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Wayne L. Gray - One of the best experts on this subject based on the ideXlab platform.
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Effect of dietary cortisol on resistance of Channel Catfish to infection by Ichthyopthirius multifiliis and Channel Catfish virus disease
Aquaculture, 2003Co-Authors: Kenneth B Davis, Billy R Griffin, Wayne L. GrayAbstract:Many diseases of fish are more likely to occur after a period of stress. A number of physiological changes occur in fish during stress including the secretion of cortisol. Cortisol has several effects including the induction of gluconeogenesis and immunosuppression. The latter activity of cortisol is thought to be the reason stress is often followed by a disease outbreak. These experiments were done to determine the role of cortisol, in the absence of stress, in affecting the susceptibility of Channel Catfish to Ichthyopthirius multifiliis (ich) and Channel Catfish virus (CCV). Cortisol mixed in the food resulted in reduced liver size and abolished the increase of plasma cortisol usually induced by confinement stress. Dietary cortisol provided at 200-mg/kg feed increased the susceptibility of Channel Catfish to infection in an immersion challenge with ich theronts. The severity of infection in fish provided cortisol at 100-mg/kg feed was not different than controls. Dietary cortisol at either 100 or 200 mg/kg did not affect mortality due to CCV exposure. These data suggest that increased cortisol suppressed the protective mechanism against ich but not against CCV.
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Channel Catfish virus gene expression in experimentally infected Channel Catfish, Ictalurus punctatus (Rafinesque)
Journal of Fish Diseases, 2003Co-Authors: Robin L. Stingley, B R Griffin, Wayne L. GrayAbstract:Channel Catfish virus (CCV) produces an acute haemorrhagic disease in fingerling Channel Catfish and establishes latent infection in fish that survive the primary infection. This study investigated CCV gene expression in tissues of experimentally infected fish. Reverse transcriptase polymerase chain reaction assays were developed for detection of transcripts expressed by each of the CCV direct repeat region genes in CCV-infected Channel Catfish ovary cells and in tissues of infected fish. Immediate-early, early and late gene transcripts were detected in the blood, brain, kidney and liver tissues of acutely infected Catfish demonstrating active viral replication in multiple tissues during the early stages of CCV infection. However, there was no evidence for viral replication by 24 days post-infection in tissues of fish that survived the acute disease. Viral latency-associated transcripts encoded by CCV direct repeat genes were not detected in latently infected Catfish. The results of this study provide a foundation for further studies to investigate the molecular basis of CCV pathogenesis and latency.
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effect of handling stress on susceptibility of Channel Catfish ictalurus punctatus to ichthyophthirius multifiliis and Channel Catfish virus infection
Aquaculture, 2002Co-Authors: Kenneth B Davis, Billy R Griffin, Wayne L. GrayAbstract:A quantitative bioassay employing immersion exposure was developed for the infection of Channel Catfish Ictalurus punctatus with the protozoan parasite Ichthyophthirius multifiliis, commonly referred to as ich. This bioassay as well as waterborne challenge of Channel Catfish with Channel Catfish virus (CCV) was used to investigate the effect of confinement stress on the sensitivity of the fish to exposure of these pathogens. Infestation by ich was shown to be proportional to the density of infective theronts in the exposure tank and low-water crowding stress was shown to increase susceptibility of Catfish to infection. Mortality from CCV was related to the virus exposure dose; however, low-water crowding stress did not affect mortality. Increased susceptibility, due to crowding stress of naive Channel Catfish to I. multifiliis but not to CCV, suggests a difference in the defence mechanisms. Stress-induced increased susceptibility to I. multifiliis may be due to a suppression of an innate protection mechanism. The lack of effect of stress on CCV mortality may be due to protection afforded by an inducible system which was not affected by the stressor, or the lethal effects of the virus were too fast for the stress to change susceptibility in fish exposed to CCV for the first time.
Kenneth B Davis - One of the best experts on this subject based on the ideXlab platform.
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Effect of dietary cortisol on resistance of Channel Catfish to infection by Ichthyopthirius multifiliis and Channel Catfish virus disease
Aquaculture, 2003Co-Authors: Kenneth B Davis, Billy R Griffin, Wayne L. GrayAbstract:Many diseases of fish are more likely to occur after a period of stress. A number of physiological changes occur in fish during stress including the secretion of cortisol. Cortisol has several effects including the induction of gluconeogenesis and immunosuppression. The latter activity of cortisol is thought to be the reason stress is often followed by a disease outbreak. These experiments were done to determine the role of cortisol, in the absence of stress, in affecting the susceptibility of Channel Catfish to Ichthyopthirius multifiliis (ich) and Channel Catfish virus (CCV). Cortisol mixed in the food resulted in reduced liver size and abolished the increase of plasma cortisol usually induced by confinement stress. Dietary cortisol provided at 200-mg/kg feed increased the susceptibility of Channel Catfish to infection in an immersion challenge with ich theronts. The severity of infection in fish provided cortisol at 100-mg/kg feed was not different than controls. Dietary cortisol at either 100 or 200 mg/kg did not affect mortality due to CCV exposure. These data suggest that increased cortisol suppressed the protective mechanism against ich but not against CCV.
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effect of handling stress on susceptibility of Channel Catfish ictalurus punctatus to ichthyophthirius multifiliis and Channel Catfish virus infection
Aquaculture, 2002Co-Authors: Kenneth B Davis, Billy R Griffin, Wayne L. GrayAbstract:A quantitative bioassay employing immersion exposure was developed for the infection of Channel Catfish Ictalurus punctatus with the protozoan parasite Ichthyophthirius multifiliis, commonly referred to as ich. This bioassay as well as waterborne challenge of Channel Catfish with Channel Catfish virus (CCV) was used to investigate the effect of confinement stress on the sensitivity of the fish to exposure of these pathogens. Infestation by ich was shown to be proportional to the density of infective theronts in the exposure tank and low-water crowding stress was shown to increase susceptibility of Catfish to infection. Mortality from CCV was related to the virus exposure dose; however, low-water crowding stress did not affect mortality. Increased susceptibility, due to crowding stress of naive Channel Catfish to I. multifiliis but not to CCV, suggests a difference in the defence mechanisms. Stress-induced increased susceptibility to I. multifiliis may be due to a suppression of an innate protection mechanism. The lack of effect of stress on CCV mortality may be due to protection afforded by an inducible system which was not affected by the stressor, or the lethal effects of the virus were too fast for the stress to change susceptibility in fish exposed to CCV for the first time.
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Responses of Blue Catfish and Channel Catfish to Environmental Nitrite
Journal of Aquatic Animal Health, 1995Co-Authors: Jerolyn E. Schoore, Bill A. Simco, Kenneth B DavisAbstract:Abstract In nitrite-exposure experiments, percent methemoglobin, plasma nitrite concentration, and plasma chloride ion concentration were compared between Channel Catfish Ictalurus punctatus and blue Catfish I. furcatus exposed to sublethal levels of nitrite for 48 h at 25°C. In nitrite-recovery experiments, fish exposed to elevated environmental nitrite for 12 h were transferred to freshwater, and blood characteristics were monitored during the 24-h recovery period. Blue Catfish appeared to be more resistant to environmental nitrite than Channel Catfish. Methemoglobin levels (percent of hemoglobin in methemoglobin form) were significantly lower in blue Catfish than in Channel Catfish. Maximum plasma nitrite concentrations were 137 mg NO2-/L plasma in blue Catfish and 164 mg NO2-/L plasma in Channel Catfish. Percent methemoglobin and plasma nitrite concentration were closely correlated. Plasma chloride decreased initially with exposure to nitrite but quickly returned to control levels. Blue Catfish expose...
William R Wolters - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Production, Meat Yield, and Meat Quality Traits of NWAC103 Line Channel Catfish, Norris Line Channel Catfish, and Female Channel Catfish × Male Blue Catfish F1 Hybrids
North American Journal of Aquaculture, 2004Co-Authors: Brian G Bosworth, William R Wolters, Juan L. Silva, Roberto S. Chamul, Sinyoung ParkAbstract:Abstract NWAC103 line Channel Catfish Ictalurus punctatus, Norris line Channel Catfish, and Norris line female Channel Catfish × Dycus Farm line male blue Catfish I. furcatus F1 hybrids were compared for production, meat yield, and meat quality traits. Juvenile fish from each genetic group were stocked at 12,000 fish/ha into three, 0.04-ha ponds per genetic group. Fish were fed once daily to satiation from June through October, and fed on days when afternoon water temperatures were above 17°C from November through December. Fish were harvested, weighed, and counted in January, and 150 fish per genetic group (50 fish per pond) were processed and measured for meat and body component yield. Instrumental and sensory panel evaluations of quality were measured on fresh, frozen-thawed, and baked fillets. Stocking weight, harvest weight, and net production (kg/ha) were highest for the NWAC103 line Channel Catfish, intermediate for the hybrid, and lowest for the Norris line Channel Catfish. Growth at unit size (a)...
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Family and genetic group effects for resistance to proliferative gill disease in Channel Catfish, blue Catfish and Channel Catfish×blue Catfish backcross hybrids
Aquaculture Research, 2003Co-Authors: Brian G Bosworth, David J. Wise, Jeffery S. Terhune, William R WoltersAbstract:The severity of gill damage (percentage of gill lamellae with lytic lesions) was determined in juveniles from 10 USDA 103 line Channel Catfish Ictalurus punctatus full-sib families, 10 Channel Catfish x blue Catfish I. furcatus backcross hybrid (7/8 Channel Catfish, 1/8 blue Catfish) full-sib families and a mixed-family group of blue Catfish placed in a commercial Catfish pond experiencing proliferative gill disease (PGD)-related fish mortalities. An initial challenge was conducted with all families, and a second challenge was conducted using the two most susceptible (most gill damage) Channel Catfish and backcross hybrid families and the two most resistant (least gill damage) Channel Catfish and backcross hybrid families. In the initial challenge, percentage gill damage was not different between Channel Catfish (12.3%) and backcross hybrids (11.6%), but was lower in blue Catfish (0.2%). Mean percentage gill damage in the second challenge was not different among resistant backcross hybrid families (6.9%), resistant Channel Catfish families (7.6%) and blue Catfish (4.8%), but was higher in susceptible backcross hybrid and Channel Catfish families (19.0% and 11.9% respectively). The correlation among family means for gill damage from challenge 1 and challenge 2 was r=0.87. Consistent differences between Channel Catfish and blue Catfish and between resistant and susceptible families within genetic groups for gill damage after PGD challenge suggest that there is a genetic component for resistance to PGD and that improving PGD resistance through selection may be possible.
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a microsatellite based genetic linkage map for Channel Catfish ictalurus punctatus
Genetics, 2001Co-Authors: Geoffrey C Waldbieser, D Nonneman, Brian G Bosworth, William R WoltersAbstract:Microsatellite loci were identified in Channel Catfish gene sequences or random clones from a small insert genomic DNA library. Outbred populations of Channel Catfish contained an average of eight alleles per locus and an average heterozygosity of 0.70. A genetic linkage map of the Channel Catfish genome (N = 29) was constructed from two reference families. A total of 293 microsatellite loci were polymorphic in one or both families, with an average of 171 informative meioses per locus. Nineteen type I loci, 243 type II loci, and one EST were placed in 32 multipoint linkage groups covering 1958 cM. Nine more type II loci were contained in three two-point linkage groups covering 24.5 cM. Twenty-two type II loci remained unlinked. Multipoint linkage groups ranged in size from 11.9 to 110.5 cM with an average intermarker distance of 8.7 cM. Seven microsatellite loci were closely linked with the sex-determining locus. The microsatellite loci and genetic linkage map will increase the efficiency of selective breeding programs for Channel Catfish.
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Survival and Antibody Response of Channel Catfish, Blue Catfish, and Channel Catfish Female × Blue Catfish Male Hybrids after Exposure to Edwardsiella ictaluri
Journal of Aquatic Animal Health, 1996Co-Authors: William R Wolters, David J. Wise, Phillip H KlesiusAbstract:Abstract Juvenile Norris strain Channel Catfish Ictalurus punctatus, blue Catfish I. furcatus, and Norris strain Channel Catfish female × blue Catfish male hybrids were challenged with Edwardsiella ictaluri by bath immersion or intraperitoneal injection (high or low dose) in aquaria. Survival (%) after bath immersion was highest for blue Catfish (89.5 ± 2.8), intermediate for hybrids (73.8 ± 6.7), and lowest for Channel Catfish (62.0 ± 4.2). Prechallenge antibody levels to E. ictaluri, measured by enzyme-linked immunosorbent assay, were negative (mean ± SE optical density [OD] = 0.010 ± 0.003). Postchallenge antibody response for blue Catfish (OD = 0.132 ± 0.045) was significantly lower than that of Channel Catfish (OD = 0.350 ± 0.045), whereas the response of the Channel × blue Catfish F1 hybrids (OD = 0.263 ± 0.051) was intermediate and not significantly different from either parental species. Intraperitoneal injections of E. ictaluri resulted in significant mortality only in Channel Catfish (88.3 ± 2.6...
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Enteric septicemia resistance in blue Catfish and three Channel Catfish strains
Journal of Aquatic Animal Health, 1994Co-Authors: William R Wolters, Michael R. JohnsonAbstract:Abstract Seven full-sib families in each of three strains of Channel Catfish Ictalurus punctatus (mean weight, 10.7 g; SD, 2.6 g) and one family of blue Catfish I. furcatus (mean, 10.9 g; SD, 0.4 g) were challenged by immersion with the bacterium Edwardsiella ictaluri, the causative agent of enteric septicemia, to evaluate variation in disease resistance. Blue Catfish were resistant to infection and had only 0.7% mortality. Significant (P < 0.001) variation in Channel Catfish resistance was found among strains, families, and body weights. Red River strain Channel Catfish were the most resistant (14.9% mortality), followed by Mississippi-select fish (67.1%) and Mississippi-normal fish (72.3%). Mean family mortality of Channel Catfish ranged from 1.3% in a Red River family to 95.3% in a Mississippi-select family. Although weight had a significant effect on survival, the regression slope of survival on weight was −0.10 (SE, 0.02). Sources of variation in Channel Catfish mortality adjusted for weight were 67....
Steven D. Mims - One of the best experts on this subject based on the ideXlab platform.
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Survival of Paddlefish Fingerlings Stocked with Large Channel Catfish
The Progressive Fish-Culturist, 1990Co-Authors: James H. Tidwell, Steven D. MimsAbstract:Abstract Fingerling paddlefish (Polyodon spathula; 9–15 cm total length, TL) were stocked with two densities of large Channel Catfish (Ictalurus punctatus; >38 cm TL). No paddlefish were recovered from any of the six ponds at harvest, probably due to predation by the large Channel Catfish. Advanced paddlefish fingerlings (25–30 cm TL) may be required for polyculture in ponds that contain large Channel Catfish.
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Winter Polyculture of Rainbow Trout and Fingerling Channel Catfish
The Progressive Fish-Culturist, 1990Co-Authors: James H. Tidwell, Steven D. MimsAbstract:Abstract The feasibility of rearing rainbow trout (Oncorhynchus mykiss) with overwintering fingerling Channel Catfish (Ictalurus punctatus) at one of two densities was examined. Individual weight gain, net production, and feed conversion were better for rainbow trout in monoculture than in either polyculture treatment. There was a significant difference in growth but not in survival of Channel Catfish polycultured at low and high densities with rainbow trout.
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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Susceptibility of Channel Catfish, blue Catfish and Channel × blue Catfish hybrid to Ichthyophthirius multifiliis
Aquaculture, 2010Co-Authors: Phillip H Klesius, Eric Peatman, Zhanjiang LiuAbstract: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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Pathogenicity of Streptococcus ictaluri to Channel Catfish
Journal of Aquatic Animal Health, 2009Co-Authors: David J. Pasnik, Phillip H Klesius, Craig A Shoemaker, Joyce J. Evans, Hung-yueh YehAbstract:Abstract The pathogenicity of a Streptococcus ictaluri isolate in Channel Catfish Ictalurus punctatus at the fry (0.5 g), fingerling (15 g), and juvenile (55 g) stages was determined by experimental bath immersion and injection experiments. Channel Catfish were exposed in 1-L immersion baths containing 108, 109, 1010, 1011, or 1012 colony-forming units (cfu) of S. ictaluri. Fish were also injected intraperitoneally with 0.1 mL of bacterial solution for final doses of 104, 105, 106, 107, or 108 cfu of S. ictaluri per fish. Streptococcus ictaluri caused mortality in fry, fingerling, and juvenile Channel Catfish within 21 d postinfection. When mortalities were calculated based on size and challenge route, the cumulative percent mortalities were 11% for fry and 0% for fingerlings by the bath immersion route and 14% for fingerlings and 6% for juveniles by the injection route. Isolation of S. ictaluri from moribund and dead Catfish was confirmed by the newly established BIOLOG profile (MicroLog3 system). The re...
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flavobacterium columnare genomovar influences mortality in Channel Catfish ictalurus punctatus
Veterinary Microbiology, 2008Co-Authors: Craig A Shoemaker, Oscar Olivaresfuster, Covadonga R. Arias, Phillip H KlesiusAbstract:Abstract Flavobacterium columnare, causal agent of columnaris disease, is pathogenic to many species of freshwater fish throughout the world. The United States Channel Catfish (Ictalurus punctatus) aquaculture industry is severely impacted by columnaris disease. The majority of the F. columnare isolates recovered from diseased Channel Catfish belonged to either genomovars I or II. The objective of the present study was to determine if differences existed in the ability of these genomovars to induce mortality in Channel Catfish. Single strand conformation polymorphism analysis (SSCP) was used to ascribe the isolates used in this study to the appropriate genomovar. Immersion challenge experiments (15 min immersion exposure to ∼5 × 105 to 1 × 106 CFU/mL) were carried out to assess virulence of genomovar I and II isolates to Channel Catfish. The results demonstrated that genomovar II (n = 4) isolates were significantly (P
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Flavobacterium columnare chemotaxis to Channel Catfish mucus.
FEMS Microbiology Letters, 2008Co-Authors: Phillip H Klesius, Craig A Shoemaker, Joyce J. EvansAbstract:Flavobacterium columnare is a Gram-negative pathogen of many species of wild and cultured fish. Isolates from diseased Channel Catfish belong to either genomovar I or II. Genomovar II isolates were found to be more virulent than genomovar I isolates. The objective of the present study was to determine whether differences exist in the chemotactic response of these genomovars to mucus obtained from the skin, gills and intestines of healthy Channel Catfish using the capillary chemotaxis assay. Mucus from the skin and gill induced a greater chemotactic response by F. columnare than mucus from the intestine. Sixty percent of mucus from the skin of individual Catfish yielded a positive chemotactic response from F. columnare. Finally, skin mucus induced a greater chemotactic response in genomovar II F. columnare than in genomovar I F. columnare isolates. The data indicate that mucus from Channel Catfish results in a chemotactic response by F. columnare. This positive chemotactic response may be an important first step for F. columnare colonization of Channel Catfish skin or gills. Although the role that chemotaxis plays in the virulence of F. columnare is not fully defined, the chemotactic response of genomovar ll isolates suggests that chemotaxis is associated with virulence.