• Journal of fish pathology
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• v.34 no.2
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• pp.243-248
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• 2021

Offshore wind power generation is an energy generation field that is rapidly developing owing to the increasing demand for clean energy. However, the physiological response of fish to the underwater noise generated during construction or operation of wind turbines is unclear. We confirmed the effects of sound pressures of 125, 135, 145, and 155 dB/µPa, including 140 dB/µPa (the standard sound pressure for noise damage recognition in South Korea), through serum analysis in rock bream (Oplegnathus fasciatus). High mortality induced by reduced immunity through artificial infection after stimulation was confirmed. These results suggest that rock bream is negatively affected by the noise generated during the construction of offshore wind power plants.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.918-924
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• 2020

This study investigated diurnal fasting and postprandial total ammonia nitrogen (TAN) excretion rates in juvenile Oplegnathus fasciatus (rock bream; mean body weight 45.8±1.1 g) at three temperatures (15, 20, and 25℃) in a recirculating system (three replicates). The fish were hand-fed twice daily (09:00 and 17:00 h) with commercial food (46.7% protein) until satiation. The results showed that the fasting and postprandial TAN excretion rates were temperature-dependent. The mean hourly rates were 7.7 (15℃), 10.2 (20℃), and 11.9 (25℃) mg kg fish-1 h-1 for fasting and 34.0 (15℃), 47.8 (20℃), and 60.2 (25℃) mg kg fish-1 h-1 for postprandial. At each temperature, two postprandial TAN excretion peaks were observed 2-4 h after feeding; the second peak was always higher. The TAN loss to nitrogen consumption ratio was 41.1-46.8 % and increased significantly with increasing temperature. Temperature affected fasting and postprandial TAN excretion in juvenile rock bream, providing insight for culture management.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.4
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• pp.455-460
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• 2022

Oxybenzone (Benzophenone-3; BP-3) is a compound used in sunscreens and enters the oceans due to improper disposal. It is known to disrupt the endocrine signaling in marine organisms, leading to immune and reproductive abnormalities in corals, shellfish and fishes. In this study, we investigated the effects of different concentrations of BP-3 (0, 10, 100 and 1,000 ㎍/L) on the fertilized eggs and hatched larvae of Oplegnathus fasciatus. The morphological changes and hatching and survival rates during embryo development were assessed. In addition, the levels of triiodothyronine (T3) were also measured. The hatched larvae exposed to BP-3 at concentrations of 10 and 100 ㎍/L for 24 h displayed malformation of the tail. After 36 h of exposure to BP-3, spinal deformity was observed at all tested concentrations. The hatching rate was significantly low when exposed to 100 ㎍/L of BP-3. A high levels of T3 was observed when the larvae were exposed to BP-3 at a concentration of 1,000 ㎍/L for 96 h (the end of the experiment). This may be related to increased size of larvae at 1,000 ㎍/L BP-3. In conclusion, our results suggested that BP-3 may interfere with embryo development, resulting in a reduction in hatching rate and malformation of larvae.

• Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.261-265
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• 2013

The study was conducted to investigate the responses of the hepatic microsomal cytochrome P450 monooxygenase system in the rock bream Oplegnathus fasciatus after chronic exposure to 0, 1, 2, 4, and $8{\mu}g/L$ tributyltin (TBT) concentrations for 4 weeks. Hepatic cytochrome 450 content and ethoxyresorufin O-deethylation (EROD) activity were found to significantly increase in fish treated with the higher concentration of TBT (${\geq}4{\mu}g/L$); however, no significant changes were observed in penthoxyresorufin O-deethylation (PROD) activity in all treated groups compared to the control group. These findings suggest that exposure to a low TBT concentration (${\geq}4{\mu}g/L$) has the potential to induce cytochrome 450 content and EROD enzyme activity in hepatic tissue in the rock bream.

• Fisheries and Aquatic Sciences
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• v.13 no.1
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• pp.56-62
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• 2010

To determine whether long double-stranded RNA (dsRNA) induces RNA interference and type I interferon (IFN) responses in fish, long dsRNAs encoding enhanced green fluorescent protein (EGFP), GFPuv, and polyinosinic-polycytidylic acid sequences were co-injected with an EGFP expressing plasmid, into rock bream (Oplegnathus fasciatus). We investigated the EGFP mRNA and protein levels, and the transcriptional responses of dsRNA-dependent protein kinase and Mx1 genes. Long dsRNAs were strong inducers of a type I IFN response in rock bream, resulting in nonspecific suppression of exogenous gene expression. Furthermore, sequence-specific knockdown of exogenous gene expression at the mRNA level was detected at an early phase (24 h). These results suggested that long dsRNA may inhibit exogenous gene expression through an early mRNA interference response and a later type I IFN response in fish.

• Journal of fish pathology
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• v.23 no.3
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• pp.429-440
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• 2010

We constructed a rock bream (Oplegnathus fasciatus) gill cDNA library and a total of 1450 expressed sequence tag (EST) clones were generated. Gene annotation procedures and homology searches of the sequenced ESTs were locally done by BLASTX for amino acid similarity comparisons. Of the 1450 EST clones, 1022 EST clones showed significant homology to previously described genes while 428 ESTs were unidentified, and 259 clones were hypothetical, or unnamed proteins. Encoding 313 different sequences were identified as putative bio-defense genes or genes associated with immune response.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.332-338
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• 2011

Two feeding trials were conducted to determine the effects of dietary supplementation with Hizikia fusiformis or Ecklonia cava on the non-specific immune responses of parrot fish Oplegnathus fasciatus. Fish were fed experimental diets to which H. fusiformis or E. cava powder were added to final concentrations of 0, 2, 4 and 6%, respectively. After feeding for two weeks, phagocytic activity was significantly higher in fish fed diets containing H. fusiformis, but not E. cava, than in fish fed the basal diet. Lysozyme activity was significantly increased in the fish fed diets containing 6% H. fusiformis and E. cava. Myeloperoxidase activity was also significantly higher in fish fed diets containing 2 and 4% H. fusiformis, as compared to the basal diet, but not in those fish fed E. cava. These two studies indicate that dietary supplementation with H. fusiformis or E. cava could enhance the innate immune responses of parrot fish during their growth stage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.874-881
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• 2014

A laboratory experiment was conducted to determine chronic effects of waterborne copper exposure on rock bream Oplegnathus fasciatus using a panel of enzymes. The activities of the following biochemical biomarkers were determined at different concentrations of $CuSO_4$ for 10 and 20 days: alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) in plasma; antioxidant enzymes including glutathione (GSH), superoxide dismutase (SOD) and glutathione peroxidase (GPx) in liver and gills; and acethylcholinesterase (AChE) in brain and muscle. After exposure to two $CuSO_4$ concentrations (200 and $400{\mu}g/L$), the activities of plasma ALT in the fish showed a tendency to increase with AST and LDH, depending on $CuSO_4$ concentration. Additionally, GSH levels and SOD activities significantly increased, depending on $CuSO_4$ concentrations in liver and gills. This involved the inactivation of reactive molecules formed during oxidative stress, which could provide protection against oxidative damage induced by $CuSO_4$. However, GPx and AChE activities significantly decreased with $CuSO_4$ in liver and gills. In conclusion, these enzymes may represent convenient biomarkers for monitoring heavy metal pollution in coastal areas. Such chronic exposure studies are necessary for improving our understanding of complementary or deleterious effects of pollutants, and for developing metal toxicity biomarkers.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.2
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• pp.126-140
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• 2011

Genetic determinants of two metallothionein isoforms (MT-A and MT-B) were isolated and characterized from the perciform species, rockbream (Oplegnathus fasciatus). Rockbream MT-A and MT-B shared a high degree of homology at amino acid levels with representative orthologs from other perciform species, especially with respect to the conserved cysteine residues. At the genomic level, both MT-A and MT-B genes represent a tripartite structure typical of vertebrate MT genes. However, rockbream MT-B showed unusually large introns (1.2 kb and 0.8 kb for intron I and II, respectively), a phenomenon that has rarely been seen in other vertebrate MT genes. MT-A and MT-B transcripts were ubiquitously detected in a wide array of tissues, wherein brain and eye showed the highest basal expression levels, and the fin exhibited the lowest expression of both isoforms. The basal expression of MT-A in most tissues was significantly higher (ranging from 4- to 10-fold) than that of MT-B. Upon heavy metal exposures to Cd, Cu or Zn at 25 ppb for 48 h, MT-A and MT-B transcripts in the liver were significantly activated by Cd and moderately by Zn. On the other hand, exposure to Cu did not result in alterations of MT-A, nor in the significant suppression of MT-B. Following bacterial challenges with Escherichia coli, Edwardsiella tarda or Streptococcus iniae, MT isoforms in the liver, kidney and spleen were highly modulated and exhibited a pattern that was dependent on the bacterial species, tissues and isoforms. These results suggest that the two MT isoforms could be taken into account as potential indicators of metal toxicity and immune perturbations of this aquaculture-relevant species.

• Applied Microscopy
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• v.34 no.2
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• pp.131-137
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• 2004

This study is observed the skin of the parrot fish, Oplegnathus fasciatus that related study of epidermal alternation with environmental and physiological change. It composed of supporting cells, unicellular glands and accessory cells. The supporting cells are classified into superficial cell, intermediated cell and basal cell. Superficial cell of epidermal layer is squamous or cuboidal and contain nucleus of ovoid type. And its free surface has many microridge which covered with glycocalyx. Intermediated cell is ovoid and has a nucleus of round shape. Basal cell is columnar, and nucleus is situated in the upper cytoplasm. Gland cells are classified into mucous cell and club cell. By the histochemical studies of the epidermal secretions the mucous materials react on blue in ABPAS (pH 2.5). Club cell is observed numerous vacuoles and microfilaments in the cytoplasm. The cytoplasm of chloride cells are occupied with numerous mitochondria. Pigment cells are classified into two type. The one contain pigment granules of electron dense, and the other contain reflecting platelets.