• Development and Reproduction
• /
• v.24 no.4
• /
• pp.317-325
• /
• 2020

The Far Eastern catfish (Silurus asotus) is an important commercial freshwater fish in Korea. Investigation of the genetic diversity of wild and cultured domestic catfish groups is essential for the restoration of fishery resources and for increasing local revenue. However, there are relatively few genetic diversity studies on wild and cultured catfish in Korea. In the present study, we analyzed the genetic diversity and association of wild and cultured catfish using five microsatellite markers. We determined that the number of alleles per locus (N_A) ranged from 9 to 25, wherein the Jeonbuk catfish demonstrated the highest mean number of alleles per locus and the cultured catfish exhibited the lowest. The average expected heterozygosity (He) of the wild catfish samples was 0.907, and that of the cultured catfish showed was 0.875. The genetic distances (GD value) among populations of all catfish ranged from 0.138 to 0.242. Jeonnam and Jeonbuk wild catfish were located closest to each other, and the cultured group was separated from the other groups. In conclusion, the present study confirmed that the genetic diversity of wild and cultured catfish was maintained at a high level. In the case of the wild group, it is effective in maintaining diversity due to the continuous fry release by the local fish research institute. However, the genetic diversity of cultured catfish declined. Low diversity is associated with slow growth and weakened immunity, and therefore continuous monitoring is necessary.

• Journal of Aquaculture
• /
• v.16 no.2
• /
• pp.124-127
• /
• 2003

Our previous studies of both microarray analysis in channel catfish muscle gene expression of 2 different ages and channel catfish muscle expressed sequence tag profiles demonstrated parvalbumin beta is one of the highly expressed muscle transcriptome. We have cloned and sequenced complementary DNA encoding the channel catfish parvalbumin which encode 109 amino acids. The deduced amino acid sequences of the catfish parvalbumin are highly conserved with those cloned from other teleosts. The availability of the catfish parvalbumin provides the opportunity of studying fish epitopes.

• Fisheries and Aquatic Sciences
• /
• v.25 no.1
• /
• pp.1-11
• /
• 2022

Catfish is one of the most important freshwater fish farming commodities in Indonesia. Higher catfish production can be achieved by cultivating transgenic catfish carrying the growth hormone (GH) gene of African catfish (Clarias gariepinus GH, CgGH). This research focuses on analysis of the presence of the CgGH gene in transgenic G₁, G₂, and G₃ mutiara catfish broodstock, as an indication of stable CgGH inheritance. CgGH gene was isolated using the RNeasy mini kit and RT-PCR. RT-PCR revealed amplicons measuring approximately 600 bp in transgenic G₀, G₁, G₂, and G₃ mutiara catfish. The CgGH consensus sequence similarities ranged from 93.76% to 97.06%, with four functional domain sites (somatotropin-1, somatotropin-2, four α-helix, N-glycosylation, four cysteine residues) of fish GH proteins. The functional domains of fish GH proteins are conserved in G₁, G₂, and G₃ and indicate stable exogenous GH inheritance to produce transgenic catfish strains in each generation.

• Fisheries and Aquatic Sciences
• /
• v.11 no.1
• /
• pp.23-31
• /
• 2008

An experiment was conducted in twelve 0.02-ha rain-fed earthen ponds for 18 weeks to evaluate the effects of including pangasiid catfish (Pangasius hypophthalmus) in polycultures of major Indian carps, catla (Catla catla), rohu (Labeo rohita), and mrigal (Cirrhinus cirrhosus), on yield and economic gain. Treatment 1 ($T_1$) consisted of 5,000 catla+2,500 rohu+2,500 mrigal per ha, treatment 2 ($T_2$) consisted of 5,000 catla+2,500 rohu+2,500 mrigal+2,500 pangasiid catfish per ha, treatment 3 ($T_3$) consisted of 5,000 catla+2,500 rohu+2,500 mrigal+5,000 pangasiid catfish per ha, and treatment 4 ($T_4$) consisted of 5,000 catla+2,500 rohu+2,500 mrigal+7,500 pangasiid catfish per ha. The growth performance of fishes was evaluated by calculating specific growth rate, daily weight gain, and percent weight gain. Inclusion of pangasiid catfish in the carp polyculture resulted in significant increases in the growth and yield of catla and rohu. Catla and rohu grew most in $T_4$, with 7,500/ha of pangasiid catfish. The presence of pangasiid catfish did not influence the growth of mrigal. The growth of pangasiid catfish varied with stocking density, and they grew best at 5,000/ha ($T_3$). The carp and the combined fish yields were significantly higher in the carp polycultures with pangasiid catfish than with carps alone. The total carp and the combined fish yields were highest in $T_4$, in which the density of pangasiid catfish was greatest. However, the total carp and the combined fish yields in $T_3$ and $T_4$ were not significantly different. Profit differed significantly among treatments. Economic gain was highest in $T_3$, with 5,000/ha of pangasiid catfish, and lowest in $T_1$. The inclusion of pangasiid catfish in major carp polycultures results in higher fish yields and greater economic gain.

• Korean Journal of Environmental Biology
• /
• v.38 no.1
• /
• pp.106-113
• /
• 2020

This study identified the differences in the morphometric characteristics of the truss and classical dimensions between diploid and triploid Far Eastern catfish, Silurus asotus, and provided methods for sorting diploid and triploid Far Eastern catfish based on morphometric observations. The significant variables were the direct distance between the anterior edge of the lower lip and the anterior insertion of the dorsal fin(DALAD), the horizontal distance between the anterior edge of the lower lip and the anterior insertion of the ventral fin (HALAV), the direct distance between the anterior edge of the upper lip and the first nostril(DAUF), the direct distance between the anterior edge of the upper lip and the second nostril(DAUS), the interorbital width(IW), and the mandible barbel length (ManBL). The more significant variables were HALAV, DALAD, DAUF, IW, and DAUS. The most useful combination of variables for separating the two groups was DALAD, IW, and DAUF, which correctly classified 85% of the catfish as triploid or diploid, and that percentage was the maximum degree of value possible (p<0.05). Triploid Far Eastern catfish had a high rate of growth in the head region and body depth during the first year after hatching. Triploid Far Eastern catfish had smaller heads and shorter mandible barbels than diploid Far Eastern catfish.

• Journal of Aquaculture
• /
• v.16 no.1
• /
• pp.8-14
• /
• 2003

To generate expressed sequence tags for genomics research involving genetic linkage analysis, to examine gene expression profiles in muscles of channel catfish in a non-normalized muscle cDNA library, to compare gene expression in young and mature channel catfish muscles using the EST reagents and gene filters to demonstrate the feasibility of functional genomics research in small laboratories. 102 randomly picked cDNA clones were analyzed from the catfish muscle cDNA library. Of the sequences generated, 90.2% of ESTs was identified as known genes by identity comparisons. These 92 clones of known gene products represent transcriptional products of 24 genes. The 10 clones of unknown gene products represent 8 genes. The major transcripts (70.1% of the analyzed ESTs) in the catfish muscle are from many major genes involved in muscle contraction, relaxation, energy metabolism and calcium binding such as alpha actin, creatine kinase, parvalbumin, myosin, troponins, and tropomyosins. Gene expression of the unique ESTs was comparatively studied in the young and adult catfish muscles. Significant differences were observed for aldolase, myostatin, myosin light chain, parvalbumin, and an unknown gene. While myosin light chain and an unknown gene (CM 192) are down-regulated in the mature fish muscle, the aldolase, myostatin, and parvalbumin are significantly up-regulated in the mature fish muscle. Although the physiological significance of the changes in expression levels needs to be further addressed, this research demonstrates the feasibility and power of functional genomics in channel catfish. Channel catfish muscle gene expression profiles provide a valuable molecular muscle physiology blueprint for functional comparative genomics.

• Korean Journal of Ichthyology
• /
• v.17 no.1
• /
• pp.36-42
• /
• 2005

Histological observations on the barbels of catfish (Siluridae) in Korea are reported. The mandibular barbel of Far Eastern catfish, Silurus asotus, has epidermis and dermis surrounding an axial rod of cartilage. The stratified epidermis embodies mucous cells, club cells, and taste buds. The mucous cells, which are thin rims of basophilic cytoplasm, and the taste buds, which are basophilic, are located at the surface and the distal portion of the epidermis, respectively. The basement membrane lies between the epidermis and dermis except in places of dermal papillae. The dermis is made up of loose connective tissue fibers enclosing nerve bundles and blood vessels. The central region of cartilage is innermost and enclosed within muscle layers. The mandibular barbel of slender catfish, S. microdorsalis, has an identical structure to those of the Far Eastern catfish however, the percentage thickness of epidermis in the upper and lower parts of the barbel and the number of taste buds in the upper and middle parts of the barbel are different from those of Far Eastern catfish. This study shows that the mandibular barbels in Far Eastern catfish and slender catfish are of a stiff and flexible type.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2004.05a
• /
• pp.321-322
• /
• 2004

Of the 20 arbitrarily chosen primers, six oligonucleotides decamer primers were used on the basis of the number of the polymorphisms generated in catfish (Silurus asotus) from Yesan and bullhead (Pseudobagrus fulvidraco) from Dangjin in Korea. Six primers were used generating a total of 602 scorable bands in catfish and 195 in bullhead population, respectively, ranging in size of DNA fragments from less than approximately 100 to larger than 2,000 base pairs (bp). Six primers yielded 199 polymorphic fragments (33.1 %) in catfish and 47 (24 %) in bullhead, respectively. In the present study, a total of 328 common fragments (an average of 54.7 per prime.) were observed in catfish population, whereas 84 (an average of 14.0 per prime.) in bullhead. The total number of specific fragments in catfish and bullhead population were 76and 64, respectively.

• Journal of Environmental Health Sciences
• /
• v.24 no.3
• /
• pp.107-113
• /
• 1998

This study was performed to investigate the effects of chitin, chitosan and dithiocarbamate chitosan on the cadmium accumulation in liver and kidney of catfish. The experimental groups were divided into four independent groups which were one control group and three experimental groups by cadmium alone treatment or chitin, chitosan and dithiocarbamate chitosan which cadmium. in order to investigate the effects of chitin, chitosan and dithiocarbamate chitosan on the cadmium accumulation in liver and kidney of catfish, the cadmium concentration, the metallothionein level were measured. The results obtained were as follows: 1. The cadmium concentrations in liver and kidney of catfish in cadmium alone treatment group were similar to that of the chitin treatment group, but chitosan and dithiocarbamate chitosan treatment groups were significantly decreased. 2. The metallothionein levels in liver and kidney of catfish alone treatment group were similar to that of the chitin treatment group, but chitosan and dithiocarbamate chitosan treatment groups were significantly increased. In conclusion, this study revealed the effect of chitin, chitosan and dithiocarbamate chitosan against cadmium accumulation in liver and kidney of catfish. It exhibited the highest effect at dithiocarbamate chitosan treatment group.

• Fisheries and Aquatic Sciences
• /
• v.11 no.1
• /
• pp.15-22
• /
• 2008

Excessive growth of phytoplankton is a common and severe problem in intensively farmed pangasiid catfish (Pangasius hypophthalmus) culture ponds. It can lead to cyanobacterial blooms, reduced fish growth, bad-tasting fish flesh, and lower market demand. To investigate how to manage undesirable phytoplankton growth, we evaluated three stocking strategies in nine rural fishponds (0.020-0.022 ha) owned by various farmers: a pangasiid catfish mono culture (treatment 1, $T_1$), and pangasiid catfish-silver carp (Hypophthalmichthys molitrix) polycultures at two stocking ratios of 1:1 (treatment 2, $T_2$) and 2:1 (treatment 3, $T_3$). The total density of all ponds was approximately 30,000 fishes/ha. Monoculture ($T_1$) resulted in significantly higher (p < 0.05) nutrient levels (nitrate and phosphate) in ponds than did polyculture ($T_2$ and $T_3$). Nutrient loads increased with culture time, resulting in increased growth of phytoplankton, including Cyanophyceae (9 genera), Chlorophyceae (15 genera), Bacillariophyceae (8 genera), and Euglenophyceae (3 genera). The introduction of silver carp as a co-species helped to regulate phytoplankton growth and to improve the water quality of pangasiid catfish culture ponds.