• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.395-398
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• 2009

This study was conducted to investigate the effects of supplemental medicinal herb mixture, laver powder and paprika powder in extruded pellet (EP) on growth and feed utilization of juvenile olive flounder. Triplicate groups of fish (average body weight of 19.6 g) were fed four experimental EPs containing 0.2% medicinal herb mixture (MHM), 1% laver powder (LP), 1% paprika powder (PP) and without supplementation (CON) for 9 weeks. Weight gain, daily feed intake, hepatosomatic index and condition factor were not influenced by dietary additives. Peed efficiency and protein efficiency ratio of flounder fed the diet containing laver powder were significantly higher than those of fish fed the medicinal herb mixture and paprika powder (P<0.05), but not significantly different from control group. The results of this study suggest that all tested additives in the dietary formulation did not affect growth and feed utilization of olive flounder.

• BMB Reports
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• v.39 no.6
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• pp.686-695
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• 2006

Interleukin-2 enhancer binding factor 2 (ILF2) was reported to regulate transcription of interleukin-2 (IL-2), a central cytokine in the regulation of T-cell responses. This property of ILF2 was well characterized in human and mammals, but little is known in bony fish. In this paper, an ILF2 homologue was cloned and well characterized from Tetraodon nigrovirid is for the further investigation of the function of ILF2 in bony fish. The full-length Tetraodon ILF2 cDNA was 1380 bp in size and contained an open reading frame (ORF) of 1164 bp that translates into a 387 amino-acid peptide with a molecular weight of 42.9 kDa, a 5' untranslated region (UTR) of 57 bp, and a 3' UTR of 159 bp containing a poly A tail. The deduced peptide of Tetraodon ILF2 shared an overall identity of 58%~93% with other known ILF2 sequences, and contained two N-glycosylation sites, two N-myristoylation sites, one RGD cell attachment sequence, six protein kinase C phosphorylation sites, one amino-terminal RGG-rich single-stranded RNA-binding domain, and a DZF zinc-finger nucleic acid binding domain, most of which were highly conserved through species compared. Constitutive expression of Tetraodon ILF2 was observed in all tissues examined, including gill, gut, head kidney, spleen, liver, brain and heart. The highest expression was detected in heart, followed by liver, head kidney and brain. Stimulation with LPS did not significantly alter the expression of Tetraodon ILF2. Gene organization analysis showed that the Tetraodon ILF2 gene have fifteen exons, one more than other known ILF2 genes in human and mouse. Genes up- and down-stream from the Tetraodon ILF2 were Rpa12, Peroxin-11b, Smad4, Snapap and Txnip homologue, which were different from that in human and mouse.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.1
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• pp.44-50
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• 2015

The basic and main nutritive ingredients of two temperature (Anguilla japonica and A. rostrata) and two tropical (A. bicolor pacifica and A. marmorata) fresh water eel species that are farmed domestically were evaluated. With exception of A. rostrata, eels cultured at the same farm were used for analysis. The contents of crude protein were in the order A. marmorata (17.7%)>A. rostrata (17.5%)>A. bicolor pacifica (17.4%)>A. japonica (15.8%) and the contents of crude lipids were A. japonica (21.5%)>A. rostrata (15.4%)>A. bicolor pacifica (10.5%)>A. marmorata (8.9%). These values differed significantly even among the three species of eel farmed under identical culture conditions. In comparison, all four species of eel showed similar pattern in overall amino acid composition, although slight differences in the compositions of some amino acids were observed. The fatty acid compositions of muscle tissues were notably different among four species of eel, especially between the tropical and temperature eels. In a taste-test of the meat of the four eel species, which considered taste, flavor and texture, the overall preference was in the order A. japonica, A. marmorata, A. bicolor pacifica and A. rostrata.

• Fisheries and Aquatic Sciences
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• v.10 no.3
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• pp.113-118
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• 2007

Bromophenols are a group of compounds found only in marine organisms. They accumulate and give a sea-like aroma to marine animals. Cultivated fishes generally contain low concentrations of bromophenols compared to wild fishes. Feeding cultivated fishes with bromophenol-containing seaweed could increase their bromophenol content and thus improve their flavor quality. We evaluated the effect of an experimental feed on the bromophenol content of green grouper, Epinephelus coioides, during an 8-week feeding period. Green grouper individuals were divided into two groups and fed with conventional feed or experimental feed containing dried seaweed. Fish were collected biweekly for 8 weeks for proximate analyses and bromophenol content evaluations. Bromophenols were extracted, identified, and quantified by gas chromatography-mass spectrometry. Both moisture and lipid contents were generally higher in the controls; however, total weight and protein content were higher in the experimental group. Only 2,4-dibromophenol and 2,4,6-tribromophenol were detected in the samples. Throughout the 8 weeks, 2,4,6-tribromophenol concentrations were higher in the experimental group (9.20-32.3 ng/g dry wt) than in the control group (7.33-18.79 ng/g dry wt), but no significant difference in 2,4-dibromophenol concentration was detected between the two groups. The total bromophenol content reached a maximum at week 4 for the experimental feed and week 6 for the control. In short, experimental feed that incorporated bromophenol-containing seaweed increased the total bromophenol content in the green grouper.

• Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.183-193
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• 2015

Several transgenic marine medaka Oryzias dancena strains harboring a green fluorescent protein (GFP) reporter construct regulated by an endogenous ${\beta}$-actin promoter were established and their expression characteristics in relation to transgene copy numbers were examined in 21 transgene genotypes. Most of the transgenic strains displayed transgene insertion patterns typical of microinjection-mediated introduction of foreign DNA into fish embryos, characterized by the random integration of multiple transgene copies (ranging from 1 - 282 copies per cell), often accompanied by the formation of concatemer(s), as assessed by genomic Southern blot hybridization analysis and qPCR. Transgenic strains showed ubiquitous and continued temporal and spatial expression patterns of the transgenic GFP during most of their life cycle, from the embryonic stage to adulthood, enabling assessment of the expression pattern of the endogenous ${\beta}$-actin gene. However, a comparative evaluation of transgene copy numbers and expression levels showed that copy number-dependent expression, the stability of the ubiquitous distribution and expression efficiency per transgene copy varied among the transgenic strains. Fluorescence expression levels were positively correlated with absolute transgene copy numbers, whereas the expression efficiency per transgene copy was inversely related to the number of transgene integrant copies. Data from this study will guide the selection of potentially desirable transgenic strains with ubiquitous expression of a fluorescent transgene, not only in this marine medaka species but also in other related model fish species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.581-588
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• 2010

To examine the functional properties of conjugated linoleic acid (CLA) and ascidian tunic extracts in fish, we compared mackerel fed ascidian tunic extract and CLA (CA25) and a control group. The daily growth index of CA25 was 1.92 compared to 1.86 in the control group. The viscerosomatic index of CA25 was 36.7% lower than that of the control group. After 8 weeks, the protein content decreased from 19.7 to 17.5% in the CA25 group. The ascidian tunic extract content in the viscera was much higher than in muscle (0.13 vs. 0.03 mg/100 g) after 8 weeks. At the start, the n-3 fatty acid content of the experimental fish was 25.2% in muscle and 23.7% in viscera. The CLA content in muscle in the CA25 group was 2.1% after 4 weeks and 2.3% after 8 weeks. By contrast, the CLA content in viscera did not change after 8 weeks.

• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.224-230
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• 2010

Growth hormone (GH) is known as one of the main osmoregulators in euryhaline teleosts during seawater (SW) adaptation. Many of the physiological actions of GH are mediated through insulin-like growth factor-I (IGF-I), and the GH/IGF-I axis is associated with osmoregulation of fish during SW acclimation. However, little information is available on the response of fish IGF-II to hyperosmotic stress. Here we present the first cloned IGF-I and IGF-II cDNAs of marine medaka, Oryzias dancena, and an analysis of the molecular characteristics of the genes. The marine medaka IGF-I cDNA is 1,340 bp long with a 257-bp 5' untranslated region (UTR), a 528 bp 3' UTR, and a 555-bp open reading frame (ORF) encoding a propeptide of 184 amino acid (aa) residues. The full-length marine medaka IGF-II cDNA consists of a 639 bp ORF encoding 212 aa, a 109 bp 5' UTR, and a 416 bp 3' UTR. Homology comparison of the deduced aa sequences with other IGF-Is and IGF-IIs showed that these genes in marine medaka shared high structural homology with orthologs from other teleost as well as mammalian species, suggesting high conservation of IGFs throughout vertebrates. The IGF-I mRNA level increased following transfer of marine medaka from freshwater (FW) to SW, and the expression level was higher than that of the control group, which was maintained in FW. This significantly elevated IGF-I level was maintained throughout the experiment (14 days), suggesting that in marine medaka, IGF-I is deeply involved in the adaptation to abrupt salinity change. In contrast to IGF-I, the increased level of marine medaka IGF-II mRNA was only maintained for a short period, and quickly returned a level similar to that of the control group, suggesting that marine medaka IGF-II might be a gene that responds to acute stress or one that produces a supplemental protein to assist with the osmoregulatory function of IGF-I during an early phase of salinity change.

• Journal of fish pathology
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• v.18 no.3
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• pp.205-214
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• 2005

The isolates, which has caused considerable damage to the olive flounder farm located in the eastern coast of Korea showed 99% sequence homology in the comparison of 16s rRNA gene of P. damselae subsp. damselae ATCC 33539. The present P. damselae was identical to the biotype No.8 in Pedersen et al. (1997) and the same LPS protein pattern as P. damselac subsp. damselae ATCC 33539. The comparison of infection rates among present P. damselae and Vibrio spp. showed that isolated P. damselae was the highest, followed by V. anguillarium, V. harveyi. and V. ordalii.

• Journal of fish pathology
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• v.21 no.1
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• pp.1-11
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• 2008

We report the existence of new type of phosphatidylcholine-hydrolyzing phospholipase D (PLD), which has been characterized and partially purified in the scuticociliate, Uronema marinum. The enzyme from partial purification showed that it was existed in membrane fraction and was a neutral PLD, which catalyzed both transphosphatidylation and hydrolysis reaction. The activity of partially purified membrane-bound PLD was also found to be optimal at pH 7.0-7.5 for 2 hours at 37℃ and depended strictly on the presence of Ca2+ (2.5 mM) and Mg2+ (1.6 mM). Immunoblot analysis indicated that the enzyme was distinct from hPLD1 (human PLD1) and hPLD2 (human PLD2) because it was not recognized by a polyclonal antibody raised to the 12 terminal amino acid of these enzymes. We also found that the membrane-bound PLD is a PIP2-dependent PLD and that GTP-binding proteins are not implicated in the regulation of this enzyme: This enzyme activity is markedly stimulated by phosphatidylinositol 4,5-bisphosphate (PIP2) but not by the small G-protein Arf and GTPrS. In addition, this enzyme was capable of hydrolyzing phosphatidylcholine (PC) but not phosphatidylethanolamine (PE), implying that PC was a preferred substrate.

• Journal of fish pathology
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• v.21 no.3
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• pp.201-208
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• 2008

We compared the pathogenicity and antigenicity of two different Edwardsiella tarda (E. tarda) strains KFE and Edk-2 isolated in Korea and Japan respectively. In the pathogenicity analysis with challenge test against loach, E. tarda KFE isolate showed stronger pathogenicity compared to that of E. tarda Edk-2 isolate. The differences were also confirmed by the comparison of OMP (outer membrane protein) in SDSPAGE which showed three major bands, 41kDa, 37kDa and 30kDa, for E. tarda KFE isolates and two major bands, 41kDa and 30kDa, for E. tarda Edk-2 isolates. On the base of these results, we tried to determine the differences of antigenicities of these two isolates in loach which is one of the important species in freshwater aquaculture in Korea. Numbers of specific antibody secreting cells (SASC), appeared to be higher in loach immunized with FKC of E. tarda Edk-2 than loach immunized with FKC of E. tarda KFE. ELISPOT-assay for the comparison of antigenicity showed relatively high percentage of cross-reaction and implied the presence of some common epitopes in the antigens of these two E. tarda isolates.