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Andrew P Shinn - One of the best experts on this subject based on the ideXlab platform.
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effects of long duration low dose bronopol exposure on the control of ichthyophthirius multifiliis ciliophora parasitising rainbow trout oncorhynchus mykiss walbaum
Veterinary Parasitology, 2012Co-Authors: Sara M Piconcamacho, James E Bron, Nick G H Taylor, Andrew P ShinnAbstract:Abstract Ichthyophthirius multifiliis Fouquet, 1876 infections on intensively reared fish stocks can increase rapidly, which if left unmanaged, can result in the heavy loss of stock. The present study explores the efficacy of long duration, low dose (1, 2 and 5 mg L −1 ) treatments of bronopol (marketed as Pyceze™, Novartis Ltd.) in reducing the number of Trophonts establishing on juvenile Oncorhynchus mykiss held under small scale culture conditions. The effect of bronopol on the colonisation success of infective theronts was also investigated by adding 2 mg L −1 bronopol to the water prior and during the infection process. The number of parasites surviving on fish treated this way was compared to groups of fish that only received treatment after infection had occurred. The effect of bronopol on exiting Trophonts throughout their external development to the point of theront release was also assessed through the delivery of 1 mg L −1 , 2 mg L −1 and 5 mg L −1 bronopol for up to 27 days consecutively (days 9–36 post-infection). The trial showed that a nominal dose of 2 mg L −1 bronopol administered prior to infection significantly reduced the number of theronts surviving in the water column at the time of the initial challenge by 35–40% ( P −1 bronopol administered as the first wave of mature I. multifiliis Trophonts exited fish ( i.e. day 11 onwards) to develop externally, reduced the number of Trophonts establishing on fish as the second cycle of infection by 52–83%. Continuous application of 2 and 5 mg L −1 bronopol throughout the second and third cycles of I. multifiliis infection gave further reductions of between 90 and 98%. The number of Trophonts on the fish in the control tanks and those treated with 1 mg L −1 and the 2 mg L −1 dose at the time of initial infection, by comparison, were observed to increase with successive cycles of infection. From these small scale tank trials, this study demonstrates that the strategic, long duration, low dose delivery of drugs like bronopol can significantly reduce the number of Trophonts establishing on fish suggesting the potential of this drug at managing I. multifiliis infections.
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effects of long duration low dose bronopol exposure on the control of ichthyophthirius multifiliis ciliophora parasitising rainbow trout oncorhynchus mykiss walbaum
Veterinary Parasitology, 2012Co-Authors: Sara M Piconcamacho, James E Bron, Nick G H Taylor, Fu Ci Guo, Andrew P ShinnAbstract:Ichthyophthirius multifiliis Fouquet, 1876 infections on intensively reared fish stocks can increase rapidly, which if left unmanaged, can result in the heavy loss of stock. The present study explores the efficacy of long duration, low dose (1, 2 and 5 mg L(-1)) treatments of bronopol (marketed as Pyceze™, Novartis Ltd.) in reducing the number of Trophonts establishing on juvenile Oncorhynchus mykiss held under small scale culture conditions. The effect of bronopol on the colonisation success of infective theronts was also investigated by adding 2 mg L(-1) bronopol to the water prior and during the infection process. The number of parasites surviving on fish treated this way was compared to groups of fish that only received treatment after infection had occurred. The effect of bronopol on exiting Trophonts throughout their external development to the point of theront release was also assessed through the delivery of 1 mg L(-1), 2 mg L(-1) and 5 mg L(-1) bronopol for up to 27 days consecutively (days 9-36 post-infection). The trial showed that a nominal dose of 2 mg L(-1) bronopol administered prior to infection significantly reduced the number of theronts surviving in the water column at the time of the initial challenge by 35-40% (P<0.05). Similarly, doses of 2 and 5 mg L(-1) bronopol administered as the first wave of mature I. multifiliis Trophonts exited fish (i.e. day 11 onwards) to develop externally, reduced the number of Trophonts establishing on fish as the second cycle of infection by 52-83%. Continuous application of 2 and 5 mg L(-1) bronopol throughout the second and third cycles of I. multifiliis infection gave further reductions of between 90 and 98%. The number of Trophonts on the fish in the control tanks and those treated with 1 mg L(-1) and the 2 mg L(-1) dose at the time of initial infection, by comparison, were observed to increase with successive cycles of infection. From these small scale tank trials, this study demonstrates that the strategic, long duration, low dose delivery of drugs like bronopol can significantly reduce the number of Trophonts establishing on fish suggesting the potential of this drug at managing I. multifiliis infections.
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efficacy of selected oral chemotherapeutants against ichthyophthirius multifiliis ciliophora ophyroglenidae infecting rainbow trout oncorhynchus mykiss
Diseases of Aquatic Organisms, 2003Co-Authors: Andrew P Shinn, R Wootten, Isabelle Cote, Christina SommervilleAbstract:The chemotherapeutic efficacy of 6 in-feed compounds against Ichthyophthirius multi- filiis Fouquet, 1876 was assessed using experimental infections of rainbow trout Oncorhynchus mykiss (Walbaum) fingerlings. Trial doses of 104 ppm amprolium hydrochloride or 65 ppm clopidol fed to fish for 10 d prior to infection significantly reduced the number of Trophonts establishing in trout fingerlings by 62.0 and 35.2% respectively. In-feed treatments of infected trout with either 63 or 75 ppm amprolium hydrochloride, 92 ppm clopidol, or 38, 43 or 47 ppm salinomycin sodium for 10 d also significantly reduced the number of surviving Trophonts by 77.6 and 32.2% for amprolium, 20.1% for clopidol and 80.2, 71.9 and 93.3% respectively for salinomycin sodium.
Nick G H Taylor - One of the best experts on this subject based on the ideXlab platform.
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effects of long duration low dose bronopol exposure on the control of ichthyophthirius multifiliis ciliophora parasitising rainbow trout oncorhynchus mykiss walbaum
Veterinary Parasitology, 2012Co-Authors: Sara M Piconcamacho, James E Bron, Nick G H Taylor, Andrew P ShinnAbstract:Abstract Ichthyophthirius multifiliis Fouquet, 1876 infections on intensively reared fish stocks can increase rapidly, which if left unmanaged, can result in the heavy loss of stock. The present study explores the efficacy of long duration, low dose (1, 2 and 5 mg L −1 ) treatments of bronopol (marketed as Pyceze™, Novartis Ltd.) in reducing the number of Trophonts establishing on juvenile Oncorhynchus mykiss held under small scale culture conditions. The effect of bronopol on the colonisation success of infective theronts was also investigated by adding 2 mg L −1 bronopol to the water prior and during the infection process. The number of parasites surviving on fish treated this way was compared to groups of fish that only received treatment after infection had occurred. The effect of bronopol on exiting Trophonts throughout their external development to the point of theront release was also assessed through the delivery of 1 mg L −1 , 2 mg L −1 and 5 mg L −1 bronopol for up to 27 days consecutively (days 9–36 post-infection). The trial showed that a nominal dose of 2 mg L −1 bronopol administered prior to infection significantly reduced the number of theronts surviving in the water column at the time of the initial challenge by 35–40% ( P −1 bronopol administered as the first wave of mature I. multifiliis Trophonts exited fish ( i.e. day 11 onwards) to develop externally, reduced the number of Trophonts establishing on fish as the second cycle of infection by 52–83%. Continuous application of 2 and 5 mg L −1 bronopol throughout the second and third cycles of I. multifiliis infection gave further reductions of between 90 and 98%. The number of Trophonts on the fish in the control tanks and those treated with 1 mg L −1 and the 2 mg L −1 dose at the time of initial infection, by comparison, were observed to increase with successive cycles of infection. From these small scale tank trials, this study demonstrates that the strategic, long duration, low dose delivery of drugs like bronopol can significantly reduce the number of Trophonts establishing on fish suggesting the potential of this drug at managing I. multifiliis infections.
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effects of long duration low dose bronopol exposure on the control of ichthyophthirius multifiliis ciliophora parasitising rainbow trout oncorhynchus mykiss walbaum
Veterinary Parasitology, 2012Co-Authors: Sara M Piconcamacho, James E Bron, Nick G H Taylor, Fu Ci Guo, Andrew P ShinnAbstract:Ichthyophthirius multifiliis Fouquet, 1876 infections on intensively reared fish stocks can increase rapidly, which if left unmanaged, can result in the heavy loss of stock. The present study explores the efficacy of long duration, low dose (1, 2 and 5 mg L(-1)) treatments of bronopol (marketed as Pyceze™, Novartis Ltd.) in reducing the number of Trophonts establishing on juvenile Oncorhynchus mykiss held under small scale culture conditions. The effect of bronopol on the colonisation success of infective theronts was also investigated by adding 2 mg L(-1) bronopol to the water prior and during the infection process. The number of parasites surviving on fish treated this way was compared to groups of fish that only received treatment after infection had occurred. The effect of bronopol on exiting Trophonts throughout their external development to the point of theront release was also assessed through the delivery of 1 mg L(-1), 2 mg L(-1) and 5 mg L(-1) bronopol for up to 27 days consecutively (days 9-36 post-infection). The trial showed that a nominal dose of 2 mg L(-1) bronopol administered prior to infection significantly reduced the number of theronts surviving in the water column at the time of the initial challenge by 35-40% (P<0.05). Similarly, doses of 2 and 5 mg L(-1) bronopol administered as the first wave of mature I. multifiliis Trophonts exited fish (i.e. day 11 onwards) to develop externally, reduced the number of Trophonts establishing on fish as the second cycle of infection by 52-83%. Continuous application of 2 and 5 mg L(-1) bronopol throughout the second and third cycles of I. multifiliis infection gave further reductions of between 90 and 98%. The number of Trophonts on the fish in the control tanks and those treated with 1 mg L(-1) and the 2 mg L(-1) dose at the time of initial infection, by comparison, were observed to increase with successive cycles of infection. From these small scale tank trials, this study demonstrates that the strategic, long duration, low dose delivery of drugs like bronopol can significantly reduce the number of Trophonts establishing on fish suggesting the potential of this drug at managing I. multifiliis infections.
Kurt Buchmann - One of the best experts on this subject based on the ideXlab platform.
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immune response to ichthyophthirius multifiliis and role of igt
Parasite Immunology, 2020Co-Authors: Kurt BuchmannAbstract:: The parasitic ciliate Ichthyophthirius multifiliis causes white spot disease in freshwater fish worldwide. The theront penetrates external surfaces of the naive fish where it develops into the feeding Trophont stage and elicits a protective immune response both at the affected site as well as at the systemic level. The present work compiles data and presents an overall model of the protective reactions induced. A wide spectrum of inflammatory reactions are established upon invasion but the specific protection is provided by adaptive factors. Immunoglobulin IgT is involved in protection of surfaces in several fish species and is thereby one of the first adaptive immune molecules reacting with the penetrating theront. IgT producing lymphocytes occur in epithelia, dispersed or associated with lymphoid cell aggregations (skin epidermis, fins, gills, nostrils and buccal cavities) but they are also present in central immune organs such as the head kidney, spleen and liver. When theronts invade immunized fish skin, they are encountered by host factors which opsonize the parasite and may result in complement activation, phagocytosis or cell-mediated killing. However, antibody (IgT, IgM and IgD) binding to parasite cilia has been suggested to alter parasite behaviour and induce an escape reaction, whereby specific IgT (or other classes of immunoglobulin in fish surfaces) takes a central role in protection against the parasite.
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dose dependent effects of dietary immunostimulants on rainbow trout immune parameters and susceptibility to the parasite ichthyophthirius
Journal of Aquaculture Research and Development, 2014Co-Authors: Jakob Skov, Per W Kania, Kurt BuchmannAbstract:Immunostimulants offered to fish in feed are considered to confer protection against various bacterial diseases but the effects on the antiparasitic response are largely unknown. Therefore effects of dietary β-1,3-glucan on innate immune parameters of juvenile rainbow trout Oncorhynchus mykiss and on susceptibility to the skin-parasitic cili- ate Ichthyophthirius multifiliis (Ich) have been investigated. A basal diet (dry pelleted feed) was supplemented with 0% (control), 0.2% (low), 2.0% (medium), and 5.0% (high) of the β-1,3-glucan particulate insoluble algae glucan, paramylon, from Euglena gracilis. Fish (total 440) were divided into four groups each with 110 fish (kept in duplicate tanks of 55) and each diet was fed to two replicate groups at a daily feeding rate of 1.5% of fish biomass for 56 consecutive days. Liver and plasma sampling was performed at day 0 and after feeding with β-1,3-glucans for 14, 28, 42, and 56 days and subsamples of fish were exposed to Ich at day 14 and 45. Gene expression in trout liver was investigated by real-time qPCR and genes encoding immune molecules including acute phase proteins (SAA, hepcidin, and precerebellin), immunoglobulins (IgM and IgT), cytokine (IL-1β), and lysozyme were investigated. In addition plasma lysozyme activity was recorded. At the start of the experiment the 5.0% glucan supplemented fish became more infected by parasites compared to control fish (0.0%) but after 45 days feeding they obtained signifi - cantly fewer Trophonts. Plasma lysozyme activity of fish fed low (0.2%) and medium (2.0%) glucan supplementation fluctuated, while high (5.0%) glucan was associated with an elevation of lysozyme activity. Plasma lysozyme activity was positively correlated to expression of the lysozyme gene and to body mass of fish. Groups fed low (0.2%) and medium (2%) glucan diets showed a trend for down-regulation of immune relevant genes whereas the group fed with high (5%) glucan showed a trend for up-regulation of genes especially the acute phase reactant SAA.
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experimental evidence for direct in situ binding of igm and igt to early Trophonts of ichthyophthirius multifiliis fouquet in the gills of rainbow trout oncorhynchus mykiss walbaum
Journal of Fish Diseases, 2011Co-Authors: L Von Gersdorff Jorgensen, Rasmus D Heinecke, Karsten Skjodt, Karina Juhl Rasmussen, Kurt BuchmannAbstract:Freshwater fish are able to mount a protectiveimmune response against the parasite Ichthyoph-thirius multifiliis (Ich) following a non-lethalexposure. Factors involved in immunity comprisecellular and humoral factors, but antibodies havebeen suggested to play a prominent role in pro-tection. However, host antibodies have not yetbeen demonstrated to bind to the parasite in situ.By the use of immunohistochemical techniques,this study demonstrated that IgT and IgM bindto surface structures, including cilia, on the earlyfeeding stage of the parasite in the gills of im-mune rainbow trout, Oncorhynchus mykiss, shortly(2 h) after invasion. No binding of IgT and no oronly a weak binding of IgM was observed on theparasites in the gills of similarly exposed but nai¨verainbow trout. This study indicates that antibod-ies play an important part in the protection ofimmune fish against Ich although additionalhumoral and cellular factors may contribute tothis reaction.Keywords: binding, Ichthyophthirius multifiliis, IgM,IgT, rainbow trout, Trophonts.
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toltrazuril baycox vet in feed can reduce ichthyophthirius multifiliis invasion of rainbow trout salmonidae
Acta Ichthyologica Et Piscatoria, 2011Co-Authors: Rzgar M Jaafar, Kurt BuchmannAbstract:Various compounds have been applied for control of Ichthyophthirius multifiliis (commonly known as Ich) which is the parasitic pathogen, responsible for the white spot disease, in freshwater aquaculture worldwide. Available methods are based on disinfection of fish tank water, targeting infective free-swimming theronts and escaped tomonts. No legal drug is available and licensed for treatment or prevention of the disease. The presently reported study was performed to test the potential of toltrazuril (Baycox® vet.)—a drug licensed for treatment of coccidial infections in other animal species—to reduce Ich infections when administered orally. Commercial pelleted feed containing 5.0 or 2.5 mg toltrazuril per 1 g of feed was offered to rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) (Actinopterygii: Salmoniformes: Salmonidae), during a three day feeding regime (1% of biomass offered per day). Two trials were performed: one with feeding before exposure to parasites and one where already infected fish were treated. Before the treatment it was tested if fish would eat feed containing different drug concentrations and it was found that feed with the high drug concentration was not eaten by the fish whereas all feed containing 2.5 mg per 1 g feed was eaten. Following the exposure to infective I. multifiliis theronts it was found that the fish treated with toltrazuril before challenge obtained a significantly lower parasite burden (number of Trophonts in the skin) compared to untreated control. On the other hand, toltrazuril proved to be ineffective when administered to the fish which were already infected before the treatment.
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effects of short and long term glucan feeding of rainbow trout salmonidae on the susceptibility to ichthyophthirius multifiliis infections
Acta Ichthyologica Et Piscatoria, 2010Co-Authors: Jesper Hauberg Lauridsen, Kurt BuchmannAbstract:Materials and Methods. The immune reactivity was assessed by measuring susceptibility to I. multifiliis infec- tions and plasma lysozyme in the host, factors which are considered innate response parameters. Rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) (Actinopterygii: Salmoniformes: Salmonidae), were fed (control feed or glucan-containing feed) for 14 or 35 days before challenge (exposure to infective I. multifiliis t heronts) and the resulting infection (number of Trophonts in the skin) was recorded on day 11 post-exposure to theronts. Results. All fish obtained infection following parasite exposure but glucan-fed fish showed a lower infection at day 46 compared to fish fed control-feed. The lysozyme activity of fish plasma was evaluated throughout the experimental period and found slightly but significantly increased in association with glucan-feeding at day 14, 17, and 46. Conclusion. N o evidence for an exhaustion of these selected innate response parameters due to prolonged glu- can-feeding could be detected within the experimental period of 46 days.
Phillip H Klesius - One of the best experts on this subject based on the ideXlab platform.
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susceptibility of channel catfish blue catfish and channel blue catfish hybrid to ichthyophthirius multifiliis
Aquaculture, 2011Co-Authors: Dehai Xu, Phillip H Klesius, Eric PeatmanAbstract:Abstract Information on the infectivity of Ichthyophthirius multifiliis (Ich), a severe fish parasite that causes high mortality, is limited for blue catfish ( Ictalurus furcatus ) and catfish hybrids (CB hybrid) resulting from female channel catfish ( Ictalurus punctatus ) × male blue catfish crosses. The objective of this study was to compare channel catfish, blue catfish and CB hybrids on the infection level and fish mortality caused by Ich using a cohabitation model. To compare the susceptibility to Ich between channel and blue catfish, fish were exposed to 5000 or 10000 theronts per fish, respectively. There were no statistical differences in the infection levels and mortalities between channel catfish and blue catfish. Channel catfish showed an infection score of 2.9 and blue catfish of 2.7 when infected by theronts at 10,000 theronts per fish. The cumulative mortalities were 86.3% and 80.6 %, respectively for channel catfish and blue catfish when exposed to theronts at 5000 theronts per fish. To compare the susceptibility to Ich between channel catfish and CB hybrid, fish were infected by cohabiting with 1 or 3 Ich-infected fish or exposure to Ich theronts at 2500–10,000 theronts per fish. Channel catfish and CB hybrid showed similar infection levels of > 150 Trophonts/fish and infection duration of 7–8 days when cohabited with 1 or 3 Ich-infected fish. All channel catfish and CB hybrid exposed to theronts at the dose of 10,000 theronts/fish showed heavy infection of > 150 Trophonts/fish. The cumulative mortalities were 90% and 80% for channel catfish and CB hybrid after exposure to 2500 theronts per fish. No statistical difference was found in the infection levels and mortalities using two infection methods between channel catfish and CB hybrid. Overall results indicated that CB hybrid were as susceptible to Ich as channel catfish or blue catfish.
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gene expression profiling of a fish parasite ichthyophthirius multifiliis insights into development and senescence associated avirulence
Comparative Biochemistry and Physiology, 2011Co-Authors: Jason Abernathy, Dehai Xu, Eric Peatman, Huseyin Kucuktas, Phillip H KlesiusAbstract:The ciliate parasite Ichthyophthirius multifiliis (Ich) infects many freshwater fish, causing white spot disease that leads to heavy economic losses to aquaculture and ornamental industries. Despite its economic importance, molecular studies examining fundamental processes such as life stage regulation and infectivity have been scarce. In this study, we developed an oligo microarray platform using all available I. multifiliis expressed sequence tag (EST) information as well as probes designed through comparative genomics to other protozoa. Gene expression profiling for developmental and virulence factors was conducted using this platform. For the developmental study, the microarray was used to examine gene expression profiles between the three major life stages of Ich: infective theront, parasitic Trophont, and reproductive tomont. A total of 135 putative I. multifiliis genes were found to be differentially expressed among all three life-stages. Examples of differentially expressed transcripts among life stages include immobilization antigens and epiplasmin, as well as various other transcripts involved in developmental regulation and host-parasite interactions. I. multifiliis has been shown to lose infectivity at later cell divisions potentially due to cellular senescence. Therefore, the microarray was also used to explore expression of senescence-associated genes as related to the passage number of the parasite. In this regard, comparison between tomont early and late passages yielded 493 differently expressed genes; 1478 differentially expressed genes were identified between Trophont early and late passages. The EST-derived oligo microarray represents a first generation array of this ciliate and provided reproducible expression data as validated by quantitative RT-PCR.
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effect of immunization of channel catfish with inactivated Trophonts on serum and cutaneous antibody titers and survival against ichthyophthirius multifiliis
Fish & Shellfish Immunology, 2009Co-Authors: Dehai Xu, Phillip H Klesius, Craig A ShoemakerAbstract:Abstract Two trials were conducted to determine the effect of immunization of channel catfish with inactivated Trophonts on serum and cutaneous antibody titers and survival against Ichthyophthirius multifiliis Fouquet (Ich). In trial I, catfish were immunized intraperitoneally (IP) with: 1) 1% formalin-inactivated Trophonts, 2) 3% formalin-inactivated Trophonts and 3) freeze-thawed Trophonts. Positive and negative control catfish were immunized with live theronts and 5% bovine serum albumin (BSA), respectively. At day 14, 28 and 50 post-immunizations, no statistical difference was noted in serum or cutaneous anti-Ich antibody titers to formalin-inactivated Trophonts or freeze-thawed Trophonts. The survival of catfish challenged with live theronts ranged from 33.3% to 43.3% for the formalin-inactivated or freeze-thawed Trophonts at 50 d post-immunization. The survival of catfish immunized with live theront and BSA was 93.3 and 0%, respectively. In trial II, catfish were IP immunized with sonicated Trophonts at doses of 1) 5 Trophonts or 10.2 μg protein g −1 fish, 2) 10 Trophonts or 20.4 μg protein g −1 fish, 3) 20 Trophonts or 40.8 μg protein g −1 fish, and 4) 5% BSA as the control. Fish immunized with 10 or 20 Trophonts g −1 fish showed highest serum (1/210 to 1/480) and cutaneous antibody titers (1/48 to 1/52), respectively, at 22 d post-immunization and survival (63.3–60.0%). The fish immunized with 5 Trophonts g −1 fish had titers of 1/52 and 1/12 for serum and cutaneous antibody and survival of 23.3%. BSA immunized catfish had background titers and a survival of 6.7%. There was a significant correlation between doses of sonicated Trophonts used to immunize and catfish survival (correlation coefficient = 0.859, p
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protective immunity of nile tilapia against ichthyophthirius multifiliis post immunization with live theronts and sonicated Trophonts
Fish & Shellfish Immunology, 2008Co-Authors: Dehai Xu, Phillip H Klesius, Craig A ShoemakerAbstract:Two immunization trials were conducted to evaluate host protection of Nile tilapia, Oreochromis niloticus against Ichthyophthirius multifiliis (Ich). Immunizations were done with live theronts or sonicated Trophonts by bath immersion and intraperitoneal (IP) injection. The immunized fish were challenged with theronts 21 days post-immunization in trial I and 180 days post-immunization in trial II. The serum anti-Ich antibody and cumulative mortalities of tilapia were determined after theront challenge. Serum anti-Ich antibody was significantly higher (P < 0.05) in tilapia immunized with live theronts by immersion or IP injection or with sonicated Trophonts administered by IP injection than tilapia immunized with sonicated Trophonts by immersion, with bovine serum albumin by IP injection, or non-immunized controls. Host protection was acquired in fish immunized with live theronts by immersion or IP injection. Tilapia immunized with sonicated Trophonts by IP injection were partially protected with a 57–77% survival in both trials. At 180 days post-immunization, serum antibody titers had declined in immunized fish yet they were still able to survive challenge. The protection appears not to be solely depending on serum antibody response against Ich.
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induced cross protection in channel catfish ictalurus punctatus rafinesque against different immobilization serotypes of ichthyophthirius multifiliis
Journal of Fish Diseases, 2006Co-Authors: Dehai Xu, Phillip H Klesius, Victor S PanangalaAbstract:: Abstract Channel catfish, Ictalurus punctatus (Rafinesque), were immunized with Ichthyophthirius multifiliis (Ich) theronts and Trophonts, and the immune response and host protection against both homologous and heterologous serotypes of Ich were evaluated. Immunizations were done with two immobilization serotypes (ARS4 and ARS6) of live theronts by bath immersion (trial I) and with sonicated Trophonts by intraperitoneal (i.p.) injection (trial II). Cutaneous and serum antibody titres against Ich following immunization were measured and survival of catfish was determined after theront challenge. Theronts were immobilized by the antiserum from fish immunized with homologous theronts or Trophonts, but not by the serum of fish immunized with the heterologous serotype. Serum from fish immunized by immersion with live theronts showed higher enzyme-linked immunosorbent assay titres against both homologous and heterologous serotypes than fish immunized by i.p. injection of Trophonts. Channel catfish immunized by immersion with live theronts or by i.p. injection with sonicated Trophonts developed an immune response against Ich and provided cross-protection against challenge from both serotypes (ARS4 and ARS6) of the parasite. Sonicated Trophont antigens in aqueous solution by i.p. injection could stimulate an immune response in fish, but the immunity was of short duration.
Dehai Xu - One of the best experts on this subject based on the ideXlab platform.
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antiparasitic efficacy of commercial curcumin against ichthyophthirius multifiliis in grass carp ctenopharyngodon idellus
Aquaculture, 2017Co-Authors: Qizhong Zhang, Yaowu Fu, Dehai Xu, Shengyu ZhouAbstract:Abstract Ichthyophthiriasis, caused by Ichthyophthirius multifiliis , is a prevalent parasitic disease in freshwater fish, it leads to a significant economic loss in fish farming industry. Following the ban of malachite green in usage of treating food fish, new antiparasitic agents for the treatment of ichthyophthiriasis is being studied. The aims of the present study were to investigate in vitro and in vivo antiparasitic efficacy of a commercial curcumin against I. multifiliis and evaluate its acute toxicity in grass carp. In vitro tests, curcumin killed all theronts at 1 mg/L for 38.7 min, caused 100.0% mortality of nonencysted tomonts at 8 mg/L for 47.3 min, and terminated the reproduction of encysted tomonts at 4 mg/L for 16 h, respectively. In vivo trials, curcumin at 4 mg/L for 10 days exposure eradicated all parasitic Trophonts in situ , and protected both infected and naive fish from I. multifiliis infections. The results of in vitro and in vivo experiments proved curcumin to be effective against the parasite. The 96 h median lethal concentration (LC 50 ) of curcumin to grass carp (58.5 mg/L) was about 146.3 times median effective concentration (EC 50 ) of curcumin to theronts (0.4 mg/L), and 18.9 times EC 50 of curcumin to nonencysted tomonts (3.1 mg/L). Therefore, the commercially available curcumin can be used as a potential lead compound for the development of commercial drugs against I. multifiliis .
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susceptibility of channel catfish blue catfish and channel blue catfish hybrid to ichthyophthirius multifiliis
Aquaculture, 2011Co-Authors: Dehai Xu, Phillip H Klesius, Eric PeatmanAbstract:Abstract Information on the infectivity of Ichthyophthirius multifiliis (Ich), a severe fish parasite that causes high mortality, is limited for blue catfish ( Ictalurus furcatus ) and catfish hybrids (CB hybrid) resulting from female channel catfish ( Ictalurus punctatus ) × male blue catfish crosses. The objective of this study was to compare channel catfish, blue catfish and CB hybrids on the infection level and fish mortality caused by Ich using a cohabitation model. To compare the susceptibility to Ich between channel and blue catfish, fish were exposed to 5000 or 10000 theronts per fish, respectively. There were no statistical differences in the infection levels and mortalities between channel catfish and blue catfish. Channel catfish showed an infection score of 2.9 and blue catfish of 2.7 when infected by theronts at 10,000 theronts per fish. The cumulative mortalities were 86.3% and 80.6 %, respectively for channel catfish and blue catfish when exposed to theronts at 5000 theronts per fish. To compare the susceptibility to Ich between channel catfish and CB hybrid, fish were infected by cohabiting with 1 or 3 Ich-infected fish or exposure to Ich theronts at 2500–10,000 theronts per fish. Channel catfish and CB hybrid showed similar infection levels of > 150 Trophonts/fish and infection duration of 7–8 days when cohabited with 1 or 3 Ich-infected fish. All channel catfish and CB hybrid exposed to theronts at the dose of 10,000 theronts/fish showed heavy infection of > 150 Trophonts/fish. The cumulative mortalities were 90% and 80% for channel catfish and CB hybrid after exposure to 2500 theronts per fish. No statistical difference was found in the infection levels and mortalities using two infection methods between channel catfish and CB hybrid. Overall results indicated that CB hybrid were as susceptible to Ich as channel catfish or blue catfish.
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gene expression profiling of a fish parasite ichthyophthirius multifiliis insights into development and senescence associated avirulence
Comparative Biochemistry and Physiology, 2011Co-Authors: Jason Abernathy, Dehai Xu, Eric Peatman, Huseyin Kucuktas, Phillip H KlesiusAbstract:The ciliate parasite Ichthyophthirius multifiliis (Ich) infects many freshwater fish, causing white spot disease that leads to heavy economic losses to aquaculture and ornamental industries. Despite its economic importance, molecular studies examining fundamental processes such as life stage regulation and infectivity have been scarce. In this study, we developed an oligo microarray platform using all available I. multifiliis expressed sequence tag (EST) information as well as probes designed through comparative genomics to other protozoa. Gene expression profiling for developmental and virulence factors was conducted using this platform. For the developmental study, the microarray was used to examine gene expression profiles between the three major life stages of Ich: infective theront, parasitic Trophont, and reproductive tomont. A total of 135 putative I. multifiliis genes were found to be differentially expressed among all three life-stages. Examples of differentially expressed transcripts among life stages include immobilization antigens and epiplasmin, as well as various other transcripts involved in developmental regulation and host-parasite interactions. I. multifiliis has been shown to lose infectivity at later cell divisions potentially due to cellular senescence. Therefore, the microarray was also used to explore expression of senescence-associated genes as related to the passage number of the parasite. In this regard, comparison between tomont early and late passages yielded 493 differently expressed genes; 1478 differentially expressed genes were identified between Trophont early and late passages. The EST-derived oligo microarray represents a first generation array of this ciliate and provided reproducible expression data as validated by quantitative RT-PCR.
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effect of immunization of channel catfish with inactivated Trophonts on serum and cutaneous antibody titers and survival against ichthyophthirius multifiliis
Fish & Shellfish Immunology, 2009Co-Authors: Dehai Xu, Phillip H Klesius, Craig A ShoemakerAbstract:Abstract Two trials were conducted to determine the effect of immunization of channel catfish with inactivated Trophonts on serum and cutaneous antibody titers and survival against Ichthyophthirius multifiliis Fouquet (Ich). In trial I, catfish were immunized intraperitoneally (IP) with: 1) 1% formalin-inactivated Trophonts, 2) 3% formalin-inactivated Trophonts and 3) freeze-thawed Trophonts. Positive and negative control catfish were immunized with live theronts and 5% bovine serum albumin (BSA), respectively. At day 14, 28 and 50 post-immunizations, no statistical difference was noted in serum or cutaneous anti-Ich antibody titers to formalin-inactivated Trophonts or freeze-thawed Trophonts. The survival of catfish challenged with live theronts ranged from 33.3% to 43.3% for the formalin-inactivated or freeze-thawed Trophonts at 50 d post-immunization. The survival of catfish immunized with live theront and BSA was 93.3 and 0%, respectively. In trial II, catfish were IP immunized with sonicated Trophonts at doses of 1) 5 Trophonts or 10.2 μg protein g −1 fish, 2) 10 Trophonts or 20.4 μg protein g −1 fish, 3) 20 Trophonts or 40.8 μg protein g −1 fish, and 4) 5% BSA as the control. Fish immunized with 10 or 20 Trophonts g −1 fish showed highest serum (1/210 to 1/480) and cutaneous antibody titers (1/48 to 1/52), respectively, at 22 d post-immunization and survival (63.3–60.0%). The fish immunized with 5 Trophonts g −1 fish had titers of 1/52 and 1/12 for serum and cutaneous antibody and survival of 23.3%. BSA immunized catfish had background titers and a survival of 6.7%. There was a significant correlation between doses of sonicated Trophonts used to immunize and catfish survival (correlation coefficient = 0.859, p
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protective immunity of nile tilapia against ichthyophthirius multifiliis post immunization with live theronts and sonicated Trophonts
Fish & Shellfish Immunology, 2008Co-Authors: Dehai Xu, Phillip H Klesius, Craig A ShoemakerAbstract:Two immunization trials were conducted to evaluate host protection of Nile tilapia, Oreochromis niloticus against Ichthyophthirius multifiliis (Ich). Immunizations were done with live theronts or sonicated Trophonts by bath immersion and intraperitoneal (IP) injection. The immunized fish were challenged with theronts 21 days post-immunization in trial I and 180 days post-immunization in trial II. The serum anti-Ich antibody and cumulative mortalities of tilapia were determined after theront challenge. Serum anti-Ich antibody was significantly higher (P < 0.05) in tilapia immunized with live theronts by immersion or IP injection or with sonicated Trophonts administered by IP injection than tilapia immunized with sonicated Trophonts by immersion, with bovine serum albumin by IP injection, or non-immunized controls. Host protection was acquired in fish immunized with live theronts by immersion or IP injection. Tilapia immunized with sonicated Trophonts by IP injection were partially protected with a 57–77% survival in both trials. At 180 days post-immunization, serum antibody titers had declined in immunized fish yet they were still able to survive challenge. The protection appears not to be solely depending on serum antibody response against Ich.
