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1.
Mar Environ Res ; 160: 105051, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907717

RESUMO

In order to detect the possible regulatory effect of non-native C. gigas on the native O. edulis, under aquaculture conditions, feeding interactions between them were investigated in a highly productive environment of Lim Bay (Adriatic Sea). The present study uses a multi-methodological approach, including stomach content, DNA barcoding and stable isotope analysis to elucidate the feeding ecology of two oyster species. The research confirmed a high overlap throughout the year in the feeding traits among native and non-native oyster species. Competition for food was not the only relationship that exists between the investigated species as the presence of O. edulis larvae in C. gigas stomach content was confirmed by DNA analysis. Findings are not in favour of introducing C. gigas to commercial aquaculture in any new areas in the Adriatic Sea and support the need to improve the existing O. edulis aquaculture and conserve its wild stocks.


Assuntos
Aquicultura , Crassostrea , Comportamento Alimentar , Ostrea , Animais , Ecologia , Cadeia Alimentar , Larva
2.
Mar Environ Res ; 160: 104986, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907724

RESUMO

Although eutrophication is considered a major driver for global seagrass loss with aquaculture effluents being a main factor, little is known about the effect on seagrass meadows in eastern Asia and their resilience to long-term nutrient impact. Seagrass meadows impacted by land-based aquaculture since the 1990s, were visited in 2008/2009 and revisited after another 9 years of effluent exposure. During that period seagrass aboveground biomass declined by 87%. Species diversity decreased with increasing effluent exposure. A δ15N of 9.0‰ of seagrass leaves and additional biogeochemical and biological indicators identify pond effluents as the driver of the observed eutrophication. When continuously exposed to dissolved inorganic nitrogen (DIN) concentrations exceeding a calculated threshold of 8 µM DIN seagrass meadows will disappear. Chronic nutrient pollution from aquaculture effluents can lead to a reduction of biodiversity and ultimately to a complete loss of seagrasses along the aquaculture-dominated coasts in E and SE Asia.


Assuntos
Aquicultura , Eutrofização , Nitrogênio , Biodiversidade , Biomassa
3.
Mar Environ Res ; 160: 104988, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907726

RESUMO

Farming damselfishes are well known for shaping benthic communities on reefs, in terms of both cultivating algae and increasing productivity. However, their capacity to shape relationships between algal turfs, detritus and sediments remains largely unknown, despite the importance of such relationships on reefs. We therefore examined the relationships between sediment loads and both algal turf length and detritus levels, inside and outside farming damselfish territories, at two reefs on the Great Barrier Reef. We found that, while sediment loads are tightly coupled with algal turfs outside territories, the nature of this coupling was fundamentally different inside damselfish territories, with significantly longer algal turfs and higher detritus levels prevailing, irrespective of sediment loads. These modified algal turf-sediment relationships may be a key factor in explaining, a) the significantly higher productivity levels reported from within farming damselfish territories and b) the ability of farming damselfishes to persist in high-sediment locations.


Assuntos
Aquicultura , Recifes de Corais , Peixes , Animais , Sedimentos Geológicos
4.
Extremophiles ; 24(5): 787-796, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32743715

RESUMO

Salted and ripened fish foods are susceptible to cause histamine poisoning. The present study focuses on microbial histamine degradation from high salted fermented fishery products to deepen our understanding about this new and growing field of research. As a result of this first study related to salted-ripened anchovies (Engraulis anchoita), fifty seven moderate and extreme halophilic microbial isolates from salt and salted-ripened anchovy processes were characterized in terms of their phenotype and histamine-degrading capacity. Only 7%-4 isolates-were able to degrade histamine. None of the histamine-degrading isolates presented proteolytic and/or lipolytic activity. One of them designated A18 was chemotactic toward histamine, an interesting property not previously reported for that chemoattractant. However, the S18 and A18 isolates, genotypically identified as Halobacterium sp. and Halomonas sp. respectively, produced indole and/or H2S, both undesirable characteristics associated to off-flavors occurrence. On the other hand, A28 and S20, identified as Halovibrio sp. and Halobacterium sp. respectively, presented desirable properties, such as cytochrome oxidase and catalase activity, and non-production of H2S and indole. These strains also showed characteristics previously reported as dominant in the ripened stage. The results are promising, and A28 and S20 may have the desirable features to improve the anchovy salting-ripening process.


Assuntos
Halobacteriales , Halomonas , Histamina , Animais , Aquicultura , Peixes , Histamina/metabolismo , RNA Ribossômico 16S , Cloreto de Sódio
5.
Environ Pollut ; 266(Pt 1): 115339, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32823042

RESUMO

Demand for aquatic products surges, due to the increasing concerns on high-quality nutrition and food security. Eastern China is the leading area in contributing significantly to both production and consumption of aquatic products from inland aquaculture, coastal fishing, and distant-water fishing. It is imperative to comprehensively assess the dietary risks of common chemical hazards, such as polycyclic aromatic hydrocarbons (PAHs) in aquatic products of these supply origins, and the contribution of aquatic product consumption to total human exposure. The observed body loads of total PAHs in the coastal aquatic products varied significantly, indicating an unstable food quality from the east coast of China. In the meantime, benzo[a]pyrene equivalent concentrations (BaPeq) exhibited the highest level in the aquatic products from inland farm ponds. High BaPeq, along with high consumption of inland aquaculture products, led to higher corresponding cumulative carcinogenic risks (ILCRs) than the other two kinds of products, which further indicate that the origins and consumption rates of the aquatic products do matter. Furthermore, it is confirmed that the consumption of aquatic products is an important contributor to the total daily exposure to PAHs, especially for children and pregnant women. Finally, it is necessary to apply practical remediation in aquaculture farm ponds to provide high-quality products, especially for the population groups of children and pregnant women, and alleviate the exposure and risk due to the PAHs in aquatic products.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/análise , Aquicultura , Carcinógenos/análise , Criança , China , Monitoramento Ambiental , Feminino , Humanos , Gravidez , Medição de Risco
6.
Mar Pollut Bull ; 158: 111367, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753171

RESUMO

Visually-based approaches using techniques such as sediment surface images as well as sediment profile imaging (SPI) have been applied previously in the assessment of benthic impacts of organic enrichment. New visually-based benthic health indices (VBH and Surface Index) that integrate various visual properties was developed for muddy and sandier sediments, respectively. Visual indices were compared to the existing sulfide-based thresholds often used in environmental monitoring programs (EMPs). We utilized both techniques as well as geochemical indicators of eutrophication to detect benthic impacts at shallow shellfish and finfish farms in Nova Scotia, Canada. The visual indices were able to capture a non-sulfidic anaerobic condition in the sediments missed by the current sulfide-based system. Our results indicate that as presently configured, the visual based index will provide a more stringent standard in the EMPs that currently rely on a sulfide-based classification system, and thus affect regulatory judgement.


Assuntos
Aquicultura , Sedimentos Geológicos , Animais , Monitoramento Ambiental , Eutrofização , Nova Escócia
7.
PLoS One ; 15(8): e0237775, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813739

RESUMO

Nile tilapia, Oreochromis niloticus is the third most commonly farmed finfish species in the world, accounting for nearly 5% of global aquaculture production. In the past few decades much of the success of this species has been attributed to the development and distribution of Genetically Improved Farmed Tilapia (GIFT). Despite the increasing availability of GIFT, the productivity of small-scale farming remains highly variable, particularly in developing nations. Commercial fish-feed pellets can increase fish farm productivity; however, many small-scale farmers rely on other means of feeding fish due to the high cost and limited availability of commercial fish feed pellets. Therefore, understanding how locally-sourced feeds affect the production of GIFT is an important step towards improving feeding practices, particularly for farmers with low financial capital. This study used stable isotope analysis (SIA) and 16S rRNA gene sequencing to compare the effects of a locally-sourced vegetable-based diet and commercial pellet-based diets on the relative condition, nutrient assimilation patterns and gastrointestinal microbiota of GIFT. GIFT fed a locally-sourced diet were smaller, and in a significantly poorer condition than those fed with commercial fish feeds. SIA showed no differences in dietary carbon between the two diets; however, δ13C, poor fish condition and the abundance of specific bacterial taxa (of such as Fusobacteria) were correlated. SIA revealed that GIFT fed locally-sourced diets that predominantly consisted of vegetables were significantly enriched in δ15N despite a perceived lack of dietary protein. This enrichment suggests that GIFT fed a locally-sourced diet may be supplementing their diet via cannibalism, a behaviour representative of poor farming practice. Overall this study highlights the need to increase the availability of suitable GIFT feeds in developing nations. The development a low-cost feed alternative could improve the success of small-scale GIFT farmers in PNG, increasing both food and income security within the region.


Assuntos
Ração Animal , Animais Geneticamente Modificados/metabolismo , Aquicultura/métodos , Ciclídeos/metabolismo , Microbioma Gastrointestinal/fisiologia , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/microbiologia , Aquicultura/economia , Aquicultura/organização & administração , Canibalismo , Ciclídeos/genética , Ciclídeos/microbiologia , DNA Bacteriano/isolamento & purificação , Suplementos Nutricionais/economia , Eficiência Organizacional/economia , Fazendas/economia , Fazendas/organização & administração , New South Wales , Nutrientes/metabolismo , RNA Ribossômico 16S/genética
8.
Ecotoxicol Environ Saf ; 204: 111111, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32795703

RESUMO

Bath treatment chemotherapeutants, used to control sea lice infestations in the salmonid aquaculture industry, are released directly into the marine environment around fish farms and pose a serious risk to non-target species, particularly crustaceans. Hydrogen peroxide (H2O2) is the most frequently used bath treatment chemotherapeutant on Norwegian fish farms, however, limited information is available on its toxicity to European lobsters (Homarus gammarus), a commercially important species at risk of exposure due to its distribution overlapping with salmon farm locations. The aim of this study was to investigate the lethal effects of H2O2 on pelagic (stage I-IV) larvae/post-larvae and its sub-lethal effects on the benthic stage V H. gammarus. To assess the lethal effects of H2O2, we carried out a series of 1 h toxicity tests and assessed mortality after a 24 h post-exposure period. Exposure to H2O2 was toxic to all pelagic larval stages tested, with estimated median lethal concentrations (LC50) of 177, 404, 665 and 737 mg/L for stage I, II, III and IV, respectively. These concentrations represent approximately 10, 23, 40 and 43%, of the recommended H2O2 concentrations used for delousing salmon on Norwegian fish farms, respectively. To assess the sub-lethal effects of H2O2 on H. gammarus, stage V juveniles were exposed to H2O2 at concentrations of 85, 170 and 510 mg/L for 1 h and shelter-seeking behaviour and mobility endpoints were assessed. Numerous behavioural parameters including distance travelled to shelter, time to locate shelter and the number of shelter inspections, were negatively affected in lobsters exposed to H2O2 when assessed immediately after the exposure period. However, no differences between control and exposed lobsters were detected after a 24 h post-exposure period. Our results demonstrate that short term exposures to H2O2 are lethal to pelagic H. gammarus life stages and can negatively affect the shelter seeking behaviour of benthic life stages, though these behavioural changes may be short-lived.


Assuntos
Peróxido de Hidrogênio/toxicidade , Nephropidae/fisiologia , Animais , Aquicultura/métodos , Comportamento Exploratório , Pesqueiros , Larva/efeitos dos fármacos , Dose Letal Mediana , Nephropidae/efeitos dos fármacos , Noruega , Salmão , Testes de Toxicidade
9.
Ecotoxicol Environ Saf ; 204: 111114, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32798752

RESUMO

The widely distributed seaweed Ulva fasciata has nutrient absorption abilities and can be used in the bioremediation of polluted maricultural environments. This study explored microbial community and antibiotic resistance gene (ARG) variation in mariculture sediments in response to different trace levels (10, 100, and 500 µg L-1) of oxytetracycline (OTC) and the presence of Ulva fasciata. The increase in OTC level promoted nutrient (NO3_-N and PO43--P) removal mainly due to Ulva fasciata adsorption. The abundances of the Euryarchaeota and Planctomycetes phyla in sediments were positively related to the increase in OTC stress, while a negative correlation occurred for the Proteobacteria phylum via metagenomic analysis. Compared with the control system, the increase rates of total ARGs were 3.90%, 7.36% and 13.42% at the OTC levels of 10, 100 and 500 µg L-1, respectively. OTC stress mainly favoured the collateral enrichment of non-corresponding polypeptide and MLS ARGs, mainly due to the enrichment of the phyla Planctomycetes and Euryarchaeota by the synergistic effect of OTC and nutrients. The results of quantitative PCR with tetracycline resistance genes (TRGs) (tetO, tetT, tetPB, tetW and otrA) and a horizontal transfer gene (intl1) demonstrated that all of genes had much higher gene numbers in sediments after 3 months of OTC stress than in those without OTC stress, which was strongly related to the variation in the phyla Bacteroidetes, Gemmatimonadetes and Acidobacteria. The significant correlation between intl1 and the target TRGs is indicative of the important role of the horizontal transfer of integron-resistant genes in the spread of TRGs.


Assuntos
Antibacterianos/toxicidade , Aquicultura , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Ulva/fisiologia , Bactérias/efeitos dos fármacos , Biodegradação Ambiental , Integrons , Microbiota/efeitos dos fármacos , Oxitetraciclina/análise , Alga Marinha/efeitos dos fármacos , Resistência a Tetraciclina/efeitos dos fármacos , Ulva/efeitos dos fármacos
10.
Dis Aquat Organ ; 140: 179-186, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32815526

RESUMO

The rearing of less established fish species in recirculating aquaculture systems (RASs) is increasing, but may require adaptations of the rearing facilities if health impairments occur. We observed several health issues in burbot Lota lota reared for up to 2 yr in a RAS and used microbiological, histological and molecular-biological methods to identify the causative agents. Minor skin trauma led to the development of ulcers. In addition, several fillets of burbot showed pronounced granulomatous inflammation and calcification with signs of muscle fiber degeneration which resembled a condition called 'sandy flesh disease' in North American walleye. Several infectious agents were able to be excluded as a cause for the disease. Carnobacterium maltaromaticum was isolated in high numbers in some of the affected muscle tissue. However, the role of this bacterium or other causative agents or husbandry conditions remains to be elucidated.


Assuntos
Gadiformes , Animais , Aquicultura , Carnobacterium , Doenças dos Peixes , Músculo Esquelético
11.
Sci Total Environ ; 745: 140949, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-32758743

RESUMO

Understanding how marine species cope with the natural environmental variability of their native habitats will provide significant information about their sensitivity to the potential environmental changes driven by climate change. In particular, marine species inhabiting upwelling ecosystems are experiencing low seawater temperatures, as well as, acidic and low oxygen conditions as a consequence of the nature of the deep upwelled waters. Our study is focused on one of the most important socio-economical resources of the Humboldt Current System (HCS): the scallop Argopecten purpuratus which has been historically subjected to intensive aquaculture in areas influenced by upwelling processes. Here, a long-term field experiment was performed to understand how tolerant and well-locally-adapted is A. purpuratus to upwelling conditions by studying a set of fitness, physiological, and biomineralogical traits. Stronger upwelling generated a minor water column stratification, with lower temperatures, pH, and oxygen conditions. On the contrary, as upwelling weakened, temperature, pH, and oxygen availability increased. Finally, upwelling intensity also determined the number, duration, and intensity of the cooling and de-oxygenation events occurring in A. purpuratus habitat, as well as, the food availability (chlorophyll-a concentration, Chl-a). Physiologically, A. purpuratus was able to cope with stressful environmental conditions imposed by higher upwelling intensities by enhancing its metabolic and calcification rates, as well, producing higher concentrations of the shell organic matter. These physiological changes impacted the total energy budget, which was highly dependent on Chl-a concentration, and revealed important traits trade-offs with significant fitness costs (higher mortalities emerged when longer and more intense upwelling events succeed). Our study increases the knowledge about the physiological performance and tolerance of this important resource to the ocean acidification and ocean-deoxygenation imposed by variable upwelling intensities, as well as, its potential vulnerability under future changing conditions driven by a potential upwelling intensification.


Assuntos
Pectinidae , Água do Mar , Animais , Aquicultura , Ecossistema , Concentração de Íons de Hidrogênio
12.
Bioresour Technol ; 314: 123701, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32629382

RESUMO

Ammonia and nitrite in aquaculture recirculating seawater need to be strictly controlled to avoid deleterious effects on aquatic organisms. However, traditional biological approach can hardly meet the standard due to the short hydraulic retention time (HRT) and nitrite accumulation. A Membrane Electro-Bioreactor (MEBR) was developed for ammonia removal enhancement and in-situ electrochemical membrane fouling mitigation. The fouling mechanism was first found to proceed via the standard filtration model. The flux decrease was mainly caused by an internal pore clogging phenomenon. Membrane fouling resistance was enhanced by increasing anode potential from 0 to 1.4 V vs. SCE (Saturated Calomel Electrode). The ammonia removal rate in the MEBR was above 95% (HRT: 2 h, after day-13) and membrane fouling was mitigated that operation duration was extended by 71.4%. Higher total proportion of Proteobacteria, Bacteroidetes, Planctomycetes and Actinobacteria was obtained in the MEBR, suggesting higher nitrification and nitrogen removal potentials.


Assuntos
Microbiota , Águas Residuárias , Aquicultura , Reatores Biológicos , Membranas Artificiais , Água do Mar
13.
Sci Total Environ ; 743: 140735, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32679499

RESUMO

Thraustochytrids such as Aurantiochytrium are heterotrophic microorganisms that are known to produce valuable polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In this study, Aurantiochytrium sp. strain L3W was used to remove dissolved organic carbon (DOC) and dissolved nitrogen (DN) from bean-boiling (BB) and miso-processing (MP) wastewater and to simultaneously produce PUFAs. Strain L3W removed 52% of the DOC and 37% of the DN from sterilized BB wastewater and produced biomass that contained 137 mg/g of fatty acids (FAs), including 96.2 mg/g of DHA. Growth of strain L3W in sterilized MP wastewater resulted in the production of biomass containing 147.6 mg/g of FAs, including 97.8 mg/g of DHA, and removal of 47% of the DOC and 55% of the DN from the wastewater. The biomass of strain L3W was digestible by the enzymes extracted from the stomachs of rainbow trout. These results confirmed the potential for use of strain L3W to remove DOC and DN from food processing wastewater and to produce PUFAs. This study also provided the first evidence that the raw biomass of Aurantiochytrium sp. can be used as a fish feed additive.


Assuntos
Estramenópilas , Águas Residuárias , Animais , Aquicultura , Ácidos Docosa-Hexaenoicos , Ácidos Graxos , Manipulação de Alimentos
14.
Environ Monit Assess ; 192(8): 528, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32676848

RESUMO

The aim of this study was to examine the possible effects of the physicochemical parameters of the water at a fish farm where aquaculture activities are carried out (temperature, pH, salinity, total dissolved solids, electrical conductivity, dissolved oxygen, Secchi depth, nitrite-nitrogen, nitrate-nitrogen, phosphate-phosphorus, ammonium-nitrogen, silica, chlorophyll-a, and suspended particle matter) and in the sediments (%burnable organic matter and %organic carbon). The area of study was an open sea network cage farm where European seabass (Dicentrarchus labrax), gilthead seabream (Sparus aurata), and meagre (Argyrosomus regius) species are cultivated with an annual capacity of 7900 tons in the Bay of Çesme Ildir (Aegean Sea). Samples of surface and bottom water and sediment were taken seasonally from four stations (three cage and one reference station) between December 2013 and October 2014. The study found that the maximum concentrations of ammonium-nitrogen, phosphate-phosphorus, and nitrite-nitrogen were observed in summer, whereas those of nitrate-nitrogen, silica, and chlorophyll-a increased in spring. In comparison with other studies conducted in the region, the amounts of nutrients, except for silica, were found to be considerably lower. Nonetheless, the values of silica and phosphate-phosphorus exceeded the limits for clean seawater. There has been no similar study conducted in recent years due to increased aquaculture capacity in this bay.


Assuntos
Baías , Água , Aquicultura , Monitoramento Ambiental , Sedimentos Geológicos , Nitrogênio/análise , Oceanos e Mares , Fósforo/análise
15.
Mar Pollut Bull ; 157: 111282, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658665

RESUMO

Assessing the carrying capacity of ecosystems is crucial to the selection of suitable and sustainable locations for aquaculture farms. In Malpeque Bay (PEI, Canada), the potential expansion of mussel farms has driven a series of numerical modelling studies. We coupled sub-models for sea lettuce, wild and cultured oysters and wild softshell clams to an existing ecosystem model to better understand nutrient dynamics and the carrying capacity of Malpeque Bay. Simulations suggested that competition for nutrients between phytoplankton and sea lettuce and filtration by cultured bivalves predominantly mitigate eutrophication effects. The addition of sea lettuce reduced mussel growth by 2% on average and up to 9% near eutrophic estuaries favouring macroalgae growth. Projected new mussel farms reduced current mussel growth by 2% also, suggesting that the carrying capacity of the bay may not be reached yet. Both current and projected aquaculture activities seemed to have limited effects on natural bivalve growth.


Assuntos
Bivalves , Ecossistema , Animais , Aquicultura , Canadá , Eutrofização
16.
Mar Pollut Bull ; 157: 111303, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658671

RESUMO

We compared changes in the benthos associated with discharges from a salmon farm at a low-flow location in Pelorus Sound, Aotearoa-New Zealand to the Pearson and Rosenberg model (PRM). As predicted by PRM, benthic enrichment resulted in significant increases in abundance of small, opportunistic macrofauna beneath salmon farm cages. In contrast, at reference sites we found fewer but larger, rare species. When estimates for biomass were calculated from macrofaunal size-classes, reference sites averaged 4.86 times more biomass and 4.35 times greater diversity than farm sites - results also consistent with the PRM. Farm sites favoured deposit feeders at the expense of suspension feeders and grazers. We discuss the significance of large rare species that contributed most to reference biomass estimates that appear under threat from multiple anthropogenic stressors.


Assuntos
Aquicultura , Salmão , Animais , Biodiversidade , Biomassa , Ecossistema , Monitoramento Ambiental , Sedimentos Geológicos , Nova Zelândia
17.
Mar Pollut Bull ; 157: 111353, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658704

RESUMO

The physiological characteristics of Ulva prolifera and Blidingia sp. during two pre-bloom stages (March & May) were compared to evaluate the competitive advantage of U. prolifera on Pyropia aquaculture rafts in Subei Shoal. (1) Compared to Blidingia sp., U. prolifera had a lower growth rate, chlorophyll content, photosynthetic efficiency, and antioxidant capacity in March. (2) In May, various indicators of U. prolifera's physiological function improved significantly, while the antioxidant capacity of Blidingia sp. decreased significantly. Large lipidic globules in U. prolifera cells became scattered small lipidic globules in May, which indicated a decrease in lipid membrane peroxidation. (3) In U. prolifera, the ratio of buoyancy to gravity of per unit volume was 1.73, and the bubbles inside the thalli provided 60% of the total buoyancy. Buoyancy generated by the inflatable structure of U. prolifera allowed this species to float after being separated from the rafts.


Assuntos
Clorófitas , Ulva , Aquicultura , China , Eutrofização , Microdomínios da Membrana
18.
Rev Bras Parasitol Vet ; 29(3): e003720, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32667502

RESUMO

The aim of this study was to report on detection of Toxoplasma gondii DNA in oysters (Crassostrea sp.) in the state of Maranhão. To conduct this study, 200 farmed oysters were acquired in the municipality of Raposa and 100 in Paço do Lumiar; and a further 100 oysters were taken from the natural stock in the municipality of Primeira Cruz. This total of 400 specimens sampled was divided into 80 pools composed of five animals each. The gills and visceral mass of each oyster were removed for DNA extraction (per pool of oysters), using a commercial kit. The nested PCR technique (with the primer SAG-1) was then used to investigate any presence of protozoa. This molecular technique demonstrated the presence of DNA of T. gondii in 2.5% of the pools of oysters (n = 2/80): these oysters were exclusively from farms. The results from this study allow the conclusion that oysters of the genus Crassostrea that are farmed in the state of Maranhão are capable of filtering oocysts of T. gondii and maintaining them in their tissues. They are therefore potential sources of contamination for humans and other animals.


Assuntos
Crassostrea , Toxoplasma , Animais , Aquicultura , Brasil , Crassostrea/parasitologia , DNA de Protozoário/genética , Oocistos/isolamento & purificação , Reação em Cadeia da Polimerase , Toxoplasma/fisiologia
19.
Dis Aquat Organ ; 140: 25-29, 2020 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-32618285

RESUMO

Oxytetracycline (OTC) has been commonly used as an effective antibiotic against various fish bacterial diseases, including vibriosis. In this study, the absorption-enhancing effect of citric acid on oral OTC pharmacokinetics and treatment of artificial Vibrio anguillarum infection was evaluated in juvenile yellowtail Seriola quinqueradiata followed by serum OTC concentration analysis. When 25 mg kg-1 body weight (BW) OTC was administered in combination with 1250 mg kg-1 BW citric acid, the serum OTC concentration reached almost the same concentration as that of the group treated with 50 mg kg-1 BW OTC. This coadministration successfully suppressed mortality due to vibriosis similar to the group treated with 50 mg kg-1 BW OTC. Conversely, poor efficacy was observed when only 25 mg kg-1 BW OTC was administered. These results suggest that coadministration of citric acid can be beneficial in reducing the dose of OTC needed for effective treatment, and thus contributes to the goal of reduced use of this antibiotic in aquaculture.


Assuntos
Vibrioses/veterinária , Vibrio , Animais , Antibacterianos , Aquicultura , Ácido Cítrico , Peixes , Oxitetraciclina
20.
Environ Monit Assess ; 192(8): 493, 2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-32642861

RESUMO

Aquaculture is an important part of agricultural economy. In the past, major farming accidents often occurred due to subjective experience. There are many factors affecting the water quality of aquaculture. Maintaining an ecological environment with good water quality is the most critical link to ensure the production efficiency and quality of aquaculture. With the continuous development of science and technology, intelligence and informatization in aquaculture has become a new trend. Smart aquaculture cannot only realize real-time monitoring, prediction, warning, and risk control of the physical and chemical factors of the aquaculture environment but can also conduct real-time monitoring of the characteristics and behaviors of the fish, which infers the changes of the aquaculture ecological environment. In this paper, the research achievements over past two decades both are summarized from four aspects: water quality factor acquisition and pre-processing, water quality factor prediction, morphological characteristics, and behavioral characteristic recognition of fish and the mechanism between fish behavior and water quality factors. The advantages and disadvantages of existing research routes, algorithm models, and research methods in smart aquaculture are summarized. The work in this paper can provide a well-organized and summative knowledge reference for further study on the dynamic mechanism between the changes of water quality factors and the fish body characteristics and behavior. Meanwhile, the work can also provide valuable reference for promoting the smart, ecological, and efficient development of aquaculture.


Assuntos
Aquicultura , Monitoramento Ambiental , Agricultura , Animais , Peixes , Qualidade da Água
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