• Korean Journal of Veterinary Service
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• v.16 no.2
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• pp.103-110
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• 1993

The Aeromonas strains were isolated from diseased cultured catfsh (Silurus asotus) in the ponds near by Gochang of Chunbuk. The present isolates were identified as A. hydrophila based on their biological and biochemica1 characteristics. The isolates of A. hydrophila were named GC-1, GC-2, GC-3, GC-4 and GC-5, Five strains were grew optimally at temperatures $35^{\circ}C,$ pH 7.5 and in 0.5 to l% NaCl. This bacterium(GC-1) was injected into health catfish in order to prove the causative agent of ascites and haemorrhagic ulcers. The symptoms in cat fish infected by this challenge method were observed to be very similar to the symptoms of a natural infection, but controls did not show any abnormal symptoms during the experimental period. At 24 post-injection, the red spot developed around the injection site and the haemorrhagic ulcers was extended near the gill and ventral fin. Five strains were tested for drug sensitivity by plate method. All strains were sensitivity to gentamicin and resistant to penicillin, streptomycin and tetracycline.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.349-353
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• 2009

Two feeding trials were conducted to evaluate the soybean meal as a substitute for the fish meal in diet (experiment I), and experimental practical diet and commercial diet (experiment II) for growth of far eastern catfish. In the experiment I, three replicate groups of juveniles (average weight 7.2 g) were fed one of diets containing 0, 10 and 20% soybean meals for 66 days. Survival and final mean weight were not significantly affected by dietary soybean meal levels. No significant differences were observed in feed efficiency, protein efficiency ratio and protein retention of fish fed between 0% (control diet) and 20% soybean meal diets. However, fish fed 10% soybean meal diet showed the lower feed efficiency, protein efficiency ratio and protein retention, and higher daily feed intake compared with fish fed control diet and 20% soybean meal diet. The contents of moisture, crude protein, crude lipid and ash in the whole body were not significantly affected by dietary soybean meal levels. In the experiment II, three replicate groups of juveniles (average weight 7.3 g) were fed either the formulated diet or commercial diet for 66 days. Survival and final mean weight were not significantly different among treatment. Significantly higher feed efficiency, protein efficiency ratio and protein retention, and lower daily feed intake were observed in fish fed experimental practical diet compared with fish fed commercial diet (P<0.05). Proximate compositions of the whole body were not significantly affected by diets. The results of these studies suggest that soybean meal can be used as a substitute for fish meal up to 20% in diet, and the dietary formulation used in the experiment II could be applied to the practical feed for far eastern catfish.

• Toxicological Research
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• v.35 no.3
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• pp.249-255
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• 2019

Cadmium is a strong toxic heavy metal which presents in paints and liquid wastes and causes oxidative stress in fish. On the other hand, lead is widely used for different purposes, e.g. lead pipes, it targets vital organs such as liver and kidney causing biochemical alterations. The present study evaluates the effects of 60 days exposure to Cd and Pb either single or combined together in African catfish. Sixty-four fishes were divided into 3 groups and exposed to $CdCl_2$ (7.02 mg/L) or $PbCl_2$ (69.3 mg/L) or a combination of them along with control group. Activities of acid phosphatase (ACP), lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) were estimated. Moreover, gill, liver and kidney were assayed for activities of superoxide dismutase (SOD), catalase (CAT) and levels of glutathione (GSH) and malondialdehyde (MDA). Individual exposure showed that both Cd and Pb significantly decreased LDH activity and SOD activity in the kidney. Pb significantly increased G-6-PDH activity and decreased GSH level in the gill. CAT activity in liver and kidney elevated significantly on Cd exposure while lead caused a significant depletion in the liver and significant elevation in the kidney. Both Cd and Pb significantly increased MDA levels in liver and kidney while Pb increased its level in gills. The combined exposure resulted in normalization of LDH, G-6-PDH activity, and CAT activity in liver and kidney as well as GSH level in both tissues and MDA in gill and kidney. The combination increased SOD activity and MDA level in liver and decreased SOD activity in kidney and GSH level in gills. In conclusion, the antioxidant system of African catfish was adversely affected by prolonged exposure to Cd and Pb. The combined exposure caused less damage than individual exposure and returned most parameters to those of controls.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.598-602
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• 2008

Concentrated catfish Silurus asotus bile (SAB) containing high amounts of ursodeoxycholic acid (UDCA) and taurocholic acid may have immunosuppressive properties. To investigate the putative immunosuppressive properties of SAB, the anti-proliferation and suppression of early T cell activation markers, and the inhibition of cytokines induced by T cells in response to anti-CD3 mAb activation in mouse splenocytes were examined. The suppression of these activation repertoires are the main properties of calcineurin inhibitors. It was found that SAB effectively suppressed the activation of T cells, and cytokines from T cell activation, at levels similar to cyclosporine A, a calcineurin inhibitor. Although the mechanism in which suppression occurs is not clear, we speculate that SAB from Silurus asotus, which has been known to switch their intake habits to zoophagy during an early adult stage, may explain the suppressive effect of SAB as a result of high amounts of functional UDCA in bile. Our results suggest that the treatment or intake of SAB, either in therapy or as a food supplement, may act as an adjuvant therapy for the prevention of transplant rejection, although further investigation is required before this treatment can be applied clinically.

• Fisheries and Aquatic Sciences
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• v.7 no.3
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• pp.109-114
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• 2004

To evaluate the impact of parathion on aquatic organisms, a freshwater bagrid catfish (Pseudobagrus fulvidraco) was exposed to sublethal concentrations $(63,\;95,\;190\;and\;380\;{\mu}g/L)$ of parathion, organophosphorus pesticide for 30 days. Glucose level in the serum of the bagrid catfish was significantly increased than that of control groups in the $190\;{\mu}g/L$ concentration at 30 days and in the $380\;{\mu}g/L$ concentration after 10 days. Bilirubin level was significantly increased in the $190\;{\mu}g/L$ concentration at the end of the experiment. After 10 days, a significant differences of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) activity increased in the ${\geq}190\;{\mu}g/L$ and $380\;{\mu}g/L$ groups. Though cholesterol concentration was stable, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in serum were significantly reduced in the $190\;{\mu}g/L$ at 10 days and in the $380\;{\mu}g/L$ concentration at the end of the experiment. In conclusion, if P. fulvidraco was chronically exposed to ${\geq}190\;{\mu}g/L$ concentration of parathion, the hematological changes may be induced due to the stress response.

• Journal of Aquaculture
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• v.9 no.3
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• pp.205-213
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• 1996

Experiments were carried out to investigate the effect of GnRH-analogue (GnRH-a) on the induction of ovulation in catfish, S. asotus. Fully matured female catfish ($250\~600\;g$) received a single intraperitoneal injection of GnRH-a ($50\~200\;{\mu}g/kg{\cdot}body$ weight) showed the successful induction of ovulation. More than $86\%$ of treated females were ovulated after injection of GnRH-a ($90\;{\mu}g/kg$) at $25{\pm}1^{\circ}C$. The majority of spawning took place within 22 to 25 hours after the injection. The gonadosomatic index (GSI) and pseudo-GSI in the group treated with $120\;{\mu}g/kg$ GnRH-a were $23-30\%$ and $18-21\%$, respectively. Average fertilization and hatching rates were $94\%\;and\;81\%$, respectively. Electron microscopically, gonadotrophs of maturing female catfish were characterized by the presence of numerous small, electron-dense granules of approximately $150\~300$ nm in diameter and a few larger, less electron-dense granules of approximately $800\~1000$ nm in size in their cytoplasm. Gonadotrophs of GnRH-a treated catfish showed that their was a distinct decrease in number of small and large granules. The rough endoplasmic reticulum was composed of numerous cisternae conspicuosly dilated to various degrees.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1364-1368
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• 2015

This study was performed to evaluate mineral contents of catfish Silurus asotus. As a result of mineral content, the mean content of the macro mineral was (in descending order): K (310.36-412.66 mg/100 g), P (186.42-223.02 mg/100 g), Na (35.32-57.87 mg/100 g), Mg (22.88-31.87 mg/100 g), Ca (9.05-13.07 mg/100 g). In comparison, the mean content of the micro mineral was (in descending order): Fe (0.26-0.95 mg/100 g), Zn (0.26-1.02 mg/100 g), Cu (ND-0.08 mg/100 g), Mn (0.01-0.03 mg/100 g). A proportion of mineral intakes with the dietary reference intakes for Koreans (KDRIs) set by the Korean Nutrition Society. Nutrient uptake proportion of mineral intakes was (in descending order): P (62.16%), K (20.71%), Mg (16.82%), Fe (13.02%), Zn (11.38%) Cu (10.94%), Na (6.59%), Ca (3.09%), Mn (0.96%). The mineral content was compared with the major protein food sources according to the Korea Health Statistics (2013) such as polished rice, pork, chicken, beef, eggs and milk. The calcium content contains; lower level of milk and eggs, chicken whereas higher levels of rice, pork and beef. Catfish has less iron content than major protein food source. Phosphorus and potassium contain higher level of major protein food sources.

• Journal of the Korean Applied Science and Technology
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• v.26 no.1
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• pp.1-9
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• 2009

Nowadays, Tra catfish fat is given attention as an appropriate material for biodiesel production in Vietnam. The aim of this work is to investigate the optimal conditions of refining biodiesel and recovering glycerin by the transesterification from Tra catfish fat using KOH catalyst. As our results, the yield of transesterification was achieved to 94.17% at $50^{\circ}C$ for 45 min with 6:1 molar ratio of methanol to fat in the presence of 0.8% KOH catalyst, and wherein the biodiesel was refined by washing with distilled water at $70^{\circ}C$ and dried in a microwave oven. The yield of raw glycerin recoveries from the transesterification process was 78.58%. The purity of raw glycerin was 84.14% by the conditions of neutralization state with $H_{3}PO_{4}$ solution (pH = 5), $70^{\circ}C$, and 60 min. Activated carbon (3.0 wt.%) was used for the bleaching process at $80^{\circ}C$ for 20 min. The biodiesel was obtained in accordance with for ASTM D 6751 (biodiesel standard). The ash and water of raw glycerins were 7.32 and 8.01%, respectively, and implied that the raw glycerin is very promising candidate to be used as a raw material for textile and cosmetic industries.

• Korean Journal of Ichthyology
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• v.20 no.2
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• pp.81-89
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• 2008

An experiment was conducted for 80 days to determine the effect of feeding and starvation on the survival, growth, gonad-somatic index (GSI), hepato-somatic index (HSI), viscera index (LSI), the morphometric changes and hematological parameter in a cultured catfish, Silurus asotus. The survival and growth of the starved group was lower than those of the fed group during the experiment. Starvation resulted in retardation of growth, which provides examples of the reduction of final body weight, growth rate of body weight, specific growth rate and condition factor, whereas the fed group continued to grow and remained in good condition. Blood analysis (cortisol, glucose, aspartate aminotransferase, alanine aminotransferase, red blood cell and hemoglobin) showed significant differences between the fed and starved groups at the end of the experiment. These results suggest that all nutritional parameters used for starvation and feeding in this study appear to be a useful index of nutritional status in the cultured catfish.

• Journal of Aquaculture
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• v.6 no.1
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• pp.47-53
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• 1993

Feeding trials were conducted for a test of the optimum dietary protein levels for the fingerling Korean catfish, Parasilurus asotus. The growth response was examined in terms of weight gain, feed coefficient. protein efficiency ratio and net protein utilization for 8 weeks at $23\~27^{\circ}C$. Within a range of 25 to 55\%$ crude protein levels in the diet, the body weight increased while the dietary protein level increased. Accumulation of protein in the body reached the maximum when the crude protein level in the diet was at $45\%$. These results indicate that the optimum dietary protein level of fingerling Korean catfish was about $45\%$ when anchovy meal was used as the protein source.