54 research outputs found

    Application of Spirulina platensis for prevention of white spot syndrome virus in post larvae and juvenile black tiger shrimp (Penaeus monodon)

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    In this study, the extract of Spirulina platensis were examined in vitro to inhibit white spot syndrome virus (WSSV) and application of dry S. platensis in diet for prevention of white spot syndrome (WSS) in post larvae and juvenile black tiger shrimp (Penaeus monodon). The results showed that the lowest concentration of the extract for inhibiting WSSV was 0.01 mg/ml, while the optimum concentration was found to be 0.1 mg/ ml in which the mortality rate of the shrimp was 4 percents and infection was not detected from survivalshrimp by the immunohistochemistry method.Furthermore, The results showed that the survival rate of the post larvae fed on steamed egg containing dry S. platensis 5 g/kg of diet was higher than that of the control (p<0.05) when challenged with WSSV and no WSSV infected shrimp examine by polymerase chain reaction (PCR) assay. In the case of juvenile shrimp, the survival rate of shrimp fed pellets containing dry S. platensis 10 g/kg of diet was higher than that of the control group (p<0.05) after challenging with WSSV. Moreover percent of WSSV infection in the survival shrimp using the immunohistochemistry method was lower than that of the control group

    Efficacy of Thai Traditional Herb Extracts against Fish and Shrimp Pathogenic Bacteria

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    Sixteen species of Thai traditional herbs were selected for this study. They were Andrographis paniculata, Cassia alata, Clinacanthus nutans, Eclipta alba, Momordica charantia, Phyllanthus acidus, P. amarus, P. debilis, P. pulcher, P. reticulatus, P. urinaria, Psidium guajava, Tinospora cordifolia, T. crispa and white and red strains or Ocimum sanctum. Using an agar plate dilution method, they were tested for antibacterial activity against the pathogenic bacteria: Aeomonas hydrophila, a Streptococcus species and 10 strains of Vibrio. Eleven of the tested herbs showed antibacterial activity. Among them, P. guajava and M. charantia displayed the highest activity against Vibrio harveyi and V. parahaemolyticus. The minimal inhibitory concentration (MIC) of P. guajava against the tested bacteria was found to be 0.625mg/ml, while the MIC of M. charantia was 1.25 mg/ml

    Protective Efficacy of Clinacanthus nutans on Yellow-head Disease in Black Tiger Shrimp (Penaeus monodon)

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    The leaves of Clinacanthus nutans Lindua, a well-known Thai traditional medicine against viral disease in human being, were used to extract antiviral substances by ethanol using soxhlet apparatus. The extract was tested for its activity against yellow-head rhabdovirus (YRV) in black tiger shrimp (Penaeus monodon). Virucidal effect was investigated by observation of mortality of the shrimp injected with the extract-treated virus. The results showed that extract of C. nutans inhibited YRV in vitro with the minimum concentration of 1μg/ml. Protective efficacy of the extract on YRV infection in shrimp was tested by oral administration of the extract mixed pellet. As the result, the protective efficacies obtained were 44.6, 57.4 and 4.2% in the shrimp groups fed the extract at 0.1, 1 and 10g/kg pellet, respectively, indicating that the C. nutans extract mixed with pellet at 1 g/kg could most effectively control YRV infection in shrimp

    Detection of antibody against Aeromonas salmonicida in the serum of salmonid fish by the enzyme linked immunosorbent assay

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    Enzyme linked immunosorbent assay (ELISA) using the anti-masu Ig rabbit serum was applied to detect the antibody against Aeromonas salmonicida in the sera or salmonid fish. This ELISA method could detect the antibody in sera of masu (Oncorhynchus masou), chum (O. keta) and coho salmon (O. kisutch) immunized by A. salmonicida and could be applied to detect the antibody against A. salmonicida in sera of matured masu, pink (O. gorbuscha), chum, and kokanee salmon (O. nerka). In 1989, 89 masu and 250 chum salmon, and 59 kokanee were examined to detect antibody against A. salmonicida by ELISA and agglutination test. The number of the fish showing the positive reaction by ELISA, agglutination test and isolation of A. salmonicida were 262, 48, and 33, respectively. In 1990, 200 masu and kokanee salmon fry released from hatchery to river were tested and antibody against A. salmonicida was detected from 111 fish by ELISA, and the incidence of the fish showing the positive reaction was ranged from 4 to 90%

    Antiviral Activity of Several Thai Traditional Herb Extracts against Fish Pathogenic Viruses

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    Extracts from 18 Thai traditional herbs were prepared by boiling with ethanol under a soxhlet apparatus and virucidal activity against fish pathogenic viruses (IHNV, OMV and IPNV) was tested by plaque reduction method using CHSE-214 cells. When the viruses were exposed to herb extract at 500μg/ml before inoculation to CHSE-214 cells, all herbs showed antiviral activity against IHNV and OMV, reducing plaques by 65-100% and 20-100%, respectively. However, in the case of IPNV, no plaque reduction was observed by any herbs tested. Some kinds of the herb extracts prevented viral infection, when CHSE-214 cells were treated with 100 μg/ml of herbs for 3h before viral infection. The percent of plaque reduction above 50% was observed in 6, 8 and 6 kinds of herb extracts for IHNV, OMV and IPNV, respectively. These extracts may inhibit the viral adsorption to the cells. When 100μg/ml of the herb extracts was applied for infected cells, the percent of plaque reduction above 50% was observed in 0.8 and 5 kinds of herb extracts for IHNV, OMV and IPNV, respectively. This means that some of the herb extracts may inhibit the replication of OMV and IPNV in CHSE-214, but no herb has any effect for IHNV infection. Moreover, all of the tested herb extracts showed low toxicity to CHSE-214 cell line, the cytotoxic 50% value being 1,200-41,500μg/ml

    Efficacy of Guava (Psidium Guajava) Extract Against Some Fish and Shrimp Pathogenic Agents

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    Guava (Psidium guajava) extract was tested for anti viral activity against the fish pathogenic viruses, infectious haematopoietic necrosis virus (IHNV), infectious pancreatic necrosis virus (IPNV), and Oncorhynchus masou virus (OMV) using plaque reduction in CHSE-214 cell lines. Anti viral tests against the shrimp pathogenic virus, yellow-head virus (YHV), was carried out using the injection method. The efficacy of guava extract was also determined using MIC of the extract against 24 strains of pathogenic bacteria including; Vibrio harveyi (9 strains), V. splendidus (7 strains), V. parahaemolyticus (2 strains) and 1 strain of each V. mimicus, V. vulnificus, V. fluvialis, V. chorelae, V. alginolyticus and Aeromonas hydrophila. A toxicity test of the extract was performed with CHSE-214 cell lines and post larvae 15 of black tiger shrimp (Penaeus monodon). The efficacy of guava extract for the prevention of viral disease and bacterial disease in aquatic animals was estimated using YHV infection in black tiger shrimp and A. hydrophila infection in catfish, respectively. The extract of guava demonstrated anti viral activity against IHNV, OMV and YHV but was not effective for IPNV. Furthermore, the MIC of the extract ranged from 625 - 5,000 μg/ml against all pathogenic bacterial strains tested. The 50% cytotoxicity of the extract to CHSE-214 was 1,923 μg/ml while the LD50 of the extract to black tiger shrimp post larvae was 2,968 ± 3.8 μg/ml. These results show that guava extract has low toxicity to salmon cell lines and black tiger shrimp. Moreover, the extract is effective for prevention of bacterial infection in catfish (Clarias macrocephalus) while not suitable for prevention of yellow-head virus infection in black tiger shrimp. From these results, guava can be recommended for treatment of bacterial disease in fish. The route of administration and effective dose should be determined before their efficacy can be tested in field trials.Third Symposium on Diseases in Asian Aquaculture. 1996. Bangkok, Thailand

    Urea as a Nitrogen Source in a Black Tiger Shrimp (Penaeus monodon) Closed Culture System

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    Urea [(NH2)2CO] is an organic compound that serves an important role in the metabolism of nitrogen-containing compound by animals. Urea is widely used in aquaculture systems. This study investigated the effects of urea on growth of Penaeus monodon. Shrimp were reared in 500 l fiber tanks. There was no exchange of water throughout the experiment. Shrimp with an average body weight of 10.99 ± 0.19 g were stocked at a density of 32 shrimp/m2 in 20 ppt diluted seawater and fed with 38 % protein diet for 9 weeks. Urea was added into the culture tanks at a concentration of 1.25 ppm once a week. The results show that urea slightly affects growth and survival of shrimp. Shrimp reared in the culture pond with added urea had a marginal better growth rate (p > 0.05) while the survival rate was significantly higher than the control group (p < 0.05). The urea in the closed culture tanks was shown to reduce the toxicity of ammonia in soil and promoted growth of plankton communities. Adding urea has no effect on water quality. This study concluded that urea is a potential nitrogen source in closed culture systems when the nitrogen input through the feeding regime is limited. It suggests that urea should be added at a concentration of 1.25 ppm once a week into culture systems with limiting nitrogen sources

    せっそう病の血清学的診断のための Aeromonas salmonicida に対するモノクローナル抗体

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    Hybridomas which produce species-specific and strain-specific monoclonal antibodies (MAbs) against Aeromonas salmonicida have been established. Reaction of three MAbs, Nos. 9, 17, and 40, was strain-specific while one MAb, No.27, was species-specific. MAb 27 reacted with A. salmonicida subsp. salmonicida, achromogenes, masoucida, and atypical A. salmonicida. The titer of this MAb, a culture fluid of hybridoma, was 1:8, 1:256, 1:8, and 1:128 for agglutination test, ELISA, FAT, and colony blotting test, respectively. The molecular weight of the antigen recognized by MAb 27 was 51 to 62 kDa
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