Unicorn Leatherjacket Research Articles

Redescription of two known species of Taeniacanthidae (Copepoda, Cyclopoida) parasitic on Japanese filefishes (Actinopterygii)

Abstract Cirracanthus monacanthi (Yamaguti, 1939) and Taeniacanthus balistae (Claus, 1864) are redescribed based on specimens recovered from Stephanolepis cirrhifer (Temminck & Schlegel, 1850) and Aluterus monoceros (Linnaeus, 1758) (Tetraodontiformes, Monacanthidae), respectively, in Japan. The description of the copepodid V female of T. balistae is the first time for the species.

COMPOSITION OF THE NEW DESIGN OF PAYANG CATCHES IN MAJENE WATERS, MAKASSAR STRAIT

In this study, a new design scottish seine net was used with larger than the general size of the Scottish seine net in the research location. The purpose of this research was to analyze the total catch, species composition and the length of the catch. The study was conducted on one case of a Scottish seine net fishery unit by making a new design of Scottish seine net and then operating it with Scottish seine net fishers in the waters of Majene Makassar Strait. The parameters observed were the fish species caught and the length of each species. From the study results, it was found that the catch of 8 species of fish with total of 15,253 fish in the other bag. The species composition consisted of Shortfin scad (Decapterus macrosoma) 66.48%, Indian mackerel (Rastrelliger kanagurta) 14.42%, Rainbow runner (Elagatis bipinnulata) 7.09%, Mackerel tuna (Euthynnus affinis) 3.83%, Malabar trevally (Carangoides malabaricus) 2.39%, Unicorn leatherjacket (Aluterus monoceros) 2.29%, Skipjack tuna (Katsuwonus pelamis) 2.19% and Goldstripe sardinella (Sardinella gibbosa) 1.31%. The length of the dominant catch Shortfin scad (Decapterus macrosoma) as much as 66.48% ranged from 12.5 - 27 cm with a catchable percentage of 82.53% while Indian mackerel (Rastrelliger kanagurta) as the second highest catch was 14.42% only about 2 ,64% worth catching.

Assessing trophic interactions among three tuna species in the Solomon Islands based on stomach contents and stable isotopes

Trophic research is essential to the conservation and management of fishery resources. This study analyzed the feeding habits and nutritional interactions among three tuna species in the waters of the Solomon Islands (5°12′S–15°20′S, 157°31′E–172°19′E). A total of 103 bigeye tuna (Thunnus obesus), 296 yellowfin tuna (Thunnus albacores), and 264 albacore tuna (Thunnus alalunga) samples were collected from September to December 2019. Samples for stomach content and stable isotope analysis were randomly selected. The stomach content analysis results showed that the stomach contents of the three tuna species were rich in prey, and 48 prey species were identified, including fish, cephalopods, and crustaceans, with high between-phenotype component (BPC). Yellowfin tuna consumed the largest variety of food and bigeye tuna consumed the smallest. The feeding intensity of bigeye tuna were higher than that of yellowfin and albacore tuna. Yellowfin tuna had the highest empty stomach rate (35.69%) and lowest average stomach fullness index (0.064). The degree of stomach fullness in the three tuna species was mainly 1, and the difference in the stomach fullness index among them was significant (P<0.001). Food overlap (0.3–0.6) and Levins index (<0.6) among the three species were low, indicating a specialized feeding tendency. Bigeye tuna mainly feed on Ommastrephes bartrami and Myctophidae, yellowfin tuna mainly feed on Hyperiidea and Aluterus monoceros, and albacore tuna mainly feed on Gempylus serpens and Loligo chinensis. The stable isotope results showed that the δ13C and δ15N values of the three tuna species were significant (P<0.001). The standard ellipse area corrected for small sample sizes (SEAc) and total niche area (TA) of bigeye tuna, range of δ15N (NR) of yellowfin tuna, and range of δ13C (CR) of albacore tuna were the highest. The results of this study will help improve our understanding of the feeding ecology of these three tuna species and their important roles in the ecosystem and food web structure.

Understanding the population parameters for unicorn leatherjacket, Aluterus monoceros (Linnaeus, 1758) exploited along the Western Bay of Bengal

Information on age and growth for monocanthid species globally is limited. Aluterus monoceros forms an important fishery in the northern Indian Ocean; however, information on its population dynamics is sparse, as the species has not been explicitly studied. This study elucidates the population parameters from 1031 individuals landed in the multi-day trawl fishery along the western Bay of Bengal from January 2017 to December 2019. Total length ranged from 21.5 to 64.4 cm with a mean of 47.54 cm. Von Bertalanffy growth equation was L t = 67.67 [1 – e –0.32 (t + 0.0592) ]. The fishery was dominated by 3 and 4-year-old age classes and the estimated lifespan was 9.32 years. Recruitment was observed throughout the year and was bimodal, with the major pulse from October – February and the minor pulse from April – June producing 52.44 % and 36.24 %, respectively of the annual recruits. Natural mortality, fishing mortality and total mortality per year were 0.66, 0.55 and 1.21, respectively. Exploitation ratio was 0.45 and exploitation rate was 0.32. Though the species is currently underexploited, considering their lower capture sizes and their occurrence as by-catch in the trawl fishery, precautionary approach is suggested with management measures targeted at protecting their early life history stages.

Reproductive and feeding biology of unicorn leatherjacket, Aluterus monoceros from the Bay of Bengal, Northern Indian Ocean

AbstractNo prior comprehensive information on the reproductive biology and trophodynamics of Aluterus monoceros was globally available. The present study was performed on 1036 individuals landed along the western Bay of Bengal during 2017 to 2019. Length ranged between 25.3–64.4 cm in females (mean at 48.34 cm) and from 21.5–64.1 cm in males (mean at 47.83 cm). Growth was negatively allometric with no significant difference between sexes. Sex ratio (F:M) was 1.03 with variations based on sizes and months. Size at sexual maturity for females and males was 40.85 and 41.60 cm, respectively. The species spawned throughout the year with major and minor peaks during February to May and October and November. Absolute fecundity increased linearly with length and weight and ranged from 33,640 eggs to 12,39,202 eggs. Stomachs were empty or with trace amounts of food in 59.17%, part-full in 34.07% and full in 6.76% of the fishes. Stomach vacuity and fullness and predator–prey weight ratios varied with an increase in body size, implying higher feeding intensity in large-sized fishes. Feeding activity was more intense during June–August and less during the peak spawning months. The species is omnivorous and a bottom feeder. Teleosts contributed the most to the prey items (43.23% by Index of Preponderance) implying preference for carnivory. Ontogenetic shifts and seasonal variations in prey items were observed. The present study provides paramount information that can significantly contribute to the management and conservation of monacanthid stocks in northern Indian Ocean.

Echinocephalus inserratus sp. n. (Nematoda: Gnathostomatidae) from the stingray Pastinachus ater (Dasyatidae) and new records of congeneric and some other nematode larvae from teleost fishes off New Caledonia.

Based on light and electron microscopical studies, a new nematode parasite, Echinocephalus inserratus sp. n. (Spirurida: Gnathostomatidae), is described from the spiral valve of the broad cowtail stingray Pastinachus ater (Macleay) (Dasyatidae, Myliobatiformes) from off New Caledonia. The new species is morphologically and biometrically most similar to Echinocephalus overstreeti Deardorff et Ko, 1983, differing from it mainly in the absence of serrations on the posterior parts of pseudolabia and on interlabia, and in having a longer gubernaculum (150-299 µm long). Morphologically unidentifiable, mostly encapsulated larvae of Echinocephalus spp. were recorded from the following six species of teleost fishes collected in New Caledonian waters, serving as paratenic hosts: Perciformes: Acanthopagrus berda (Forsskål) (Sparidae) and Nemipterus furcosus (Valenciennes) (Nemipteridae); Tetraodontiformes: Abalistes stellatus (Anonymous), Pseudobalistes fuscus (Bloch et Schneider) (both Balistidae), Lagocephalus sceleratus (Gmelin) (Tetraodontidae) and Aluterus monoceros (Linnaeus) (Monacanthidae). Co-parasitising larvae of Ascarophis sp. and Hysterothylacium sp. were also collected from P. fuscus. All these findings represent new host and geographical records. A key to valid species of Echinocephalus Molin, 1858 is provided.

Documenting the first record of the Unicorn leatherjacket filefish Aluterus monoceros (Tetraodontiformes: Monacanthidae) from the marine waters of Odisha coast, Bay of Bengal, India

The unicorn leatherjacket filefish Aluterus monoceros (Linnaeus, 1758) belonging to family Monacanthidae inhabits in the coastal waters of Indo-West pacific, western India to Andaman Sea. For the first time, three specimens of this species were caught in the Odisha coast, Bay of Bengal, India. The morphological characteristics of the collected specimens are given and its geographical distribution have been reviewed based on available literatures.

Characterization of gelatin obtained from unicorn leatherjacket (Aluterus monoceros) and reef cod (Epinephelus diacanthus) skins

The properties of gelatin oven dried at three different temperatures from unicorn leatherjacket (L50, L60 and L70) and reef cod skin (R50, R60 and R70) were investigated. The gelatin yield was higher in unicorn leatherjacket skin (12.2%) than reef cod skin (9.8%). Unicorn leatherjacket skin gelatin had a higher protein content of 88.0–88.61%, lower moisture (9.51–9.91%), fat (0.18–0.29%) and ash (0.60–0.71%) compared to reef cod skin gelatin which had 87–87.73% protein, 10.29–11.03% moisture, 0.23–0.31% fat and 0.69–0.73% ash. SDS-PAGE revealed all the gelatin samples had α and β chains. Gelatin samples had a good proportion of imino acid, hydrophobic and essential amino acid. Fourier transform infrared (FTIR) spectra showed the presence of amide regions in all the samples. Differential scanning calorimetry (DSC) showed a higher melting temperature in unicorn leatherjacket skin gelatin (115.54–120.80 °C) than reef cod skin (106.25–118.92 °C). Foaming capacity and stability and emulsion stability were higher in unicorn leatherjacket skin gelatin. Emulsion activity index, fat binding and water holding capacities were higher in reef cod skin gelatin. Different oven drying temperatures has not affect the yield and quality of gelatin. This study could pave the way to utilize oven drying for the extraction of gelatin from fish skin.

Aluterus monoceros (Acanthopterygii, Tetraodontiformes) southwards distribution range extension in Argentine waters

The presence of Aluterus monoceros (Linnaeus, 1758) in Mar del Plata, Argentina (38° S) was registered over 40 years ago. This new report extends its southernmost distribution limit to 39° S (Necochea: ~ 120 km). The presence of the species could be associated to the warm subtropical water derived from the Brazilian continental shelf. The hypothesis was tested with satellite images of the sea surface temperature recorded during the cruise the specimen was caught.

New Distributional Records for Monacanthid Fishes (Tetradontiformes: Monacanthidae) from North East Arabian Sea, Western Indian Ocean

Fishes of family Monacanthidae, popularly known as filefishes are a specialized group of fishes with low commercial importance in the studied region barring Aluterus monoceros, which has emerged as commercial fish in the region in last few years. Three species, namely Aluterus scriptus, Stephanolepis diaspros, and Stephanolepis auratus, have been reported for the first time from the region, adding to the monacanthid diversity of the region. Morphometric assessment of the four species revealed several discriminating attributes capable of separating the species from each other.

Studies on the Development and Quality of Fish Chiffon Cake and its Storage Stability

ABSTRACTThirty percent flour was substituted with dolphinfish (Coryphaena hippurus) and unicorn leatherjacket (Aluterus monoceros) paste in a cake recipe to evaluate the quality and shelf life of fish chiffon cakes stored at 4℃ and 25℃. Proximate composition, free amino acid (FAA), aerobic plate count (APC), total volatile basic nitrogen (T-VBN), and texture profile and sensory evaluation of fish chiffon cakes were conducted. Fish paste addition increases proteins. Cakes made with dolphinfish paste had the highest FAA content, followed by the cake made with unicorn leatherjacket. Histidine is the predominant FAA in dolphinfish chiffon cake, and it is significantly higher than the other two cakes. T-VBN values and APC increased with the addition of fish paste and was lower than the upper limit of acceptable fish products during storage period. The hardness of the two fish cakes was slightly lower than the control after 1 and 2 days storage at 25℃ or 3 and 5 days storage at 4℃ and increased during storage. Sensory evaluation showed no significant differences among the ordinary cake and two fish chiffon cakes for odor, texture, flavor, and overall acceptability. Therefore, incorporation of white fish meat is feasible for chiffon cake.

New host records of monacanthid fish for three Kudoa spp. (K. septempunctata, K. thyrsites, and K. shiomitsui) prevalent in the olive flounder (Paralichthys olivaceus), with the description of K. parathyrsites n. sp. from a black scraper (Thamnaconus modestus).

Kudoa septempunctata (Myxosporean: Multivalvulida) is known as a cause of foodborne disease associated with consumption of raw flesh of the olive flounder (Paralichthys olivaceus). Knowledge of its life cycle, particularly alternate annelid hosts and reservoirs or susceptible fish hosts in natural waters, may facilitate disease control in aquaculture farms. Our recent survey of myxosporean infection in monacanthid fish in natural waters around Japan revealed infection with three kudoid species prevalent in the olive flounder, i.e., K. septempunctata, Kudoa thyrsites, and Kudoa shiomitsui. Of the 51 black scrapers (Thamnaconus modestus) examined, five fish were infected: two fish with K. septempunctata and three with K. thyrsites. One of the fish infected with K. septempunctata was also infected with a K. thyrsites-like species. One of the 17 threadsail filefish (Stephanolepis cirrhifer) and two of four unicorn leatherjackets (Aluterus monoceros) were parasitized with K. shiomitsui. Three modest filefish (Thamnaconus modestoides) had no kudoid infection. K. septempunctata from a black scraper fished in the Inland Sea of Japan off Yamaguchi had 6-8 (predominantly 7) shell valves/polar capsules, whereas K. septempunctata found in another black scraper from the Sea of Japan off Tottori had 5 or 6 (predominantly 6). However, the two isolates displayed identical 18S and 28S ribosomal RNA gene (rDNA) nucleotide sequences, which were also identical to the isolates from the olive flounder. K. thyrsites from the Inland Sea of Japan off Yamaguchi and Sea of Japan off Tottori and K. shiomitsui from the Sea of Japan off Shimane and western Pacific Ocean off Kochi were also morphologically and genetically characterized. They were found to be coincident with the previous reports from olive flounders. Furthermore, the K. thyrsites-like species found in a black scraper from the Inland Sea of Japan off Yamaguchi was morphologically and genetically characterized; a new species, Kudoa parathyrsites n. sp., is erected for this species. The relationships of the new species with K. thyrsites and related species as well as those of K. shiomitsui with Kudoa pericardialis and related species parasitizing the pericardium are briefly discussed.

In vitro cellular bioactivities of Maillard reaction products from sugar-gelatin hydrolysate of unicorn leatherjacket skin system

The effects of Maillard reaction products (MRP), produced from galactose and a gelatin hydrolysate which was derived from unicorn leatherjacket skin, on in vitro cellular antioxidant activity, immunomodulatory properties and anti-cancer activity were investigated. MRP (750–1500 µg/mL) protected against H2O2-induced DNA damage in U937 cells. DNA damage was reduced by approximately 50% at the highest MRP concentration (1500 µg/mL). The activities of cellular antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) were decreased in HepG2 cells exposed to H2O2 but were induced in the presence of MRP. MRP reduced the production of pro-inflammatory cytokines (IL-1β and IL-6) and nitric oxide in LPS-induced RAW264.7 cells. The proliferation of colon carcinoma, Caco-2 cells was inhibited in the presence of MRP with an IC50 of 1.7 mg/mL. Therefore, MRP demonstrated bioactive potential through the suppression of oxidative stress and inflammation in vitro in addition to inhibiting the proliferation of human colon cancer cells.

Antioxidant, immunomodulatory and antiproliferative effects of gelatin hydrolysate from unicorn leatherjacket skin

The in vitro cellular bioactivities including, antioxidant, immunomodulatory and antiproliferative effects of a gelatin hydrolysate (GH) prepared from unicorn leatherjacket skin, using partially purified glycyl endopeptidase, were investigated in order to optimize the use of fish skin waste products as functional food ingredients. GH under the tested concentrations (750-1500 µg mL(-1) ) protected against H2 O2 -induced DNA damage in U937 cells. GH also protected against the H2 O2 -induced reduction in cellular antioxidant enzyme activities, superoxide dismutase and catalase, in HepG2 cells. GH demonstrated immunomodulatory potential by reducing pro-inflammatory cytokine (interleukin-6 (IL-6) and IL-1β) production and nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 macrophage cells. Cell proliferation in human colon cancer (Caco-2) cells was significantly reduced in a dose-dependent manner following incubation with GH. These results indicate that GH has several bioactivities which support its potential as a promising functional food ingredient with various health benefits. © 2015 Society of Chemical Industry.

New Approaches for the Effective Utilization of Fish Skin Wastes of Aluterus monoceros

Context: Unicorn leatherjacket (Aluterus monoceros) is an export quality fish mainly used for fillet production, the skin of which is discarded as waste due to its toughness. Wastes emanated from the fish processing industry have become an important source of environmental pollution. Aim: The study investigates the potentials of A. monoceros skin to produce value-added products viz., fish leather and fish meal. Materials and Methods: 5 kg of fish skin from 20 kg of fish was used for the present study. Leather produced from fish skin was characterized for its physico-chemical properties using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), etc. Biochemical components viz., protein, fat, and salt content of the fish skin were also estimated. Results: Leather produced from fish skin possessed 88 MPa tensile strength. Biochemical estimations proved that the fish skin had 28% protein content. Conclusion: On the basis of the characterization and evaluation results, it could be concluded that this processed fish skin could be used for leather goods production. In addition, this fish skin could be included as a component in fish meal preparation.

The complete mitochondrial genome of the Aluterus monoceros

The complete mitochondrial genome of Aluterus monoceros (A. monoceros) has been sequenced. The mitochondrial genome of A. monoceros is 16,429 bp in length, consisting of 22 tRNA genes, 2 rRNA genes, 13 protein-coding genes and a D-loop region (Gen Bank accession number KP637022). The base A + T of the mitochondrial genome is 63.25%, including 33.16% of A, 30.09% of T and 20.74% of C. Twelve protein-coding genes start with a standard ATG as the initiation codon, expect for the COXI, which begins with GTG. Some of the termination codons are incomplete T or TA, except for the ND1, COXI, ATP8, ND4L1, ND5 and ND6, which stop with TAA. Construction of phylogenetic trees based on the entire mitochondrial genome sequence of 14 Tetrodontiformes species constructed has suggested that A. monoceros has closer relationship with Acreichthys tomentosus and Monacanthus chinensis, and they constitute a sister group.

Trypsin from unicorn leatherjacket (Aluterus monoceros) pyloric caeca: purification and its use for preparation of fish protein hydrolysate with antioxidative activity

Fish proteases, especially trypsin, could be used to prepare fish protein hydrolysates with antioxidative activities. In this study, trypsin from the pyloric caeca of unicorn leatherjacket was purified by ammonium sulfate precipitation and soybean trypsin inhibitor (SBTI)-Sepharose 4B affinity chromatography. Hydrolysate from Indian mackerel protein isolate with different degrees of hydrolysis (20, 30 and 40% DH) was prepared using the purified trypsin, and antioxidative activities (1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging activities, ferric-reducing antioxidant power and ferrous-chelating activity) of the hydrolysate were determined. Trypsin was purified 26.43-fold with a yield of 13.43%. The purified trypsin had a molecular weight (MW) of 23.5 kDa and optimal activity at pH 8.0 and 55 °C. It displayed high stability in the pH range of 6.0-11.0 and was thermally stable up to 50 °C. Both SBTI (0.05 mmol L(-1)) and N-p-tosyl-L-lysine-chloromethylketone (5 mmol L(-1)) completely inhibited trypsin activity. Antioxidative activities of the hydrolysate from Indian mackerel protein isolate increased with increasing DH up to 40% (P < 0.05). Based on sodium dodecyl sulfate polyacrylamide gel electrophoresis, the hydrolysate with 40% DH had a MW lower than 6.5 kDa. The purified protease from unicorn leatherjacket pyloric caeca was identified as trypsin based on its ability to hydrolyze a specific synthetic substrate and the response to specific trypsin inhibitors. The purified trypsin could hydrolyze Indian mackerel protein isolate, and the resulting hydrolysate exhibited antioxidative activity depending on its DH.

Antioxidative gelatin hydrolysate from unicorn leatherjacket skin as affected by prior autolysis

Gelatin hydrolysates from autolysed non-swollen and swollen unicorn leatherjacket skin prepared using partially purified glycyl endopeptidase (GE) from papaya latex were examined for their antioxidative activities. Autolysed swollen skin was more hydrolysed by GE as indicated by higher α-amino group content, compared with autolysed non-swollen skin. ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP) of hydrolysates were increased with increasing levels of GE used. Antioxidative gelatin hydrolysate from autolysed skin, both non-swollen and swollen skins, using 8 % GE termed ‘NS-8GE’ and ‘SS-8GE’ exhibited different modes of action. When both hydrolysates were tested in lecithin liposome system, the efficiency in retardation of lipid oxidation was in a dose-dependent manner. Antioxidative activity of hydrolysates at 5.0 g/L was comparable to that of 0.1 g/L Trolox, in which the oxidation was almost completely inhibited. NS-8GE and SS-8GE also showed their antioxidative activities in gastrointestinal tract model system (GIMs). ABTS radical scavenging activity of both hydrolysates increased, but FRAP decreased in a duodenal condition. Based on size exclusion chromatography, major antioxidative peptides in NS-8GE and SS-8GE had molecular weight of 1,170 and 750 Da, respectively. Therefore, GE could enhance antioxidative activity of autolysed skin. Additionally, swelling process directly determined the modes of actions of resulting gelatin hydrolysates. NS-8GE had high ABTS radical scavenging activity, whereas SS-8GE showed high FRAP.

Purification and Characterization of Extracellular Gelatinolytic Protease from B acillus Amyloliquefaciens H11

Extracellular gelatinolytic enzyme from Bacillus amyloliquefaciens H11 was purified by gel filtration chromatography on Sephacryl S-200 and ion exchange chromatography on diethylaminoethyl-cellulose with 35% yield and 14-fold increase in purity. Based on sodium dodecyl sulfate–polyacrylamide gel electrophoresis, the molecular weight of the purified enzyme was estimated to be 21 kDa. The optimum gelatinolytic activities of purified enzyme toward porcine gelatin were 50C and pH 8.0. The inhibitor study revealed that the purified enzyme was a metallo-serine protease and activated by Ca2+ and Mg2+ but resistant to Triton X-100 and methanol at a concentration of 10% (v/v). Among all gelatins, that from unicorn leatherjacket fish skin was the most preferred for hydrolysis by the purified enzyme, in comparison with porcine and tilapia counterparts. Thus, the enzyme from B. amyloliquefaciens H11 could be used as a potential protease for production of gelatin hydrolysate. Practical Applications Extracellular protease from Bacillus amyloliquefaciens H11 plays a specific catalytic role in the hydrolysis of gelatin and can be used for production of gelatin hydrolysate with bioactivities. It can also be a potential alternative for commercial protease in conversion of marine processing by-products to generate high value-added products.

Cryoprotective and antioxidative effects of gelatin hydrolysate from unicorn leatherjacket skin

Cryoprotective properties of gelatin hydrolysates from autolysed non-swollen and swollen unicorn leatherjacket skin using partially purified glycyl endopeptidase (GE) from papaya latex were examined. Gelatin hydrolysates from autolysed non-swollen skin showed higher cryoprotective property in salt solution system than that from autolysed swollen skin as indicated by lower enthalpy for melting of eutectic and ice crystal. The cryoprotective effect of gelatin hydrolysate (0.5 and 1.0%) was in dose-dependent manner. Gelatin hydrolysate retarded physicochemical changes of natural actomyosin from washed mince system, as evidenced by lower changes in Ca2+-ATPase activity, surface hydrophobicity and disulfide bond formation, compared with the control. Based on DSC analysis, the enthalpy of myosin and actin was also higher in the presence of gelatin hydrolysate. Gelatin hydrolysate could prevent lipid oxidation in washed mince system as shown by lower TBARS value and less abundance of hexanal, heptanal and 1-pentene-3-ol.