• Title/Summary/Keyword: Catfish

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Electrophysiological Analysis of GABA and Glycine Action on Neurons of the Catfish Retina

  • Bai, Sun-Ho;Jung, Chang-Sub;Lee, Sung-Jong
    • The Korean Journal of Physiology
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    • v.27 no.2
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    • pp.163-174
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    • 1993
  • Vertebrate retinal neurons, like brain tracts farm complex synaptic relations in the enter and inner plexiform layers which ape equivalent to the central nervous system nuclei. The effects of $\gamma-aminobutyric$ acid(GABA) and glycine on retinal neurons were explored to discern the mechanisms of action of neurotransmitters. Experiments were performed in the superfused retina-eyecup preparation of the channel catfish, Ictalurus punctatus, using intracellular electrophysiological techniques. The roles of GABA and glycine as inhibitory neurotransmitters are well established in the vertebrate retina. But, we found that the depolarizing action of GABA and glycine on third-order neurons in the catfish retina. GABA and glycine appeared to act on retinal ueurons based on the observations that (1) effects on photoreceptors were not observed, (2) horizontal cells were either hyperpolarized $({\sim}33%)$ or depolarized $({\sim}67%)$, (3) bipolar cells were all hyperpolarized (4) amacrine and ganglion cells were either hyperpolarized $({\sim}37%)$ or depolarized $({\sim}63%)$, (5) GABA and glycine may be working to suppress presynaptic inhibition. The results suggest that depolarization of third-order neurons by GABA and glycine is due to at least two mechanisms; a direct postsynaptic effect and an indirect effect. Therefore, in the catfish retina, a mechanism of presynaptic inhibition or disinhibition including the direct postsynaptic effect may exist in the third-order neurons.

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Edwardsiella ictaluri Infection in Cultured Yellow Catfish Pelteobagrus fulvidraco Fingerlings in Korea (양식 동자개(Pelteobagrus fulvidraco)의 Edwardsiella ictaluri 감염)

  • Kim, Jin Do;Park, Sung Woo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.48 no.5
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    • pp.725-730
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    • 2015
  • We observed yellow catfish Pelteobagrus fulvidraco fingerlings cultured in land ponds in Korea swimming in a corkscrew spiral pattern while hanging head-up and tail-down at the water surface, before eventually dying. Externally, these fish displayed “hole in the head” disease, pale gills, and hemorrhages in the base of the pectoral and caudal fins; internally they had liver hemorrhages and kidney discoloration. The bacterium Edwardsiella ictaluri (YCK-01 and YCL-01) was identified in the kidneys and livers of diseased fish via phenotypic characteristics and PCR analysis using the ictaluri-specific primers IVS (an intervening sequence) and IRS (the inter-ribosomal spacer). Infectivity challenges by intraperitoneal and immersion routes showed that a representative bacterial strain (YCK) exhibited strong virulence to yellow catfish, with an LD50 of 3.2×104 CFU/fish and 2.5×106 CFU/mL, respectively. This is the first report of E. ictaluri infection in yellow catfish from Korea.

Effects of Cryoprotectants and Diluents on the Cryopreservation of Spermatozoa from Far Eastern Catfish, Silurus asotus

  • Gil, Hyun Woo;Lee, Tae Ho;Park, In-Seok
    • Development and Reproduction
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    • v.21 no.1
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    • pp.79-91
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    • 2017
  • The aim of this study was to compare the efficacy of cryopreservation methods for ex situ conservation of spermatozoa from far eastern catfish, Silurus asotus. The spermatozoa activity index (SAI) and hatching rates were higher in spermatozoa stored in Alserver's solution than those of spermatozoa stored in glucose solution. The SAI and hatching rates in all experimental groups gradually decreased with increasing duration of storage. Additionally, the SAI and hatching rates gradually decreased with increasing thawing temperatures at all storage durations (P<0.05). Based on the SAI and hatching rates, our results suggest that the optimal cryopreservation conditions of catfish spermatozoa involve storage in Alserver's solution with 15% ethylene glycol, and thawing at $25^{\circ}C$. Cryopreservation of spermatozoa is a useful and reliable technique for conserving gene resources and for artificial propagation of far eastern catfish.

Epithelioma of farmed catfish Silurus asotus in Korea (국내산 메기, Silurus asotus의 상피종)

  • Yu, Jin-Ha;Park, Sung-Woo;Kim, Dong-Wan
    • Journal of fish pathology
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    • v.22 no.2
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    • pp.107-113
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    • 2009
  • Catfish Silurus asotus sampled from a pond farm in Korea, was affected with an epithelial tumor resembling catfish Ameiurus nrbulosus lip and mouth epithelioma. The neoplasm appeared in the form of solitary, multiple, large and fleshy masses upon the skin, fin or barbel. The epithelial tumor proliferation causes papillary folds supported by connective tissue cords. These folds extended above the normal skin surface and into the underlying dermis. In some area, proliferation of mucous cells or club cells were observed. The epithelial cells of the tumor were dispersed with no orderly arrangement. This is the first report on epithelioma of catfish in Korea.

Fish farm monitoring report for outdoor aquaculture of far eastern catfish Silurus asotus in Korea

  • Hyeongsu Kim;Jongsung Park;Bokki Choi
    • Fisheries and Aquatic Sciences
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    • v.26 no.11
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    • pp.660-668
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    • 2023
  • This study aimed to investigate the growth performance of far eastern catfish (Silurus asotus) on outdoor fish farms to obtain basic data for the domestic eastern catfish aquaculture industry. An outdoor fish farm was directly monitored from June 2018 to October 2019 to determine the farming conditions, growth performance, and water quality. The growth performance in 2017 was analyzed using data from the same fish farm. Three years of monitoring showed that the fish farm required approximately 5-6 months between stocking, harvesting, and selling an S. asotus batch. The growth parameters, namely, the weight gain rate (WGR), specific growth rate (SGR) for culture periods, SGR for feeding periods, and feed coefficient rate (FCR), were 4,664.7%, 1.27%, 2.43%, and 1.25 in 2017; 6,452.0%, 1.52%, 2.79%, and 1.42 in 2018; and 3,270.0%, 1.11%, 2.12%, and 1.38 in 2019, respectively. Moreover, the WGR was two-fold higher in 2018 than 2019, whereas the FCR was more effective in 2019 than 2018, presumably because of the stocking density. No mass mortality was observed during the water quality analysis. The results of this study provide basic data for the development of the catfish industry.

Newly Developed Microsatellite Markers of Mystus nemurus Tested for Cross-Species Amplification in Two Distantly Related Aquacultured Catfish Species

  • Chan, S.C.;Tan, S.G.;Siraj, S.S.;Yusoff, K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.11
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    • pp.1513-1518
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    • 2005
  • The work reported here is an attempt to explore the possibility of DNA microsatellite loci transfer (cross-species amplification) to other economically important aquacultured catfish species other than its source species. A total of 25 new microsatellite loci developed for riverine catfish, Mystus nemurus were successfully cross-amplified in two distantly related catfish species within the suborder Siluroidei. Five out of the 19 loci that successfully cross-amplified in Pangasius micronemus were polymorphic, while for Clarias batrachus, cross-amplification was successful using 17 polymorphic loci. The observed heterozygosities were high for all the three catfishes. The results indicated that microsatellite loci could be as polymorphic in non-source species as in the source species.

Molecular cloning, sequence polymorphism and genomic organization of far eastern catfish (Silurus asotus) GH gene

  • Park, Byul-Nim;Bang, In-Chul;Kim, Dong-Soo;Nam, Yoon-Kwon
    • Proceedings of the Korean Aquaculture Society Conference
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    • 2003.10a
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    • pp.42-42
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    • 2003
  • The far eastern catfish (Silurus asotus) growth hormone (GH) gene was cloned and characterized. The complete nucleotide sequences of genomic GH gene sequences as well as a catfish GH cDNA were obtained by RT-PCR and gene filter screening. The GH cDNA and genomic gene span 1.0 and 1.8 kb from the start codon to the polyadenylation signal, respectively. Both on cDNA and gDNA GH genes, the sequence polymorphism was detected including various silence mutations. The genomic GH gene comprised of only four exons and three introns, which was novel type of fish GH gene structure. The evolutionary relation of the catfish GH gene was inferred based on the comparative phylogenic analysis using the gene structures and sequences.

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Effect of L-theanine on non-specific immunoparameters in catfish (Silurus asortus)

  • Heo, Gang-Joon;Shin, Gee-Wook
    • Korean Journal of Veterinary Service
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    • v.35 no.4
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    • pp.347-350
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    • 2012
  • L-theanine was examined for its effects on the generation of superoxide anion, lysozyme and anti-protease in the plasma of catfish (Silurus asotus) by a single intraperitoneal injection with five different concentrations (0, 3, 6, 9 and 12 mg/kg). When compared with the mock-injected group (0 mg/kg), both groups injected with 6 and 9 mg/kg were significantly enhanced in levels of superoxide anion in leukocytes, lysozyme and anti-protease in plasma. Based on the results, L-theanine is thought to function as an immunostimulant and/or immunomodulator on non-specific immune responses in catfish.

Discovery of Performance Traits-Linked Microsatellite Markers in Channel Catfish (Ictalurus punctatus)

  • Kim, Soon-Hag
    • Journal of Aquaculture
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    • v.18 no.2
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    • pp.130-132
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    • 2005
  • Genomics research has two ultimate applied goals: to Isolate and clone genes of economic importance for bio-technology and gene-assisted selection (GAS), and to locate and use markers for marker-assisted selection (MAS) in selective breeding programs. To this end, we have identified linked markers for feed conversion efficiency growth rate, and disease resistance to enteric septicemia of catfish (ESC). Three microsatellite markers Ip266, Ip384, and Ip607 were identified to be linked to feed conversion efficiency. Similarly one marker each was identified to be linked to growth rate (Ip607) and disease resistance to ESC (Ip477). Ip607 marker linked to both growth rate and feed conversion efficiency, indicating that the QTL for both growth rate and feed conversion efficiency may either be the same or located in the same chromosomal region in the catfish genome. On phenotypic evaluation, certain traits such as growth rate can be accurately evaluated by body weight evaluation while other traits such as disease resistance can be quite complex. The linked DNA markers will be highly useful for MAS programs and for directing further efforts of genomic mapping for important quantitative traits.

The Effect of Sodium Nitrite Exposure on Physiological Response of Starved Far Eastern Catfish, Silurus asotus

  • Park, In-Seok;Gil, Hyun Woo
    • Development and Reproduction
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    • v.22 no.4
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    • pp.319-329
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    • 2018
  • The experiment was conducted for 210 days to determine the effect of feeding, and starvation, and exposure to sodium nitrite ($NaNO_2$) on the survival, physiological changes, hematological parameter, and stress response of Far Eastern catfish, Silurus asotus. The survival of the starved group was lower than that of the fed group during the experiment. Starvation resulted in retardation of growth, which provides an example of fish that failed to continue to grow and remain in a good condition. Blood analyses (cortisol and glucose) showed significant differences of stress response between the fed and starved groups exposed to $NaNO_2$ at the conclusion of the experiment (p<0.05). These results suggest that all nutritional parameters used for starvation and feeding with $NaNO_2$ stress in this experiment appear to be a useful index of nutritional status in Far Eastern catfish.