首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 100 毫秒
1.
Infectious salmon anaemia (ISA), caused by ISA virus (ISAV), is a serious disease of farmed Atlantic salmon, Salmo salar L. Recently, molecular‐ and immunofluorescent‐based techniques have become powerful diagnostic tools for ISAV detection, but culture‐based techniques remain the gold standard. A disadvantage of ISAV culture is that the incubation time required before cytopathic effect (CPE) is observed in cell monolayers. To decrease time until CPE is observed, a low‐speed centrifugation technique was applied to existing standard operating procedures for ISAV culture in three fish cell lines. Time until CPE observation was compared in CHSE, SHK and ASK cells, treated or not treated with low‐speed centrifugation after inoculation with ISAV. Low‐speed centrifugation treatment significantly enhanced observable cell infection. Compared to control cells, the length of time until ISAV CPE observation decreased in centrifuged ASK and CHSE cells. Low‐speed centrifugation was also incorporated into a modified clinical shell vial assay. At 48 h post‐inoculation with approximately 20 viral particles, ISAV was detected by an immunofluorescence antibody test in treated ASK and SHK1 cells but not in control cells. Finally, this enhanced viral adsorption assay performed in ASK cells demonstrated higher sensitivity than a real‐time RT‐PCR assay performed on RNA isolated from ISAV‐spiked salmon kidney homogenates.  相似文献   

2.
Bivalve cultivation, in single cultivation or in polyculture (including integrated multitrophic aquaculture; IMTA), is generally limited to eutrophic waters. We carried out a modeling study to test if, under meso- and oligotrophic conditions, depth could be a key factor for bivalve productivity associated to IMTA and other polyculture strategies. We applied the model Farm Aquaculture Resource Management (FARM) at three strata of the water column in two coastal fish farm areas in the Mediterranean Sea, using water column variables sampled seasonally to estimate the potential mussel production. According to FARM, mussel production was high in both areas and, in some cases, almost doubled when mussels were cultured below 25-m depth compared to shallower levels. Phytoplankton abundance is expected to notably influence mussel production compared to particulate organic matter. Thus, in meso- and oligotrophic stratified waters, where chlorophyll maximum is relatively deep, depth can be a key factor for the productivity of mussel cultivation. The obtained results could help to maximize the production of suspension-feeding bivalve cultivation and, therefore, the expansion and development of sustainable aquaculture in non-eutrophic marine waters.  相似文献   

3.
  相似文献   

4.
Molecular (PCR) diagnostic tests for the detection and identification of aquareovirus in general, and Tasmanian Atlantic salmon reovirus (TSRV) specifically, were developed, and their diagnostic sensitivity and specificity were determined and compared with virus isolation in cell culture. Intralaboratory and interlaboratory comparison of PCR (conventional hemi‐nested RT‐PCR & RT‐qPCR) and virus isolation in cell culture using finfish cell lines, CHSE‐214 and EPC, was carried out for the detection and identification of TSRV using field samples of farmed Atlantic salmon Salmo salar, L. from various aquaculture sites around Tasmania. The interlaboratory comparison of diagnostic methods was carried out between two laboratories, AAHL‐CSIRO and DPIPWE‐Tasmania. A total of 144 fish from nine sites (12–33 fish per site) were sampled from two regions of Tasmania (Tamar River estuary in the north and Huon River estuary in the south‐east) during late spring to early summer of 2009, and the data were analysed using different statistical approaches. The prevalence of TSRV ranged from 6% to 22% in both regions. All the diagnostic methods (data from both laboratories) had high specificity, while the estimated sensitivity varied between tests with RT‐qPCR being the most sensitive (95.2%) method followed by virus isolation and then conventional hemi‐nested RT‐PCR.  相似文献   

5.
    相似文献   

6.
A pilot project in the Bay of Fundy, Canada, is growing kelps, mussels, and salmon in an integrated multi-trophic aquaculture (IMTA) system. Biological and economic results are positive, but social acceptability is also a critical component of aquaculture sustainability. Focus group sessions with several segments of the population (restaurateurs, residents of communities near aquaculture facilities, and the general population) were held and the participants’ knowledge of, and opinions on, IMTA were recorded. Most participants felt that IMTA had the potential to reduce the environmental impacts of salmon farming, benefit community economies, and improve industry competitiveness and sustainability. All felt that seafood produced in IMTA systems would be safe to eat and 50% of the participants were willing to pay 10% more for these products if labelled as such. The participants felt that IMTA appears to be an improvement over current monoculture practices and would be cautiously welcomed in the marketplace. A promotional campaign educating the general public, food distributors, and other industry stakeholders about the positive benefits of IMTA would go a long way in gaining mainstream acceptance of this aquaculture practice.  相似文献   

7.
Real‐time PCR and immunohistochemistry (IHC) assays were developed to detect fish mycobacterial infections at the genus level, based on the RNA polymerase β subunit (rpoB) gene and polyclonal anti‐Mycobacterium rabbit serum, respectively. The PCR assay positively identified a number of pathogenic mycobacteria including Mycobacterium abscessus, M. avium ssp. avium, M. bohemicum, M. chelonae ssp. chelonae, M. farcinogenes, M. flavescens, M. fortuitum ssp. fortuitum, M. gastri, M. gordonae, M. immunogenicum, M. malmoense, M. marinum, M. montefiorense, M. phlei, M. phocaicum, M. pseudoshottsii, M. salmoniphilum, M. senegalense, M. shottsii, M. smegmatis, M. szulgi and M. wolinskyi. A detection limit equivalent to 102 cfu g?1 was registered for M. salmoniphilum‐infected fish tissue. The IHC precisely localized both free and intracellular mycobacteria in tissues and detected mycobacterial infections down to 102 cfu g?1 tissue. Both assays were found to be more sensitive than Ziehl–Neelsen (ZN) staining, where the detection limit was below 8 × 103 cfu g?1 tissue. Although specificity testing of the real‐time PCR against a panel of non‐Mycobacterium spp. revealed a degree of cross‐reaction against pure DNA extracted from Nocardia seriolae and Rhodococcus erythropolis, no cross‐reactions were identified (by either real‐time PCR or IHC) on testing of formalin‐fixed paraffin‐embedded (FFPE) tissues confirmed to be infected with these bacteria. The broad applicability of both assays was confirmed by analysis of FFPE tissues from a range of fish species infected with diverse Mycobacterium spp. The results indicate that both assays, alone or in combination, constitute sensitive tools for initial, rapid diagnosis of mycobacteriosis in fish. This should in turn allow rapid application of more specific studies, i.e. culture based, to identify the specific Mycobacterium sp. involved.  相似文献   

8.
  相似文献   

9.
Integrating mussel and finfish aquaculture has been recognized as a way to increase profits and decrease environmental impacts of finfish aquaculture, but not enough is known about the effects of finfish aquaculture on mussel growth. Here we present a pilot study aimed at determining how distance from finfish aquaculture affects mussel growth. To this end, we measured growth and condition index of mussel (Mytilus galloprovincialis) at three different distances (0, 60 and 700 m) from finfish aquaculture in the eastern Adriatic Sea. There was a statistically significant difference in growth of tagged mussels with respect to site. Average measured lengths of mussels at sites 1, 2 and 3 after the 10 months of the experiment were 57.60, 62.73 and 58.66 mm. Mussels grew fastest from March to May, and slowest from July to September, regardless of their position. Condition index showed spatial and temporal variations with higher values during fall and winter (∼23), and lower values during spring and summer (∼20). Our results show that production cycle in areas traditionally considered suboptimal for aquaculture can be equivalent to the cycle in areas traditionally considered optimal for mussel aquaculture if mussel aquaculture is integrated with finfish aquaculture.  相似文献   

10.
A rickettsia‐like organism, designated NZ‐RLO2, was isolated from Chinook salmon (Oncorhynchus tshawytscha) farmed in the South Island, New Zealand. In vivo growth showed NZ‐RLO2 was able to grow in CHSE‐214, EPC, BHK‐21, C6/36 and Sf21 cell lines, while Piscirickettsia salmonis LF‐89T grew in all but BHK‐21 and Sf21. NZ‐RLO2 grew optimally in EPC at 15°C, CHSE‐214 and EPC at 18°C. The growth of LF‐89 T was optimal at 15°C, 18°C and 22°C in CHSE‐24, but appeared less efficient in EPC cells at all temperatures. Pan‐genome comparison of predicted proteomes shows that available Chilean strains of P. salmonis grouped into two clusters (p‐value = 94%). NZ‐RLO2 was genetically different from previously described NZ‐RLO1, and both strains grouped separately from the Chilean strains in one of the two clusters (p‐value = 88%), but were closely related to each other. TaqMan and Sybr Green real‐time PCR targeting RNA polymerase (rpoB) and DNA primase (dnaG), respectively, were developed to detect NZ‐RLO2. This study indicates that the New Zealand strains showed a closer genetic relationship to one of the Chilean P. salmonis clusters; however, more Piscirickettsia genomes from wider geographical regions and diverse hosts are needed to better understand the classification within this genus.  相似文献   

11.
An integrated multi-trophic aquaculture (IMTA) system consisting of the ascidian Styela clava and the sea cucumber Apostichopus japonicus with microalgae was grown in a seawater mesocosm. Microbial populations in the water, sediment and shelters were monitored over time. The composition of the water microbial community in the IMTA system did not differ significantly from that of the traditional culture system without ascidians. Bacterial populations in the water, sediment and shelters were low in the traditional A. japonicus aquaculture system, and lower in the IMTA system. The number of Vibrios in the water, sediment and shelters in the IMTA system was significantly lower than in the traditional culture (p < 0.05), while the quantity of Bacillus was higher in the sediment and shelters. All of these results indicate that the IMTA system effectively inhibited the growth of harmful bacteria, an important positive function in the health of the culture. The bacterial diversity index in the water in the IMTA system was between those of the baited and non-baited traditional aquacultures and was slightly reduced in the shelters. Over time, the bacterial diversity index in the sediment gradually dropped, especially in summer and autumn, when it was significantly lower than in the traditional culture. In winter, the diversity index increased to some extent, approaching that of the traditional culture.  相似文献   

12.
Bivalves have been proven to be an inexpensive method for removing suspended solids, dissolved nutrients, and controlling algal growth through suspension feeding. The freshwater mussel, Elliptio complanata, is one of the most abundant species in Delaware, and it is additionally favorable for this experiment because of its hardiness against environmental stress and its filtration efficiency. This study examines the possibility that biomechanical filters such as E. complanata can supplement existing chemical and mechanical filtration regiments in aquaculture pond management. Twelve earthen aquaculture ponds located at the Delaware State University were stocked at a density of 4,000 catfish (Ictalurus punctatus) per hectare. Four different concentrations (0, 75, 150, and 300) of E. complanata were placed in trays within the ponds with three replicates of each concentration. The trays were suspended 15 cm below the surface of the water for a period of five months. Fish were fed a 32% protein diet twice daily at a rate of 1% of their body weight. Water quality was analyzed weekly while fish and mussel growths were measured biweekly. Results from water quality parameters varied significantly and were not conclusive based on the data obtained in this study. Water quality did not improve within the mussel treatment ponds during the course of this study and was found to be significantly below that of control ponds for all of the water chemistry parameters measured, with the exception of ammonia. Catfish in the 150 mussel treatment ponds grew the fastest; the 75 mussel treatment provided the most growth in mussels; and the 300 mussel group maintained the highest mussel survivorship. Although there were differences between ponds, fish growth and survivorship were not significantly different between treatments. While our mussel densities may have not been sufficient, their placement within the water column may have added additional stress. Being removed from the sediment can result in a decreased clearance rate in a benthic species such as E. complanata. This study may not have been conclusive in proving that mussels can be used to maintain water quality in aquaculture ponds, but we did see positive growth and survivorship of mussels and fish that indicated that the mussels were thriving in the aquaculture pond setting. This study may show that aquaculture ponds provide a suitable habitat in which propagated mussels may be held until their release into native areas.  相似文献   

13.
Abstract

Shellfish farming is the most common and the longest established aquaculture activity in France and in the EU15. Unlike for most other aquatic species, the bulk of French supplies of mussels and oysters come from mariculture. France is the leading European producer of oysters and is almost self sufficient in oysters. The sustainable development of shellfish farming is analysed through a “market and consumer‐ oriented‐approach”, covering trading and marketing issues as well as consumer analysis. Comparisons between mussel and oyster markets highlights some key differences in terms of their distribution network, demand attributes, consumer profiles and regions. There are differences in identification of origin and quality labelling approaches. Producer organizations are becoming more involved in such matters but they do not have the same stake in the two sectors. A review of the current quality control schemes applied in marketing both farmed oysters and mussels completes the economic analysis of these French bivalve markets.  相似文献   

14.
The bottom culture of southward‐transplanted sea cucumber Apostichopus japonicus in a subtropical fish farm was investigated in a field study at Dapeng Cove, Daya Bay, from January 5–August 5 2011, with the aim of finding the ideal period for culturing A. japonicus in fish farms, and developing an integrated multi‐trophic aquaculture (IMTA) in southern China. Results showed that the bottom‐cultured sea cucumbers survived well (100%) before summer, survival rates decreased to 65.00 ± 21.21% in July, and all animals had died at the end of the study. Specific growth rates of the sea cucumbers were high during winter (1.05 ± 0.03% d?1), decreased in early spring (0.44 ± 0.11% d?1) and became negative in the following months. Growth rate was mainly influenced by water temperature, dissolved oxygen and sulphide content; the anoxia caused by water column stratification at the seafloor in the summer were the main causes of mass mortality. Our results indicate that bottom culture in the temperate season (winter and spring, optimally from late November to early April) is a viable way to rear the deposit feeder A. japonicus underneath a subtropical fish farm.  相似文献   

15.
Carp oedema virus (CEV) and koi herpes virus (KHV) are of major concern to common carp breeders and koi enthusiasts worldwide. The viruses cause diseases that exhibit similar external signs; thus, it is difficult to distinguish between them clinically. In this study, we developed and optimized rapid and accurate single‐ and multiplex isothermal diagnostic tools, based on recombinase polymerase amplification (RPA), for detection and differentiation of CEV and KHV. The assays were combined with a lateral flow dipstick to enable visual detection of amplification products and simplify post‐amplification analysis. Both CEV‐ and KHV‐RPA assays were specific for their target virus. The lower detection limits of the assays were similar to those of established diagnostic PCR tests for the viruses. A sample preparation method was optimized to eliminate the need for total DNA extraction from fish tissues. The estimated time to perform these RPA assays, from receiving the sample to having a result, is 50 min, compared to 10 and 7 hr for CEV‐ and KHV‐PCR tests, respectively. The assays can be performed in field situations to improve screening of fish and reduce spread of these viruses and thereby enhance the common carp and koi industries.  相似文献   

16.
This study investigated the use of alkaline hydrolysis at ambient temperature for inactivation of selected fish pathogens in fish tissues under conditions approximating those that are likely to be found in the aquaculture industry. Infectious salmon anaemia virus (ISAV) and Lactococcus garvieae have been determined in a previous study to be the most resistant virus and bacteria to pH 12 from a wide range of viruses and bacteria tested. They were spiked at high titres into fish extracts that were then treated with 1 m sodium hydroxide (NaOH). Viable L. garvieae was not detected in the treated fish extract after 1 h, and ISAV was not detected after 24‐h exposure. Field mortalities of Atlantic salmon, Salmo salar L., caused by infectious pancreatic necrosis virus were treated by alkaline hydrolysis at ambient temperature. The macerated fish mortalities contained a high titre of virus (3.38 × 108 TCID50 g?1) that was reduced to approximately 2.2 × 103 TCID50 g?1 after 24‐h exposure to NaOH, and virus was not detected after exposure for 48 h. The results suggest that alkaline hydrolysis at ambient temperature has potential as a biosecure treatment method for fish by‐products containing fish pathogens.  相似文献   

17.
This work determined the nitrogen inputs, outputs and accumulation in compartments of stagnant earthen ponds for the monoculture and integrated multi‐trophic aquaculture (IMTA) of the Amazon river prawn (Macrobrachium amazonicum) and tambaqui (Colossoma macropomum), using recycled hypereutrophic water. A completely randomized experiment was designed with four treatments and three replications: PM–monoculture with 30 prawns/m2, FM ‐ monoculture with 3 fish/m2, IMTA ‐ polyculture with 30 prawns/m2 and 30 fish/m2 free, POLY‐CAGE ‐ polyculture with 30 prawns/m2 free and 40 fish/m3 in net‐cages. Animals, rain, water, feed, soil, gas, accumulated sludge, and suspended sediments were collected throughout the experiment to determine their nitrogen contents and to calculate the nitrogen budget. Results showed that much of the nitrogen available escapes to atmosphere as N2 (~40%–56%) after denitrification or accumulated within bottom sludge (~14%–42%). The remaining nitrogen was converted in animal biomass (~5%–21%) or was discharged to receiving waterbodies in the outlet water (~11%–13%). Feed management appeared to influence the major biological processes in the aquatic nitrogen cycle, such as photosynthesis and denitrification. The fish‐prawn IMTA systems converted approximately 53%–75% of feed nitrogen into harvestable products, which is more efficient than the 19%–46% of feed nitrogen converted in the monocultures. However, a large amount of nitrogen is accumulated in the pond bottom in all systems. An increased prawn density or the addition of a mud‐feeder species to the culture may enhance the incorporation of this material in harvested biomass, improving the efficiency of the systems.  相似文献   

18.
Streptococcus parauberis is an increasing threat to aquaculture of olive flounder, Paralichthys olivaceus Temminck & Schlegel, in South Korea. We developed a real‐time polymerase chain reaction (PCR) method using the TaqMan probe assay to detect and quantify S. parauberis by targeting the gyrB gene sequences, which are effective for molecular analysis of the genus Streptococcus. Our real‐time PCR assay is capable of detecting 10 fg of genomic DNA per reaction. The intra‐ and interassay coefficient of variation (CV) values ranged from 0.42–1.95%, demonstrating that the assay has good reproducibility. There was not any cross‐reactivity to Streptococcus iniae or to other streptococcal/lactococcal fish pathogens, such as S. agalactiae and Lactococcus garvieae, indicating that the assay is highly specific to S. parauberis. The results of the real‐time PCR assay corresponded well to those of conventional culture assays for S. parauberis from inoculated tissue homogenates (r = 0.957; P < 0.05). Hence, this sensitive and specific real‐time PCR is a valuable tool for diagnostic quantitation of S. parauberis in clinical samples.  相似文献   

19.
The production and livelihood of aquaculture facilities depend on increased growth of species being harvested. Only 15%-25% of nitrogen and phosphorus are retained in farmed fish even when all feed is consumed. In both marine and freshwater aquaculture systems, bivalves have proven to be an inexpensive method for controlling algal growth through suspension feeding. With 25% of the native U.S. freshwater mussel species under federal protection, their use in aquaculture ponds could lead to further propagation and restoration of natural populations. Elliptio complanata is an important species in Delaware rivers and connected estuaries; a recent two-year study by the United States Geological Survey found that 98% of mussels found in the Delaware River were Elliptio complanata. The objective of this study was to calculate the clearance rate of E. complanata in a laboratory study. This would help us determine if mussels can serve as an addition to chemical and mechanical filtration regiments and thrive in an aquaculture setting. Using feeding chambers we investigated the effect of E. complanata on algae grown from an aquaculture pond and on a cultured alga over a four-hour period. Temperature, dissolved oxygen, and pH were monitored, and samples were than analyzed for total chlorophyll-α. The average of both the single cell using Chlorella vulgaris and mixed assemblage treatments chlorophyll-α clearance rate was 0.187 liters per hour per mussel. Prior to this experiment, these mussels were held for a period for two months in the holding system in the laboratory. The resulting low clearance rate as compared to the previous studies in the field is possibly due to the stress from holding these mussels. However, our study demonstrated that mussels have the potential to be used in an aquaculture setting and/or recreational ponds to help reduce algae populations that can occur as a result of eutrophication.  相似文献   

20.
This study aimed at assessing the pathogenicity of two Vibrio splendidus-related species and evaluating the influence of the origin and annual life cycle of mussels on their sensitivity during a bacterial challenge. Thus, in vivo infection assays were made with Vibrio crassostreae 7T4_12 and Vibrio splendidus 3G1_6, over, respectively, thirteen and 9 months, on adult blue mussels from five recruitment areas in France. Two bacterial concentrations were tested: one consistent with the loads of Vibrio spp. in environment and mussel tissues (~105 CFU/ml) and another one much higher (~108 CFU/ml). The tested environmental concentration has no pathogenic effect whatever the time of year, the strain used and the origin of mussels. However, at the highest concentration, a pathogenic effect was observed only at specific moments, and one of the origins appeared to be more resistant. The physiological state of mussels—depending on the time of year—seemed significant in mussels’ sensitivity, as their recruitment origin. This study is the first to test the pathogenicity of V. splendidus-related strains at concentrations close to what is found in the wild, over the annual cycle of mussels, and considering their origin.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号