共查询到20条相似文献，搜索用时 93 毫秒
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Rhoda Mae C. Simora Shangjia Li Nermeen Y. Abass Jeffery S. Terhune Rex A. Dunham 《Journal of fish diseases》2020,43(12):1553-1562
Cathelicidins are a class of antimicrobial peptides (AMPs) known to possess rapid and direct antimicrobial activities against a variety of microorganisms. Recently identified cathelicidins derived from alligator and sea snake were found to be more effective in inhibiting microbial growth than other AMPs previously characterized. The ability of these two cathelicidins along with the peptides, cecropin and pleurocidin, to protect channel catfish (Ictalurus punctatus, Rafinesque) and hybrid catfish (I. punctatus ♀ × blue catfish, Ictalurus furcatus, Valenciennes ♂) against Edwardsiella ictaluri, one of the most prevalent pathogens affecting commercial catfish industry, was investigated. Cathelicidin-injected fish (50 µg ml−1 fish−1) that were simultaneously challenged with E. ictaluri through bath immersion at a concentration of ~1 × 106 CFU/ml had increased survival rates compared with other peptide treatments and the infected control. Bacterial numbers were also reduced in the liver and kidney of channel catfish and hybrid catfish in the cathelicidin treatments 24 hr post-infection. After 8 days of challenge, serum was collected to determine immune-related parameters such as bactericidal activity, lysozyme, serum protein, albumin and globulin. These immune-related parameters were significantly elevated in fish injected with the two cathelicidins as compared to other peptide treatments. These results indicate that cathelicidins derived from alligator and sea snake can stimulate immunity and enhance the resistance to E. ictaluri infection in channel catfish and hybrid catfish. 相似文献
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班点叉尾鮰是我国引进的新的养殖品种。本文作者对斑点叉尾鮰养殖技术作扼要概述。 相似文献
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斑点叉尾鮰传染性套肠症是近年来在我国发生的一种斑点叉尾鮰的新型细菌性传染病，初步认为病原为嗜麦芽寡养单胞菌（Stenotrophomonas maltophilia）。该病发病突然，来势凶猛，传染快，发病率和死亡率高，以发生严重的肠炎、肠套叠和脱肛为特征，已对斑点叉尾鮰养殖造成了严重的危害。本文比较详细介绍了该病发生的背景与危害、流行情况、病原及致病机理，症状与病理变化，并根据该病的特点提出了防治措施。 相似文献
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Land-based production of sea bream (S. aurata) isone of the alternative types of aquaculture for different areas of theMediterranean coast, but its future development will mainly depend both on thecapacity to make this technology compatible with other uses of the land and thecapacity to make it cost-effective, especially in comparison with production incages. The present work analyzes all costs related to sea bream production inland-based facilities. With this aim in mind, a standard facility,growing 200 t per year of fish from 10 to 400 g, isdefined. It is assumed that there will be a collective utilization by some farmsof the infrastructure for intake, transport and outfall of water as well as theeffluent treatment system. The work is developed for a specific area, The EbroDelta in Spain, but intends to be a wide approach to the subject and to offergeneral conclusions. The average total production cost obtained, around four anda half euro per kg, allows us to consider that this type of technologyis feasible under the conditions considered. The different items that couldaffect this cost are also discussed. Feed and juveniles represent respectively30% and 25% of average total cost. Those costs differentiating betweenland-based and cage technology, i.e. oxygen and power, amount to only 6.3% ofthe average total cost. 相似文献
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本试验通过应用AQUAVAC-ESC^R疫苗在广西进行斑点叉尾鮰肠道败血症的免疫预防试验，以评估该疫苗的效能。试验将体长2cm的鱼苗用疫苗浸泡后，投放于柳州柳江河段的网箱进行养殖。经过7个月的观察，结果表明：疫苗对鱼苗是安全的。ELISA的分析结果表明，AQUAVAC-ESC^R灵敏度高，甚至于鱼苗阶段就能刺激鱼的免疫系统产生特异性抗体。由于在试验中没有自然选择的压力，免疫接种的试验组成活率和体重增量，与对照组差异不显著。而免疫组的饵料系数比对照组低16．0％，这表明，合理使用AQUAVAC-ESC^R可以提高饲料转化率，降低生产成本，给养殖户带来一定的经济效益。 相似文献
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Phillip Joschka Haubrock Martina Azzini Paride Balzani Alberto Francesco Inghilesi Elena Tricarico 《Ecology of Freshwater Fish》2020,29(1):4-17
Due to the increasing globalisation and ongoing introduction of alien species specifically regarding European freshwater ecosystems, native and already present alien species will be confronted with competitors with unknown outcomes. One such case is the situation of the European catfish Silurus glanis introduced in the Arno River (Central Italy), a species sought after by anglers, which is facing competition from the later introduced alien North American channel catfish Ictalurus punctatus. Large catfish species are highly valued among anglers, but their interspecific interactions and potential ecosystem-level impacts are still poorly known. We used stomach contents and stable isotope analyses to study niche partitioning between these two alien catfish species, coexisting in the Arno River. The results suggest partial niche segregation, with immature S. glanis showing a narrower dietary and isotopic niche and a slightly higher trophic position than I. punctatus. Monitoring the catfish population sizes, trophic niches and effects on lower trophic levels are essential for future management and mitigation of their potential impacts on invaded freshwater ecosystems. 相似文献
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Timothy J. Dalton Kate M. Waning Linda Kling 《Aquaculture Economics & Management (Blackwell Science)》2013,17(1-2):41-59
Abstract The risk efficient live feed system for juvenile haddock production is derived through recursive ex‐ante stochastic cost estimation. Four alternative feeding technologies are simulated to capture the economic costs associated with live feed and juvenile production and scale economies are investigated by simulating three production levels. Using Monte Carlo simulation techniques, multivariate stochastic cost functions are derived in a time‐dependent recursive production model. With the current technologies and price levels, land‐based juvenile haddock production is viable. The marginal impact, in terms of cost‐savings, to additional research on optimal feeding periods will be minimal. On the other hand, the high opportunity cost of capital used in aquaculture production, due to numerous perceived risk premia, may pose a more immediate constraint for capital formation and industry development. 相似文献
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The rapid intensification of the aquaculture system has led to several environmental impacts involving water quality deterioration, pollution, and disease outbreaks. Consequently, an eco-friendly technique is inevitable that could ensure better production with less impact on the environment by minimizing the effluent discharge from aquaculture practice. Biofloc technology is such a kind breakthrough that would be easy to perform; operation and establishment procedure is quite simple at a relatively low cost that would be convenient to fish farmers. It can serve as a perfect solution for aquaculture species through improving its all characteristics such as substantial biomass density, survival, and disease resistance ability to the pathogen by an immunostimulatory effect of microbial floc on the immune system that would assure the biosecurity and sustainability of this extraordinary technique.
相似文献11.
Yoshiki Takayama Minamo Hirahara Xin Liu Syuhei Ban Tatsuki Toda 《Aquaculture Research》2020,51(9):3741-3750
The understanding of the biological responses of copepods under crowding conditions contributes to establish their stable cultures at high densities for aquaculture industry, which are preferred live feeds for fish larvae. The present study investigated survivorship, fecundity, hatching success and respiration rate, of Acartia steueri raised under five densities, from 100 to 2,000 ind. L?1, to clarify the biological responses of the copepod under dense culture. There were no significant differences in survival, fecundity and hatching success among all density conditions, whereas the respiration rate at 2,000 ind. L?1 decreased by 80% as compared with a condition at 100 ind. L?1. The female copepods raised under a copepod density of >500 ind. L?1 probably invested a larger proportion of energy in reproduction in relation to total assimilated energy as compared with females under lower copepod densities. This change of energy allocation may allow A. steueri under high densities to maintain high fecundity. Acartia steueri might be a promising species for dense culture because its mortality and fecundity were independent of the effect of crowding, and the density‐dependent reduction in the metabolic rate might increase reproductive investment to maintain a constant rate of reproduction even under high densities. 相似文献
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Lise M. H. Ferreira Gabriele Lara Wilson Wasielesky Jr. Paulo Cesar Abreu 《Aquaculture International》2016,24(4):921-930
The aim of this study was to evaluate the addition of artificial substrates in biofloc technology systems that are used for the intensive production of Litopenaeus vannamei. The experiment lasted 35 days. Tanks each with a useful volume of 800 L were filled with water containing bioflocs (25 % of the total volume) and filtered seawater. Three treatments with three replicates each were compared: (1) Ctrl (control), i.e., without the addition of artificial substrate, (2) 200 and (3) 400, with added artificial substrate equivalent to 200 and 400 % of the lateral area of the tanks, respectively. The shrimp with initial weight of 0.40 ± 0.15 g were stocked at a density of 300 shrimp/m2. Feed (Guabi/38 Active, Brazil) was supplied two times per day. The water quality parameters were suitable for the production of L. vannamei. The settleable solids (SS) were higher in the Ctrl treatment (82.1 ± 19 mL L?1) and differed statistically from the 200 and 400 treatments that presented average SS values below 10 mL L?1. The reuse of water with bioflocs accelerated nitrification in the tanks, and no significant differences were shown between tanks. The presence of biofilm did not interfere with ammonium or nitrite levels, but it did serve as a food source that optimized shrimp performance, as shown by higher final weights. More studies are needed to evaluate the circulation and mixing intensity effects of the substrates on water throughout the production cycle. 相似文献
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Hypnea musciformis: alternative or complement to the production of Kappaphycus alvarezii introduced in tropical countries? 
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下载免费PDF全文 Beatriz Castelar Renata P Reis Fernando Azeredo Pedro Mattos Gian Berardinelli 《Aquaculture Research》2016,47(11):3538-3550
Hypnea musciformis that are harvested from natural beds and introduced Kappaphycus alvarezii are the two main sources of raw material for the production of carrageenan in Brazil. The daily growth rate (DGR) and carrageenan yield (CY) of both species were evaluated in vitro and in the sea to assess the feasibility of cultivating H. musciformis as a complement or as an alternative to the production of K. alvarezii. The DGR of H. musciformis (10.8 ± 0.6% day?1) was higher than the DGR of K. alvarezii (5.6 ± 0.3% day?1) in vitro, and the CY extracted using NaOH (62.3 ± 0.15%) was better than using KOH (32.0 ± 0.3%). In eutrophic medium, the DGR of H. musciformis (9.4 ± 2.1% day?1) was higher than that of K. alvarezii (5.0 ± 1.2% day?1). However, in this condition, the CY was similar for both species (50.2 ± 3.5%), and both species were effective in removing nutrients (30% NH4+, 18% NO2? and 2.4% ). H. musciformis did not survive when cultivated in the sea, neither in monospecific nor in multispecific cultivation. Moreover, K. alvarezii grew better in monospecific cultivation throughout the year (from 1.73 to 5.15% day?1) except during the wet period and the CY was high in both cultivation types (33.7–50.8%). We conclude that the cultivation of H. musciformis is not an alternative to K. alvarezii on the Brazilian southeastern coast. However, the results in vitro suggested its use as a complementary source of carrageenan or as a biological filter. 相似文献
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《水生生物资源》2001,13(6):461-469
This paper critically reviews the theoretical and practical implications of adopting the original ‘ecological footprint’ concept as an index of the sustainability of aquaculture production systems. It is argued that the concept may provide a reasonable visioning tool to demonstrate natural resource dependence of human activities to politicians and the public at large. However, due to its inherent weaknesses, the ‘ecological footprint’ fails to provide a cohesive analytical tool for management. From an ecological perspective, its two-dimensional interpretation of complex ecologically and economically interacting systems is one major weakness. From an economic perspective, the ‘footprint’ fails to recognise factors such as consumer preferences and property rights which have a major influence on the allocation and sustainable use of resources. The interactions among social, ecological and economic factors are discussed in an attempt to foster a broader inter-disciplinary view of criteria required for a sustainable use of aquatic resources. 相似文献
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In a search for new antitumor drugs, we collected 334 species of marine algae from the Japanese coastline and screened these
for tumor necrosis factor-alpha (TNF-α) production-promoting activity in an in vitro assay with the mouse macrophage-derived
cell line RAW264.7. A phosphate-buffered saline extract from the marine brown alga Chordaria flagelliformis was found to strongly promote TNF-α activity. Further purification of this alga by precipitation with ethanol and two-step
chromatography yielded an approximately 3,000-kDa polysaccharide as the active substance, which we designated MC25. MC25 exhibited
TNF-α production-promoting activity in RAW264.7 cells in a dose-dependent manner, and we established its temperature and pH
stabilities and non-cytotoxic character. Its molecular structure is similar to that of a fucoidan in terms of composition,
including glucose, fucose, xylose, and uronic acid. The molecule hydrolyzed to a size of 180–370 kDa still retained strong
TNF-α production-promoting activity, suggesting that MC25 might be a promising candidate in the development of novel antitumor
agents. 相似文献
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Salmon pituitary glands contain two structurally distinct -subunit proteins (1 and 2) of glycoprotein hormones: the 2-subunit is common to all salmon gonadotropins (GTH I and GTH II), whereas the 1-subunit is present in only some GTH I molecules. GTH I is predominant in the pituitary gland and plasma during gametogenesis of salmon, but the roles of the 2 GTHs in gametogenesis remain unclear. To understand the roles of GTH I, it is important to clarify patterns of 1- and 2-subunit production with sexual maturity. Thus, we produced antisera that recognized the 1- or 2-subunit, and then immunohistochemically examined the production sites of these subunits in the trout pituitary gland during ovarian development. In all pituitary glands examined, the immunoreactivity of both the 1- and 2-subunits was strong in the GTH II-producing cells, although salmon GTH II, both 1- and II-subunits, has not been detected. However, GTH I-producing cells showed a less dense immunoreactivity for 1- and 2-subunits, whereas the I-subunit was abundant. On the other hand, TSH cells, reacted with 2 but not with 1. 相似文献
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Is fisheries production within Large Marine Ecosystems determined by bottom‐up or top‐down forcing? 下载免费PDF全文
下载免费PDF全文 Chris J Mcowen William W L Cheung Ryan R Rykaczewski Reg A Watson Louisa J Wood 《Fish and Fisheries》2015,16(4):623-632
Understanding the mechanisms driving fisheries production is essential if we are to accurately predict changes under climate change and exploit fish stocks in a sustainable manner. Traditionally, studies have sought to distinguish between the two most prominent drivers, ‘bottom‐up’ (resource driven) and ‘top‐down’ (consumer driven); however, this dichotomy is increasingly proving to be artificial as the relative importance of each mechanism has been shown to vary through space and time. Nevertheless, the reason why one predominates over another within a region remains largely unknown. To address this gap in understanding, we identified the dominant driver of commercial landings within 47 ecosystems, encompassing a wide range of biogeochemical conditions and fishing practices to elucidate general patterns. We show that bottom‐up and top‐down effects vary consistently with past fishing pressure and oceanographic conditions; bottom‐up control predominates within productive, overfished regions and top‐down in relatively unproductive and under‐exploited areas. We attribute these findings to differences in the species composition and oceanographic properties of regions, together with variation in fishing practices and (indicative) management effectiveness. Collectively, our analyses suggest that despite the complexity of ecological systems, it is possible to elucidate a number of generalities. Such knowledge could be used to increase the parsimony of ecosystem models and to move a step forward in predicting how the global ocean, particularly fisheries productivity, will respond to climate change. 相似文献
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Khem R. Sharma Pingsun Leung 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3-4):169-189
Abstract A stochastic meta‐production frontier model is estimated to examine the inter‐country differences in levels of technical efficiency of semi‐intensive/intensive and extensive carp pond culture systems among the major carp producing countries in South Asia, namely India, Bangladesh, Pakistan, and Nepal. The mean technical efficiencies for semi‐intensive/intensive farms vary from 0.68 for Nepal to 0.79 for India, with an overall average of 0.75 and those for extensive farms vary from 0.48 for Bangladesh to 0.62 for Pakistan, with an overall mean of 0.57. Differences in efficiency levels are explained in terms of various farm‐specific and country‐specific factors by estimating a model for technical inefficiency effects. The adoption of recommended fish, water, and feed management practices is found to be critical for improved performance of carp producers. For each country, the study also compares the efficiency scores based on its own production frontier with those obtained from the meta‐production frontier. 相似文献
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Integrated aquaculture has been widely used for pearl production in the freshwater pearl mussel Hyriopsis cumingii farming in China, but the production technology has not reached the state of the art. This study explored the optimal stocking ratio of fish to mussel (fish–mussel) through a 90-day experiment conducted in land-based enclosures. The integrated system included pearl mussel, grass carp, gibel carp, silver carp and bighead carp, with four fish–mussel stocking ratios by number: 1:1 (R1), 2:1 (R2), 3:1 (R3) and 4:1 (R4). The pearl yield was higher in the R2 enclosures than in the R1 and R4 enclosures, whereas the fish yield was higher in the R3 and R4 enclosures than in the R1 and R2 enclosures. The phosphorus (P) utilization efficiency was higher in the R2, R3 and R4 enclosures than in the R1 enclosures. The wastes of nitrogen (N) and P enhanced with the increase of fish–mussel ratio. Regression analyses indicated that the fish–mussel ratio was 2.3:1 for the maximal pearl yield, and 3.6:1 for the maximal fish yield, and 1.6–2.3:1 for the minimal N waste, and 1.9–2.9:1 for the minimal P waste. This study indicated that the suitable fish–mussel stocking ratio was 2:1 in the integrated culture of H. cumingii, grass carp, gibel carp, silver carp and bighead carp. 相似文献