiro, Brasil, para o estudo da sua parasitofauna. A superfície do corpo foi raspada e os monogenéticos obtidos foram identificados como N. melleni, que apresentaram prevalência de 8,3% e intensidade média de infecção 1,2 ± 0,42. O presente trabalho teve como objetivo fazer o primeiro registro de N. melleni parasitando hospedeiro silvestre na costa brasileira, aumentando, dessa forma, a distribuição geográfica conhecida dessa espécie de parasito.

Neobenedenia melleni (MacCallum, 1927) is a widely spread pathogen in teleost maricultures with a very low host specificity. Between July of 2006 to June of 2007, 120 specimens of Trichiurus lepturus Linnaeus, 1758 were acquired of local fishermen in the Guanabara Bay (22º 57' S and 42º 41' W), State of Rio de Janeiro, Brazil, to the study of the parasite fauna. The surface of the host body was scraped and the monogeneans obtained were identified as N. melleni, which showed prevalence of 8.3% and mean intensity of infection 1.2 ± 0.42. Data about morphology of the specimens collected were included herein. Neobenedenia melleni is recorded by the first time parasitizing on a wild host from the Brazilian coastal zone.

Concentração de mercúrio e análise histopatológica em músculo, rim e cérebro de peixe-espada (Trichiurus lepturus) coletados na praia de Itaipu - Niterói, Rio de Janeiro, Brasil / Mercury level and histopathologic analysis of muscle, kidney and brain of largehead hairtail (Trichiurus lepturus) collected in Itaipu beach - Niterói, Rio de Janeiro, Brazil

O pescado e seus derivados destacam-se como fonte de exposição e contaminação por metais pesados para o homem. A acumulação do metal mercúrio (Hg) ocorre de forma progressiva através da cadeia trófica e da água sendo o peixe-espada um carnívoro localizado no topo da cadeia alimentar ele pode representar o grau de contaminação da região estudada. Os objetivos neste estudo foram determinar os teores de mercúrio (Hg) e realizar análise histopatológica em órgãos da espécie Trichiurus lepturus em peixes comercializados na região da praia de Itaipu, Niterói - RJ. Foram analisados trinta e um animais, nos quais foram encontrados em musculatura e rim valores médios de Hg de 0,051±0,031µ g g-1 e 0,006±0,004µ g g-1, respectivamente. No pool de cérebro de todos os animais obteve-se o valor de 0,019µ g g-1. Os valores individuais mínimos e máximos de Hg na musculatura e no rim demonstraram uma ampla dispersão. Nas análises de correlação entre comprimento total e teores de Hg em musculatura, e peso total e teores de Hg em musculatura, foi verificada uma correlação positiva (r=0,85 e r=0,88 respectivamente) altamente significativa (P<0,0001). Entretanto, na correlação entre peso do rim e os teores de Hg no mesmo órgão, não foi demonstrada uma correlação significativa (r=0,24) ao nível de confiança de 95 por cento (P>0,19). Nos testes de comparação múltipla entre os teores médios encontrados em musculatura, rim e cérebro, foi observada uma diferença altamente significativa entre os valores do músculo e do rim, assim como entre os do músculo e do cérebro (P<0,001 para ambos). Na comparação entre rim e cérebro, também foi verificada uma diferença significativa ao nível de 5 por cento de probabilidade (P<0,05). Na análise histopatológica, foram observadas lesões no rim, caracterizando-se por metaplasias cartilaginosas em alguns exemplares e uma intensa presença de corpos melanomacrofágicos.

Fish is an important source of heavy metal exposition and contamination for human being. Accumulation of mercury (Hg) in men occurs by chronicle exposition, through the food chain, by ingestion of fish contaminated with mercury. Because of biomagnifications the carnivorous fish that is on the top of the food chain shows a higher concentration of mercury in their tissues and can represent the aquatic environmental contamination. This work aims to establish histopathologic analysis and total mercury concentration in different tissues from thirty-one Trichiurus lepturus, a commercial fish from Itaipu Beach, Niterói, RJ. T. lepturus collected showed mean values of total mercury concentration of 0.051±0.031µ g g-1 and 0.006±0.004µ g g-1, respectively in muscle and kidney tissues. It was also conducted an analysis of mercury concentration from a pool of brain tissue from all individuals (0.019µ g g-1). Minimum and maximum mercury values in muscular and kidney tissues showed a wide dispersion. There was a positive correlation between total length and mercury muscular tissue concentration (R=0.85) and between body weight and mercury muscular tissue concentration (R=0.88), both highly significant. No significant correlation (r=0.24) was observed between kidney weight and mercury tissue concentration (P>0.19). In a multiple comparison test among muscle, kidneys and brain mercury tissue concentration, it was observed a highly significant difference between muscle and kidneys (P<0.001), as well as between muscle and brain (P<0.001). Comparison between kidney and brain mercury tissue concentration also showed a significant difference with a probability level of 5 percent (P<0.05). Histopathology demonstrated damage in the kidneys (cartilaginous metaplasia in some individuals and a high presence of melanomacrophage centers).

Ocorrência de Neobenedenia melleni (Monogenea; Capsalidae) em Trichiurus lepturus (Perciformes; Trichiuridae), naturalmente infestados, no litoral do Rio de Janeiro, Brasil

Neobenedenia melleni (MacCallum, 1927) is a widely spread pathogen in teleost maricultures with a very low host specificity. Between July of 2006 to June of 2007, 120 specimens of Trichiurus lepturus Linnaeus, 1758 were acquired of local fishermen in the Guanabara Bay (22º 57' S and 42º 41' W), State of Rio de Janeiro, Brazil, to the study of the parasite fauna. The surface of the host body was scraped and the monogeneans obtained were identified as N. melleni, which showed prevalence of 8.3% and mean intensity of infection 1.2 ± 0.42. Data about morphology of the specimens collected were included herein. Neobenedenia melleni is recorded by the first time parasitizing on a wild host from the Brazilian coastal zone.

Neobenedenia melleni (MacCallum, 1927) é um conhecido patógeno de teleósteos confinados que exibe baixo grau de especificidade ao hospedeiro. Entre julho de 2006 a junho de 2007, 120 espécimes de Trichiurus lepturus Linnaeus, 1.758 foram adquiridos de pescadores locais na Baia de Guanabara (22º 57' S e 42º 41' O), Estado do Rio de Janeiro, Brasil, para o estudo da sua parasitofauna. A superfície do corpo foi raspada e os monogenéticos obtidos foram identificados como N. melleni, que apresentaram prevalência de 8,3% e intensidade média de infecção 1,2 ± 0,42. O presente trabalho teve como objetivo fazer o primeiro registro de N. melleni parasitando hospedeiro silvestre na costa brasileira, aumentando, dessa forma, a distribuição geográfica conhecida dessa espécie de parasito.