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

• Molecular & Cellular Toxicology
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• v.4 no.4
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• pp.311-317
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• 2008

Zebrafish were exposed to commercial silver nanoparticles (${\sim}$10-20 nm) at 0.4 and 4 ppm during cadual fin regeneration. The silver was in the $Ag^+$ ionic form. Fin regeneration was slow in the group exposed to the lower concentration. The cadual fin, gill, and muscle were assayed after 48 hours and subjected to histological analysis. In all tissues sampled, fish exposed to nanoparticles exhibited infiltration, large mitochondria with empty matrices, and accumulation of nano-sized silver in blood vessels. The results suggested mitochondrial damage and induction of inflammation. Microarray analysis of RNA from young zebrafish (52 hours post-fertilization) that were exposed to nanometer-sized silver particles, showed alteration in expression of the p53 gene pathway related to apoptosis. Gene expression changes in the nanoparticle-treated zebrafish led to phenotypic changes, reflecting increased apoptosis.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1179-1184
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• 2008

Commercial nanometer sized silver is widely used for its antibacterial effect; however, nanoparticles may also have ecotoxicological effects after being discharged into water. Nanometer sized silver can flow into aquatic environments, where it can exert a variety of physiologically effects in living organisms, including fish. The present study aimed to investigate the effect of nanometer sized silver on the development of zebrafish embryos, analyze the properties of commercial nanometer sized silver and define the toxicity relationship between embryogenesis and hatched flies. The commercial nanometer sized silver was analyzed in the $Ag^+$ ion form. The hatch rate decreased in the nano-silver exposed groups (10 and 20 ppt); furthermore, the hatched flies had an abnormal notochord, weak heart beat, damaged eyes and curved tail. The expression of the Sel N1 gene decreased in the nano-silver exposed groups, and the catalase activities of the exposed groups increased relative to those in the control group. Therefore, the $Ag^+$ ions in commercial nanometer sized silver could accumulate in aquatic environments and seriously damage the development of zebrafish embryos.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7879-7884
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• 2014

To investigate the association between intake of freshwater fish and their fatty acids and the risk of breast cancer in Chinese women, we conducted a case-control study with 669 cases and 682 population-based controls in Jiangsu Province of China. A structured questionnaire was used to elicit detailed information. Unconditional logistic regression analysis was performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Total freshwater fish intake was linked to decrease in the adjusted OR for breast cancer, but without dose-dependence. Analyses by freshwater fish species showed that consumption of black carp and silver carp was inversely related to breast cancer risk, with adjusted-ORs for the highest intake category of black carp (${\geq}500g/month$) of 0.54 (95%CI=0.33-0.92; $P_{trend}$ <0.002) and for silver carp (${\geq}1000g/month$) of 0.19 (95%CI=0.11-0.33; $P_{trend}$ <0.001). In contrast, consumption of crucian carp was positively related to breast cancer risk, with an adjusted OR for the highest intake category (${\geq}1000g/month$) of 6.09 (95%CI=3.04-12.2; $P_{trend}$ <0.001). Moderate intakes of SFA, PUFA, n3-PUFA and n6-PUFA from freshwater fish may decrease the risk of breast cancer among premenopausal women. The findings of this study suggest that intake of freshwater fish and their fatty acids may modify risk of breast cancer, and that different species of freshwater fish could have a different actions on breast cancer risk. Future epidemiologic studies are needed to know the effects of freshwater fish intake on breast cancer risk and the cause of these effects.

• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.98-105
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• 2001

Two-monthold silver carps were cultured with seven algal species and zooplankton (Moina macrocopa) in the laboratory. The carps were reared in 10 L translucent cylindrical aquaria with algae and zooplankton for 8 days. The Moina effectively fed almost cultured algae: perfectly removed Cryptomonas (NIES-282) within 60 min. Both algal diets Cryptomonas and Fragilaria (NIES-391) significantly increased the Moina population ($r^2$>0.93, p<0.005), while Microcystis (MIES-90) and Oscillatoria (NIES-204) reduced the zooplankton ($r^2$=0.97, p<001). Fish removed about 50% of all algae for 52 hrs, even 60% of Microcystis still remained: all algae reduced ca. 5${\sim}$12% of initial weight. Furthermore, a continuous supply of algae with same density resulted in the death of fish, e.g. 11 days in cyanobacteria Microcystis. Therefore, the growth limitation of silver carp by algae indicates that zooplankton is of direct dietary contributor in planktivores feeding behavior.

• Genomics & Informatics
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• v.21 no.4
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• pp.47.1-47.12
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• 2023

Silver barb (Barbonymus gonionotus) is among the most economically important freshwater fish species in Thailand. It ranks fourth in economic value and third in production weight for fisheries and culture in Thailand. An XX/XY sex-determination system based on gynogenesis was previously reported for this fish. In this study, the molecular basis underlying the sex-determination system was further investigated. Genome-wide single-nucleotide polymorphism data were generated for 32 captive-bred silver barb individuals, previously scored by phenotypic sex, to identify sex-linked regions associated with sex determination. Sixty-three male-linked loci, indicating putative XY chromosomes, were identified. Male-specific loci were not observed, which indicates that the putative Y chromosome is young and the sex determination region is cryptic. A homology search revealed that most male-linked loci were homologous to the Mariner/Tc1 and Gypsy transposable elements and are probably the remnants of an initial accumulation of repeats on the Y chromosome from the early stages of sex chromosome differentiation. This research provides convincing insights into the mechanism of sex determination and reveals the potential sex determination regions in silver barb. The study provides the basic data necessary for increasing the commercial value of silver barbs through genetic improvements.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.6131-6134
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• 2013

Background: The two basic methods that are currently accepted to identify the HER2 status are immunohistochemistry and flyorescence in situ hybridization (FISH). The aim of this study was to perform the dual-color silver in situ hybridization (dc-SISH) technique as an alternative to FISH. Materials and Methods: A total of 40 invasive breast carcinoma cases were assessed for HER2 gene amplification by FISH and dual-color SISH. Results: Significant correlation was found in the HER2 expression results obtained with the two approaches (p=0.001, p<0.05). The concordance rate was 92.3%. Conclusions: Foutine practical use of the dc-SISH method, which is much easier to apply, score, and evaluate, has many advantages. HER2 and CEN17 status can be evaluated simultaneously with the newly developed "Dual-Color Probe". All these specifications and the reliable results obtained support the widespread use of SISH technique in clinical practice.

• Journal of Aquaculture
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• v.19 no.4
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• pp.267-274
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• 2006

To understand the changes in plasma levels of sex steroids in the wild Japanese eel Anguilla japonica during artificially maturing process, eels received weekly intraperitoneal injections of a water-in-oil (W/O) type emulsion with Freund`s incomplete adjuvant containing salmon pituitary extract (SPE; 20 mg pituitary powder/fish) were examined. In the weekly Eel's Ringer-treated control wild eels, the body weight (BW) changes of fish decreased slowly during the experiment period. Plasma testosterone (T), $estradiol-17{\beta}\;(E_2)$ and $17a,20{\beta}-dihydroxyprogesterone$ (DHP) levels did not change significantly at the end of the experiment. In the weekly SPE-treated silver eels, however, rapid increase in BW changes occurred after 6 to 10 weeks, and the oocytes of all fish were observed to be in the migratory nucleus stage. Furthermore, significant increase in sex steroid hormones (T and $E_2$) levels occurred from 6 weeks. In the weekly SPE-treated yellow eels, the BW changes of fish increased slowly at 6 weeks and then increased. In these fish, the oocytes were at the tertiary yolk globule stage even at the end of the experiment. Plasma sex steroid hormones profiles revealed individual variability in SPE-treated yellow eels. Plasma T and $E_2$ levels significantly increased at 8 weeks and after 6 weeks, respectively, in SPE-treated yellow eels. In the weekly SPE-treated wild eels (silver and yellow eels), however, plasma DHP levels did not change significantly during the experiment period. In silver eel, final maturation could be induced by weekly administration of SPE using W/O type emulsion.

• Journal of fish pathology
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• v.30 no.2
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• pp.135-148
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• 2017

Pathogen introductions associated with aquatic invasive species threaten ecosystems and biodiversity worldwide. Bigheaded carps (BHC), including Silver Carp Hypophthalmichthys molitrix, Bighead Carp H. nobilis, and their hybrids, are prolific, invasive pests in central US rivers. However, little is known about pathogen effects on invading BHC or how BHC affect the disease risk profile for native fishes in receiving ecosystems. We therefore conducted, from May 2013-December 2014, a systematic pathogen survey for BHC and native fishes in the Wabash River watershed, Indiana, USA. We found Pseudomonas fluorescens, P. putida, and Salmonella enterica DNA in BHC as well as native fishes, although none of these bacteria were exclusively present in BHC. DNA from other bacterial taxa was detected only in native fishes and Common Carp Cyprinus carpio. No gastrointestinal helminths were detected in BHC, although they were common in most native fishes examined. We also conducted in vitro studies on BHC tissues (skin, gill, fin, and fry) and found high sensitivity to Largemouth Bass virus, viral hemorrhagic septicemia virus, and infectious pancreatic necrosis virus. We conclude that BHC are not heavily burdened by bacteria, viruses and parasites in the invaded study ecosystems, although they do harbor native bacteria and show potential for high sensitivity to endemic viruses.

• Journal of Veterinary Clinics
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• v.34 no.4
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• pp.261-267
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• 2017

The aim of this study was to investigate the antibacterial properties of chitosan silver nanocomposites (CAgNCs) using pathogenic Vibrio ichthyoenteri as a bacterial model. Results of agar disc diffusion and turbidimetric assays showed that CAgNCs could inhibit the growth of V. ichthyoenteri in concentration dependent manner. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CAgNCs were 75 and $125{\mu}g/mL$, respectively. Furthermore, CAgNCs treatment induced the reactive oxygen species (ROS) level in V. ichthyoenteri cells in concentration and time dependent manner, suggesting that it generates oxidative stress, leading to bacterial cell death. The field emission scanning electron microscope (FE-SEM) images of CAgNCs treated V. ichthyoenteri exhibited strong cell membrane damage than un-treated control bacteria. MTT assay results showed the highest cell viability (22%) at $75{\mu}g/mL$ of CAgNCs treated bacteria samples. The results from this study suggest that CAgNCs is a potential antibacterial agent to control fish pathogenic bacteria.