Displaying publications 181 - 200 of 236 in total

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  1. Bioprospecting of indigenous marine microalgae with ammonium tolerance from aquaculture ponds for microalgae cultivation with ammonium-rich wastewaters
    Katayama T, Nagao N, Kasan NA, Khatoon H, Rahman NA, Takahashi K, et al.
    J Biotechnol, 2020 Nov 10;323:113-120.
    PMID: 32768414 DOI: 10.1016/j.jbiotec.2020.08.001
    We isolated fifty-two strains from the marine aquaculture ponds in Malaysia that were evaluated for their lipid production and ammonium tolerance and four isolates were selected as new ammonium tolerant microalgae with high-lipid production: TRG10-p102 Oocystis heteromucosa (Chlorophyceae); TRG10-p103 and TRG10-p105 Thalassiosira weissflogii (Bacillariophyceae); and TRG10-p201 Amphora coffeiformis (Bacillariophyceae). Eicosapentenoic acid (EPA) in three diatom strain was between 2.6 and 18.6 % of total fatty acids, which were higher than in O. heteromucosa. Only A. coffeiformi possessed arachidonic acid. Oocystis heteromucosa naturally grew at high ammonium concentrations (1.4-10 mM), whereas the growth of the other strains, T. weissflogii and A. coffeiformi, were visibly inhibited at high ammonium concentrations (>1.4 mM-NH4). However, two strains of T. weissflogii were able to grow at up to 10 mM-NH4 by gradually acclimating to higher ammonium concentrations. The ammonium tolerant strains, especially T. weissflogii which have high EPA contents, were identified as a valuable candidate for biomass production utilizing NH4-N media, such as ammonium-rich wastewater.
    Matched MeSH terms: Aquaculture/methods*
  2. Prevalence, mean intensity and site preference of Caligus rotundigenitalis Yü, 1933 (Copepoda: Caligidae) on cage cultured crimson snapper (Lutjanus erythropterus Bloch, 1790) from Bukit Tambun, Penang, Malaysia
    Leaw YY, Faizah S, Anil C, Kua BC
    Vet Parasitol, 2012 Jul 6;187(3-4):505-10.
    PMID: 22425490 DOI: 10.1016/j.vetpar.2012.02.003
    Snapper had been cultured in Malaysia since 1980 due to the fry availability and the high demand. However, details on the caligids infestation were not properly documented. This study was carried out to determine the prevalence, mean intensity and site preference of Caligus rotundigenitalis (Caligidae, Siphonostomatoida) a parasitic copepod on cage cultured crimson snapper, Lutjanus erythropterus from Bukit Tambun, Penang, Malaysia. A total of 70 specimens of cultured snapper were examined based on different infestation sites such as head, body as well as operculum. The specimens were separated into three groups according to the size of the fish. C. rotundigenitalis was found to be the only species infesting L. erythropterus with the prevalence and the mean intensity of 81.4% and 5.6±4.4, respectively. There was a significant difference between the prevalence of site infestation of the body and inner operculum sites. The prevalence of C. rotundigenitalis was highest on inner operculum of the fish followed by the body and head. However, there was no significant difference in the distribution of C. rotundigenitalis over the different infestation sites derived from the three groups. The information obtained from this study can be used for more effective control measures of ectoparasitic copepod infestation in floating cages.
    Matched MeSH terms: Aquaculture
  3. Assessing water hyacinth (Eichhornia crassopes) and lettuce (Pistia stratiotes) effectiveness in aquaculture wastewater treatment
    Akinbile CO, Yusoff MS
    Int J Phytoremediation, 2012 Mar;14(3):201-11.
    PMID: 22567705
    Water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) were analyzed to determine their effectiveness in aquaculture wastewater treatment in Malaysia. Wastewater from fish farm in Semanggol Perak, Malaysia was sampled and the parameters determined included, the pH, turbidity, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), nitrite phosphate (PO4(3-)), nitrate (NO(3-)), nitrite (NO(-2)), ammonia (NH3), and total kjedahl nitrogen (TKN). Also, hydroponics system was set up and was added with fresh plants weights of 150 +/- 20 grams Eichhornia crassipes and 50 +/- 10 grams Pistia stratiotes during the 30 days experiment. The phytoremediation treatment with Eichhornia crassipes had pH ranging from 5.52 to 5.59 and from 4.45 to 5.5 while Pistia stratiotes had its pH value from 5.76 to 6.49 and from 6.24 to 7.07. Considerable percentage reduction was observed in all the parameters treated with the phytoremediators. Percentage reduction of turbidity for Eichhornia crassipes were 85.26% and 87.05% while Pistia stratiotes were 92.70% and 93.69% respectively. Similar reductions were observed in COD, TKN, NO(3-), NH3, and PO4(3-). The capability of these plants in removing nutrients was established from the study. Removal of aquatic macrophytes from water bodies is recommended for efficient water purification.
    Matched MeSH terms: Aquaculture
  4. Assessing the suitability of stream water for five different uses and its aquatic environment
    Fulazzaky MA
    Environ Monit Assess, 2013 Jan;185(1):523-35.
    PMID: 22373956 DOI: 10.1007/s10661-012-2572-6
    Surface water is one of the essential resources for supporting sustainable development. The suitability of such water for a given use depends both on the available quantity and tolerable quality. Temporary status for a surface water quality has been identified extensively. Still the suitability of the water for different purposes needs to be verified. This study proposes a water quality evaluation system to assess the aptitude of the Selangor River water for aquatic biota, drinking water production, leisure and aquatic sport, irrigation use, livestock watering, and aquaculture use. Aptitude of the water has been classified in many parts of the river segment as unsuitable for aquatic biota, drinking water production, leisure and aquatic sport as well as aquaculture use. The water quality aptitude classes of the stream water for nine locations along the river are evaluated to contribute to decision support system. The suitability of the water for five different uses and its aquatic ecosystem are verified.
    Matched MeSH terms: Aquaculture
  5. Ovarian development of a river catfish Hemibagrus nemurus (Valenciennes, 1840) in captivity
    Adebiyi FA, Siraj SS, Harmin SA, Christianus A
    J Exp Zool A Ecol Genet Physiol, 2011 Nov 1;315(9):536-43.
    PMID: 21898849 DOI: 10.1002/jez.702
    Hemibagrus nemurus is a riverine catfish with high economic and nutritive values. Investigations on ovarian development of this fish were carried out to determine the mode of ovarian development and describe the oocyte developmental stages. Histological studies were done on ovaries using light microscopy and scanning electron microscopy. Fish were sampled monthly for a period of six months (August 2009 to January 2010). The mean oocyte diameter (OD) ranged from 871 ± 161.41 µm to 1,167 ± 26.77 µm and the highest OD was in November. Oocyte size-frequency distribution showed a polymodal distribution. The mean gonadosomatic index (GSI) ranged from 1.14 ± 0.87% to 7.06 ± 1.40% and highest GSI was in November. The ovaries exhibited three phases of oocyte growth, which were primary growth, secondary growth and maturation phases. Based on histological criteria, the oocyte developmental stages were divided into seven stages as chromatin nucleolar, early perinucleolar, late perinucleolar, cortical alveolar, vitellogenesis, mature oocyte and germinal vesicle migration stages. All the seven stages of oocyte development were observed in the ovaries. Oogonia were always present throughout the developmental stages. The ovaries had more than two stages of oocyte development. This is the first report on the mode of ovarian development of H. nemurus. These findings indicated that H. nemurus has asynchronous mode of ovarian development and is capable of spawning several times in a year under favourable conditions.
    Matched MeSH terms: Aquaculture
  6. Genome analysis of Betanodavirus from cultured marine fish species in Malaysia
    Ransangan J, Manin BO
    Vet Microbiol, 2012 Apr 23;156(1-2):16-44.
    PMID: 22051446 DOI: 10.1016/j.vetmic.2011.10.002
    Betanodavirus is the causative agent of the viral nervous necrosis (VNN) or viral encephalopathy and retinopathy disease in marine fish. This disease is responsible for most of the mass mortalities that occurred in marine fish hatcheries in Malaysia. The genome of this virus consists of two positive-sense RNA molecules which are the RNA1 and RNA2. The RNA1 molecule contains the RdRp gene which encodes for the RNA-dependent RNA polymerase and the RNA2 molecule contains the Cp gene which encodes for the viral coat protein. In this study, total RNAs were extracted from 32 fish specimens representing the four most cultured marine fish species in Malaysia. The fish specimens were collected from different hatcheries and aquaculture farms in Malaysia. The RNA1 was successfully amplified using three pairs of overlapping PCR primers whereas the RNA2 was amplified using a pair of primers. The nucleotide analysis of RdRp gene revealed that the Betanodavirus in Malaysia were 94.5-99.7% similar to the RGNNV genotype, 79.8-82.1% similar to SJNNV genotype, 81.5-82.4% similar to BFNNV genotype and 79.8-80.7% similar to TPNNV genotype. However, they showed lower similarities to FHV (9.4-14.2%) and BBV (7.2-15.7%), respectively. Similarly, the Cp gene revealed that the viruses showed high nucleotide similarity to RGNNV (95.9-99.8%), SJNNV (72.2-77.4%), BFNNV (80.9-83.5%), TPNNV (77.2-78.1%) and TNV (75.1-76.5%). However, as in the RdRp gene, the coat protein gene was highly dissimilar to FHV (3.0%) and BBV (2.6-4.1%), respectively. Based on the genome analysis, the Betanodavirus infecting cultured marine fish species in Malaysia belong to the RGNNV genotype. However, the phylogenetic analysis of the genes revealed that the viruses can be further divided into nine sub-groups. This has been expected since various marine fish species of different origins are cultured in Malaysia.
    Matched MeSH terms: Aquaculture
  7. Effect of mangosteen (Garcinia mangostana L.) extracts as a feed additive on growth and hematological parameters of African catfish (Clarias gariepinus) fingerlings
    Soosean C, Marimuthu K, Sudhakaran S, Xavier R
    Eur Rev Med Pharmacol Sci, 2010 Jul;14(7):605-11.
    PMID: 20707250
    The efficacy of dietary inclusion of various parts of mangosteen (Garcinia mangostana L.) extract on growth and hematological parameters of African catfish (Clarias gariepinus) fingerlings were investigated.
    Matched MeSH terms: Aquaculture
  8. Potential of nanofiltration and low pressure reverse osmosis in the removal of phosphorus for aquaculture
    Leo CP, Yahya MZ, Kamal SN, Ahmad AL, Mohammad AW
    Water Sci Technol, 2013;67(4):831-7.
    PMID: 23306262 DOI: 10.2166/wst.2012.625
    Aquaculture activities in developing countries have raised deep concern about nutrient pollution, especially excess phosphorus in wastewater, which leads to eutrophication. NF, NF90, NF450 and XLE membranes were studied to forecast the potential of nanofiltration and low pressure reverse osmosis in the removal of phosphorus from aquaculture wastewater. Cross-sectional morphology, water contact angle, water permeability and zeta potential of these membranes were first examined. Membrane with higher porosity and greater hydrophilicity showed better permeability. Membrane samples also commonly exhibited high zeta potential value in the polyphosphate-rich solution. All the selected membranes removed more than 90% of polyphosphate from the concentrated feed (75 mg/L) at 12 bar. The separation performance of XLE membrane was well maintained at 94.6% even at low pressure. At low feed concentration, more than 70.0% of phosphorus rejection was achieved using XLE membrane. The formation of intermolecular bonds between polyphosphate and the acquired membranes probably had improved the removal of polyphosphate at high feed concentration. XLE membrane was further tested and its rejection of polyphosphate reduced with the decline of pH and the addition of ammonium nitrate.
    Matched MeSH terms: Aquaculture
  9. Study on organochlorine compounds in cockles, Anadara granosa and mussels, Perna viridis from aquaculture sites in peninsular Malaysia
    Ang CW, Mazlin NM, Heng LY, Ismail BS, Salmijah S
    Bull Environ Contam Toxicol, 2005 Jul;75(1):170-4.
    PMID: 16228889
    Matched MeSH terms: Aquaculture
  10. Fulltext Diverse and abundant multi-drug resistant E. coli in Matang mangrove estuaries, Malaysia
    Ghaderpour A, Ho WS, Chew LL, Bong CW, Chong VC, Thong KL, et al.
    Front Microbiol, 2015;6:977.
    PMID: 26483759 DOI: 10.3389/fmicb.2015.00977
    E.coli, an important vector distributing antimicrobial resistance in the environment, was found to be multi-drug resistant, abundant, and genetically diverse in the Matang mangrove estuaries, Malaysia. One-third (34%) of the estuarine E. coli was multi-drug resistant. The highest antibiotic resistance prevalence was observed for aminoglycosides (83%) and beta-lactams (37%). Phylogenetic groups A and B1, being the most predominant E. coli, demonstrated the highest antibiotic resistant level and prevalence of integrons (integron I, 21%; integron II, 3%). Detection of phylogenetic group B23 downstream of fishing villages indicates human fecal contamination as a source of E. coli pollution. Enteroaggregative E. coli (1%) were also detected immediately downstream of the fishing village. The results indicated multi-drug resistance among E. coli circulating in Matang estuaries, which could be reflective of anthropogenic activities and aggravated by bacterial and antibiotic discharges from village lack of a sewerage system, aquaculture farms and upstream animal husbandry.
    Matched MeSH terms: Aquaculture
  11. Improving protein production of indigenous microalga Chlorella vulgaris FSP-E by photobioreactor design and cultivation strategies
    Chen CY, Lee PJ, Tan CH, Lo YC, Huang CC, Show PL, et al.
    Biotechnol J, 2015 Jun;10(6):905-14.
    PMID: 25865941 DOI: 10.1002/biot.201400594
    Fish meal is currently the major protein source for commercial aquaculture feed. Due to its unstable supply and increasing price, fish meal is becoming more expensive and its availability is expected to face significant challenges in the near future. Therefore, feasible alternatives to fish meal are urgently required. Microalgae have been recognized as the most promising candidates to replace fish meal because the protein composition of microalgae is similar to fish meal and the supply of microalgae-based proteins is sustainable. In this study, an indigenous microalga (Chlorella vulgaris FSP-E) with high protein content was selected, and its feasibility as an aquaculture protein source was explored. An innovative photobioreactor (PBR) utilizing cold cathode fluorescent lamps as an internal light source was designed to cultivate the FSP-E strain for protein production. This PBR could achieve a maximum biomass and protein productivity of 699 and 365 mg/L/day, respectively, under an optimum urea and iron concentration of 12.4 mM and 90 μM, respectively. In addition, amino acid analysis of the microalgal protein showed that up to 70% of the proteins in this microalgal strain consist of indispensable amino acids. Thus, C. vulgaris FSP-E appears to be a viable alternative protein source for the aquaculture industry.
    Matched MeSH terms: Aquaculture
  12. Investigating the biometric and physicochemical characteristics of freshly harvested Pacific white shrimp (Litopenaeus vannamei): a comparative approach
    Okpala CO, Bono G
    J Sci Food Agric, 2016 Mar 15;96(4):1231-40.
    PMID: 25866918 DOI: 10.1002/jsfa.7211
    The practicality of biometrics of seafood cannot be overemphasized, particularly for competent authorities of the shrimp industry. However, there is a paucity of relevant literature on the relationship between biometric and physicochemical indices of freshly harvested shrimp. This work therefore investigated the relationship between biometric (standard length (SL), total weight (TW) and condition factor (CF)) and physicochemical (moisture content, pH, titratable acidity, water activity, water retention index, colour values and fracturability) characteristics of freshly harvested Pacific white shrimp (Litopenaeus vannamei) obtained from three different farms. The relationships between these parameters were determined using correlation and regression analyses.
    Matched MeSH terms: Aquaculture
  13. Fulltext Comparing Genomic Signatures of Selection Between the Abbassa Strain and Eight Wild Populations of Nile Tilapia (Oreochromis niloticus) in Egypt
    Nayfa MG, Jones DB, Benzie JAH, Jerry DR, Zenger KR
    Front Genet, 2020;11:567969.
    PMID: 33193660 DOI: 10.3389/fgene.2020.567969
    Domestication to captive rearing conditions, along with targeted selective breeding have genetic consequences that vary from those in wild environments. Nile tilapia (Oreochromis niloticus) is one of the most translocated and farmed aquaculture species globally, farmed throughout Asia, North and South America, and its African native range. In Egypt, a breeding program established the Abbassa Strain of Nile tilapia (AS) in 2002 based on local broodstock sourced from the Nile River. The AS has been intensively selected for growth and has gone through genetic bottlenecks which have likely shifted levels and composition of genetic diversity within the strain. Consequently, there are questions on the possible genetic impact AS escapees may have on endemic populations of Nile tilapia. However, to date there have been no genetic studies comparing genetic changes in the domesticated AS to local wild populations. This study used 9,827 genome-wide SNPs to investigate population genetic structure and signatures of selection in the AS (generations 9-11) and eight wild Nile tilapia populations from Egypt. SNP analyses identified two major genetic clusters (captive and wild populations), with wild populations showing evidence of isolation-by-distance among the Nile Delta and upstream riverine populations. Between genetic clusters, approximately 6.9% of SNPs were identified as outliers with outliers identified on all 22 O. niloticus chromosomes. A lack of localized outlier clustering on the genome suggests that no genes of major effect were presently detected. The AS has retained high levels of genetic diversity (Ho_All = 0.21 ± 0.01; He_All = 0.23 ± 0.01) when compared to wild populations (Ho_All = 0.18 ± 0.01; He_All = 0.17 ± 0.01) after 11 years of domestication and selective breeding. Additionally, 565 SNPs were unique within the AS line. While these private SNPs may be due to domestication signals or founder effects, it is suspected that introgression with blue tilapia (Oreochromis aureus) has occurred. This study highlights the importance of understanding the effects of domestication in addition to wild population structure to inform future management and dissemination decisions. Furthermore, by conducting a baseline genetic study of wild populations prior to the dissemination of a domestic line, the effects of aquaculture on these populations can be monitored over time.
    Matched MeSH terms: Aquaculture
  14. Fulltext Genetic diversity of Nile tilapia (Oreochromis niloticus) throughout West Africa
    Lind CE, Agyakwah SK, Attipoe FY, Nugent C, Crooijmans RPMA, Toguyeni A
    Sci Rep, 2019 11 14;9(1):16767.
    PMID: 31727970 DOI: 10.1038/s41598-019-53295-y
    Nile tilapia (Oreochromis niloticus) is a globally significant aquaculture species rapidly gaining status as a farmed commodity. In West Africa, wild Nile tilapia genetic resources are abundant yet knowledge of fine-scale population structure and patterns of natural genetic variation are limited. Coinciding with this is a burgeoning growth in tilapia aquaculture in Ghana and other countries within the region underpinned by locally available genetic resources. Using 192 single nucleotide polymorphism (SNP) markers this study conducted a genetic survey of Nile tilapia throughout West Africa, sampling 23 wild populations across eight countries (Benin, Burkina Faso, Côte d'Ivoire, Ghana, Togo, Mali, Gambia and Senegal), representing the major catchments of the Volta, Niger, Senegal and Gambia River basins. A pattern of isolation-by-distance and significant spatial genetic structure was identified throughout West Africa (Global FST = 0.144), which largely corresponds to major river basins and, to a lesser extent, sub-basins. Two populations from the Gambia River (Kudang and Walekounda), one from the western Niger River (Lake Sélingué) and one from the upper Red Volta River (Kongoussi) showed markedly lower levels of diversity and high genetic differentiation compared to all other populations, suggesting genetically isolated populations occurring across the region. Genetic structure within the Volta Basin did not always follow the pattern expected for sub-river basins. This study identifies clear genetic structuring and differentiation amongst West African Nile tilapia populations, which concur with broad patterns found in previous studies. In addition, we provide new evidence for fine-scale genetic structuring within the Volta Basin and previously unidentified genetic differences of populations in Gambia. The 192 SNP marker suite used in this study is a useful tool for differentiating tilapia populations and we recommend incorporating this marker suite into future population screening of O. niloticus. Our results form the basis of a solid platform for future research on wild tilapia genetic resources in West Africa, and the identification of potentially valuable germplasm for use in ongoing breeding programs for aquaculture.
    Matched MeSH terms: Aquaculture
  15. Natural Concurrent Infection of Vibrio harveyi and V. alginolyticus in Cultured Hybrid Groupers in Malaysia
    Mohamad N, Mohd Roseli FA, Azmai MNA, Saad MZ, Md Yasin IS, Zulkiply NA, et al.
    J Aquat Anim Health, 2019 03;31(1):88-96.
    PMID: 30536485 DOI: 10.1002/aah.10055
    In September 2016, a marine fish farm operator in Selangor, Malaysia, reported a disease outbreak affecting juvenile hybrid groupers (Camouflage Grouper Epinephelus polyphekadion × Tiger Grouper E. fuscoguttatus). The average daily mortality was 120 fish, resulting in a cumulative mortality rate of 29% within 10 d. The affected hybrid groupers displayed lethargy, excessive mucus production, rotten fins, congestion of livers and kidneys, and enlargement of spleens. Microscopically, general congestion of the brains and internal organs was evident. Vibrio harveyi and V. alginolyticus were successfully isolated from the diseased fish. The isolated pathogens were found to be sensitive to oxytetracycline and tetracycline, but resistant towards ampicillin and vancomycin. Experimental infections using the isolated V. harveyi (108  CFU/mL), V. alginolyticus (108  CFU/mL), and concurrent infection by V. harveyi (108  CFU/mL) and V. alginolyticus (108  CFU/mL) in juvenile Asian Seabass Lates calcarifer resulted in 60, 100, and 100% mortality, respectively, within 240 h postinfection. The experimentally infected Asian Seabass demonstrated similar clinical signs and histopathological changes as the naturally infected hybrid groupers. However, concurrently infected fish demonstrated severe clinical signs and histopathological changes compared with single infections. These results suggest that both isolates of Vibrio are pathogenic to fish and responsible for the disease outbreak. However, concurrent infection involving V. alginolyticus and V. harveyi leads to a more devastating impact to the cultured fish. This is the first report of concurrent Vibrio infection in cultured marine fish in Malaysia.
    Matched MeSH terms: Aquaculture
  16. Fulltext Aquaponics recirculation system: a sustainable food source for the future water conserves and resources
    Azizah Endut, Fathurrahman Lananan, Ahmad Jusoh, Wan Norsani Wan Nik, Nora'aini Ali
    Malaysian Journal of Applied Sciences, 2018;1(1):1-12.
    MyJurnal
    The current and escalating extent of soil degradation, water scarcity and environmental concern
    plaguing agricultural productivity, demands re-assessing the direction of food production. Aquaponics
    is a concept relatively new to modern food production methods and can contribute to food security.
    This study was conducted to establish sustainable aquaculture systems that maximize benefits and
    minimize the accumulation of detrimental compounds and other types of negative impacts on both
    natural and social environments. This study carried out at an average inflow rate of 1.28 m/day to
    evaluate the operation of the aquaponics recirculation system (ARS) on nutrients removal and growth
    and yield of African catfish as well as water spinach. A special design of ARS was used to provide
    nitrification of fishery wastewater, where the combination of sands and gravels in hydroponics trough,
    providing both surfaces for biofuel development and cultivation area for plants. Removal efficiencies
    of 5-day biochemical oxygen demand (BOD5), total suspended solids (TSS), total ammonia nitrogen
    (TAN), nitrite-nitrogen (NO2-N), nitrate-nitrogen (NO3-N), and orthophosphate (PO4
    3-
    ) were 82%, 89%,
    93%, 94%, 81%, and 80%, respectively. The feed conversion ratio (FCR) and specific growth rate
    (SGR) of African catfish were 1.08 and 3.34% day-1
    , respectively. The average water spinach
    production was 3.56 kg per m2
    . This study showed that ARS is a method of producing crop along with
    a healthy protein source and among the best alternatives for achieving economic and environmental
    sustainability.
    Matched MeSH terms: Aquaculture
  17. Histopathology and cytopathology of white spot syndrome virus (WSSV) in cultured Penaeus monodon from peninsular Malaysia with emphasis on pathogenesis and the mechanism of white spot formation
    Wang YG, Hassan MD, Shariff M, Zamri SM, Chen X
    Dis Aquat Organ, 1999 Dec 22;39(1):1-11.
    PMID: 11407399
    Since 1994, white spot syndrome virus (WSSV) has been detected in cultured shrimp Penaeus monodon in Peninsular Malaysia. The gross signs, target organs and histo-cytopathology for the viral infection were studied and it was found to infect most organs and tissues including oocytes, but not hepatopancreatocytes and epithelial cells of the midgut, which were regarded as refractory tissues. Based on a time-sequence of ultrastructural cytopathology, 4 cytopathic profiles and 6 phases of viral morphogenesis were described. The virions were elliptical to short rods with trilamilar envelopes that measured 305 +/- 30 x 127 +/- 11 nm. Viral nucleosomes were often present singly in infected nuclei and were associated with the early stages of viral replication. The structure of WSSV pathognomonic white, cuticular lesions was examined at the microscopic and ultrastructural levels and the mechanism of their formation appeared to be related to the disruption of exudate transfer from epithelial cells to the cuticle via cuticular pore canals.
    Matched MeSH terms: Aquaculture
  18. A new bacterial white spot syndrome (BWSS) in cultured tiger shrimp Penaeus monodon and its comparison with white spot syndrome (WSS) caused by virus
    Wang YG, Lee KL, Najiah M, Shariff M, Hassan MD
    Dis Aquat Organ, 2000 May 25;41(1):9-18.
    PMID: 10907134
    This paper describes a new bacterial white spot syndrome (BWSS) in cultured tiger shrimp Penaeus monodon. The affected shrimp showed white spots similar to those caused by white spot syndrome virus (WSSV), but the shrimp remained active and grew normally without significant mortalities. The study revealed no evidence of WSSV infection using electron microscopy, histopathology and nested polymerase chain reaction. Electron microscopy indicated bacteria associated with white spot formation, and with degeneration and discoloration of the cuticle as a result of erosion of the epicuticle and underlying cuticular layers. Grossly the white spots in BWSS and WSS look similar but showed different profiles under wet mount microscopy. The bacterial white spots were lichen-like, having perforated centers unlike the melanized dots in WSSV-induced white spots. Bacteriological examination showed that the dominant isolate in the lesions was Bacillus subtilis. The occurrence of BWSS may be associated with the regular use of probiotics containing B. subtilis in shrimp ponds. The externally induced white spot lesions were localized at the integumental tissues, i.e., cuticle and epidermis, and connective tissues. Damage to the deeper tissues was limited. The BWS lesions are non-fatal in the absence of other complications and are usually shed through molting.
    Matched MeSH terms: Aquaculture
  19. Muscle cellularity, growth performance and growth-related gene expression of juvenile climbing perch Anabas testudineus in response to different eggs incubation temperature
    Ahammad AKS, Asaduzzaman M, Uddin Ahmed MB, Akter S, Islam MS, Haque MM, et al.
    J Therm Biol, 2021 Feb;96:102830.
    PMID: 33627269 DOI: 10.1016/j.jtherbio.2020.102830
    Although indigenous climbing perch (Anabas testudineusis) is a highly valuable species, slow growth pattern during the culture period impeding its commercial success in aquaculture. In many fish species, it has been demonstrated that incubation temperature of eggs influenced the muscle development and growth rates, which persisted throughout the subsequent larval and juvenile phases. Therefore, this study aimed to investigate whether different incubation temperature of eggs prior to hatching can stimulate the muscle development, growth, and growth-related gene expression of the slow-growing indigenous species of climbing perch. The fertilized eggs of A. testudineus from an artificial breeding program were incubated under control temperature of 24 °C (IT24), 26 °C (IT26), 28 °C (IT28), and 30 °C (IT30) in 10L glass aquaria with four replicated units for each temperature treatment. After hatching, the larvae from each incubated temperature were separately reared at ambient temperature for 10 days in aquarium, 20 days in hapas, and the next 42 days in cages, totaling 72 days post-hatching (dph). The hatching rates were found significantly (P 
    Matched MeSH terms: Aquaculture
  20. Fulltext Sex determination in the GIFT strain of tilapia is controlled by a locus in linkage group 23
    Taslima K, Wehner S, Taggart JB, de Verdal H, Benzie JAH, Bekaert M, et al.
    BMC Genet, 2020 04 29;21(1):49.
    PMID: 32349678 DOI: 10.1186/s12863-020-00853-3
    BACKGROUND: Tilapias (Family Cichlidae) are the second most important group of aquaculture species in the world. They have been the subject of much research on sex determination due to problems caused by early maturation in culture and their complex sex-determining systems. Different sex-determining loci (linkage group 1, 20 and 23) have been detected in various tilapia stocks. The 'genetically improved farmed tilapia' (GIFT) stock, founded from multiple Nile tilapia (Oreochromis niloticus) populations, with some likely to have been introgressed with O. mossambicus, is a key resource for tilapia aquaculture. The sex-determining mechanism in the GIFT stock was unknown, but potentially complicated due to its multiple origins.

    RESULTS: A bulk segregant analysis (BSA) version of double-digest restriction-site associated DNA sequencing (BSA-ddRADseq) was developed and used to detect and position sex-linked single nucleotide polymorphism (SNP) markers in 19 families from the GIFT strain breeding nucleus and two Stirling families as controls (a single XY locus had been previously mapped to LG1 in the latter). About 1500 SNPs per family were detected across the genome. Phenotypic sex in Stirling families showed strong association with LG1, whereas only SNPs located in LG23 showed clear association with sex in the majority of the GIFT families. No other genomic regions linked to sex determination were apparent. This region was validated using a series of LG23-specific DNA markers (five SNPs with highest association to sex from this study, the LG23 sex-associated microsatellite UNH898 and ARO172, and the recently isolated amhy marker for individual fish (n = 284).

    CONCLUSIONS: Perhaps surprisingly given its multiple origins, sex determination in the GIFT strain breeding nucleus was associated only with a locus in LG23. BSA-ddRADseq allowed cost-effective analysis of multiple families, strengthening this conclusion. This technique has potential to be applied to other complex traits. The sex-linked SNP markers identified will be useful for potential marker-assisted selection (MAS) to control sex-ratio in GIFT tilapia to suppress unwanted reproduction during growout.

    Matched MeSH terms: Aquaculture
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