• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.3
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• pp.227-233
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• 2014

We designed a 16-week feeding experiment to test the effects of dietary supplementation with distillers' dried grain (DDG) on the growth, feed utilization, and body composition of juvenile muddy loach Misgurnus anguillicaudatus. Seven isonitrogenous and isocaloric diets were formulated to contain 0% DDG (Control); 10%, 20%, and 30 % DDG from rice (diets RM10, RM20 and RM30); and 10%, 20%, and 30% DDG from rice and wheat flour (diets RWM10, RWM20 and RWM30), respectively. Three replicate groups of juvenile muddy loach averaging $1.5{\pm}0.10$ g were fed one of the diets to satiation twice daily. Survival of juvenile muddy loach fed the RWM20 and RWM30 diets was higher than that of the control group (P<0.05), while weight gain tended to decrease when fish were fed diets containing DDG. Weight gain of fish fed the RWM10 diet was greater than that of fish fed other diets, but the RM30 diet resulted in less weight gain than did the control (P<0.05). The feed and protein efficiency ratios of fish fed the RM10, RM20, RM30, RWM10, RWM20 and RWM30 diets were all similar to the control (P>0.05). Neither daily feed intake nor proximate composition of the whole body was affected by dietary DDG (P>0.05). The compositions of isoleucine, leucine, lysine, threonine, and valine were all elevated in fish fed the RM30, RWM10, RWM20 and RWM30 diets relative to those of other groups (P<0.05). In contrast, methionine + cystine and phenylalanine + tyrosine were all lower in fish fed the RM30, RWM10, RWM20 and RWM30 diets, as compared to those of other groups (P<0.05). Our results suggest that DDG is suitable as a partial replacement for soybean meal and wheat flour, and could be used at a rate of up to 20% for rice, or 30% for rice and wheat flour, for optimum growth performance of juvenile muddy loach.

• Korean Journal of Ichthyology
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• v.22 no.4
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• pp.230-237
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• 2010

Histological observation on the seasonal variation of mucus cells of the mud loach Misgurnus mizolepis inhabiting a natural stream was carried out on three skin regions (dorsal, lateral and occiput) from March 2008 to February 2009. Our results showed no differences in general morphology by season, but the mucus cells of the epidermis showed significant seasonal change in their size and number as the water temperature changed. The ratio of surface area of the mucus cell layer and mucus cells, and the number of mucus cells in surface area of the epidermis were the greatest in the cold winter and the least in the hot summer in all regions of the epidermis. In particular, the occiput seemed to be a very sensitive region in response to environmental change, showing wide fluctuations in the size of mucus cells throughout the year and a great change in between seasons, especially from late autumn to early winter when the temperature decreased. As the temperature became colder, a small and spherical-shaped mucus cell was transformed into a large and elongated columnar form with a lot of secreted mucus material in a superficial layer of the epidermis. From our results, we can safely surmise that cold temperature is an important environmental factor having a close relationship with the modification of mucus cells of M. mizolepis in winter.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.65-77
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• 2006

Gene transcripts potentially responsive to the heat stress were surveyed by cDNA microarray analysis in mud loach (Misgurnus mizolepis). Transcriptional profiles of hepatic tissue in the fish exposed to either $23^{\circ}C$ or $32^{\circ}C$ for 4 weeks were compared each other by 3 replicated hybridization assays using 1,124 unigene clones selected from mud loach liver expressed sequence tags (ESTs). A total of 93 clones showed the substantially increased mRNA levels (>2-fold) in $32^{\circ}C$-exposed group when compared in $23^{\circ}C$control group. It includes various enzymes and proteins involved in energy pathway, protease/protein metabolisms, immune/antioxidant functions, cytoskeleton/cell structure, transport and/or signal transduction. Maximum level of increase was up to 15-fold relative to $23^{\circ}C$ treatment. Heat exposure also resulted in the significant decrease (less than 50% relative to $23^{\circ}C$-exposed fish) of the transcriptional activities in 85 genes. Besides the above categories, yolk protein (vitellogenin) and ribosomal proteins were notably down regulated in the fish exposed to heat stress. A number of novel gene transcripts were also detected in both up-regulated and down-regulated groups.

• Journal of Aquaculture
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• v.20 no.1
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• pp.65-72
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• 2007

Full length complementary DNA encoding apolipoprotein A-I (apoA-I) was isolated and characterized in mud loach (Misgurnus mizolepis). Mud loach apoA-I cDNA encoding 24 bp of 5'-untranslated region (UTR), 762 bp of single open reading frame (ORF) consists of 254 amino acids and 293 bp of 3'-UTR excluding stop codon and poly (A+) tail. Two overlapping polyadenylation signals (AATAAAATAAA) was found 9 bp prior to the poly (A+) tail. Mud loach apoA-I represented considerable homology to those from other teleost species at amino acid level with conserving common features of vertebrate apoA-I. Molecular phylogenetic analysis inferred the phylogenetic hypothesis that was generally in accordance with the previous taxonomic relationship. Apolipoprotein A-I mRNA was detected in various tissues, but the mRNA levels were quite varied depending on tissues based on semi-quantitative RT-PCR. Liver and brain showed the significantly higher levels of apoA-I transcripts than other tissues. mRNA expression of apoA-I was quite low in very early stage of embryonic development, however dramatically enhanced from 8 hours post fertilization. This increased mRNA level was retained consistently up to 14 days post hatching.

• Journal of Aquaculture
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• v.19 no.3
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• pp.166-172
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• 2006

Induced androgenesis, a form of artificial parthenogenesis is an important tool for the generation and use of genetically isogenic or clonal fish strain. An optimized protocol for the genetic inactivation of mud loach (Misgurnus mizolepis) oocytes (i.e. production of androgenetic haploid) was developed using UV-irradiation. Various dose levels of UV significantly affected the fertilizing capacity of the eggs, hatchability of embryos and incidence of haploidy. Based on the extensive examinations of treatment conditions on embryo viability and haploid incidence, the optimum dose level of UV irradiation was turned out to be $10,800ergs/mm^2$ with 56.9% of hatching success and 94.6% of haploidy. The overall yield of putative androgen under optimized treatment condition was more than 50% out of total eggs inseminated. The success of androgenetic reproduction of haploid genome was verified by flow cytometry and PCR amplification of transgene that is exclusive to either one of parental sexes. However, a small portion $(8\sim11%)$ of presumed androgenetic haploid larvae was proven to contain residual DNA fragment(s) from maternal parent.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.419-428
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• 2013

The objectives of this research were to determine ecological characteristics and chemical gradients in two different loach populations-Misgurnus anguillicaudatus ($M_a$) and Koreocobitis rotundicaudata ($K_r$). Eight chemical parameters were compared to test the chemical preferences between the two species. The population of Kr occurred more in better water quality, compared to the $M_a$-population. The $M_a$-population co-occurred more with tolerant species (TS) and omnivores, whereas the $K_r$-population co-occurred more with sensitive species (SS) and insectivores. The differences in the tolerance and trophic composition matched well with the result of stream health assessment, based on the multi-metric model of Index of Biological Integrity (IBI). The IBI value in habitat with the $M_a$-population was "19.6" (range: 8~40) indicating a fair condition, and the IBI values of $K_r$-population was 29.4 (range: 12~40) indicating good condition. Similar results were found in physical habitat health analysis (QHEI). Overall, data analysis showed that the $M_a$-population belong to the tolerant species and $K_r$-population belong to sensitive species in the tolerance classification.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.232-238
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• 2020

The objective of the present study was to investigate fish farm and growth performances of Chinese muddy loach (Misgurnus mizolepis) under indoor and outdoor aquaculture conditions for the domestic loach aquaculture industry. The investigation was conducted from August 2017 to October 2019 at one indoor farm (D-site) and two outdoor farms (P1-site and P2-site). Results showed that WG (weight gain), DWG (daily weight gain), and SWG (specific weight gain) based on growth measurements were 175.27±36.2%, 7.98±3.3%, and 0.94±0.2% at D-site, 320±34%, 4.07±0.6%, and 0.55±0.1% at P1-site, and 295.9±53%, 4.15±0.5%, and 0.62±0.1% at P2-site, respectively. WG was higher in outdoor farms (P1-site and P2-site), while DWG and SWG were higher in the indoor farm (D-site). Such differences of the present study might be due to differences in growth, water quality, plant and sale frequency depending on aquaculture types. In particular, outdoor farms takes more than a year to have sales whereas indoor farms can have sales three times in a year.

• Proceedings of the Zoological Society Korea Conference
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• 2000.04a
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• pp.73.1-73
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• 2000

No Abstract, See Full Text

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.190-190
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• 2005

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.38-38
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• 2003

Blocking the first mitotic cleavage of the zygote is a key tool for chromosome-set manipulations in fish. We developed an improved method for inducing tetraploidy by blocking the mitosis with a combination of heat shock at 40.5$^{\circ}C$ for 1, 2 or 3 min followed by cold shock at $1.5^{\circ}C$ for 30, 45 or 60 min. When applied during the first cleavage metaphase of mud loach (Misgurnus mizolepis) zygotes, the optimal combination was heat for 2 min followed by cold for 45 min. At 1 month, the frequency of 4N survivors and the yield from total eggs fertilized was 55.7% and 14.4%, respectively, compared to heat shock alone with 20.0% efficiency and 3.6% yield. The effectiveness of the procedure was confirmed by diploid mitotic gynogenesis using transgenic markers. The overall yield of homozygous diploids, 34.0%, was better than that for single heat shock, 17.3%. The tetraploids and homozygous diploids had higher early mortality than normal diploid controls. However at 1 month, the viability of the tetraploids was the same as normal diploids. For gynogenetic diploids, the survival was similar to normal diploids after 3 months. The high efficiency of this new protocol extends the opportunity to study polyploidy in basic and applied research.