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Juvenile Channel Catfish (juvenile + channel_catfish)
Selected AbstractsDietary Bovine Lactoferrin Increases Resistance of Juvenile Channel Catfish, Ictalurus punctatus, to Enteric SepticemiaJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2010Thomas L. Welker Juvenile channel catfish, Ictalurus punctatus, were fed nutritionally complete, practical basal diets supplemented with bovine lactoferrin (Lf) at 0, 200, 400, 800, or 1600 mg/kg diet for 5 wk. Feed intake was significantly higher in fish-fed diets supplemented with Lf compared to the control diet, but the increased feed intake did not translate to significant increases in growth performance. Hemoglobin, white and red blood cell counts, and resistance to low-water stress also were not different among dietary groups (P > 0.05). Levels of Lf in diets had a significant effect on survival of channel catfish following challenge with Edwardsiella ictaluri: catfish fed 800 or 1600 mg/kg Lf had higher survival than the groups fed the control or 200 mg Lf diet. We established the break point minimum concentration of Lf for resistance to E. ictaluri infection as 1136 mg/kg. There was not a corresponding increase in activity of nonspecific or specific immune parameters with addition of Lf to diets, but plasma iron decreased significantly in channel catfish fed bovine Lf compared to the control group. However, no clear trend for level of dietary Lf, iron status, and resistance to E. ictaluri infection could be established. [source] Influence of Dietary Levels of Magnesium on Growth, Tissue Mineral Content, and Resistance of Channel Catfish Ictalurus punctatus Challenged with Edwardsiella ictaluriJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2003Chhorn Lim Juvenile channel catfish were fed purified diets supplemented with magnesium (Mg) from Mg sulfate at levels of 0, 200, 400, 600, 800, and 1,000 mg/kg and 0, 200, 400, 600, and 800 mg/kg in two separate feeding studies. In study I, the effect of dietary levels of Mg on growth response, vertebral mineral content, and macrophage chemotaxis were evaluated. Study II had similar objectives except that whole body mineral content was measured, and resistance of channel catfish to Edwardsiella ictaluri challenge was also determined. Fish with an average weight of 10.89 g were stocked at a rate of 50 fish/110-L aquarium (study I). In study II, fish with an average weight of 4.14 g were stocked at rates of 40 fish/110-L aquarium. Prior to stocking, each batch of fish was acclimated to laboratory conditions and fed the basal diet for 2 wk. The concentration of Mg in rearing water was 1.8 mg/L. Each diet was fed to fish in quadruplicate and triplicate aquaria to apparent satiation for 10 wk for studies I and II, respectively. Fish fed the basal diet started to die as early as 3 d after the study began (17 d of feeding the diet without Mg supplementation). In both studies, weight gain, survival, and feed efficiency were lowest for fish fed the basal diet but increased with increasing dietary levels of Mg. However, the differences between the values of each of these parameters for fish fed diets containing supplemental Mg were not always significant. Magnesium-deficiency signs observed were anorexia, sluggishness, convulsions, deformed snout, vertebral curvature, muscle flaccidity, and high mortality. Vertebral and whole body ash concentrations were high, but Mg content was low for fish fed the basal and the 200-mg Mg diets. Bone Ca content did not differ among fish fed different diets (study I), but whole body Ca tended to increase for fish fed the basal diet, suggesting the possibility of calcification of soft tissues. Macrophage chemotaxis in the presence of exoantigen was highest for fish fed diets supplemented with Mg at 400 and 200 mgkg for studies I and II, respectively. When expressed in terms of chemotaxis index, however, maximum or near maximum value was observed at a dietary Mg level of 400 mg/kg. Thus, a dietary level of Mg of 400 mg/kg from Mg sulfate was required for optimum growth and survival, maintaining high tissue levels of Mg, prevention of muscle flaccidity and skeletal deformity, and stimulating macrophage chemotaxis. Dietary levels of Mg had no effect on the resistance of juvenile channel catfish to Edwarsiella. ictaluri challenge. [source] Effects of various corn distillers by-products on growth, feed efficiency, and body composition of channel catfish, Ictalurus punctatusAQUACULTURE NUTRITION, Issue 2 2010M.H. LI Abstract A study was conducted to examine the use of corn distillers' by-products in diets and the effects of additional dietary fat on channel catfish, Ictalurus punctatus, performance. Juvenile channel catfish (initial weight: 12.6 g per fish) were stocked in flow-through aquaria and fed one of six practical diets for 9 weeks. Fish fed the control + fat diet consumed more diet and had higher feed efficiency ratio (FER) than fish fed the control diet, but weight gain was not significantly different between fish fed these two diets. Fish fed the diet containing 300 g kg,1 distillers dried grains with solubles (DDGS) consumed more diet and gained more weight, but had similar FER compared with fish fed the control + fat diet. The diet containing 200 g kg,1 high-protein distillers grains (HPDDG) resulted in similar diet consumption, weight gain and FER as the control + fat diet. Fish fed the diet containing 100 g kg,1 distillers solubles (DS) consumed more diet, but had similar weight gain and FER compared with fish fed the 300 g kg,1 DDGS diet. The presence of distillers solubles in the diet (300 g kg,1 DDGS, 100 g kg,1 DS, 100 g kg,1 EDS diets) appears to increase diet consumption, weight gain, and FER over the control diets with or without additional fat. [source] Effect of Sublethal Hypoxia on the Immune Response and Susceptibility of Channel Catfish, Ictalurus punctatus, to Enteric SepticemiaJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2007Thomas L. Welker The effect of sublethal hypoxia exposure on stress and immune responses and susceptibility to Edwardsiella ictaluri infection in juvenile channel catfish, Ictalurus punctatus, was investigated. Fish were monitored for temporal changes in glucose and cortisol concentrations before, during, and after 2 h exposure to sublethal hypoxia (<2 mg/L dissolved oxygen [DO]) and when maintained under normoxic conditions (6.0 ± 0.3 mg/L DO). Both blood glucose and plasma cortisol increased significantly in response to hypoxic conditions. Fish exposed to hypoxic or normoxic conditions were challenged with a high dose (1.3 × 107 colony-forming units [CFU]/mL) or a low dose (1.3 × 105 CFU/mL) of E. ictaluri or sterile culture broth by 30-min immersion bath. Approximately 1% of fish in both the normoxic and the hypoxic groups died when challenged with the low dose of E. ictaluri. However, when challenged with the high dose of E. ictaluri, catfish exposed to hypoxic conditions had significantly higher cumulative mortality (36 ± 12.1%) than those maintained under normoxic conditions (12 ± 1.1%). Total hemolytic complement and bactericidal activities and antibody response were lower in hypoxia-exposed channel catfish, indicating that increased susceptibility of channel catfish to E. ictaluri may be the result of the immunosuppressive effects of the stress response to hypoxia. [source] Immune Response and Resistance to Stress and Edwardsiella ictaluri Challenge in Channel Catfish, Ictalurus punctatus, Fed Diets Containing Commercial Whole-Cell Yeast or Yeast SubcomponentsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2007Thomas L. Welker Dietary supplementation of yeast or yeast subcomponents (YYS) as commercial preparations of ,-glucan (MacroGard®; Biotec-Mackzymal, Tromsø, Norway; and Betagard A®; Aqua-In-Tech, Inc., Seattle, WA, USA), mannan oligosaccharide (Bio-MosÔ Aqua Grade; Alltech, Nicholasville, KY, USA), or whole-cell Saccharomyces cerevisiae (Levucell SB20®; Lallemand Animal Nutrition, Milwaukee, WI, USA) at the manufacturer's recommended levels was evaluated on the physiological performance of juvenile channel catfish, Ictalurus punctatus. Fish were fed YYS diets for 4 wk, followed by 2 wk of control diet. Fish were sampled at the end of each feeding period (4 and 6 wk) to measure hematological and immune parameters and growth and to determine the effects of dietary ,-glucan on resistance to Edwardsiella ictaluri infection and to low-water stress (6 wk). Supplementation of YYS in diets did not affect growth performance, hematology, or immune function. Survival from E. ictaluri infection was from 5 to 17.5% higher in fish fed YYS diets than in the control group, but the increases were not significant. Some improvement in stress resistance was observed in YYS-fed catfish after exposure to low-water stress. Stress reduction in fish fed diets supplemented with yeast subcomponents has been reported previously, but thus far, no explanation has been proposed for this effect. The present study and the previously published research suggest that dietary YYS supplementation does not appear to improve resistance of channel catfish to E. ictaluri. [source] Influence of Dietary Levels of Magnesium on Growth, Tissue Mineral Content, and Resistance of Channel Catfish Ictalurus punctatus Challenged with Edwardsiella ictaluriJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2003Chhorn Lim Juvenile channel catfish were fed purified diets supplemented with magnesium (Mg) from Mg sulfate at levels of 0, 200, 400, 600, 800, and 1,000 mg/kg and 0, 200, 400, 600, and 800 mg/kg in two separate feeding studies. In study I, the effect of dietary levels of Mg on growth response, vertebral mineral content, and macrophage chemotaxis were evaluated. Study II had similar objectives except that whole body mineral content was measured, and resistance of channel catfish to Edwardsiella ictaluri challenge was also determined. Fish with an average weight of 10.89 g were stocked at a rate of 50 fish/110-L aquarium (study I). In study II, fish with an average weight of 4.14 g were stocked at rates of 40 fish/110-L aquarium. Prior to stocking, each batch of fish was acclimated to laboratory conditions and fed the basal diet for 2 wk. The concentration of Mg in rearing water was 1.8 mg/L. Each diet was fed to fish in quadruplicate and triplicate aquaria to apparent satiation for 10 wk for studies I and II, respectively. Fish fed the basal diet started to die as early as 3 d after the study began (17 d of feeding the diet without Mg supplementation). In both studies, weight gain, survival, and feed efficiency were lowest for fish fed the basal diet but increased with increasing dietary levels of Mg. However, the differences between the values of each of these parameters for fish fed diets containing supplemental Mg were not always significant. Magnesium-deficiency signs observed were anorexia, sluggishness, convulsions, deformed snout, vertebral curvature, muscle flaccidity, and high mortality. Vertebral and whole body ash concentrations were high, but Mg content was low for fish fed the basal and the 200-mg Mg diets. Bone Ca content did not differ among fish fed different diets (study I), but whole body Ca tended to increase for fish fed the basal diet, suggesting the possibility of calcification of soft tissues. Macrophage chemotaxis in the presence of exoantigen was highest for fish fed diets supplemented with Mg at 400 and 200 mgkg for studies I and II, respectively. When expressed in terms of chemotaxis index, however, maximum or near maximum value was observed at a dietary Mg level of 400 mg/kg. Thus, a dietary level of Mg of 400 mg/kg from Mg sulfate was required for optimum growth and survival, maintaining high tissue levels of Mg, prevention of muscle flaccidity and skeletal deformity, and stimulating macrophage chemotaxis. Dietary levels of Mg had no effect on the resistance of juvenile channel catfish to Edwarsiella. ictaluri challenge. [source] Chironomid abundance and consumption by juvenile channel catfish in plastic-lined and earthen culture pondsAQUACULTURE RESEARCH, Issue 9 2010Bonnie L Mulligan Abstract In 2004, research was conducted to compare chironomid larvae populations and their use by channel catfish (Ictalurus punctatus) fingerlings in two different culture systems. Over a 4-month culture period, chironomid larvae densities in plastic-lined ponds were significantly less than those in earthen ponds. The consumption of chironomid larvae by channel catfish fingerlings was related to chironomid abundance in earthen ponds. The significance of these findings is the possible relationship among pond type, initial consumption of commercial diets and subsequent survival rates of fingerling channel catfish. [source] Comparison of susceptibility of various fish species to experimental infection with channel catfish virusAQUACULTURE RESEARCH, Issue 16 2009Wan-An Yuan Abstract Channel catfish virus (CCV) disease is an acute haemorrhagic disease in juvenile channel catfish (Ictalurus punctatus). To date channel catfish is the only species affected by natural outbreaks of the CCV but juvenile large mouth bass (Micropterus salmoides) and silurus (Silurus meriaionalis) have suffered high mortalities in recent years in China. Histopathological phenomenon of sick fish is similar to CCV disease, and the identified virus was CCV. In this report, the pathogenicity of infectious CCV was examined by infection trials on the first known host species, the channel catfish and other teleosts. Our results indicated that there were higher detection rates of CCV from large mouth bass and silurus fish. Channel catfish virus did not induce mortality in other cypriniformes, but histopathological studies revealed that carp might be infected by both bathing and intraperitoneal infection. No deaths, clinical or histopathological signs, were found in the six other species exposed by immersion or injection. Experimental infection studies confirm that CCV infect not only channel catfish but also other species (large mouth bass, silutus and carp). The outbreaks of CCV disease only occurred when the cultured temperature was above 25 °C. [source] | ||||||||||