• Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.249-255
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• 2015

An 8 week feeding trial was conducted to evaluate whether methionine and cysteine would effectively spare taurine supplementation on growth performance in juvenile rock bream Oplegnathus fasciatus. Triplicate groups of 25 fish averaging $2.74{\pm}0.04g$ ($mean{\pm}SD$) were fed one of the experimental diets. Five experimental diets including a fish meal based control diet were prepared by adding sulfur amino acid at fixed level of 1.0% and taurine at graded levels of 0%, 0.25%, 0.5% and 1.0% ($S+Tau_0$, $S+Tau_{0.25}$, $S+Tau_{0.5}$ and $S+Tau_{1.0}$, respectively). After the feeding trial, growth performance of fish fed the $S+Tau_{0.25}$, $S+Tau_{0.5}$ and $S+Tau_{1.0}$ diets were significantly higher (P < 0.05) than those of fish fed the Control diet. ANOVA test suggested that when sulfur amino acid were supplemented to the diets, the optimum taurine supplementation level could be 0.25% in the diet, and broken line analysis of weight gain indicated a level of 0.33%, for positive effects on growth and feed utilization. Fish whole-body protein content and taurine concentration steadily increased with the increase of dietary level in the presence of sulfur amino acid in the diets. On the other hand, whole-body lipid content significantly decreased with the incremental levels of dietary taurine. In conclusion, the results of the present study clearly indicated that dietary supplementation of methionine and cysteine at a level of 1% could spare 0.25 to 0.33% of taurine in juvenile O. fasciatus diets.

• Journal of Environmental Analysis, Health and Toxicology
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• v.21 no.4
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• pp.252-263
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• 2018

Distributions of 15 PAHs and 82 PCBs were investigated in sediment and fish samples collected from the Suyoung Estuary of Busan, one of the most urbanized and newly contaminated areas in Busan. The concentrations of $S_{15}PAH$ in sediments ranged from 17.9 to 777 ng/g-dry and were mainly originated from combustion processes. The concentrations of $S_{82}PCB$ in sediments ranged from 0.55 to 12.5 ng/g-dry and were significantly correlated with those of 12 dioxin-like PCBs and 6 non-dioxin like PCBs. Higher concentrations of PAHs and PCBs were found in the upper river and the inner Suyoung Bay than in marina and the outer Suyoung Bay. No sites exceeded the ecotoxicological values of PAHs and PCBs in marine sediments. Benzo[a]-pyrene was not detected in fish samples and the concentrations of $S_4PAH$ (0.15~0.45 ng/g-wet) were lower than the maximum level set by EU. The levels of PCBs in fish samples were at less than 1% of the Korean maximum level and 2% of the EU maximum level. The concentrations of dioxin-like PCBs were $0.01{\sim}0.32pg-TEQ_{WHO-2005}/g-wet$, and the highest concentration was found in eels, which were at less than 5% of the EU maximum level. Dietary intakes of PAHs and PCBs through fish consumption were estimated, and their lifetime cancer risk and non-cancer risk were much lower.

• Journal of Animal Science and Technology
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• v.52 no.4
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• pp.337-346
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• 2010

We report non-specific immune responses and disease resistance against Vibrio anguillarum, Streptococcus iniae and Edwardsiella tarda by dietary supplementation of fermented garlic powder (FGP) in olive flounder for the first time. Four isonitrogenous (45% crude protein) and isocaloric (17.1 MJ/kg) diets were formulated to have 0%, 0.5%, 1% and 2% of the FGP (G-0, G-0.5, G-1 and G-2). The experimental diets were fed to juvenile olive flounder averaging 23.4 g in triplicate groups (90 fish/group) in a flow-through system. After a five-week feeding trial, healthy fish with similar sizes from each tank were selected and injected with 1 ml of three bacteria each to evaluate disease resistance of the fish. During the 5-week feeding trial, the weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio, and survival of the fish were not significantly affected by the experimental diets. However, feed intake was significantly lower (P<0.05) in the fish fed the G-2 diet compared with the control group. Hemoglobin, myeloperoxidase activity, cholesterol and HDL-cholesterol were not different between the dietary groups. However, hematocrit, nitroblue tetrazolium (NBT) activity, and lysozyme activity were increased (P<0.05) with an increment of dietary FGP. Plasma triglyceride of the fish fed the G-0.5 diet was significantly lower than that of fish fed the control diet. The cumulative mortality was lower in the fish fed diets containing FGP compared with the control group in the challenge test except for the bacteria Edwardsiella tarda. The results in this study indicate that dietary supplementation of FGP can enhance the non-specific immune responses and disease resistance of olive flounder against V. anguillarum and S. iniae.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.99-110
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• 2022

We investigated physicochemical properties and isotopic compositions of organic matter (δ¹³C_TOC and δ ¹⁵N_TN) in the old fish farming (OFF) site after the cessation of aquaculture farming. Based on this approach, our objective is to determine the organic matter origin and their relative contributions preserved at sediments of fish farming. Temporal and spatial distribution of particulate and sinking organic matter(OFF sites: 2.0 to 3.3 mg L^-1 for particulate matter concentration, 18.8 to 246.6 g m^-2 day^-1 for sinking organic matter rate, control sites: 2.0 to 3.5 mg L^-1 for particulate matter concentration, 25.5 to 129.4 g m^-2 day^-1 for sinking organic matter rate) between both sites showed significant difference along seasonal precipitations. In contrast to variations of δ¹³C_TOC and δ¹⁵N_TN values at water columns, these isotopic compositions (OFF sites: -21.5‰ to -20.4‰ for δ¹³ C_TOC, 6.0‰ to 7.6‰ for δ¹⁵N_TN, control sites: -21.6‰ to -21.0‰ for δ¹³C_TOC, 6.6‰ to 8.0‰ for δ¹⁵N_TN) investigated at sediments have distinctive isotopic patterns(p<0.05) for seawater-derived nitrogen sources, indicating the increased input of aquaculture-derived sources (e.g., fish fecal). With respect to past fish farming activities, representative sources(e.g., fish fecal and algae) between both sites showed significant difference (p<0.05), confirming predominant contribution (55.9±4.6%) of fish fecal within OFF sites. Thus, our results may determine specific controlling factor for sustainable use of fish farming sites by estimating the discriminative contributions of organic matter between both sites.

• Ocean and Polar Research
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• v.30 no.4
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• pp.401-406
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• 2008

Early gonadal development and sexual differentiation of dark-banded rockfish (Sebastes inermis Cuvier) were followed from parturition to 400 days post parturition (dpp). During this period, average total length (TL) increased from 0.57 to 13.18 cm. Primordial germ cells (PGCs) were first detected at 0.68 cm TL (10 dpp). When fish reached 1.52 cm TL (50 dpp), initial stages of ovarian differentiation were identified by the presence of PGCs containing condensed chromatin and their transformation into meiotic oocytes. At 10.23 cm TL (300 dpp), the ovaries gradually developed into oocytes in the primary yolk stages. Ovary growth was rapid after sex differentiation, but testis tissue continued to multiply without growing until fish reached 6.97 cm TL (200 dpp), after which the production of spermatocytes, spermatogonia, and cyst cells was apparent. Histological analysis of gonadal structure suggested a gonochoristic sexual development pathway. Our analysis of the sex ratio at 400 dpp showed a significantly higher proportion of males.

• Journal of fish pathology
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• v.20 no.1
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• pp.93-98
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• 2007

The prevalence of the scuticociliatosis in flounder farms of Jeju island was surveyed for ten years from 1995 to 2004. The occurrence ratio had maintained as less than 10% until mid 1990s, and shown increasing trends to year 1998. The ratio was equivalent to over 40% of overall disease occurrences in flounder farms since year 2000. The monthly infection rates by the scuticociliates indicated relatively higher levels from May to September, and mixed infection phenomena with bacterial disease of vibriosis were common.

• Journal of fish pathology
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• v.25 no.1
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• pp.11-20
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• 2012

C-type lectins are crucial for pathogen recognition, innate immunity, and cell-cell interactions. In this study, a C-type lectin gene was cloned from the rock bream. The full-length RbCTL cDNA was 729 bp with a 429 bp ORF encoding a 164-residue protein. The deduced amino acid sequence of RbCTL had all of the conserved features crucial for its fundamental structure, including the four cysteine residues involved in sulfide bridge formation and potential $Ca^2+$/carbohydrate-binding sites. RbCTL contains a signal peptide one single carbohydrate recognition domain. It showed 29.4% similarity to the C-type lectin of rainbow trout. RbCTL mRNA was predominately expressed in gill and head-kidney tissue and expressed less in peripheral blood leukocytes, trunk-kidney, spleen, liver, intestine and muscle. Expression of RbCTL was differentially upregulated in rock bream stimulated with LPS, Con A/PMA and poly I:C.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.745-751
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• 2019

Seasonal variation in species composition of fishes in the Sannam reservoir in Changwon, Korea was determined using samples collected by a three-sided fyke net in 2018. During the study period, we collected 2,181 individuals of 9 species, with a total weight of 111,552.2 g. The dominant species were Lepomis macrochirus, Carassius carassius, Erythroculter erythropterus, and Cyprinus carpio. These species accounted for 96.1% of the total number of individuals. The number of fish species, number of individuals, biomass and species diversity indices fluctuated with the seasons. The peak number of fish species occurred in May and August, the biomass of fishes was highest in May. Whereas the number of individuals was highest in February.

• Journal of fish pathology
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• v.22 no.3
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• pp.343-352
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• 2009

Natural-killer-cell-enhancing factor (NKEF) belongs to the newly defined peroxiredoxin (Prx) family. It was originally isolated from human erythroid cells. The black rockfish NKEF cDNA was identified through the expressed sequence tag (EST) analysis of PBLs libraries. The full-length NKEF cDNA was 1433 bp long and contained an open reading frame (ORF) of 594 bp that encoded 198 amino-acid residues. The 5' UTR had a length of 39 bp, and the 3’UTR 800 bp. The deduced amino-acid sequence of the black rockfish had a density 93.4, 92.9, 87.8, 85.8, 84.8, 83.8, 80.3, 79.7, 77.2, and 75.2% that of the pufferfish, olive flounder, channel catfish, zebrafish, chicken, common carp, Myotis lucifugus, cattle, human PrxI, rat PrxI, human NKEF-A, and Xenopus tropicalis, respectively. The NKEF gene was expressed in all the tissues of the black rockfish. The RT-PCR indicated that the NKEF transcripts were predominantly in the spleen and gill, less dominantly in the PBLs, head kidney, trunk kidney, and liver, and least in the intestine and muscles. This is the first report on the existence of the NKEF-A gene in black rockfish.

• Journal of fish pathology
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• v.22 no.3
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• pp.353-366
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• 2009

We constructed a rock bream Oplegnathus fasciatus leukocyte cDNA library and a total of 795 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 795 EST clones, 491 different ESTs showed significant homology to previously described genes while 304 ESTs were unidentified, hypothetical, or unnamed proteins. Encoding 121 different sequences were identified as putative bio-defense genes or genes associated with immune response.