Displaying publications 121 - 140 of 240 in total

Abstract:
Sort:
  1. Microalgal-bacterial granular sludge process for non-aerated aquaculture wastewater treatment
    Fan S, Ji B, Abu Hasan H, Fan J, Guo S, Wang J, et al.
    Bioprocess Biosyst Eng, 2021 Aug;44(8):1733-1739.
    PMID: 33772637 DOI: 10.1007/s00449-021-02556-0
    Microalgal-bacterial granular sludge (MBGS) process has become a focal point in treating municipal wastewater. However, it remains elusive whether the emerging process can be applied for the treatment of aquaculture wastewater, which contains considerable concentrations of nitrate and nitrite. This study evaluated the feasibility of MBGS process for aquaculture wastewater treatment. Result showed that the MBGS process was competent to remove respective 64.8%, 84.9%, 70.8%, 50.0% and 84.2% of chemical oxygen demand, ammonia-nitrogen, nitrate-nitrogen, nitrite-nitrogen and phosphate-phosphorus under non-aerated conditions within 8 h. The dominant microalgae and bacteria were identified to be Coelastrella and Rhodobacteraceae, respectively. Further metagenomics analysis implied that microbial assimilation was the main contributor in organics, nitrogen and phosphorus removal. Specifically, considerable nitrate and nitrite removals were also obtained with the synergy between microalgae and bacteria. Consequently, this work demonstrated that the MBGS process showed a prospect of becoming an environmentally friendly and efficient alternative in aquaculture wastewater treatment.
    Matched MeSH terms: Aquaculture*
  2. Selection and evaluation of Malaysian Bacillus spp. strains as potential probiotics in cultured tiger grouper (Epinephelus fuscoguttatus)
    Yasin IM, Razak NF, Natrah FMI, Harmin SA
    J Environ Biol, 2016 07;37(4 Spec No):791-800.
    PMID: 28779739
    A total of 58 Gram-positive bacteria strains were isolated from the marine environment and screened for potential probiotics for disease prevention and improving the productivity of tiger grouper Epinephelus fuscoguttatus larvae and juveniles. The bacteria were identified as Bacillus licheniformis, B. subtilis, B. circulans, B. sphaericus, B. cereus, Brevibacillus brevis, Corynebacterium propinquum, Leifsonia aquatica and Paenibacillus macerans. Only 24 strains showed antagonistic activities against four pathogenic strains; Vibrio alginolyticus, V. harveyi, V. parahaemolyticus and Aeromonas hydrophila, where two of the Bacillus strains, B12 and B45 demonstrated intermediate to highest level of inhibitory activity against these pathogenic strains, respectively. Further assessment by co-culture assay showed that Bacillus strain B12 exhibited a total inhibition of V. alginolyticus, while B45 strain displayed no inhibitory activity. Mixed culture of Bacillus B12 and B45 strains to outcompete V. alginolyticus was observed at a cell density of 10(7) CFU ml(-1). Molecular identification and phylogenetic tree analysis have categorized Bacillus strain B12 to the reference strains GQ340480 and JX290193 of? B. amyloliquafaciens, and Bacillus strain B45 with a reference strain JF496522 of B. subtilis. Safety tests of probionts by intraperitoneal administration of B12 and B45 strains at cell densities of 103, 105 and 10(7) CFU ml(-1) revealed no abnormalities and cent percent survival for healthy Epinephelus fuscoguttatus juveniles within 15 days of experimental period. Overall, the study revealed that Bacillus B12 strain possesses tremendous probiotic potential that could be used as a feed supplement in tiger grouper diets. ?
    Matched MeSH terms: Aquaculture*
  3. Fulltext Electronic Properties of Synthetic Shrimp Pathogens-derived DNA Schottky Diodes
    Rizan N, Yew CY, Niknam MR, Krishnasamy J, Bhassu S, Hong GZ, et al.
    Sci Rep, 2018 01 17;8(1):896.
    PMID: 29343758 DOI: 10.1038/s41598-017-18825-6
    The exciting discovery of the semiconducting-like properties of deoxyribonucleic acid (DNA) and its potential applications in molecular genetics and diagnostics in recent times has resulted in a paradigm shift in biophysics research. Recent studies in our laboratory provide a platform towards detecting charge transfer mechanism and understanding the electronic properties of DNA based on the sequence-specific electronic response, which can be applied as an alternative to identify or detect DNA. In this study, we demonstrate a novel method for identification of DNA from different shrimp viruses and bacteria using electronic properties of DNA obtained from both negative and positive bias regions in current-voltage (I-V) profiles. Characteristic electronic properties were calculated and used for quantification and further understanding in the identification process. Aquaculture in shrimp industry is a fast-growing food sector throughout the world. However, shrimp culture in many Asian countries faced a huge economic loss due to disease outbreaks. Scientists have been using specific established methods for detecting shrimp infection, but those methods do have their significant drawbacks due to many inherent factors. As such, we believe that this simple, rapid, sensitive and cost-effective tool can be used for detection and identification of DNA from different shrimp viruses and bacteria.
    Matched MeSH terms: Aquaculture/methods
  4. Responses of phytoplankton community to eutrophication in Semerak Lagoon (Malaysia)
    Er HH, Lee LK, Lim ZF, Teng ST, Leaw CP, Lim PT
    Environ Sci Pollut Res Int, 2018 Aug;25(23):22944-22962.
    PMID: 29858995 DOI: 10.1007/s11356-018-2389-0
    Effects of aquaculture activities on the environmental parameters and phytoplankton community structure were investigated in a semi-enclosed lagoon located at Semerak River, Malaysia. Elevated concentrations of phosphate and ammonia were observed at the aquaculture area and the inner lagoon. Relatively low dissolved oxygen, high total chlorophyll a, and high phytoplankton abundances but low species richness were recorded. Chaetoceros, Pseudo-nitzschia brasiliana, Blixaea quinquecornis, and Skeletonema blooms were observed, and some were associated with anoxia condition. Eutrophication level assessed by UNTRIX suggests that the water quality in the lagoon is deteriorating. Dissolved inorganic phosphorus and nitrogen at the impacted area were 15 and 12 times higher than the reference sites, respectively. Such trophic status indices could provide a useful guideline for optimal aquaculture management plan to reduce the environmental impact caused by aquaculture.
    Matched MeSH terms: Aquaculture/methods*
  5. Epidemiological aspects of aquaculture in relation to fish borne trematodiasis in Malaysia
    Shekhar KC
    Southeast Asian J Trop Med Public Health, 1997;28 Suppl 1:54-7.
    PMID: 9656350
    Epidemiological studies have been conducted to determine the association between fish and disease. The fish were obtained from rivers, streams, ponds and lakes but few from aquaculture farms. While no defined studies have been carried out in Malaysia, baseline data show that fish obtained from aquaculture farms (mixed farming) contributed to cases of opisthorchiasis and clonorchiasis.
    Matched MeSH terms: Aquaculture*
  6. Isolation of Potential Bacteria as Inoculum for Biofloc Formation in Pacific Whiteleg Shrimp, Litopenaeus vannamei Culture Ponds
    Kasan NA, Ghazali NA, Ikhwanuddin M, Ibrahim Z
    Pak J Biol Sci, 2017;20(6):306-313.
    PMID: 29023055 DOI: 10.3923/pjbs.2017.306.313
    BACKGROUND AND OBJECTIVE: A new green technology to reduce environmental damages while optimizing production of Pacific Whiteleg shrimp, Litopenaeus vannamei was developed known as "Biofloc technology". Microbial communities in biofloc aggregates are responsible in eliminating water exchange and producing microbial proteins that can be used as supplemented feed for L. vannamei. This study aimed to isolate and identify potential bioflocculant-producing bacteria to be used as inoculum for rapid formation of biofloc.

    MATERIALS AND METHODS: For the purpose of this study, bacterial communities during 0, 30 and 70 days of culture (DOC) of L. vannamei grow-out ponds were isolated and identified through phenotypic and 16S rDNA sequences analysis. Phylogenetic relationships between isolated bacteria were then evaluated through phylogenetic tree analysis. One-way analysis of variance (ANOVA) was used to compare the differences of microbial communities at each DOC.

    RESULTS: Out of 125 bacterial isolates, nine species of bacteria from biofloc were identified successfully. Those bacteria species were identified as Halomonas venusta, H. aquamarina, Vibrio parahaemolyticus, Bacillus infantis, B. cereus, B. safensis, Providencia vermicola, Nitratireductor aquimarinus and Pseudoalteromonas sp., respectively. Through phylogenetic analysis, these isolates belong to Proteobacteria and Firmicutes families under the genera of Halomonas sp., Vibrio sp., Bacillus sp., Providencia sp., Nitratireductor sp. and Pseudoalteromonas sp.

    CONCLUSION: In this study, bioflocculant-producing bacteria were successfully identified which are perfect candidates in forming biofloc to reduce water pollution towards a sustainable aquaculture industry. Presence of Halomonas sp. and Bacillus sp. in all stages of biofloc formation reinforces the need for new development regarding the ability of these species to be used as inoculum in forming biofloc rapidly.

    Matched MeSH terms: Aquaculture/methods*
  7. Issues of livelihood, sustainable development, and governance: Bay of Bengal
    Samarakoon J
    Ambio, 2004 Feb;33(1-2):34-44.
    PMID: 15083648
    This article is based on the findings of the Global International Waters Assessment (GIWA) Subregion 53, Bay of Bengal. It introduces the Subregion. The wide disparity in development indicators in the Bay of Bengal Subregion (BOBSR) is presented. The large population of poor people living in South Asia is presented as a factor that needs special attention. The article focuses on the 3 geographic sites selected for detailed analysis: i) the Ganges-Brahmaputra-Meghna river systems; ii) the Merbok Estuary mangroves, Malaysia; and iii) the Sunderbans mangroves, Bangladesh. Integrated water management based upon regional cooperation among Bangladesh, India and Nepal holds opportunities for mutual benefit. Policy options are proposed. For mangrove ecosystems, the impacts of urbanization in Malaysia and the unmanaged expansion of shrimp farming in Bangladesh are analyzed. Improved governance was seen to hold promise for enhancing economic benefits from shrimp farming while safeguarding the natural ecological system. However, these measures need to be a part of national efforts to achieve the UN Millennium Development Goals.
    Matched MeSH terms: Aquaculture/economics
  8. Potential of palm oil utilisation in aquaculture feeds
    Ng WK
    Asia Pac J Clin Nutr, 2002;11 Suppl 7:S473-6.
    PMID: 12492637
    One key ingredient used in the formulation of aquafeed is fish oil, which is produced from small marine pelagic fish and represents a finite fishery resource. At the present time, global fish oil production has reached a plateau and is not expected to increase beyond current levels. Recent estimates suggest that fish oils may be unable to meet demands from the rapidly growing aquaculture industry by as early as 2005. Therefore, there is currently great interest within the aquafeed industry in evaluating alternatives to fish oils. The ever-expanding oil palm cultivation in Malaysia and other tropical countries offers the possibility of an increased and constant availability of palm oil products for aquafeed formulation. Research into the use of palm oil in aquafeed begun around the mid-1990s and this review examines some of the findings from these studies. The use of palm oil in fish diets has generally shown encouraging results. Improved growth, feed efficiency, protein utilisation, reproductive performance and higher concentrations of alpha-tocopherol in fish fillets have been reported. Recent evidence for the ability of palm oil to substitute for fish oil in catfish diets is reviewed. The potential of palm oil use in aquafeed and future experimental directions are suggested. The aquaculture feed industry offers a great avenue to increase and diversify the use of palm oil-based products.
    Matched MeSH terms: Aquaculture*
  9. Fulltext Occurrence and Antibiotic Resistance of Vibrio parahaemolyticus from Shellfish in Selangor, Malaysia
    Letchumanan V, Pusparajah P, Tan LT, Yin WF, Lee LH, Chan KG
    Front Microbiol, 2015;6:1417.
    PMID: 26697003 DOI: 10.3389/fmicb.2015.01417
    High consumer demand for shellfish has led to the need for large-scale, reliable shellfish supply through aquaculture or shellfish farming. However, bacterial infections which can spread rapidly among shellfish poses a major threat to this industry. Shellfish farmers therefore often resort to extensive use of antibiotics, both prophylactically and therapeutically, in order to protect their stocks. The extensive use of antibiotics in aquaculture has been postulated to represent a major contributing factor in the rising incidence of antimicrobial resistant pathogenic bacteria in shellfish. This study aimed to investigate the incidence of pathogenic Vibrio parahaemolyticus and determine the antibiotic resistance profile as well as to perform plasmid curing in order to determine the antibiotic resistance mediation. Based on colony morphology, all 450 samples tested were positive for Vibrio sp; however, tox-R assay showed that only 44.4% (200/450) of these were V. parahaemolyticus. Out of these 200 samples, 6.5% (13/200) were trh-positive while none were tdh-positive. Antibiotic resistance was determined for all V. parahaemolyticus identified against 14 commonly used antibiotics and the multiple antibiotic resistance index (MAR) was calculated. The isolates demonstrated high resistance to several antibiotics tested- including second and third-line antibiotics- with 88% resistant to ampicillin, 81% to amikacin,70.5% to kanamycin, 73% to cefotaxime, and 51.5% to ceftazidime. The MAR index ranged from 0.00 to 0.79 with the majority of samples having an index of 0.36 (resistant to five antibiotics). Among the 13 trh-positive strains, almost 70% (9/13) demonstrated resistance to 4 or more antibiotics. Plasmid profiling for all V. parahaemolyticus isolates revealed that 86.5% (173/200) contained plasmids - ranging from 1 to 7 plasmids with DNA band sizes ranging from 1.2 kb to greater than 10 kb. 6/13 of the pathogenic V. pathogenic strains contained plasmid. After plasmid curing, the plasmid containing pathogenic strains isolated in our study have chromosomally mediated ampicillin resistance while the remaining resistance phenotypes are plasmid mediated. Overall, our results indicate that while the incidence of pathogenic V. parahaemolyticus in shellfish in Selangor still appears to be at relatively reassuring levels, antibiotic resistance is a real concern and warrants ongoing surveillance.
    Matched MeSH terms: Aquaculture
  10. First report of methicillin-resistant Staphylococcus aureus from cage-cultured tilapia (Oreochromis niloticus)
    Atyah MA, Zamri-Saad M, Siti-Zahrah A
    Vet Microbiol, 2010 Aug 26;144(3-4):502-4.
    PMID: 20189324 DOI: 10.1016/j.vetmic.2010.02.004
    Swabs from the brain, eyes and kidneys of tilapia from 11 farms were collected for a period of 2 years. They were grown on blood agar before cultures of suspected Staphylococcus aureus were subjected to ABI STAPH Detection Kit and PCR for identification. They were then grown on oxacillin resistance screening agar base (ORSAB) and subjected to PCR using the MRSA 17 kb forward and reverse primers to identify the methicillin-resistant S. aureus (MRSA). A total of 559 isolates of Staphylococcus spp. were obtained, from which 198 (35%) isolates were identified as S. aureus. Of the 198 S. aureus isolated from tilapias, 98 (50%) were identified as methicillin-resistant S. aureus (MRSA). Since global spread of multi-drug-resistant bacteria has increased in the past decade, this new finding in fish should be of concern.
    Matched MeSH terms: Aquaculture
  11. Mercury levels in the green-lipped mussel Perna viridis (Linnaeus) from the west coast of peninsular Malaysia
    Yap CK, Ismail A, Tan SG
    Bull Environ Contam Toxicol, 2003 Sep;71(3):570-6.
    PMID: 14567584
    Matched MeSH terms: Aquaculture
  12. Isolation of AHL-degrading bacteria from micro-algal cultures and their impact on algal growth and on virulence of Vibrio campbellii to prawn larvae
    Pande GS, Natrah FM, Flandez AV, Kumar U, Niu Y, Bossier P, et al.
    Appl Microbiol Biotechnol, 2015 Dec;99(24):10805-13.
    PMID: 26344339 DOI: 10.1007/s00253-015-6918-1
    Inactivation of quorum sensing (QS) signal molecules, such as acylhomoserine lactones (AHLs) of pathogenic bacteria, has been proposed as a novel method to combat bacterial diseases in aquaculture. Despite the importance of micro-algae for aquaculture, AHL degradation by bacteria associated with micro-algal cultures has thus far not been investigated. In this study, we isolated Pseudomonas sp. NFMI-T and Bacillus sp. NFMI-C from open cultures of the micro-algae Tetraselmis suecica and Chaetoceros muelleri, respectively. An AHL degradation assay showed that either monocultures or co-cultures of the isolates were able to degrade the AHL N-hexanoyl-L-homoserine lactone. In contrast, only Bacillus sp. NFMI-C was able to inactivate N-hydroxybutanoyl-L-homoserine lactone, the AHL produced by Vibrio campbellii. The isolated bacteria were able to persist for up to 3 weeks in conventionalized micro-algal cultures, indicating that they were able to establish and maintain themselves within open algal cultures. Using gnotobiotic algal cultures, we found that the isolates did not affect growth of the micro-algae from which they were isolated, whereas a mixture of both isolates increased the growth of Tetraselmis and decreased the growth of Chaetoceros. Finally, addition of Bacillus sp. NFMI-C to the rearing water of giant river prawn (Macrobrachium rosenbergii) larvae significantly improved survival of the larvae when challenged with pathogenic V. campbellii, whereas it had no effect on larval growth.
    Matched MeSH terms: Aquaculture
  13. Phototrophic purple bacteria as feed supplement on the growth, feed utilization and body compositions of Malaysian mahseer, tor tambroides juveniles
    Nor Hafizah Zakaria, Mohammad Mustafizur Rahman, Ahmed Jalal Khan Chowdhury, Zaima Azira Zainal Abidin
    Sains Malaysiana, 2016;45:135-140.
    The application of microbial techniques in aquaculture has been playing a vital role to increase the production yield by improving the nutritional values of the targeted fish. Phototrophic purple bacteria as single cell protein (SCP) appears to be a promising substitution for protein rich supplement for aquaculture feeds making them a promising growth enhancer in aquaculture industry. Two species of phototrophic purple bacteria, Marichromatium sp. and Rhodopseudomonas sp. were used in the commercial diet to compare the growth, survival rate and feed utilizationon for Tor tambroides juvenile. Purple bacteria were isolated from mangrove sediment and fish tank and mass cultured using 112 synthetic media under anaerobic light condition. Bacterial cells were included in the diets by mixing the fresh biomass with the crushed commercial pellet, re-pelleted and air-dried. The experimental diets were fed to the fingerlings twice per day for 10 weeks to satiation level. The results showed that there were trends of increased growth, better survival rate and improved feed conversion ratio when fed with diet 1 (Marichromatium sp.) compared with other diets. There was significant difference (p<0.05) between the sampling days. The specific growth rate and weight gain of the fish fed with diet 1 were 0.49 % and 4.92 g, respectively, compared to 0.42% and 4.11 g from the control. This study suggested that purple bacteria could be used in feed formulation as a supplement to promote growth and survival of freshwater fishes in Malaysia.
    Matched MeSH terms: Aquaculture
  14. Fulltext Molecular Characterization of Microbiota Associated With Sperm of Malaysian Mahseer Tor tambroides
    Koh ICC, Badrul Nizam BH, Muhammad Abduh Y, Abol Munafi AB, Iehata S
    Evol Bioinform Online, 2019;15:1176934319850821.
    PMID: 31217688 DOI: 10.1177/1176934319850821
    Malaysian Mahseer (Tor tambroides) is considered as a good prospect for aquaculture in Malaysia. However, knowledge about Malaysian Mahseer-associated sperm microbiota is still limited, although some studies reported that sperm-related bacteria are a factor in the decline of sperm quality, as sperm may become the carrier of pathogenic bacteria to the egg. The goal of this study was to evaluate the sperm microbiota associated with Malaysian Mahseer from 3 different locations (Universiti Malaysia Terengganu [UMT], Ajil, and Pahang) using polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting and to compare location differences by cluster analysis. Our results showed that the UMT sample had different sperm microbiota composition and a different trend in its relationship with sperm quality. Correlation analysis showed a relationship between bacterial diversity and sperm quality. Phylogenetic analysis indicated that sperm microbiota was composed of diverse phyla, including Proteobacteria, Firmicutes, and Actinobacteria. Interestingly, bacteria such as Salinisphaera sp., Pelomonas sp., and Staphylococcus spp. were detected in all the locations, suggesting that these bacteria are indigenous bacterial members of the Malaysian Mahseer sperm microbiota, although their function is still unclear.
    Matched MeSH terms: Aquaculture
  15. Fulltext First record of Phyllorhiza sp. (Cnidaria: Scyphozoa) in a Chinese coastal aquaculture pond
    Dong Z, Morandini AC, Schiariti A, Wang L, Sun T
    PeerJ, 2019;7:e6191.
    PMID: 30643699 DOI: 10.7717/peerj.6191
    Background: It has been suggested that aquaculture ponds on the Chinese coast could act as breeding grounds for scyphozoans. Here, we present the first record of the scyphomedusa Phyllorhiza sp. in an aquaculture pond on the coast of the southern Yellow Sea, based on a combination of morphological characteristics and mitochondrial 16S DNA sequence data.

    Methods: A field survey was performed on June 29, 2017 in a pond used for culturing the shrimp Penaeus japonicus, located in the southern Yellow Sea, China. Jellyfish specimens were collected for morphological and genetic analysis. The morphological characters of the jellyfish specimens were compared to taxonomic literature. Additionally, phylogenetic analysis of the mitochondrial 16S fragments of these specimens were also conducted.

    Results: These specimens had the following morphological characters: hemispherical umbrella without scapulets; J-shaped oral arms; a single larger terminal club on each arm; bluish colored with a slightly expanded white tip; and mouthlets present only in the lower half to one-third of each arm. These morphological features of the medusae indicated that the specimens found in the shrimp culture ponds belong to the genus Phyllorhiza Agassiz, 1862, but did not match with the description of any of the known species of the genus Phyllorhiza. Phylogenetic analyses of the mtDNA 16S regions revealed that these specimens, together with Phyllorhiza sp. from Malaysian coastal waters, belong to a sister group of Phyllorhiza punctata. Juveniles and ephyrae of Phyllorhiza sp. were observed in the aquaculture pond. The mean density of Phyllorhiza sp. medusa in the surface water within the pond was estimated to be 0.05 individuals/m2.

    Discussion: Based on our observations of the gross morphology and molecular data, we state that the specimens collected in the aquaculture pond can be identified as Phyllorhiza sp. This is the first record of Phyllorhiza sp. in Chinese seas. Large scale dispersal through ballast water or the expansion of jellyfish aquarium exhibitions are possible pathways of invasion, but this needs to be confirmed in further studies.

    Matched MeSH terms: Aquaculture
  16. Fulltext Improving Survival of Juvenile Scalloped Spiny Lobster (Panulirus homarus) and Crucifix Crab (Charybdis feriatus) Using Shelter and Live Prey
    Ma CH, Huang PY, Chang YC, Pan YJ, Azra MN, Chen LL, et al.
    Animals (Basel), 2021 Feb 02;11(2).
    PMID: 33540637 DOI: 10.3390/ani11020370
    Cannibalism is a major problem in lobster and crab aquaculture. Reducing the aggressive characteristics of lobsters and crabs can improve survival during the culturing process. In this study, juvenile scalloped spiny lobsters (Panulirus homarus) and crucifix crabs (Charybdis feriatus) were both cultured under different shelter and live prey conditions. Groups with shelter (seaweed and cotton filter) showed a better survival rate than the control group (no shelter; p < 0.05) for both Pa. homarus and Char. feriatus. Co-culturing with live prey (Litopenaeus vannamei) significantly benefited the juveniles of Pa. homarus and visibly increased the survival of juvenile Char. feriatus. Although providing shelter is currently the main method for reducing agonistic behavior, it must be continually altered as the lobsters and crabs grow. Live prey can grow and attract lobsters and crabs to hunt them, and live prey can be supplemented at any time. They can also be used as an additional source of income during the harvest season.
    Matched MeSH terms: Aquaculture
  17. Fulltext Isolation and Characterization of Six Vibrio parahaemolyticus Lytic Bacteriophages From Seafood Samples
    Tan CW, Rukayadi Y, Hasan H, Abdul-Mutalib NA, Jambari NN, Hara H, et al.
    Front Microbiol, 2021;12:616548.
    PMID: 33776954 DOI: 10.3389/fmicb.2021.616548
    Vibrio parahaemolyticus is a foodborne pathogen that is frequently isolated from a variety of seafood. To control this pathogenic Vibrio spp., the implementation of bacteriophages in aquaculture and food industries have shown a promising alternative to antibiotics. In this study, six bacteriophages isolated from the seafood samples demonstrated a narrow host range specificity that infecting only the V. parahaemolyticus strains. Morphological analysis revealed that bacteriophages Vp33, Vp22, Vp21, and Vp02 belong to the Podoviridae family, while bacteriophages Vp08 and Vp11 were categorized into the Siphoviridae family. All bacteriophages were composed of DNA genome and showed distinctive restriction fragment length polymorphism. The optimal MOI for bacteriophage propagation was determined to be 0.001 to 1. One-step growth curve revealed that the latent period ranged from 10 to 20 min, and the burst size of bacteriophage was approximately 17 to 51 PFU/cell. The influence of temperature and pH levels on the stability of bacteriophages showed that all bacteriophages were optimally stable over a wide range of temperatures and pH levels. In vitro lytic activity of all bacteriophages demonstrated to have a significant effect against V. parahaemolyticus. Besides, the application of a bacteriophage cocktail instead of a single bacteriophage suspension was observed to have a better efficiency to control the growth of V. parahaemolyticus. Results from this study provided a basic understanding of the physiological and biological properties of the isolated bacteriophages before it can be readily used as a biocontrol agent against the growth of V. parahaemolyticus.
    Matched MeSH terms: Aquaculture
  18. Fulltext Efficacy of the Aqueous Extract of Azadirachta indica Against the Marine Parasitic Leech and Its Phytochemical Profiling
    Venmathi Maran BA, Josmeh D, Tan JK, Yong YS, Shah MD
    Molecules, 2021 Mar 29;26(7).
    PMID: 33805254 DOI: 10.3390/molecules26071908
    Zeylanicobdella arugamensis (Hirudinea), a marine parasitic leech, not only resulted in the mortality of the host fish (Groupers) but also caused economic losses. The current study aimed to elucidate the antiparasitic efficacy of the aqueous extract of the Azadirachta indica leaves against Z. arugamensis and to profile the composition via LC-Q Exactive HF Orbitrap mass spectrometry. Different concentrations (25, 50 and 100 mg/mL) of A. indica extract were prepared and tested on the parasitic leeches. The total mortality of leeches was noticed with an exposure to the A. indica aqueous extract. The average times required for the aqueous extract at concentrations of 25, 50 and 100 mg/mL to kill the leeches were 42.65 ± 9.20, 11.69 ± 1.11 and 6.45 ± 0.45 min, respectively, in a dose-dependent manner. The Orbitrap mass spectrometry analysis indicated the presence of five flavonoids (myricetin 3-O-galactoside, trifolin, isorhamnetin, quercetin and kaempferol), four aromatics (4-methoxy benzaldehyde, scopoletin, indole-3-acrylic acid and 2,4-quinolinediol), three phenolics (p-coumaric acid, ferulic acid and phloretin) and two terpenoids (pulegone and caryophyllene oxide). Thus, our study indicates that A. indica aqueous extract is a good source of metabolites with the potential to act as a biocontrol agent against the marine parasitic leech in aquaculture.
    Matched MeSH terms: Aquaculture
  19. Fulltext Megalocytiviruses in ornamental fish: A review
    Johan CAC, Zainathan SC
    Vet World, 2020 Nov;13(11):2565-2577.
    PMID: 33363355 DOI: 10.14202/vetworld.2020.2565-2577
    Iridoviruses, especially megalocytiviruses, are related to severe disease resulting in high economic losses in the aquaculture industry worldwide. The ornamental fish industry has been affected severely due to Megalocytivirus infections. Megalocytivirus is a DNA virus that has three genera; including red sea bream iridovirus, infectious spleen and kidney necrosis virus, and turbot reddish body iridovirus. Megalocytivirus causes non-specific clinical signs in ornamental fish. Cell culture, histology, immunofluorescence test, polymerase chain reaction (PCR) assay, and loop-mediated isothermal amplification assay have been used to diagnose megalocytiviruses. Risk factors such as temperature, transportation (export and import), and life stages of ornamental fish have been reported for the previous cases due to Megalocytivirus infections. In addition, other prevention and control methods also have been practiced in farms to prevent Megalocytivirus outbreaks. This is the first review of megalocytiviruses in ornamental fish since its first detection in 1989. This review discusses the occurrences of Megalocytivirus in ornamental fish, including the history, clinical signs, detection method, risk factors, and prevention measures.
    Matched MeSH terms: Aquaculture
  20. Fulltext Enhancement of Live Food Nutritional Status with Essential Nutrients for Improving Aquatic Animal Health: A Review
    Samat NA, Yusoff FM, Rasdi NW, Karim M
    Animals (Basel), 2020 Dec 21;10(12).
    PMID: 33371528 DOI: 10.3390/ani10122457
    At the present time, no artificial larval diet is capable of entirely fulfilling the dietary requirements of several larval fish and crustacean species. Zooplankton live food is the basic foundation of fish larviculture, and successful rearing of fish larvae still heavily depends on an adequate supply of nutritious live food. Despite being important, the production protocols of copepods and cladocerans (Moina) are still underdeveloped in hatcheries. Rotifers and Artemia are the most commonly used live foods. However, these live foods are evidently lacking in crucial nutrient constituents. Hence, through nutrient enrichment, live food with the nutritional profile that meets the requirements of fish larvae can be produced. With the aim to maximize the effectiveness of production to optimize profitability, it is important to evaluate and improve culture techniques for the delivery of micro- and macro-nutrients as feed supplements to larvae in aquaculture systems. Bioencapsulation and enrichment are the evolving techniques in aquaculture that are commonly employed to enhance the nutritional quality of live food by integrating nutrients into them, which subsequently improves the growth, survival, and disease resistance of the consuming hosts. This review aims to highlight some of the approaches and methods used to improve the nutritional quality of live food by modifying their nutrient composition, which could have immense promise in the enhancement of aquatic animal health.
    Matched MeSH terms: Aquaculture
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links