ORCID Profile
0000-0003-0744-6040
Current Organisation
CSIRO
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Publisher: Wiley
Date: 23-07-2014
Publisher: Hindawi Limited
Date: 28-08-2002
Publisher: Publishing House for Science and Technology, Vietnam Academy of Science and Technology (Publications)
Date: 14-12-2018
DOI: 10.15625/1811-4989/15/4/13423
Abstract: Shrimp farming plays a key role in economy of many countries all over the world. Unfortunately, a disease called Acute Hepatopancreatic Necrosis Disease (AHPND) or Early Mortality Syndrome (EMS) caused by Vibrio parahaemolyticus spreading from Asia to Central America costs shrimp industry billions of dollars annually. In the past few years, scientists from multi-disciplinary field collaborated to find out a solution for this disease. Until now, there are not any effective approaches to prevent and cure this disease. However, co-culturing shrimp with tilapia was carried out to limit the outbreak of AHPND in farm scale in many countries. Some previous studies also mentioned the benefits of this farming method to prevent other pathogens. The aim of this research is to determine whether intrinsic factors or cultured water of tilapia play role in inhibition of V. parahaemolyticus – pathogen causing AHPND. These factors include: mucus on tilapia gill and skin, tilapia fecal material, and microbiota or dissolved chemicals in culturing of tilapia. Anti-V. parahaemolyticus activity of tilapia (Oreochromis niloticus) fresh and overnight incubated feces and mucus were tested using agar well diffusion method. The effectiveness of feces and mucus inhibition was not clear, both of s les generated a weak inhibition on V. parahaemolyticus. Determination of V. parahaemolyticus inhibiting factor of tilapia cultured water using challenge test showed that dissolved compounds (smaller than 0.22 µm) inhibited the growth of V. parahaemolyticus. The presence of these compounds in tilapia-cultured water reduced V. parahaemolyticus to 17 times lower than that of the negative control with the seawater alone within the first three hours post challenge.
Publisher: MDPI AG
Date: 22-10-2021
Abstract: The importance of microalgal lipids for the survival and growth of shrimp postlarvae has been recognized in a range of studies. Microalgae with fast growth rates and high levels of polyunsaturated fatty acids (PUFA) are considered vital to maximise production and minimise cost in shrimp larviculture. The lipid content and fatty acid composition of microalgae used in shrimp production varies substantially between the algal classes and species being used in Vietnam. This study aims to characterise microalgal lipid and fatty acid (FA) profiles and evaluate the most promising species under growth conditions that are most suitable for shrimp aquaculture. Here, we report that the highest lipid contents were obtained in the Haptophyta microalgae, Tisochrysis lutea and Isochrysis galbana, at 90.3 and 61.1 mg/g, respectively. In contrast, two of the most popular diatom species being used for shrimp larval cultivation in Vietnam, Thalassiosira pseudonana and T. weissflogii, displayed the lowest lipid contents at 16.1 mg/g. Other microalgal species examined showed lipid contents ranging from 28.6 to 55 mg/g. Eicosapentaenoic acid (EPA, 20:5ω3) ranged from 0.6 to 29.9% across the species, with docosahexaenoic acid (DHA, 22:6ω3) present at 0.01 to 11.1% the two omega (ω)–3 long-chain (LC, ≥C20) LC-PUFA varied between the microalgae groups. Polar lipids were the main lipid class, ranging from 87.2 to 97.3% of total lipids, and triacylglycerol was detected in the range of 0.01 to 2.5%. Saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) increased and PUFA decreased with increasing growth temperatures. This study demonstrated the differences in the lipid contents and FA profiles across 10 microalgal species and the effect of the higher temperature growing conditions encountered in Vietnam.
Publisher: Publishing House for Science and Technology, Vietnam Academy of Science and Technology (Publications)
Date: 16-10-2013
Publisher: Publishing House for Science and Technology, Vietnam Academy of Science and Technology (Publications)
Date: 14-12-2018
DOI: 10.15625/1811-4989/15/4/13413
Abstract: Acute Hepatopancreatic Necrosis Disease (AHPND) is a widespread disease targeting cultured shrimps, which results in heavy losses in many regions around the world including Vietnam. The causative agent of the disease is Vibrio paraheamolyticus which is a Gram-negative bacterium present ubiquitously in marine environment. However, this normal floral organism once acquired a plasmid containing Pir- toxin encoding gene (AHPND plasmid) can transform into a highly toxic strain (AHPND strain) with the ability to kill a large number of cultured shrimps in a short period. To understand more on the virulence of V. parahaemolyticus, 17 different V. parahaemolyticus isolates collected from different locations in Southern Vietnam have been analyzed for the presence of AHPND plasmid using PCR method and their extracellular enzyme profile using agar- based method. Seven enzymes which are known to be important virulence factors of the bacterium were studied including caseinase, gelatinase, lecithinase, hemolysin, elastase, lipase and chitinase. Results showed that among 17 studied isolates, six were detected to have AHPND plasmid. Enzymatic activity was observed for caseinase, gelatinase and lecithinase while undetectable for others. The ability to produce these three enzymes varied among different V. parahaemolyticus isolates. Lecithinase appeared in all isolates while the presence of caseinase and gelatinase varied. This indicated that lecithinase seems to be core enzyme of V. paraheamolyticus and the extracellular enzymes do not correlate with the presence of AHPND plasmid. In conclusion, our data suggested that the virulence of Vibrio parahaemolyticus mostly depends on the presence of AHPND plasmid other than extracellular enzymes.
Publisher: Hindawi Limited
Date: 04-2002
Publisher: Elsevier BV
Date: 09-2002
Publisher: Elsevier BV
Date: 05-2003
Publisher: Elsevier BV
Date: 05-2002
Publisher: Wiley
Date: 18-04-2022
DOI: 10.1002/AFF2.41
Abstract: This study investigated short‐term effects of temperature on survival, body weight and the fatty acid profile of farmed marine polychaete Perinereis helleri —an excellent live feed maturation diet for penaeid shrimp broodstock. Two consecutive experiments were conducted to evaluate the effects of low temperature (4, 8, 12, 16 and 20°C) and high temperature (20, 24, 28, 32 and 36°C) on a 7‐month‐old population of P. helleri farmed at Bribie Island Research Centre, Australia. The experimental polychaetes were purged for 24 h at 20°C before being transferred directly into 500 ml glass chambers, sealed and submersed in different target temperature water baths. The jars were then kept for 3 or 6 h in the low‐temperature experiment and 1 or 3 h in the high‐temperature experiment, respectively. Results showed that mortality occurred only at 4°C and 8°C ( p 0.01). Weight loss occurred across all treatments of the low‐temperature experiment, but only at 36°C in the high‐temperature one. Analysis of lipid classes and fatty acids show that farmed P. helleri is rich in polyunsaturated fatty acids (PUFA, i.e. 37% of total fatty acids), especially arachidonic acid (ARA, 20:4 n ‐6). The total value of essential fatty acids was 15.8% of total fatty acids or 16.8 mg/g dry matter. The n‐ 3: n‐ 6 ratio was 1.07 ± 0.04. This study suggests that P. helleri can be transported at ambient temperature of 16–20°C and can be farmed in a tropical climate.
Publisher: Informa UK Limited
Date: 08-2007
DOI: 10.1080/02652030701245171
Abstract: The toxicity of the gastropod Nassarius papillosus implicated in a food paralytic poisoning incident in Liuchiu Island, Taiwan, in October 2005 is reported. The symptoms of a victim (67 years old) were featured by general paresthesia, paralysis of phalanges and extremities, paralysis, coma, and aphasia. The remaining specimens of shell were assayed for toxicity. The range of specimen toxicity was found to be 63-474 mouse units (MU) per specimen for N. papillosus by a tetrodotoxin (TTX) bioassay. The mean (SD) toxicity of the digestive gland and other portions were 296 +/- 120 and 382 +/- 156 MU in N. papillosus. The toxin was partially purified from the acidic methanol extract of the gastropod by using a C18 solid-phase extraction column. The eluate was then filtered through a 3000 MW cut-off ultrafree microcentrifuge filter. It was shown that the toxin purified from gastropods analysed by high-performance liquid chromatography and liquid chromatography/mass spectrometry contained TTX 42-60 microg g(-1) (about 90%), whereas along with minor paralytic shellfish poisons (PSP) it was 3-6 microg g(-1) (about 10%).
Publisher: Elsevier BV
Date: 10-2002
Publisher: Elsevier BV
Date: 06-2002
Publisher: Hindawi Limited
Date: 13-09-2015
DOI: 10.1111/ARE.12289
Publisher: Hindawi Limited
Date: 12-2002
Publisher: Springer Science and Business Media LLC
Date: 24-01-2014
DOI: 10.1007/S11274-014-1601-8
Abstract: Tetrodotoxin (TTX) is a potent toxin but it could be used in pharmaceutical field. Identification of TTX producing bacteria in pufferfish is necessary for TTX yield and the pufferfish conservation. In this study, Lagocephalus was collected from Cam Ranh Sea, a central part of Vietnam during spring season. The liver and intestine were incubated in 0.9 % NaCl for TTX detection in pufferfish. To be benefited from the isolation of new TTX producing bacteria, the liver and intestine were incubated in 6.5 % NaCl. The cultures were used to test the toxin and to isolate the bacterial community that could yield TTX. Surprisingly, Providencia rettgeri T892 in intestine could produce TTX identified by biochemical test and 16S rRNA sequencing. This strain was used to test the production of TTX, based on thin layer chromatography (TLC), mouse bioassay and high performance liquid chromatography (HPLC) analysis. The bacterium was optimized for TTX production in media prepared from the meat-washing water of Auxis thazard, Megalaspis cordyla and Decapterus maruadsi. Interestingly, the TTX obtained 0.106 mg/mL and 0.055 mg/mL in medium prepared from A. thazard and M. cordyla, respectively while there was no TTX production detected in medium prepared from D. maruadsi. This paper could contribute to warn to the human health care system about a possible TTX poisoning in some cases related to eating fishes.
Publisher: Hindawi Limited
Date: 2002
Publisher: Hindawi Limited
Date: 03-01-2020
DOI: 10.1111/ARE.14493
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 02-2003
Location: Australia
Location: Australia
No related grants have been discovered for Tung Hoang.