• Journal of fish pathology
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• v.28 no.3
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• pp.157-164
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• 2015

The effect of dietary carrot extract on skin pigmentation and non-specific immunity of red seabream was evaluated in a six-week feeding trial compared to that of astaxanthin. Fish were fed different experimental diets supplemented with three levels of carrot extract (30, 100, and 300 mg ${\beta}$-carotene/kg diet or CE30, CE100, and CE300), 100 mg astaxanthin/kg diet (AXT100), or a diet without supplement as control for 6 weeks. Our results revealed that the specific growth rate and feed conversion rate were not significantly (p>0.05) affected by carrot extract or astaxanthin supplementation for 6 weeks. After 3 weeks of feeding, the dietary carrot extract significantly (p<0.05) influenced the redness ($a^*$) and hue ($H^*{_{ab}}$) of fish skin. CE300 showed the highest $a^*$ and the lowest $H^*{_{ab}}$, suggesting that carrot extract increased the redness of skin color. However, after 6 weeks of feeding, dietary carrot extract significantly (p<0.05) increased the values of yellowness $b^*$ at all three levels. In contrast, AXT100 significantly (p<0.05) increased the values of $a^*$ but decreased the value of $H^*{_{ab}}$. Only CE300 significantly (p<0.05) increased the serum lysozyme activity. These findings suggest that dietary carrot extract can be utilized as a natural feed additive to improve skin pigmentation and health condition of fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.5
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• pp.269-275
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• 2007

The toxicity of two species of puffer fish, Takifugu pardalis and T. niphobles, collected from the coastal regions of Korea was determined using a mouse bioassay. In T. pardalis collected at Tongyeong, the proportion of toxic specimens containing ${\geq}10MU/g$ exceeded 90% for the skin, fins, liver, intestine, ovary, and gallbladder, 11.1% for the testis, and 6.9% for the muscle. In each of the organs, the highest toxin levels were several tens (14-39) of mouse units (MU) per gram in the muscle, testis, and eyeball, but thousands (1,444-5,755) of MU per gram in the skin, liver, intestine, ovary, and gallbladder. The organs of T. pardalis exhibited remarkable variation in toxicity. In T. niphobles, the proportion of toxic specimens exceeded 90% for the ovary and skin, 60-80% for the fins, liver, intestine, and gallbladder, and 4.5% for the muscle; no toxicity was detected in the testis or eyeball using the mouse bioassay. The highest toxin levels were thousands (2,291-7,777) of MU per gram in the liver, intestine, ovary, and gallbladder, hundreds(146-328) of MU per gram in the skin and fins, and 18 MU/g in the muscle. Takifugu niphobles toxicity also exhibited remarkable regional variation. The toxicity in the edible muscle of T. pardalis and T. niphobles was at acceptable levels for human consumption, while the toxicity of the skin of both species of puffer fish was very high, so that care must be taken when used for human consumption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.5
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• pp.309-314
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• 2008

The toxicity of five species of puffer fish, Arothron firmamentum (Byeolbok), Lagocephalus gloveri (Heukmilbok), L. wheeleri (Eunmilbok), L. inermis (Minmilbok) and L. lunaris (Milbok), collected from fish markets in Korea, was determined using a mouse bioassay. In A. firmamentum, the proportion of toxic specimens containing >10 MU/g was 87.5% in the ovaries, and 10.0% in the skin; no toxicity was detected in the muscle, fin, liver, intestine and gallbladder using the mouse bioassay. The highest toxin levels were found to be 87 MU/g in the ovaries, and 13 MU/g in the skin. Toxic specimens containing >10 MU/g were not detected from samples taken from any of the organs in L. wheeleri and L. inermis. In L. gloveri, most specimens were found to be non-toxic, but toxin levels of 11-72 MU/g were detected from within the skin, fins, and intestines in one specimen. In L. lunaris, the proportion of toxic specimens was 50.0% in the ovaries, and 7.1% in the gallbladder; no toxicity was detected in the other organs by the mouse bioassay. The highest toxin levels were 75 MU/g in the ovaries, and 14 MU/g in the gallbladder. Therefore, the toxicities of edible muscle and skin in the five species of puffer fish marketed in Korea were found to be within acceptable levels for human consumption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.3
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• pp.175-178
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• 2004

We here report that the muscle of 'gukmeri-bok' puffer fish (Takifugu vermicularis radiatus) is intoxicated after freezing and thawing processes even though it is not toxic when it is fresh. This study was carried out to investigate the effect of different freezing and thawing conditions as well as the effect of the presence of skin or viscera on the intoxication of muscle of 'gukmeri-bok' puffer during freezing and thawing process. As a result of this investigation, thawing condition, but not freezing conditions or periods played an important role in muscle intoxication. Tetrodotoxin secretory grands exist in the skin of toxic puffer fish, the skin was more responsible for the muscles intoxication than the viscera during the freezing-thawing process. In other words, no toxicity was measured in the muscle of skinned-frozen specimens even when thawed. According to this result, it is recommended that the skin and viscera must be removed before being frozen for edible purpose. Otherwise, when a whole fish should be frozen, alternative half-thawing and removal of skin from frozen specimens is recommended.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.231-235
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• 2006

The objectives of this study were to investigate the effects of dietary fish oil inclusion on the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contents and organoleptic characteristics of breast meat in mule ducks. Three hundred mule ducks at four weeks of age were randomly assigned to three dietary treatments with five replicate pens in each. One replicate pen had ten males and females each with a total of 100 ducks in each treatment. The diet in the three treatments contained 0, 1.5, and 3.0% fish oil, respectively. Body weights at 4, 6, 8, and 10 weeks of age, and feed efficiency at 4 to 6, 6 to 8, and 8 to 10 weeks of age were recorded. At 10 weeks of age, one male and one female from each replicate were sacrificed for oxidative stability of breast meat and the sacrificed males were employed for the analysis of fatty acids in breast meat and skin. Sensory evaluation of breast meat was also performed. A level of 3.0% fish oil in the diet significantly deteriorated feed efficiency and body weight gain. Dietary fish oil inclusion had a trend of increasing abdominal fat deposition and decreasing the flavor of breast meat. The EPA and DHA contents in the breast meat were higher than those in the breast skin irrespective of oil sources. The EPA and DHA contents in breast meat and breast skin was significantly increased in the 3.0% fish oil group. Although EPA and DHA were not efficiently deposited in the duck meat through dietary fish oil inclusion, this method can still provide a partial supplementation of EPA and DHA.

• Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.233-239
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• 2012

Hematological analysis can provide crucial information for monitoring the health of fish. However, there is no current information available regarding hematological changes in olive flounder following infection by Vibrio scophthalmi. In this study, hematological and biochemical alterations were determined in olive flounder infected by the high virulence strain (HVS) and low virulence strain (LVS) of V. scophthalmi. Survival in serum, skin mucus, and macrophages of olive flounder was also compared between the HVS and LVS. The results demonstrated that the hematocrit value in infected fish declined from 23.4% at 0 h to 18.0% at 168 h post infection. The total protein concentration in fish infected with the HVS was significantly higher than in fish infected with the LVS and a non-infected control. Lysozyme activity was significantly different between infected and control fish. The HVS survived in serum and cell numbers increased substantially, while cell numbers of the LVS in serum decreased. These changes in hematological characteristics in fish infected by V. scophthalmi can be used as an effective and sensitive index to monitor the physiological and pathological conditions of fish. The survival and reproduction of V. scophthalmi in host serum, skin mucus, and macrophages play a major role in systemic infection and can serve as a virulence indicator for different strains.

• Applied Biological Chemistry
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• v.37 no.2
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• pp.85-93
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• 1994

The fish skin gelatin hydrolysates were produced using a continuous two-stage membrane (MWCO 10,000, MWCO 5,000) reactor, and molecular weights, amino acids and functional properties of the hydrolysates were investigated. The major molecular weights distribution of the major fractions were $8{\sim}10\;KDa$ and $4.5{\sim}6.5\;KDa$ in the 1st-step hydrolysates, $2{\sim}6\;KDa$ and $0.5{\sim}2\;KDa$ in the 2nd-step hydrolysates. Among the amino acids in the hydrolysates, glycine, proline, serine, alanine, hydroxyproline, glutamic acid and aspartic acid having sweet taste were responsible for $68{\sim}72%$ of the total amino acids. But valine, methionine, isoleucine, leucine, phenylalanine and histidine having a bitter taste were only $23{\sim}25%$ Taste evaluations show that the gelatin hydrolysates have a brothy and sweet taste, 2nd-step hydrolysate have more a favorable taste than 1st-step hydrolysate. The hydrolysates were completely soluble and clear over the entire pH range. Moisture sorption at intermediate water activities of the 2nd-step hydrolysate was much higher than the unmodified fish skin gelatin, but foaming and emulsification properties were poor. Buffer capacity of the 2nd-step hydrolysate was higher than the fish skin gelatin and 1st-step hydrolysate, while viscosities of the hydrolysates were lower than the fish skin gelatin.

• Journal of fish pathology
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• v.18 no.1
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• pp.1-18
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• 2005

This study was performed to investigate the myxosporidian parasites from several organs of freshwater fishes caught from Dongjin River, Jeonbuk Province of Korea. Twelve myxosporidian species were dectected from five fish species out of sixteen fish species. From the gall bladder of Opsariichthys uncirostris amurensis, Zschokkella opiocephali was found; from the skin, gall bladder, liver and spleen of Pseudobagrus fulvidraco, Zschokkella opiocephali and Myxobolus cheisini were found; from the gill, skin, gall bladder and kidney of Carassius carassius, Zschokkella ctenopharyngodonis, Chloromyxum koi, Sphaerospora sinensis, Myxosoma abbottinae, Myxobolus koi and Myxobolus suturalis were found; from the kindney of Misgumus anguillicaudatus, Myxidium lieberkuhni, Neomyxobolus ophicephali and Telohanellus misgurni were found; from the gill of Cyprinus carpio, Myxosoma abbottinae and Myxobolus dispar were found. All these parasitized fishes didn't show any specific symptom.

• Journal of fish pathology
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• v.35 no.1
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• pp.135-140
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• 2022

In this study, we determined the cause of a disease outbreak in small yellow croaker(Larimichthys polyactis) in Jeju island. The major external signs in the dead fish were hemorrhage of the skin. Vibrio harveyi were isolated from a few fishes and viruses were not detected from the diseased fish. However, flukes were confirmed on the skin and we conducted molecular identification and phylogenetic analysis of the isolated parasites. The obtained 28S rRNA sequence of our specimen(Accession No. OM333244) showed the highest homology with Neobenedenia girellae, while the COI sequence of our specimen showed the highest homology with N. melleni. Further sequence analysis with other genes and morphological observation are necessary for accurate identification.

• Journal of Aquaculture
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• v.22 no.1
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• pp.100-104
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• 2009

This study was conducted to evaluate the effect of dietary supplementation of paprika powder as carotenoid source with three different zooplankton on carotenoid deposition and skin pigmentation of rose bitterling Rhodeus ocellatus. Two replicate groups of fish (initial average weight 0.8 g) were fed the five experimental diets containing 5% paprika (P5) and mixture of 5% paprika with 3% three zooplankton of water flea Moina macrocopa (P5M3), Artemia nauplius Artemia sp. (P5A3) and rotifer Brachionus plicatilis (P5R3) and without supplementation of carotenoid source (Con) for 10 weeks. Survival of fish among the treatments was not affected by dietary supplementation. Total carotenoid contents of whole body in fish fed the diets containing 3% zooplankton was higher than that of fish fed other diets. Especially, the highest total carotenoid contents of whole body was observed in fish fed the P5A3 diet. Similarity, Lightness, $a^*$ and $b^*$ values of the fish fed the diets containing 3% zooplankton tended to be higher than that in fish fed control and P5 diets. The apparent color intensity of skin and fin in fish fed the diets containing paprika with Artemia nauplius and rotifer was better than those of fish fed other diets. The results of this study suggest that dietary supplementation of paprika with Artemia nauplius and rotifer can improve skin pigmentation of rose bitterling.