Young-Gun Moon

Histopathological changes of Korea cultured olive flounder, Paralichthys olivaceus due to scuticociliatosis caused by histophagous scuticociliate, Philasterides dicentrarachi

Recently, mass mortality due to histophagous scuticociliate, Philasterides dicentrarachi in olive flounder, Paralichthys olivaceus occurred in aquaculture farms of Jeju Island, South Korea. We have artificially induced infection through immersion on day 12, the density of ciliates slowly decreased in the experimental tanks; on day 28 to 2300cells/ml in 3cm group and 1800cells/ml in 5cm group. The survival rate of P. olivaceus on days 24 and 28 of infection in the 3cm group was decreased to 4 and 6, respectively; however, no mortality was recorded in the 5cm group. In the control group 100% survival in the chosen period of both groups occurred except in the 3cm group whereas on days 24 and 28 the death rate was 1 and 2, respectively. Many ciliates with ingested red blood cells were observed in the gills, skeletal muscle, skin, fins and brains of infected flounder. The parasites were also observed in the lamina propria of the digestive tract, pharynx, peritoneal fluid, cerebrospinal fluid and cornea. Histopathological and inflammatory changes were characterized by swelling and generalized erythema and muscle tissue necrosis. Affected fish showed varying levels of tissue damage including severe epidermal and dermal necrotic lesions. Loss of scales, appearance of bleached spots that coalesced to form brownish patches, haemorrhagic and severe dermal necrotic lesions were the major clinico-pathological manifestations. The parasite was also seen distributed extensively in the entire brain causing widespread nerve necrosis after a prolonged period of infection. These results appear to support the hypothesis that the P. dicentrarchi may be penetrating via the gills or the skin, and then travel via the bloodstream to other parts of the body, including the body cavity.

Effectiveness of chemotherapeutants against scuticociliate Philasterides dicentrarchi, a parasite of olive flounder.

The histophagous scuticociliate Philasterides dicentrarchi causes fatal scuticociliatosis in farmed olive flounder Paralichthys olivaceus. The average monthly prevalence of scuticociliatosis with P. dicentrarchi infections was very high from May to July (40+/-3 to 79+/-2%) in olive flounder at farms of Jeju Island, South Korea, from 2000 to 2004. The prevalence of mixed infection along with Vibrio spp. infection was higher (49+/-8%) than that of scuticociliatosis alone. To date no effective control measure for P. dicentrarchi infection has been described and large economic losses continue. In the present study 3 chemotheraputants (formalin, hydrogen peroxide and Jenoclean) were used. Among these, bath treatment with Jenoclean at a low concentration of 50ppm proved effective; the results were confirmed with in vitro motility assessments and morphological changes in P. dicentrarchi. A similar trend was noted following hydrogen peroxide treatment. However, formalin was only moderately effective at this concentration. Therefore, hydrogen peroxide and Jenoclean are the promising compounds effective at low concentrations with short application time.

Phytotherapy of ulcerative dermatitis induced by Aeromonas hydrophila infection in goldfish ( Carassius auratus ).

Goldfish ( Carassius auratus ) weighing 13 +/- 2 g were administered intramuscularly a sublethal dose (1.8 x 10 3 cfu/ml) of Aeromonas hydrophila to induce ulcerative dermatitis. On day 3 and day 6 after infection the fish were dip-treated (for 5 min/day) with a tri-herbal concoction of Curcuma longa, Ocimum sanctum and Azadirachta indica (1%). The LD 50 value was recorded at a concentration of 2.3 x 10 4 between 30 and 36 days after infection. In the infected untreated group the cumulative mortality was higher, while in the early-treated group (day 3) there was no mortality. In the late-treated group (6th day) the mortality increased to 23.3% on day 36. In the infected group the size of ulcers progressively increased from 43.3% of the body length on day 18 to 86.7% on day 36. In the early-treated fish the size of ulcers was 23.3% of the body length on day 18; by day 36 after treatment the ulcer had completely healed. In contrast, there was only a moderate recovery in the late-treated group. From the results it can be concluded that early tri-herbal treatment ensures successful recovery from ulcerative dermatitis induced by A. hydrophila .

Antibacterial Activities of Suaeda maritima Extract.

To develop natural food preservatives, methanol and water extracts were prepared from the Suaeda maritima and their antibacterial activities were examined against 12 microorganisms which were food borne pathogens bacteria, food poisoning microorganisms and food-related bacteria. Methanol extracts exhibited antibacterial activities for the 5 Gram positve and 7 Gram negative bacteria by agar diffusion method, The antibacterial activities and cell growth inhibition were investigated on each strain with the different concentrations of Suaeda maritima extracts. Antibacterial activities were shown in root, stem, furit extracts of Suaeda maritima. However stem and fruit extracts showed weak antibacterial activity against the tested microorganisms. Root extracts showed the highest antibacterial activities against microorganisms tested, such as Bacillus cereus,Bacillus subtilis, Vibrio parahaemolyticus, Staphylococcus aureus. The highest antibacterial activity against bacteria test was found in the methanol extract.

Growth and Antioxidant Activity on Lactic Acid Bacteria and Antimicrobial Activity on Fish Pathogenic Bacteria By Prunella vulgaris var. aleutica Fernald Extracts

In this study was investigated the growth effect of Prunella vulgaris. aleutica Fernald(leaf and flower) extracts on various lactic acid bacterias, electron donating ability and hydroxyl radical scavenging activity. The total cell count of Enterococcus faecium KCCM 12118, Lactobacillus rhamnosus KCCM 32826, Lactobacillus plantarum KCCM 11542, Pediococcus pentosaceus KCCM 40464 in the absence at after 48hr were . On the other hand, the total cell count of E. faecium KCCM 12118, L. rhamnosus KCCM 32826, L. plantarum KCC 11542, P. pentosaceus KCCM 40464 in the presence of Prunella vulgaris. aleutica Fernald(leaf and flower) extracts(10%) at after 48hr were . The electron donating ability indicated to E. faecium KCCM 12118, L. rhamnosus KCCM 32826, L. plantarum KCCM 11542, P. pentosaceus KCCM 40464 added by 10% Prunella vulgaris. aleutica Fernald(leaf and flower) extracts, respectively. when 10% native plant extracts were added lactic acid bacterias, the electron donating ability is the highest. Hydroxyl radical scavenging activity of L. plantarum KCCM 11542, L. rhamnosus KCCM 32826, E. faecium KCCM 12118, P. pentosaceus KCCM 40464 showed higher than that of control.

Investigation of Microbial Contamination the Level in Fish Farms of Jeju East Coast.

Level of microbial contamination was examined in four fish farms of Jeju east coast for sanitary indication of bacterial contamination such as heterotrophic bacteria, Escherichia coli O157:H7, Salmonella spp., Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus and total coliforms. The samples were collected and investigated from June to October in 2007. Bacterial species of S. aureus, B. cereus and Salmonella spp. were frequently detected from the seawater of above fish farms. Salmonella spp., S. aureus, B. cereus were detected in the range of CFU/ml, respectively, from the fish feed used in all four selected farms. Additionally, Salmonella spp., S. aureus, B. cereus were detected in oliver flounder (Paralichthys olivaceus) of these farms, however total coliforms and E. coli O157:H7 were not detected during our experimental period. For the production of microbiologically safe and healthy oliver flounder, proper quality control of feed, sanitation programs, and continuous monitoring of microorganism are essential practices, which required to include in the farm management system.

Amylase Activity and Characterization of Microorganism Isolated from in Aquacultural Effluents Sediment Layer

In the course of screening of useful enzyme-producing microorganisms from marine sedimentary layers, we isolated 2 amylase producing strains and tested their amylase producing activities. Analyses of 16S rDNA sequences and biochemical methods (BIOLOG) of two isolates showed that they were confirmed to be a gram positive Bacillus sp. and gram negative Pseudoalteromonas sp., respectively. Excellent amylase producing strains were termed Bacillus sp. ST-63 and Pseudoalteromonas sp. ST-140, and further studies were conducted on their amylase producing characteristics. Optimum conditions for cell growth in amylase activity were obtained when the isolate (Bacillus sp. ST-63 and Pseudoalteromonas sp. ST-140) was cultured at and pH .