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Abstract: Four patients with refractory epilepsy and hypermotor seizures (HMS) benefited from an intracerebral investigation after a presurgical evaluation and demonstrated an ictal onset zone primarily involving the posterior cortex, specifically the posterior cingulate gyrus in two patients. At seizure onset, these two patients reported a falling sensation, followed by HMSs characterized by swinging movements of the trunk with intense grasping of the bed railing. The two other patients with lateral parietal seizure onset reported blurred vision and dizziness, followed by a mixed pattern of the previously described type 1 and 2 HMSs. Three patients have been operated on, including two class I of Engel after 36 and 52months of follow-up. One patient developed a postoperative infection and continues to suffer seizures. Pathological findings disclosed a type IIa focal cortical dysplasia in all the patients. The last patient is awaiting surgery. Posterior cortex epilepsies, including those originating from the posterior cingulate cortex, can be responsible for HMSs. [Copyright &y& Elsevier]

This research was designed to produce a standardized set of microsatellite loci for parentage and kinship analyses in channel catfish, the leading species of US aquaculture. Three panels of five to six markers each were developed that contained a total of two dinucleotide-, eight trinucleotide- and seven tetranucleotide-microsatellite loci respectively. The loci had a range of nine to 31 alleles per locus in an outbred population. Based on the allele frequencies measured in commercial randomly bred broodstock, the combined probability of non-exclusion of an unrelated candidate parent pair was 5.36e-18. The combined probability of non-exclusion of unrelated identical genotypes was 2.58e-08. The microsatellite panels were validated by parentage and kinship evaluation in three populations. A total of 697 spawns were collected from matings of outbred broodstock over three spawning seasons, and parents were determined unambiguously for all but three spawns. Genotype analysis also enabled the identification of half-sibling and full-sibling families produced by pond spawning. In a second experiment, parentage was unambiguously determined in nine spawns from a population consisting of broodstock derived from only four families. A third experiment demonstrated that all but one of 374 individuals from 10 full-sibling families could be assigned to a family after coculture in an earthen pond for 1 year. The standardized microsatellite panels enable the development of pedigreed catfish populations and large-scale performance evaluations in common environments to support the genetic improvement of cultured catfish through selective breeding. [ABSTRACT FROM AUTHOR]

Mosquitofish, Gambusia sp., have been spread throughout the world to biologically control mosquitoes. However, the fish has gained a reputation as an invasive species and has been implicated in displacing native aquatic species. Gambusia affinis are native to the southeastern United States and commonly occur in commercial channel catfish, Ictalurus punctatus, production ponds. We investigated effects of mosquitofish presence on zooplankton populations, water quality, disease occurrence, and fish production in experimental ponds. There were no differences between ponds with or without mosquitofish in numbers of calanoid copepods, cyclopoid copepods, total copepods, Bosmina sp., Ceriodaphnia sp., Moina sp., Daphnia sp., or total cladocerans. There were also no differences in copepod and cladoceran sizes. Copepod nauplii were more numerous during the summer months in ponds with mosquitofish. There were no differences in water quality variables (soluble reactive phosphorus, nitrate, nitrite, ammonia, total nitrogen, total phosphorus, pH) or phytoplankton density between ponds stocked with and without mosquitofish. Catfish production and disease occurrence were also similar between ponds with and without mosquitofish. Although mosquitofish may cause problems when stocked outside their native range, there does not appear to be any adverse effects of mosquitofish presence in catfish production ponds. [ABSTRACT FROM AUTHOR]

Diseases are of particular importance for aquaculture worldwide, particularly in intensive culture. In Mexico, intensive culture of channel catfish is mainly done in floating cages. The aim of the present study was to determine the presence of the myxozoan Henneguya and the effect of site, period and host length on its prevalence in cage-cultured channel catfish. Over a year, fish were examined on six different sites. Results showed the presence of Henneguya exilis in all the farms. However, no significant effects were observed for site and season on prevalence, nor was there a correlation between host length and infection prevalence [ABSTRACT FROM AUTHOR]

An unidentified xiphidio-type cercaria, previously thought inconsequential to catfish health, was found to be released from marsh rams-horn snails (Planorbella trivolvis) inhabiting ponds on a commercial catfish operation in the Mississippi Delta. A preliminary challenge of cohabiting channel catfish (Ictalurus punctatus) with snails actively shedding the unidentified cercariae resulted in death of some fish. A second cohabitation trial yielded similar results, as did a third challenge of 250 cercariae/fish. Histopathology revealed developing metacercariae concentrated in the cranial region, especially within the branchial chamber, with several metacercariae at the base of the branchial arches within, or adjacent to, blood vessels, possibly the proximate cause of death. Genetic sequence analysis of the 18S small subunit ribosomal DNA (ssDNA), 28S large subunit rDNA (lsDNA), and cytochrome oxidase (Cox1) genes all matched the cercariae to Drepanocephalus spathans (Digenea: Echinostomatidae), a parasite of the double- crested cormorant (Phalacrocorax auritus), a piscivorous bird endemic on most catfish farms. This is the first commentary regarding pathology of D. spathans in juvenile channel catfish as well as the first report of the marsh rams-horn snail as an intermediate host in the D. spathans life cycle. The data presented here suggest this parasite could have limiting effects on catfish production, further supporting the need for adequate snail control programs to reduce trematode prevalence on commercial catfish operations. [ABSTRACT FROM AUTHOR]

The present study was designed to determine the optimal level of calcium hardness in hatching waters to incubate channel catfish Ictalurus punctatus × blue catfish I. furcatus hybrid catfish eggs. Hatching success of hybrid catfish eggs was higher (P < 0.05) at a calcium hardness (CaCO3) of 75 mg/L in hatching waters than at a calcium hardness of 25 or 50 mg/L; however, further increases in calcium concentration did not improve hatching success. A minimum water hardness of CaCO3 at 75 mg/L is recommended for incubating hybrid catfish eggs. Received September 13, 2011; accepted November 22, 2011 [ABSTRACT FROM AUTHOR]

Here we present evidence of the first field observation of the nonnative Ictalurus furcatus (Blue Catfish) occurring on the Satilla River, GA, in May 2011, and additional collections since then. This is the second large, non-native riverine catfish to be found in the Satilla River basin. Pylodictis olivaris (Flathead catfish) was first collected from the Satilla River in May 1996. The ecological effects of Blue Catfish on native mussel and fish species in the Satilla River are currently unknown, but competition with native catfishes is likely. [ABSTRACT FROM AUTHOR]

Edwardsiella bacteria are leading fish pathogens causing huge losses to aquaculture industries worldwide. E. tarda is a broad-host range pathogen that infects more than 20 species of fish and other animals including humans while E. ictaluri is host-adapted to channel catfish causing enteric septicemia of catfish (ESC). Thus, these two species consist of a useful comparative system for studying the intricacies of pathogen evolution. Here we present for the first time the phylogenomic comparisons of 8 genomes of E. tarda and E. ictaluri isolates. Genome-based phylogenetic analysis revealed that E. tarda could be separate into two kinds of genotypes (genotype I, EdwGI and genotype II, EdwGII) based on the sequence similarity. E. tarda strains of EdwGI were clustered together with the E. ictaluri lineage and showed low sequence conservation to E. tarda strains of EdwGII. Multilocus sequence analysis (MLSA) of 48 distinct Edwardsiella strains also supports the new taxonomic relationship of the lineages. We identified the type III and VI secretion systems (T3SS and T6SS) as well as iron scavenging related genes that fulfilled the criteria of a key evolutionary factor likely facilitating the virulence evolution and adaptation to a broad range of hosts in EdwGI E. tarda. The surface structure-related genes may underlie the adaptive evolution of E. ictaluri in the host specification processes. Virulence and competition assays of the null mutants of the representative genes experimentally confirmed their contributive roles in the evolution/niche adaptive processes. We also reconstructed the hypothetical evolutionary pathway to highlight the virulence evolution and niche adaptation mechanisms of Edwardsiella. This study may facilitate the development of diagnostics, vaccines, and therapeutics for this under-studied pathogen. [ABSTRACT FROM AUTHOR]

Abstract: Peracetic acid (PAA) can potentially be used to treat against freshwater fish pathogens; however, there is a paucity of data about its toxicity to fish. Channel catfish Ictalurus punctatus yolk-sac fry and swim-up fry were exposed to PAA for 48h in static toxicity bioassays at 23°C. The test water was 217 and 126mg/L (as CaCO3) total alkalinity and total hardness, respectively. Probit LC50 values were estimated with the trimmed Spearman–Karber method using nominal PAA concentrations (1.0, 1.3, 1.7, 2.2, 2.8, 3.7, 4.8, 6.3, and 8.2mg/L PAA). The mean 24- and 48-h LC50 values for yolk-sac fry and swim-up fry was 2.6mg/L PAA and 1.6mg/L PAA, respectively; the 24-h no observed effect concentration (NOEC) was 2.2mg/L PAA for yolk-sac fry and 1.3mg/L PAA for swim-up fry. Catfish yolk-sac fry were more tolerant of PAA than catfish swim-up fry by about 1.6-fold. Peracetic acid-related histopathology was analyzed in whole-body serial sections of swim-up fry at two selected doses of PAA: 2.2mg/L (1h post-treatment) and 1.7mg/L (48h post-treatment). Lesions consisted of severe gill damage in fish treated with 2.2mg/L PAA, and a moderate degeneration of the renal tubule epithelium within the posterior kidney in fish treated with 1.7mg/L PAA. An advantage to using PAA includes very low environmental impact considerations as it degrades to harmless residues rapidly. Results of the present study are important information needed by the aquaculture industry on a new, potential therapeutant. [Copyright &y& Elsevier]

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This study addresses rapid methods to identify mature channel catfish, Ictalurus punctatus, females for induced spawning with luteinizing hormone releasing hormone analog (LHRHa) and common carp pituitary extract (CPE) and the effects of stage of maturity, hormone dose, season, and cannulation before hormone injection. Hormonal intervention is the most effective method for inducing maturation and spawning in channel catfish × blue catfish, Ictalurus furcatus, hybrids. A total of 80 mature channel catfish were staged for maturity based on secondary sexual characteristics and 20-30 oocytes cannulated to ascertain their maturation stage based on the position of gonadal vesicle. Twenty females were randomly assigned to one of the four hormone regimes (priming + resolving dose): CPE 2 + 8 mg/kg (CPEC); LHRHa 20 + 40 µg/kg (LHRHaL); LHRHa 20 + 60 µg/kg (LHRHaM); and LHRHa 20 + 80 µg/kg (LHRHaH) and a fifth treatment consisted of 20 females selected based on apparent maturity as evidenced by external appearance were injected with CPE, 2 + 8 mg/kg without cannulation (CPEO). Two trials were conducted in early part of the spawning season and two trials in peak season. External methods to identify maturity correlated ( r = 0.63) with that of 'germinal vesicle position' method to identify the stage of maturity in females. Mean percent of females that ovulated, hatched, and fry produced per kg body weight did not differ ( P > 0.05) among the five hormone treatments. The mean percent females that ovulated was higher ( P < 0.05) for CPE-induced females that were identified as 'excellent' females based on external examination. The performance of cannulated females did not differ ( P > 0.05) with that of non-cannulated catfish. The mean egg quality of hormone-induced females and percent of females ovulated in response to hormone treatment established a weak but significant linear relationship ( Y = 3.85 + 0.008 × ovulation, r2 = 0.39, P < 0.05). [ABSTRACT FROM AUTHOR]

The article discusses a study which evaluated in vivo the adhesion dynamics of Flavorium columnare to fish tissues such as that of catfish Ictalurus punctatus. Scanning electron microscopy (SEM) was used to observe gill-adhered bacterial cells after immersion challenge, bacterial plate count and confirmation. The study found that particular strains of Flavobacterium columnare exhibit different levels of specificity to their fish hosts, and that adhesion to fish tissues is not sufficient to cause columnaris disease.

The article presents a study on the pathological changes in channel catfish or Ictalurus punctatus that is spontaneously infected by Streptococcus iniae. The researchers gathered about 200 diseased channel catfish from a commercial aquaculture farm in Guangxi province in China, which were affected by a streptococcosis outbreak. They also examined the body surface and gills microscopically for the presence of parasites. They found that Streptococcus iniae has emerged as a very important bacteria infecting warm water fish and aquaculture animals, which leads to major economic losses across the world.

lloglossidium fonti sp. nov. is described based on specimens from black bullheads ( Ameiurus melas) collected from several localities in northwestern Minnesota. The new species is morphologically closest to A. corti and A. geminum. These two species were also found in the same region as A. fonti sp. nov. and sometimes in the same individual fish. Examination of numerous genetically marked specimens has demonstrated that the most reliable distinguishing feature among the three species is the position of anterior margin of the vitelline fields. In the new species they are situated at the level of anterior margin of ventral sucker while in A. corti it is at the level of intestinal bifurcation or even further anteriorly, and in A. geminum it is at the level of posterior margin of ventral sucker or further posteriorly. The new species has a relatively smaller cirrus sac than A. geminum. Despite rather minor, albeit stable morphological differences, the molecular data strongly supported the status of A. fonti sp. nov. as a new species. Moreover, molecular data and morphological examination of new material suggested that A. kenti, earlier synonymized with A. corti, is a valid species that is resurrected here. Comparison of 2420 base long sequences of nuclear rDNA (partial 18S, complete ITS region, and partial 28S) obtained from multiple specimens of all 4 species collected in Minnesota, North Dakota, Nebraska and Mississippi, showed essentially no intraspecific variability (except for 1 base difference in the ITS2 region of A. fonti sp. nov.), but has demonstrated pronounced interspecific differences. The new species was not found in the four examined catfish species from the Red River of the North (on the border between North Dakota and Minnesota) and neighbouring North Dakota. [ABSTRACT FROM AUTHOR]

The article discusses a study on Icalurus punctatus, a pond-reared channel catfish with proliferative gill disease (PGD) caused by Henneguya species, a myxozoan parasite, using light and transmission electron microscopy, to characterize the inflammatory response during infection. In the study, the early lesions lacked inflammatory response around the disrupted cartilage, a chondrocyte response was not apparent, and the parasite was not present, indicating that the cartilage breaks occur before inflammation and arrival of the parasite in the gill. The study concluded that other chondrocytes in the lesions had ultrastructural features suggesting cell death.

This study demonstrated the feasibility of producing soluble protein (CFSP) and insoluble protein (CFISP) fractions from catfish muscle protein. CFSP and CFISP contained 60.6% and 73.8% protein and 8.6% and 20.3% fat, respectively. Both CFSP and CFISP contained essential amino acids. Differences were observed between physicochemical properties of the 2 protein fractions, including nitrogen solubility, emulsion stability, and fat adsorption capacity. The flow and viscoelastic properties of the emulsions prepared with CFSP and CFISP were investigated using a rheometer. The power law model and the Casson model were used to determine the flow behavior index ( n), consistency index ( K), and yield stress. Emulsion containing CFSP (ECFSP) had a higher K value than emulsion containing CFISP (ECFISP). Both ECFSP and ECFISP emulsions exhibited pseudoplastic behavior and viscoelastic characteristics. The G′ (an elastic or storage modulus) and G″ (a viscous or loss modulus) values for ECFSP were higher than ECFISP. Catfish muscle tissue can be easily separated into soluble and insoluble protein powders that have desirable functional properties. [ABSTRACT FROM AUTHOR]

Channel catfish ( Ictalurus punctatus) muscle was subjected to 6 protein extraction and precipitation techniques using acid solubilization (pH 2.0, 2.5, and 3.0) or alkaline solubilization (pH 10.5, 11.0, 11.5) followed by precipitation at pH 5.5. The catfish protein isolate was compared with ground defatted white muscle. Alkali-processed catfish showed increased gel rigidity, gel strength, and gel flexibility compared to acid-processed catfish, which exhibited inconsistent functional performance, increasing and decreasing gel rigidity, gel strength, and gel flexibility. The gel rigidity ( G′) at pH 3.0 in the absence of salt had the highest G′ of the acid treatments and was not significantly different from the alkaline-treated catfish muscle ( P > 0.05). However in the presence of added salt pH treatment it had the lowest G′ and was different from alkaline treatments ( P < 0.05) during break force testing. These results show that pH-shift processing of channel catfish muscle provides highly functional isolates with a potentially broad range of applications. This range of applications is possible due to the modification of the textural properties of catfish muscle protein produced using different acidic or alkaline pH solubility treatments. [ABSTRACT FROM AUTHOR]

A study was conducted to determine the clearance time of yellow pigments lutein and zeaxanthin in channel catfish at various temperatures. Fish of initial weight of 13.4 g were stocked into flow-through aquaria and fed daily with a pigment-enhanced diet for 11 wk when yellow color became visible in the flesh. All fish were then transferred into tanks in three recirculating systems that were assigned one of the three temperatures (10, 20, and 30 C). During the pigment clearance period, fish were fed a control diet without added pigments daily to satiation for 12 wk. Every 4 wk, fish from three randomly chosen tanks per temperature were euthanized and fillets were analyzed for yellow color intensity (Commission Internationale de I'Eclairage [CIE] b*) and lutein and zeaxanthin concentrations. The b* values of fillets of fish reared at 20 and 30 C decreased linearly as time progressed. There was no significant linear regression of b* value against time for fish raised at 10 C. The rate of pigment clearance was similar for fish reared at 20 and 30 C. Results demonstrate that about 8 wk were needed for catfish to "purge most of yellow pigment at warm temperatures (20 and 30 C). A longer period of time (>12 wk) was required at 10 C. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate various ingredient combinations in a 28% or 32% protein diet for optimum performance of channel catfish Ictalurus punctatus. All diets contained soybean meal and corn, but with or without cottonseed meal, wheat middlings or fish meal (FM). Channel catfish fingerlings were stocked into 0.04 ha earthen ponds at 18 530 fish ha−1. Fish were fed one of eight diets once daily to apparent satiation for two growing seasons. Results demonstrated that the dietary ingredient composition used had significant effects on fish performance, but magnitude of differences was relatively small. Overall, diets containing FM resulted in greater weight gain (Experiments 1 and 2) and lower feed conversion ratio (Experiment 1) than fish fed all-plant diets. However, certain combinations of plant ingredients provided the similar fish growth as some diets containing FM. There were no significant differences in weight gain between fish fed soybean meal–corn or soybean meal–corn–wheat middlings-based diets with cottonseed meal or FM. The use of wheat middlings in the diet had no significant effects on fish production characteristics. [ABSTRACT FROM AUTHOR]

A 2 x 2 factorial experiment was conducted to evaluate the effects of commercial diets (32% protein, 3% fat [32/3 diet] or 36% protein, 8% fat [36/8 diet]; Malick Aquafeed, Inc.) and the influence of strain (U.S. Department of Agriculture [USDA] 103 or Norris) on performance variables and mitochondrial respiratory chain enzyme activities in the liver, muscle, and intestine of channel catfish Ictalurus punctatus. Juvenile channel catfish (average weight = 29.71 and 38.79 g for USDA 103 and Norris strains, respectively) were stocked into sixteen 152-L aquaria at a density of l0 fish/aquarium. Four aquaria were used for each dietary treatment. Fish were fed twice daily to apparent satiation for 16 weeks. Results indicated that diet and strain had significant (P < 0.05) main effects on weight gain, feed consumption, feed efficiency, and specific growth rate. Diet composition had a significant main effect on condition factor, regardless of strain. There was a significant (P < 0.0007) fish strain x diet composition interaction effect on feed efficiency. Regardless of strain, fish fed the 36/8 diet formula had higher activities for respiratory enzyme complexes I, II, III, and IV in the liver, intestine, and muscle than fish fed the 32/3 diet. The main effect was significant but not consistent for complex I and IV activities in the liver and muscle and complex II activities in the liver and intestine. The fish strain x diet composition interaction effect was significant for complex I activity in the liver and for complex II and IV activities in the muscle. These data demonstrate that the USDA 103 strain of channel catfish appears to possess superior traits in growth performance compared with the Norris strain. Our data indicate that diet has an important effect on channel catfish production and that a commercial 36/8 diet produces enhanced growth performance and mitochondrial enzyme activities relative to a 32/3 diet. [ABSTRACT FROM AUTHOR]

This study was conducted to gain a better understanding of the effect of exposure to the myxozoan Henneguya ictaluri (the agent of proliferative gill disease [PGD]) on host physiology by measuring the variation in selected blood characteristics in three differently affected host taxa (channel catfish Ictalurus punctatus, blue catfish I. furcatas, and blue catfish x channel catfish hybrid fingerlings). Forty-five fish of each host taxon were exposed to PGD, mad 10 fish of each host taxon were sampled at 24, 96, and 168 h. Fish were weighed, blood was collected and analyzed for a suite of physiological variables, and wet mount preparations of gill clips were examined grossly for the presence of cartilage breaks. The results of this study are consistent with the current knowledge regarding H. ictaluri infections in blue catfish, channel catfish, and blue catfish x channel catfish hybrids. Chondrocytic lysis was observed in channel catfish and hybrid catfish at 96 and 168 h but was not observed in blue catfish. There was an observed reduction in oxygen partial pressure (pO2) and an increase in carbon dioxide partial pressure (pCO2) at 96 h in the blood of channel catfish and hybrid catfish, but these changes were not exhibited by blue catfish. For all species, pH decreased as lactate concentrations increased. The lack of physiological changes and the absence of H. ictaluri sporozoites and DNA in gill tissue lead us to speculate that H. ictaluri is unable to estabfish infection in blue catfish. Current research investigating the mechanisms of infection and portals of parasite entry into blue catfish, channel catfish, and blue catfish x channel catfish hybrids is underway to better elucidate the defenses employed by blue catfish against H. ictaluri. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated the association between improved body condition and superabundant food at catfish aquaculture facilities in American White Pelicans (Pelecanus erythrorhynchos). The study was conducted in four geographic regions in Mississippi and Louisiana. It was observed that Pelicans that foraged on catfish during spring have better physical condition.

The channel catfish Ictalurus punctatus is a popular sport fish commonly maintained by annual stocking in small impoundments. We sought to determine whether channel catfish negatively affect two other sport fishes (bluegill Lepomis macrochirus and largemouth bass Micropterus salmoides) in Alabama's state public fishing lakes (ASPF lakes) through competition or predation. Using a variety of gears, we sampled channel catfish, largemouth bass, and bluegills in 12 ASPF lakes with variable channel catfish stocking and harvest rates. Four of these lakes were sampled more intensively to quantify the diets of these three species. Bioenergetics simulations were used to predict the annual consumption of channel catfish and largemouth bass populations of average density, size structure, and growth from these impoundments. Metrics of growth, condition, abundance, and population structure were not related between species. Latitude was negatively related to channel catfish growth. The diets of channel catfish and bluegills were moderately similar across all seasons in all lakes, while those of channel catfish and largemouth bass were highly dissimilar. Within species, diet similarity was high among lakes. Bioenergetics simulations suggest that the channel catfish populations in these lakes consume relatively little fish, particularly when compared with a typical largemouth bass population. We found little evidence of negative effects of channel catfish on the bluegill and largemouth bass populations in ASPF lakes, although largemouth bass growth and condition were poorest in the lake with the highest channel catfish stocking rate. However, current stocking and exploitation rates in most lakes appear to maintain channel catfish abundance below the level at which negative effects may occur. [ABSTRACT FROM AUTHOR]

Ictalurid herpesvirus-2 (IcHV-2) is a pathogen of cultured black bullhead, Ameiurus melas (Rafinesque), and has been shown to produce high mortality in experimental exposures of channel catfish, Ictalurus punctatus (Rafinesque). During acute infections, the virus grows readily in cell cultures but produces a cytopathic effect (CPE) similar to that of Ictalurid herpesvirus-1 (IcHV-1) and the channel catfish reovirus. We have developed a quantitative PCR assay that can be used to detect IcHV-2 in fish tissues and cell culture supernatants. The assay does not amplify other fish herpesviruses tested or host DNA. It is quantitative over a range of eight logs, and the limit of detection is <10 copies per reaction. In replicate assays carried out on different days, the coefficient of variability was 10%. The best organs for the detection of acute IcHV-2 infections by our assay are the spleen and kidney. This assay should be useful for the diagnosis of IcHV-2 disease, the identification of syncytial CPEs in cell cultures, and for the detection of latent infections in carrier fish. [ABSTRACT FROM AUTHOR]

Sagittal otoliths and the articulating process of the pectoral spine have both been validated as accurate techniques for estimating the age of channel catfish Ictalurus punctatus (≤age 4). However, there is limited information on the relative precision of estimates from these two structures. Thus, we analyzed the precision of age estimates derived from otoliths and the articulating process of the pectoral spine and compared the dynamic processes (recruitment, growth, and mortality) resulting from those estimates. Aging structures were removed from 110 channel catfish captured from the Wabash River (river kilometers 550-9.6) via day--time electrofishing. The age estimation methodologies were similar to those described in previous studies. Agreement between the ages derived from the two structures was high: the average percent error was 8.4%, the coefficient of variation was 11.4, and the slope of the age bias plots did not differ from 1, indicating similar age assignments between structures. The corresponding recruitment patterns, von Bertalanffy growth models, and mortality rates did not differ between the aging structures. We conclude that the articulating process of the pectoral spine provides age assignments similar to those of otolighs and that the dynamic processes do not differ between structures. Further, based on the results of this study, the articulating process of the pectoral spine provides a suitable alternative to otoliths and has the advantage that channel catfish do not have to be sacrificed. [ABSTRACT FROM AUTHOR]

The basic nutrient requirements for channel catfish, Ictalurus punctatus, are well known, with anecdotal evidence suggesting that catfish fry grow faster and have better survival when fed an animal protein diet. However, the ability to grow channel catfish as small as 11 g on all plant diets and a lack of published data showing the superiority of fish or animal proteins compared to nutritionally equivalent plant proteins for catfish fry indicates that it may be possible to raise channel catfish fry on diets with only plant protein sources. Therefore, an experiment was conducted to compare the effects of 36 and 45% animal protein diets and 36 and 45% all plant protein diets on catfish fry growth and survival. Experimental diets were formulated to contain: 36% all plant protein (primarily from soybean meal); 36% animal and plant protein (≥45% of crude protein as fish meal); 45% all plant protein (primarily from soy protein concentrate and soybean meal); and 45% animal and plant protein (≥60% of crude protein as fish meal). The catfish were fed at a rate of 20% of body weight daily for 28 d using 24-h automated feeders. Mean ending weights and lengths of catfish fry were not significantly different ( P > 0.05) for any treatment. Mean mortality was also not significantly different ( P > 0.05) among diets. Regression analysis of growth rate and analysis of variance of final weights revealed that there was no significant difference in growth rate for any of the four diets. These results indicate that growth is not limited in channel catfish fry fed all plant protein diets, and that there is no apparent advantage to the inclusion of animal protein in diets for channel catfish fry. [ABSTRACT FROM AUTHOR]

Glycerol is the main by-product of biodiesel production from vegetable oils and animal fats. It has been evaluated as an energy source for several farm animals. A study was conducted to examine the effects of various levels of glycerol in channel catfish, Ictalurus punctatus, diets. Fish with mean initial weight of 6.8 ± 0.1 g were stocked in 110-L flow-through aquaria and fed practical diets containing 0, 5, 10, 15, and 20% glycerol for 9 wk. There were no significant differences in feed consumption, weight gain, feed efficiency ratio, and liver lipid level among fish fed diets containing 0, 5, and 10% glycerol. However, fish fed diets containing 15 and 20% glycerol had reduced weight gain, feed efficiency, and liver lipid content. Survival was not affected by dietary glycerol levels. Blood glucose level was significantly higher in fish fed 5% glycerol than fish fed other diets. Fillet protein and fat generally decreased and fillet moisture increased as dietary glycerol level increased. It appears that channel catfish can utilize about 10% glycerol in the diet without adverse effects on feed consumption, weight gain, feed efficiency ratio, hemoglobin, hepatosomatic index, and liver lipid. [ABSTRACT FROM AUTHOR]

The article examines whether feeding yeast-derived mannans in the form of Bio-Mos could improve growth, feed efficiency, and improve resistance of channel catfish challenged with Edwardsiella ictaluri (E. ictaluri). E. ictaluri is a bacterium that causes enteric septicemia of catfish. The results show that the addition of Bio-Mos to catfish diet does not improve weight gain, but may improve resistance to E. ictaluri.

Over-fertilization with phosphorus and carryover copper residual in the sediment from copper sulfate treatment in double-cropped ponds were suspected as the primary causes of low larval percid survival in coolwater aquaculture ponds. Consequently, in this study, we compared saugeye (male sauger Sander canadensis X female walleye S. vitreus) survival, growth, and yield among ponds that were single-cropped with only saugeyes in the spring during the previous two consecutive years (SS ponds) and ponds that were double-cropped (with saugeye culture in the spring and channel catfish Ictalurus punctatus culture in the summer) during the previous two consecutive years (DD ponds). We also compared sediment phosphorus (soluble reactive phosphorus [SRP] and total phosphorus [TP]), sediment copper concentrations, phytoplankton biomass, and zooplankton biomass. Fish survival (number harvested) and fish yield (mass harvested) were significantly lower in DD ponds than in SS ponds in 2001 but were similar in 2002 (a year of wide temperature fluctuation early in the production season). Sediment analyses revealed that DD ponds had significantly lower SRP and TP but higher copper concentrations than did SS ponds. A detailed study done in 2002 revealed that individual length and wet weight of percids were significantly higher in the SS ponds than in DD ponds; phytoplankton biomass was similar in both sets of ponds, while zooplankton biomass was significantly lower in DD ponds. These results suggest that residual materials used in double-cropped channel catfish ponds may negatively affect subsequent years' percid culture. [ABSTRACT FROM AUTHOR]

The nominal Yaqui catfish,Ictalurus pricei, is a species of Ictaluridae (Siluriformes) often recorded from Northwest Mexico. Southern distribution members of theI. priceicomplex in Northwest Mexico include at least one undescribed species that differs from Yaqui catfish in morphological features, herein called “Sinaloa Catfish”. Sequencing of four geographical mitogenome haplotypes of Yaqui catfish and Sinaloa catfish showed geographical haplotypes ofI. priceiwithin a clade of specific identity, close to Sinaloa catfish haplotypes. Our molecular phylogeny represents a working hypothesis supporting information on the evolutionary relationships of theIctalurusspecies from Western Mexico and Western USA. [ABSTRACT FROM AUTHOR]

Abstract: A comprehensive understanding of animal growth requires adequate knowledge of protein synthesis (PS), which in fish, has traditionally been determined by the flooding dose method. However, this procedure is limited to short-term assessments and may not accurately describe fish growth over extended periods of time. Since deuterium oxide (2H2O) has been used to non-invasively quantify PS in mammals over short- and long-term periods, we aimed at determining if 2H2O could also be used to measure PS in channel catfish. Fish were stocked in a 40-L aquarium with ~4% 2H2O and sampled at 4, 8 and 24h (n =6 at each time period) to determine 2H-labeling of body water (plasma), as well as protein-free and protein-bound 2H-labeled alanine. The labeling of body water reflected that of aquarium water and the labeling of protein-free alanine remained constant over 24h and was ~3.8 times greater than that of body water. By measuring 2H-labeled alanine incorporation after 24h of 2H2O exposure we were able to calculate a rate of PS: 0.04±0.01% h−1. These results demonstrate that PS in fish can be effectively measured using 2H2O and, because this method yields integrative measures of PS, is relatively inexpensive and accounts for perturbations such as feeding, it is a novel and practical assessment option. [Copyright &y& Elsevier]

The interspecific hybridization of channel catfish, Ictalurus punctatus, females with blue catfish, I. furcatus, males has been identified as a method to further improve production; however, lack of spawning success has affected its commercial application. To facilitate our understanding of the interaction of brood stock nutrition and reproductive performance, we evaluated the interaction of feed quality and feeding frequency. Channel catfish females were classified into two genetic groups, namely, high and low spawning. The treatments were offered during the spring season 70–90 d prior to the start of the spawning season. Induced reproduction was performed using luteinizing hormone releasing hormone analog. Condition of the fish as well as reproductive performance using spawning success, egg production, egg size, and fertilization at 48 h were determined. Changing protein level of the diet from 32 to 42% did not influence spawning, fecundity, or fertilization, but affected egg size and biochemical composition of the eggs. Increasing the feeding frequency from three to six times per week negatively affected spawning in one of the two genetics groups, did not affect egg production and egg fertilization, but had a significant effect on egg size. Older fish performed better than younger fish in terms of spawning success and egg production. [ABSTRACT FROM AUTHOR]

The fish candirú known also as Vandellia cirrhosa can be catalogued as one of the most chilling beings of the planet. This fish of the family of the bullheads, also known as cat fish is the only vertebrate that parasitizes the man. Using of his hooks that act as gaffs. [ABSTRACT FROM AUTHOR]

Cooking to 63C for 15 s remains an important step to ensure safe fish for human consumption. Methods for heat process verification have not been validated for channel catfish (Ictalurus punctatus ). The present research compared extractable protein quantification, lactate dehydrogenase, acid phosphatase and catalase activity assays for verification of internal cooking temperature of channel catfish fillets. Ground raw catfish fillet samples (fresh and frozen) were cooked to 55, 60, 62, 63, 64 and 66C. Extractable protein, acid phosphatase and catalase activities decreased as internal cooking temperature increased, but lactate dehydrogenase activity remained unchanged. Samples cooked to 63C had extractable protein concentrations between 9.11 and 10.02 mg/g (95% confidence). Catalase was rapidly inactivated between 55 and 60C and may be suitable for identification of severely undercooked product. Acid phosphatase activity was influenced by method of storage (fresh versus frozen). A method based on total extractable protein appeared to be the most promising for determining the end point cooking temperature of catfish. PRACTICAL APPLICATIONS The most precise and reliable method to verify maximum cooking temperature attained during heat treatment of catfish fillets was total extractable protein. This finding may be useful for critical control point verification and may be valuable where claims of foodborne illness associated with catfish consumption are being litigated or investigated. To confirm gross undercooking, an easier test would be to measure catalase activity. [ABSTRACT FROM AUTHOR]

Fungal infestations of channel catfish Ictalurus punctatus eggs can lower hatch rate, which requires the producer to spawn more channel catfish or risk fingerling shortages. Hydrogen peroxide (H2O2) treatments (0.0, 15.6, 31.3, 62.5, 125,250, 500, 1,000, 2,000, and 4,000 mg/L) were evaluated to determine their effect on channel catfish hatch rate (number of fry/number of eggs X 100) and control of naturally occurring infestations of fungi Saprolegnia spp. in an experimental compartmentalized trough hatching system. Experiments were run at water temperatures of 23.2-24.0°C, dissolved oxygen concentrations of 4.5- 6.8 mg/L (53-79% saturation), total alkalinity of 209-217 mg/L, and total hardness of 91-110 mg/L. Treatments were applied to hatching compartments while well water was flowing at a rate of one water exchange every 30 rain and egg density was 2.5 g eggs/L of water. Observations for fungal development were made daily, and the maximum measure of fungal growth was recorded. An initial range-finding study demonstrated that H2O2 concentrations greater than 500 mg/L lowered the hatch rate. In later experiments, concentrations of 125, 250, and 500 mg/L applied for 6 d significantly increased the hatch rate and reduced fungal growth when compared with the controls. The 250-mg/L H2O2 treatment had the highest mean hatch rate (64.4% compared with 24.7% for the controls), lowest incidence of fungal infestation (27.3% compared with 100% for the control), and the lowest average fungal growth (an average measure of 0.95 cm compared with 7.23 cm for the controls). [ABSTRACT FROM AUTHOR]

A 4-year pond study was conducted to compare net production, feed conversion, processing yield, and body composition of channel catfish Ictalurus punctatus that were fed once daily, fed every other day (EOD) to satiation, or fed an amount not exceeding 110 kg.ha⋅ha-1⋅d-1 in a multiple-batch cropping system. The greatest amount of feed administered was observed for the daily satiation group, followed by the 110-kg⋅ha-1d-1 group and the EOD group (P ≤ 0.05). Net production of fish fed daily to satiation did not significantly differ from that of fish fed up to 110 kg⋅ha-1⋅-1, but that of fish fed daily (satiation or ≤ 110 kg/ha) was significantly higher than that of fish fed EOD to satiation. Feed conversion ratio was significantly lower in fish fed up to 110 kg⋅ha-1⋅d-1 or EOD to satiation than that of fish fed daily to satiation. Carcass, fillet, and total meat yields did not differ among feeding regimens. Fish fed EOD to satiation had lower fillet fat and higher fillet moisture than fish fed daily to satiation. Feed restriction to no more than 110 kg⋅ha-1⋅d-1 did not significantly affect fillet composition of channel catfish compared with fish fed daily to satiation. It appears that limiting the feeding rate to 110 kg⋅ha-1⋅-1 at a stocking density of 14,830 fish/ha would improve feed efficiency without causing significant reduction in weight gain, net production, or processing yield and would thus increase farm profits. Feeding channel catfish EOD to satiation may be acceptable as a short-term strategy when economic conditions justify it. However, it may not be economical for the long term because of lower production, increased length of the production cycle, and reduced processing yield. [ABSTRACT FROM AUTHOR]

A study was conducted to examine the effect of dietary levels of distiller’s dried grains with solubles (DDGS) on growth, body composition, hematology, immune response, and resistance of channel catfish, Ictalurus punctatus, to Edwardsiella ictaluri challenge. Five diets containing 0, 10, 20, 30, and 40% DDGS with supplemental lysine (Diets 1–5) as partial replacements of a combination of soybean meal and cornmeal on an equal protein basis were fed to juvenile catfish (13.33 ± 0.25 g) for 12 wk. Growth performance and feed utilization efficiency were similar for fish in all treatments. Body lipid and moisture increased and decreased, respectively, in fish feed DDGS-containing diets relative to the control group. Dietary treatment had no effect on red and white blood cell counts. Hemoglobin and hematocrit were significantly higher in fish fed diets containing DDGS than in those fed the control diet. Fish fed 20–40% DDGS diets had increased serum total immunoglobulin, and those fed the 30% DDGS diet had significantly increased antibody titers 21 d following E. ictaluri challenge. Other immune variables evaluated were not affected by dietary treatments. Preliminary results on bacterial challenge showed an increased resistance against E. ictaluri in fish fed DDGS-containing diets (Diets 2–5). [ABSTRACT FROM AUTHOR]

Black bullheads Ameiurus melas are an environmentally tolerant omnivorous fish species that are found throughout much of North America and parts of Europe. Despite their prevalence, black bullheads are an infrequently studied species making their biology, ecology, and life history poorly understood. Although limited information has been published on black bullheads, evidence suggests that bullheads can dominate the fish biomass and have profound influences on the fish community in some north temperate USA lakes. The goal of our study was to provide additional information on black bullhead population demographics, growth rates, life history characteristics, and seasonal diet preferences in a northern Wisconsin lake. Using common fish collection gears (fyke netting, electrofishing), fish aging protocols, fecundity assessments, and diet indices, our results suggested that black bullheads exhibited relatively fast growth rates, early ages at maturity, moderate fecundity, and a diverse omnivorous diet. Due to these demographic and life history characteristics, black bullheads have the potential to dominate fish community biomass in their native and introduced range. Results from our study may inform the management of black bullhead as native and invasive species. [ABSTRACT FROM AUTHOR]

Animal protein, generally fish meal, has traditionally been used in the diet of channel catfish. However, our previous research indicates that animal protein is not needed for growing stocker-size catfish to food fish when the fish are stocked at densities typical of those used in commercial catfish culture. Whether this holds when fish are stocked at high densities is not known; thus, we conducted an experiment to evaluate the effect of feeding diets with and without fish meal to channel catfish stocked in earthen ponds at different densities. Two 32% protein practical diets containing 0% or 6% menhaden fish meal were compared for pond-raised channel catfish, Ictalurus punctatus, stocked at densities of 14,820, 29,640, or 44,460 fish/ha. Fingerling channel catfish with average initial weight of 48 g/fish were stocked into 30, 0.04 ha ponds. Five ponds were randomly allotted for each fish meal level × stocking density combination. Fish were fed once daily to satiation for two growing seasons. There was a significant interaction between stocking density and fish meal for net production; net production increased in fish fed a diet containing fish meal compared with those fed an all-plant diet at the highest stocking density, but not at the two lower stocking densities. Net production of fish fed diets with and without fish meal increased as stocking density increased. Viewing the main effect means, weight gain decreased and FCR increased for fish stocked at the two highest densities, and survival was significantly lower at the highest stocking density. Visceral fat decreased in fish at the two highest stocking densities. Body composition data were largely unaffected by experimental treatment except for a reduction in percentage of filet fat in fish at the highest stocking density, and fish that were fed diets containing fish meal had a lower percentage of fillet protein and a higher percentage of fillet fat. It appears that at stocking densities two to three times higher than generally used, animal protein (fish meal) may be beneficial in the diet of channel catfish. In regard to stocking densities, high stocking results in higher overall production, but the average fish size decreased as stocking density increases. [ABSTRACT FROM AUTHOR]

A multiple-batch study was conducted using stocker catfish (0.09 kg/fish) and carryover fish (0.39 kg/fish) to look at the effects of different stocker densities on fish production. Twelve 0.1-ha ponds were stocked with 7,400; 11,120; or 14,825 stockers/ha, and equal weights of carryover fish (2,268 kg/ha). Fish were fed once daily to apparent satiation with a 32% protein floating feed and aerated with a single 0.37-kW electric paddlewheel aerator. No significant differences were detected for gross, net, and net daily yields, growth (g/d), or survival. Sub-marketable yield (<0.57 kg) increased as stocking density increased. However, marketable yields (≥0.57 kg) were not affected by density. Carryover fish in high-density ponds had a significantly lower (P < 0.05) mean weight at harvest, but mean stocker weight was not different across densities. Economic analysis found breakeven prices increased and net returns decreased with increased stocking density when sub-marketable fish were not considered as revenue. The study indicated the possibility that stockers compete with large carryover fish, particularly at higher densities. [ABSTRACT FROM AUTHOR]

Abstract: B cell receptor (BCR) accessory molecules CD79a and CD79b homologs were identified in the channel catfish, Ictalurus punctatus. Both are found as single copy genes that encode proteins containing a signal peptide, an extracellular immunoglobulin domain, a transmembrane region and a cytoplasmic tail containing an immune-receptor tyrosine-dased activation motif (ITAM). IpCD79a and IpCD79b transcripts correlate well with IgM message expression. They are highly expressed in peripheral blood leukocytes (PBL) enriched in membrane (m) IgM+ cells and catfish clonal B cell lines, but not in catfish clonal T cells, indicating that IpCD79a and IpCD79b expression is B cell restricted. Studies using catfish clonal B cells (3B11) transfected with constructs encoding epitope-tagged IpCD79a and IpCD79b revealed that IpCD79a was expressed as a 45kDa protein and IpCD79b was expressed as a 32kDa protein. Furthermore, co-immunoprecipitations of epitope-tagged CD79 proteins demonstrate that these molecules are non-covalently associated with mIgM. These data correlate with some of the previous immunoprecipitation data demonstrating that catfish mIgM associates with proteins of 45 and 32kDa. [Copyright &y& Elsevier]