Infected Catfish Research Articles

Low potential of fish as a source of infection with Angiostrongylus cantonensis

Abstract Objectives Fish are hypothesized to act as paratenic hosts for the zoonotic nematode Angiostrongylus cantonensis, cause of human eosinophilic meningitis. There is a lack of data confirming the relevance of fish in A. cantonensis life cycle and their contribution to human infection. Materials and methods We conducted a series of experiments to investigate survival and infectivity of A. cantonensis larvae in Clarias gariepinus (catfish; n=30) and Oreochromis niloticus (tilapia; n=24). Each fish was inoculated with 10,000 third-stage larvae (L3). Larval survival was assessed through artificial digestion of fish tissues one, two, and three weeks post-infection. To investigate early stages of infection, four catfish were inoculated with 10,000 L3 each and sacrificed 3 days post-infection. qPCR and histopathological examinations were performed to evaluate larval distribution and tissue reactions. Two infected catfish, sacrificed one week post-infection, were used to feed Wistar rats. Results After 45 days, the rats were not shedding L1, indicating the absence of infection. One week post-infection, dead larvae were present in digested tissues of both fish species, and the same was observed two and three weeks after exposure. qPCR analysis revealed that intestine was the most heavily infected organ. Histopathology identified dead larvae within granulomas in intestines and liver. Early-stage infection experiment showed that fish sacrificed three days post-inoculation contained viable L3 which were infective to Wistar rats. Conclusions While A. cantonensis L3 can survive and remain infective in fish for a short period, they typically die within first few days post-infection. This suggests that fish may not be significant long-term paratenic hosts for A. cantonensis but may play a temporary role in its transmission to mammals (including humans) and birds. These results are consistent with previous studies on freshwater shrimps and highlight the importance of understanding aquatic host interactions in the epidemiology of this zoonotic food-borne pathogen.

Comparative Effects of Moringa oleifera upon Blood of Clarias batrachus (Linnaeus, 1758) Infected by Fenvalerate and Cypermethrin

Abstract: After the application of Moringa oleifera as a herbal agent upon the infected Catfish Clarias batrachus (Linnaeus, 1758) by Fenvalerate and Cypermethrin used as Insecticide and Pesticides shows many Biochemical fluctuations in their Comparative parameters. Fishes were acclimatized with pesticides for 96 hours (4 days) in two different tanks. Concentration of toxic agent Cypermethrin and Fenvalerate was taken as 0.25 µg/l of LC50 ¼ from 20EC stock solution and 25 µg/l of LC50 1/10 respectively which was continued as studies at every 24h of time interval as lethal concentration for acute toxicity. Powder of dried grinded green leaves and pod of herbal agent Moringa oleifera used in ratio of 1:1 proportion respectively taken as 0.125 gm / litre according to the capacity of water per day continued till 120 h of dose acclimatization upon fish infected with both pesticidal agents individually. Haematological changes were observed and compared among Normal, Fenvalerate, Cypermethrin, Fen Mo and Cyp Mo conditions.

Isolation, genetic characterization, and virulence profiling of different Aeromonas species recovered from moribund hybrid catfish (Clarias spp.).

The high diversity of Aeromonas spp. results in various pathogenicity levels. This group of bacteria causes a serious disease named motile Aeromonas septicemia (MAS) in catfish (Clarias spp.). This study aimed to characterize the species and virulence gene diversity of Aeromonas spp. isolated from diseased catfish. Nine Aeromonas spp. were isolated from infected catfish cultivated in Java, Indonesia, and they were identified at the phenotypic and molecular levels (16S rDNA). The virulence genes assessed included aer/haem, alt, ast, flaA, lafA, and fstA. Phylogenetic analysis identified nine isolates of Aeromonas spp.: Aeromonas hydrophila (11.11%), Aeromonas caviae (11.11%), Aeromonas veronii bv. veronii (44.44%), and Aeromonas dhakensis (33.33%). Virulence genes, such as aer/haem, alt, ast, flaA, lafA, and fstA, were detected in all isolates at frequencies of approximately 100%, 66.67%, 88.89%, 100%, 55.56%, and 66.67%, respectively. This study is the first report on A. dhakensis recovered from an Indonesian catfish culture. Furthermore, our study revealed the presence of A. veronii bv veronii, a biovar that has not been reported before in Indonesia. This finding confirms that MAS was caused by multiple species of Aeromonas, notably A. dhakensis and A. veronii bv veronii, within Indonesian fish culture. The presence of these Aeromonas species with multiple virulence genes poses a significant threat to the freshwater aquaculture industry.

The Potential of Sponge-Associated Bacillus spp. as A Biocontrol Agent to Inhibit Several Bacteria from Infected Catfish (Clarias gariepinus Burch)

Catfish is one of the freshwater aquaculture commodities with a high level of consumption and production in Indonesia. Disease outbreaks could occur in catfish farming activities caused by pathogenic bacteria. Several species of pathogenic bacteria can cause disease in catfish, resulting in mass death. This can lead to decrease in the food quality of freshwater fishery products, especially catfish. In cultured system, aquaculture occurrence of diseases can cause severe financial losses. Catfish samples were obtained from catfish farming with clinical symptoms of reddish spots on the outside of the body. Bacteria were isolated from the kidney and liver under aseptic conditions. These bacteria isolates were identified through their colony morphology, Gram staining, biochemical tests, molecular test, and antibacterial test of Bacillus spp. using spot and disc diffusion test. Identification based on 16S rRNA gene showed that GL1 was 99.92% closely related to Aeromonas widowei, HL1 was 100% closely to Bacillus amyloliquefaciens, and GL2 and HL2 was closely related to Bacillus cereus. The antibacterial test results of APD10 isolates of Bacillus velenzensis species inhibited GL2 pathogenic bacteria with an inhibition zone of 22.15 mm in the very strong inhibition zone and HL2 pathogenic bacteria with an inhibition zone of 8.5 mm in the moderate inhibition zone. Bacillus velezensis was isolated from the sponge Aplysina sp. could be further utilized as a biocontrol agent for the pathogenic bacteria, Bacillus cereus, that infects catfish.

The Potential of Sponge-Associated Bacillus spp. as A Biocontrol Agent to Inhibit Several Bacteria from Infected Catfish (Clarias gariepinus Burch)

Catfish is one of the freshwater aquaculture commodities with a high level of consumption and production in Indonesia. Disease outbreaks could occur in catfish farming activities caused by pathogenic bacteria. Several species of pathogenic bacteria can cause disease in catfish, resulting in mass death. This can lead to decrease in the food quality of freshwater fishery products, especially catfish. In cultured system, aquaculture occurrence of diseases can cause severe financial losses. Catfish samples were obtained from catfish farming with clinical symptoms of reddish spots on the outside of the body. Bacteria were isolated from the kidney and liver under aseptic conditions. These bacteria isolates were identified through their colony morphology, Gram staining, biochemical tests, molecular test, and antibacterial test of Bacillus spp. using spot and disc diffusion test. Identification based on 16S rRNA gene showed that GL1 was 99.92% closely related to Aeromonas widowei, HL1 was 100% closely to Bacillus amyloliquefaciens, and GL2 and HL2 was closely related to Bacillus cereus. The antibacterial test results of APD10 isolates of Bacillus velenzensis species inhibited GL2 pathogenic bacteria with an inhibition zone of 22.15 mm in the very strong inhibition zone and HL2 pathogenic bacteria with an inhibition zone of 8.5 mm in the moderate inhibition zone. Bacillus velezensis was isolated from the sponge Aplysina sp. could be further utilized as a biocontrol agent for the pathogenic bacteria, Bacillus cereus, that infects catfish.

Characterization of digenetic trematodes infecting African catfish (Clarias gariepinus) based on integrated morphological, molecular, histopathological, and immunological examination.

Parasitic infection may cause massive losses in Clarias gariepinus fries and fingerlings. Therefore, this study aimed to characterize the digenetic trematodes species (two adults' flukes and one metacercariae) infecting African catfish Clarias gariepinus, as well as their histopathological impacts on infected fish. The intestinal flukes were identified as Orientocreadium batrachoides and Masenia bangweulensis based on their morphological and molecular characteristics. Sequencing of their 28S (LSU rRNA) and 18S rRNA (SSU rRNA) genes confirmed that these trematodes belong to the families Orientocreadiidae and Cephalogonimidae, respectively. The metacercariae trematode infecting skin and muscles were only morphologically identified as Cyanodiplostomum sp. The gene expression levels of MHC II increased in naturally infected fish either with O. batrachoides or Cyanodiplostomum sp. alone, compared with uninfected catfish. In addition, lysozyme levels in individual fish serum increased in catfish infected either with O. batrachoides or Cyanodiplostomum sp. alone. Histopathological examination of the skin revealed embedded parasitic cysts that displaced tissue in the dermis. Surrounding tissues were infiltrated with melanomacrophages and displayed dermal edema. Histopathological analysis showed O. batrachoides or M. bangweulensis between the gastric folds of the stomach of infected catfish, causing infiltration of mononuclear inflammatory cells in the lamina propria.

Effect of Propolis, a Honeybee Product, Against a Parasite (Ligictaluridus floridanus) from Catfish (Ictalurus punctatus) Gills.

The aim of this study was to evaluate the in vitro and in vivo efficacy of propolis against Ligictaluridus floridanus on Ictalurus punctatus gills. This study used an ethanol extract of propolis at a concentration of 300mgmL-1, with a total polyphenol concentration of 2.77mgmL-1 as determined by chromatography. In vitro trial used propolis concentrations at 5, 30 as well as 60mg L-1 and a 70% ethanol control group to treat naturally infected catfish. The in vivo experiment was 16weeks in duration, consisting of seventy-two fish infected by cohabitation and subjected to one-hour baths every 72h during the trial. In vitro studies showed that parasites exposed to 60mg L-1 of propolis displayed a significant reduction (p < 0.05) in their survival time. In vivo studies confirmed the reduction of intensity and abundance of Ligictaluridus floridanus on the gills of channel catfish. This study has provided the first challenge of propolis against L. floridanus on I. punctatus gills and shows that propolis has an anthelmintic effect.

Prevalence and Intensity of Ectoparasites on Clarias gariepinus From Aquaculture Pond in Aceh Besar District, Indonesia

Information related to the prevalence and intensity of para-sites in an aquatic environment is crucial as preventive and responsive efforts to manage aquatic resources, especially for fish farming pur-poses. Up to now, information related to the prevalence and intensity of ectoparasites on catfish from aquaculture ponds in Aceh Besar Dis-trict is rare. This study aims to investigate the prevalence, intensity, and dominance of ectoparasites on catfish from aquaculture ponds in Aceh Besar district. The total of 200 catfish from four research stations at Sibreh, Kareung, Lambaro, and Limpok was observed in this study. The ectoparasites observation was focused on the skin, fins, and gill of the catfish. The observation parameter consists of prevalence, in-tensity, domination, length-weight relationship, and condition factor. Identification result showed that there were four types of ectoparasites infect the catfish in the aquaculture ponds in Aceh Besar District i.e Trichodina sp., Gyrodactylus sp., Dactylogyrus sp. and Ichthyopthyri-us multifiliis. Station 3 (Lambaro) had the highest prevalence and in-tensity, which were 64% and 5.87 ectoparasites/fish, respectively. In-fected catfish tended to have a lower weight growth than healthy catfish.

Prevalence and identification fungal of fungal disease on Catfish (Clarias gariepinus) juvenile at Kendal Coastal Region, Central Java

Fungal disease on fish frequently as secondary infection and can cause death. It found on wound of fish. The aim of this study was to identify fungi that appeared on catfish hatchery at Kendal Coastal area. Methodology of this research was experimental at exploratory. Based on the method, 10 fungal infected catfish consisted of fish at 5-7 cm and another 5 fish at 8-10 cm length. Prevalence obtained from 80 fish observed in every pond, from 4 ponds. Body wound such as lessions and fin rot suspected of fungal infection were streaked on to Sabouraud Dextrose Agar (SDA) and incubated in room temperature for 2 to 7 days. nine fungi found infected fish sample with various character. The fungi then purified and identified. Based on the morphology characters, the fungi were identified as K.21 (Microsporum sp.), K.22 (Fusarium sp.), K.31 (Aspergillus flavus), K.33 (A. fumigatus), K.71 (A. niger), K.72 (A. nidulans), K.73 (Fusarium oxysporum), K.8 (Trichophyton sp.), and K.9 (Rhizopus stolonifer) the prevalence was 30% (Pond A), 20% (Pond B), 25% (Pond C), 22,5%(Pond D)and fungal dominant rate between 8 and 16%. Postulate Koch were conducted with twice repetition for each fungi to 10 fishes indicated. A. flavus was the most pathogenic fungal species to catfish with mortality 85% while the lowest of causing mortality was R. stolonifer with only 15%.

Pengaruh Ekstrak Rimpang Kencur (Kaempferia galanga L.) terhadap Tingkat Kesembuhan Benih Ikan Lele Dumbo (Clarias sp.) yang Terinfeksi Saprolegnia sp. &lt;br&gt;&lt;i&gt;[Effect of Rhizome Extract (Kaempferia kalanga L.) for the Cure Rate of Catfish (Clarias sp.) Infected by Saprolegnia sp. ]&lt;i&gt;

Abstract Saprolegnia sp. is a fungus that causes the disease Saprolegniasis on eggs and fresh water fish such as catfish (Clarias sp.). Treatment of Saprolegniasis have done using chemical drugs such as malachite green, formalin, sodium chloride and asetic acid. However, the use of chemical drugs is bad for the environment and biota. The purpose of this study is to determined the antifungal activity from rhizome extract (Kaempferia galanga L.) for the cure rate of catfish fry (Clarias sp) infected by Saprolegnia sp. The research was conducted on June 2013 at Fisheries and Marine Faculty of Airlangga University. The method used in this study is experimental method using Kruskall Wallis followed by Two Sample Independent test design with 5 treatments and four repetitions. Results showed that the extract of Kaempferia galanga L. has antifungal activity to recovery infected catfish fry. The optimal concentration from this research is 64%. The existence of antifungal activity of Kaempferia galanga L. extracts to Saprolegnia sp. showed that Kaempferia galanga L. extract consists some compounds as fungistatic and fungicidal such as flavonoid, saponin, phenolic and essential oil compounds.

Pharmacokinetics and Tissue residues of Ceftiofur in normal and Aeromonas Hydrophilia Infected Catfish (Clarias lazera)

Pharmacokinetics and Tissue residues of Ceftiofur in normal and Aeromonas Hydrophilia Infected Catfish (Clarias lazera)

Effects of chemotherapeutics against experimentally injured stinging catfish Heteropneustes fossilis

Effects of different chemotherapeutics were examined against experimentally infected stinging catfish Heteropneustes fossilis. Fish were collected from a fish market in Mymensingh, acclimatized for 7 days in laboratory condition from January to February, 2016 in aquaria at Fish Clinic of Bangladesh Agricultural University, Mymensingh, experimentally injured by using forceps and knife and waited seven days for the establishment of infection. Before starting chemotherapeutic trial, it was confirmed that the fish were infected with microorganisms by clinical diagnosis in laboratory condition. They showed hemorrhages and ulcerative lesions over the infected area. A total of 80 such experimentally infected stinging catfish having average body weight of 18 g were used for the experiment. Two chemotherapeutics: antibiotic, Eryvet (erythromycin thiocyanate INN, sulphadiazine (NaUSP) &amp; trimithoprim BP) and antifungal, methylene blue were used in separate and combined treatment with three different doses of antibiotic. The same dose of methylene blue, 0.2 mg/l, was used for separate and combined treatment by antibiotic. Doses of antibiotic (Eryvet) were 0.8 g/10 kg body weight of fish, 1g/10 kg body weight of fish and 1.2 g/10 kg body weight of fish as lower dose, recommended dose and higher dose respectively. For combined treatment the above different doses of antibiotic and the same dose of antifungal were used. Water was exchanged regularly. The chemotherapeutic trial was conducted for 7 days and observation was continued for another 8 days to observe the effect of treatment. Combined treatment with the recommended dose of the antibiotic and methylene blue showed the best result where 90% fish were recovered. By the treatment with the higher dose of the antibiotic 70% fish were recovered. Antifungal treatment showed that 20% fish were recovered. All the fish in negative control aquarium died.Asian J. Med. Biol. Res. December 2017, 3(4): 476-487

Isolation, molecular identification and characterization of Aeromonas hydrophila from infected air-breathing catfish Magur (Clarias batrachus) cultured in Mymensingh, Bangladesh

The study was carried out from November, 2014 to February, 2015 with the objective of isolating Aeromonas hydrophila an important fish pathogen from infected air-breathing catfish Magur (Clarias batrachus) in Mymensingh district. Quantitative study of the isolated bacteria from infected C. batrachus was found variation of number in different organs. Total bacterial load was found to be 1.16 x 105 to 3.15 x 106 cfu/g in lesions, 2.14 x 108 to 4.17 x 109 cfu/g in liver, 1.90 x 107 to 5.12 x 108 cfu/g in spleen and 2.32 x 106 to 5.24 x 108 cfu/g in kidney of infected C. batrachus in Mymensingh district. The isolates were found to produce acid from arabinose, whereas acid and gas from different sugar media such as maltose, sucrose, and dextrose. Morover, they were capable to ferment glucose but resistant to vibriostatic agent 0129 test. Further identification of A. hydrophila was accomplished using PCR. The PCR products of desired 760 bp were obtained for A. hydrophila. The isolated A. hydrophila were 96% sensitive to Enrofloxacin followed by 88% to Ciprofloxacin and 76% to Levofloxacin. On the other way, 100% were resistant to the Ampicillin followed by 96% to Penicillin and 92% to Novobiocin. So far, this is the first molecular identification of A. hydrophila from farmed C. batrachus in Bangladesh. The present study will provide future research scopes on identification of pathogenicity island in chromosome and serotyping of all A. hydrophila isolates.&#x0D; Asian Australas. J. Food Saf. Secur. 2017, 1 (1), 17-24

23. IDENTIFIKASI PARASIT PADA IKAN LELE DUMBO (Clarias gariepinus) DI DESA LAMBRO DEYAH KECAMATAN KUTA BARO KABUPATEN ACEH BESAR Identification of Parasites in Catfish (Clarias gariepinus) in Lambro Deyah Kuta Baro Aceh Besar

The study aimed at identifying the types of parasites that infect catfish as well as to determine the prevalence of the parasite species. A total of 30 catfish were collected using nets then examined at Parasitology Laboratory, Veterinary Medicine Faculty, Syiah Kuala University Banda Aceh. Ectoparasites examination was carried out by directly observed the outer surface of fish body and by mucus smear examination microscopically. While endoparasites examination was done by observation on the inner surface of the digestive tract. The study revealed that five types of parasites infected catfish were Dactylogyrus (43.33%), Gyrodactylus (20%), Tricodina (3.33%), Camallanus sp (3.33%), and unidentified worm (3.33%). ____________________________________________________________________________________________________________________ Key words: catfish, ectoparasite, endoparasite

Chronic saline exposures interfere with basal and induced immunity in striped catfish (Pangasianodon hypophthalmus, sauvage) exposed to virulent strain of Edwardsiella ictaluri

Hyperosmotic stress has often been investigated from osmoregulation perspectives while the effects of such stress on the immune capacity remain largely unexplored. In this study, stenohaline striped catfish Pangasianodon hypophthalmus were submitted to gradual hyperosmotic stress during 20 days up to 10 and 20 ppt. Hyperosmotic stress was followed by an infection with a highly virulent strain of an intracellular gram negative bacteria, Edwardsiella ictaluri, responsible for Enteric Septicemia of Catfish (ESC). Osmoregulatory (i.e. plasma osmolarity and NaK ATPase activity), immune (i.e. lysozyme, complement, respiratory burst, white blood cells, heat shock protein and high-mobility group B1 protein) parameters and mortality rates were monitored. Moreover, a label free quantitative proteomics workflow was performed to study how salinity affects the proteome of kidney in healthy and infected catfish. The flow consisted in initial global profiling of relative peptide abundances (by LC/MS, peak area quantification based on extracted ion currents) followed by MS/MS identification. In total, 496 differentially expressed proteins were analyzed in DAVID interface to isolate functional pathways and categories involved in the response to bacterial infection and which were influenced by salinity changes. Pathways and functional categories, particularly those related to stress, immunity and ion homeostasis, are discussed. We hypothesized that prolonged exposure to mild and high hyperosmotic stress may induce chronic sterile inflammation and disruption of immune homeostasis that may lead to excessive inflammatory response and serious ESC disease.

Investigation of Bacteria and Fish Pathogenic Bacteria Found in Freshwater Aquaponic System

Bacteria are very vital organisms in aquaponic system decomposing and converting the toxic components of the fish waste into usable vegetable nutrients; however, some unwanted bacteria could cause fish diseases. The purposes of this research were to compare the amount of bacteria in water from aquaponic catfish cultured in different stocking densities and Denaturing Gradient Gel Electrophoresis (DGGE) of Polymerase Chain Reaction (PCR)-amplified 16S rDNA was applied to characterise the bacterial populations. Three different stocking densities; 80, 100 and 120 fish/m2 of hybrid catfish were cultured in aquaponic system. Each treatment contained 3 replications; Treatment 1, 360 catfish (80 fish/m2, without lettuce); Treatment 2, 360 catfish (80 fish/m2, without lettuce); Treatment 3, 450 catfish (100 fish/m2); and treatment 4, 540 catfish (120 fish/m2). This research was conducted for 4 months. Water was sampled two times before fish stocking, it was found that the number of bacteria in the first week were higher than the third week. The average number of bacteria in water from treatment 1, 2, 3 and 4 were (2.49 ± 0.40) ×107, (2.43 ± 0.23) ×107, (2.48 ± 2.22) ×107 and (2.29 ± 2.38) ×107 Colonies forming unit (CFU)/ml respectively. According to four-time samplings after catfish were stocked, the average number of bacteria in water from treatment 1, 2, 3 and 4 were (1.85 ± 0.53) ×107, (2.73 ± 0.15) ×107, (2.45 ± 0.30) ×107 and (2.24 ± 0.19) ×107 CFU/ml respectively. The average number of bacteria in water after lettuce harvest from treatment 1, 2, 3 and 4 were (0.185 ± 0.04) ×107, (0.26 ± 0.04) ×107, (0.30 ± 0.01) ×107 and (0.29 ± 0.05) ×107 CFU/ml respectively. There were no differences in bacterial counts among treatments (p > 0.05). In addition, no significant difference was observed in the number of bacteria in filter tanks (p > 0.05) and the number were quite similar to the ones in catfish tanks. Aeromonas hydrophila and Flavobacterium columnare infected catfish at the beginning of the experiment; however, it got better and no more death found after acclimation. The DGGE analysis of PCR-amplified 16S rDNA fragments revealed that bacterial populations in water were dominated by Aeromonas spp., Pseudomonas spp. and Staphylococcus spp. Antibiotic sensitivity test indicated that enrofloxacin might be the best option for bacterial infection treatment. The results indicate that aquaponic system could reduce the wastewater from catfish culture; however, maintaining a good water quality environment for fish culture should take into account.

Isolation and In Vitro Maintenance of Trypanosomes from Naturally Infected and Commercially Important Brazilian Fish

Fish trypanosomes are widely distributed in commercially important fish, with high prevalence in some Brazilian species. This study provides the first record of the isolation and in vitro maintenance of trypanosomes from Brazilian fish. We produced 49 trypanosome isolates from naturally infected catfish (Hypostomus affinis and Hypostomus luetkeni), using 9 different culture media (out of 31 tested). Trypanosomes were maintained in culture for at least 15 mo and were successfully cryopreserved. Culture forms-epimastigotes and short trypomastigotes-were capable of dividing in vitro. Our study is an important step in the investigation of ultrastructure, taxonomy, and phylogeny of trypanosomes from commercially important Brazilian fish.

Pharmacokinetics and Tissue Residues of Levofloxacin in Normal and Aeromonas Hydrophilia Infected Catfish(Clarias Lazera)

Pharmacokinetics and Tissue Residues of Levofloxacin in Normal and Aeromonas Hydrophilia Infected Catfish(Clarias Lazera)

Evaluation of an antiparasitic compound extracted from Galla chinensis against fish parasite Ichthyophthirius multifiliis

Ichthyophthirius multifiliis (Ich) is an important ectoparasitic ciliate that parasitizes gills and skin of freshwater fish resulting in massive mortality of fish. Currently there is no chemotherapeutant available to treat Ich effectively and economically. There is an urgent need to discover effective and safe parasiticides to control ichthyophthiriasis. In this study, anti-Ich efficacy of pentagalloylglucose, a compound extracted from the plant Galla chinensis was evaluated and the toxicity of the compound on channel catfish was determined. Pentagalloylglucose can kill all theronts at concentrations of 2.5–20mg/L during 5.6–233.9min and terminate reproduction of tomonts at 40mg/L. Pentagalloylglucose significantly reduced infective ability of theronts at 1, 2 and 5mg/L. The survival of naive channel catfish was 70% when treated with 10mg/L and 100% when treated with 20mg/L of pentagalloylglucose. For Ich infected catfish, the survival was 53.3% when treated with 10mg/L and 93.3% when treated with 20mg/L of pentagalloylglucose. Pentagalloylglucose at 20mg/L was effective for treating Ich infected catfish or preventing naive catfish from Ich infestation. Median lethal concentration of the compound to catfish was 151.3mg/L, which was 5 times the median effective concentration (30.5mg/L) for killing tomonts. The compound killed Ich by destroying the plasma membrane of the parasite. The result demonstrated pentagalloylglucose as a safe, effective potential parasiticide against I. multifiliis.

Apolipoprotein A1 in channel catfish: Transcriptional analysis, antimicrobial activity, and efficacy as plasmid DNA immunostimulant against Aeromonas hydrophila infection

The objectives of this study were to: 1) determine transcriptional profiles of apolipoprotein A1 (ApoA1) in collected channel catfish tissues after infection with Aeromonas hydrophila by bath immersion; 2) investigate whether recombinant channel catfish apolipoprotein A1 produced in Escherichia coli expression system possesses any antimicrobial activity against A. hydrophila; 3) evaulate whether recombinant channel catfish apolipoprotein A1 plasmid DNA could be used as immunostimulant to protect fish against A. hydrophila infection. Quantitative PCR revealed that the transcription levels of ApoA1 in infected catfish were significantly (P < 0.05) more induced in the anterior kidney. Recombinant apoA1 produced in E. coli expression system exhibited lytic activity against Gram-positive Micrococcus lysodeikticus and Gram-negative A. hydrophila. When pcDNA3.2-vectored recombinant apoA1 was transfected in channel catfish gill cells G1B, the over-expression of pcDNA-ApoA1 offered significant (P < 0.05) protection to G1B cells against A. hydrophila infection. When channel catfish were intraperitoneally injected with QCDCR adjuvant formulated pcDNA-ApoA1 and challenged with a highly virulent A. hydrophila strain AL-09-71 at two days post injection, pcDNA-ApoA1 injection offered 100% protection to channel catfish. Macrophages of fish injected with pcDNA-ApoA1 produced significantly (P < 0.05) higher amounts of reactive oxygen species and nitric oxide than that of fish injected with pcDNA vector alone. Our results suggest that pcDNA-ApoA1 could be used as a novel immunostimulant to offer immediate protection to catfish against A. hydrophila infection.