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1.
Before transfer to larval incubators, water was membrane filtered to remove >95% of the bacteria and then transiently maintained in a biofilter that promoted recolonization of the water by non-opportunistic bacteria. The process is termed microbial maturation of the water. Hypothetically the bacterial flora in the matured water should protect the marine larvae from colonization and proliferation by opportunistic bacteria. Testing of the hypothesis demonstrated 76% higher survival of yolk sac larvae of Atlantic halibut (Hippoglossus hippoglossus) in matured than in membrane filtered water. Proliferation of opportunistic bacteria was observed in the rearing water after hatching of turbot eggs (Scophthalmus maximus), but to a less extent in the microbially matured water. In the early phase of first feeding of turbot larvae, the matured water induced qualitative differences in the gut microflora. Significantly higher initial growth rate of the turbot larvae in the matured water affected 51% higher average weight of 13 days old larvae than in membrane filtered water. Algal addition to the matured water enhanced the larval growth further. The experiments conducted supported the proposed hypothesis that microbial maturation selects for non-opportunistic bacteria, which protects the marine larvae from proliferation of detrimental opportunistic bacteria.  相似文献   

2.
采用基于Illumina测序平台的高通量测序技术,对大菱鲆(Scophthalmus maximus)幼鱼肠道及其养殖水体、生物饵料中细菌种类及丰度进行研究。测序结果显示,养殖水体、生物饵料和大菱鲆幼鱼肠道等19个样品共获得有效序列547621条,可聚类于3771个可分类操作单元(OTUs),归属于养殖水体、生物饵料、健康幼鱼和发病幼鱼的操作分类单元(OTU)个数分别为3038、1090、87和777,其中,健康幼鱼与生物饵料、健康幼鱼与养殖水体特有的OTU个数分别为57和0,发病幼鱼与生物饵料、发病幼鱼与养殖水体特有的OTU个数分别为481和31。表明幼鱼肠道微生物多样性与生物饵料密切相关。根据细菌注释结果,拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)和变形菌门(Proteobacteria)在大菱鲆幼鱼肠道中占优势地位,其中,健康幼鱼肠道微生物共聚类为8个门,发病幼鱼的肠道微生物可聚类为19个门。与健康幼鱼相比,发病幼鱼肠道门水平上的3种主要优势菌群落结构出现失衡。此外,对各样品中丰度最高的100位OTU分析显示,幼鱼肠道优势菌种类与生物饵料中的优势菌种类密切相关,而每个发病幼鱼肠道优势菌种类具有一定的独立性。本研究旨在为大菱鲆健康养殖和微生态调控提供实验依据。  相似文献   

3.
Abstract. The adherent aerobic bacterial flora present in the gastrointestinal tract and faeces of free-living Arctic charr, Salvelinus alpinus (L.), from Lake Takvatn, Northern Norway, were identified both qualitatively and quantitatively. Approximately 105 bacteria g−1 were found in both the small and large intestines. The predominant bacterial species were identified as Aeromonas , Enterobacteriaceae, Micrococcus and Lactobacillus. Other microorganisms isolated included Acinetobacter, Cytophaga, Flavobacterium, Moraxella, Pseudomonas, Vibrio , Coryneforms and Streptococcus. The intestinal microflora of free-living fish was dominated by Aeromonas and Lactobacillus , but the intestinal bacterial flora of wild fish transferred to hatchery was affected by feeding them either a capelin roe diet or a commercial feed in fresh and sea water. Approximately 55% of the bacterial flora in intestinal contents from fish fed the capelin roe diet was Enterobacteriaceae when the fish were held in fresh and sea water. However, when the wild-caught charr were fed a commercial diet in fresh water, Aeromonas and Pseudomonas dominated in faeces, while Vibrio and Pseudomonas were predominant in the diet group held in sea water.  相似文献   

4.
大菱鲆仔稚鱼发育早期肠道菌群结构形成的影响因素   总被引：1，自引：0，他引：1  
为研究鱼类发育早期肠道菌群结构的演变过程及影响因素,运用高通量测序技术,分析了处于不同发育阶段的大菱鲆(Scophthalmus maximus)仔稚鱼肠道、受精卵、不同类型的饵料和水源中的菌群结构,以及它们之间的相关性。结果显示,以不同的OTU(Operational Taxonomic Units,可操作分类单元)作为分类依据,发现大菱鲆仔稚鱼的肠道菌群结构在开口摄食后不久已趋于稳定,其优势菌与受精卵所携带的细菌关联较大。并且在大菱鲆仔稚鱼不同的发育时期,这一菌群的结构非常稳固,几乎不受水和饵料中优势细菌的影响而发生改变。乳球菌属的Lactococcus piscium菌株一直是大菱鲆仔稚鱼肠道中的优势菌种,在不同发育时期的优势度高达45%~65%。本研究还发现,大菱鲆仔稚鱼肠道可能对定植的菌种具有选择性,一些水环境和饵料中的非优势菌,如Streptococcus sp.,Pseudomonas sp.,Carnobacterium sp.等细菌也会定植于肠道,成为大菱鲆肠道中的次优势菌。  相似文献   

5.
The initial counts of bacteria associated with farmed giant freshwater prawn (Macrobrachium rosenbergii de Man) as well as with the water and sediment from two farms located at Kottayam district in Kerala (India) were determined. A total of 367 randomly selected isolates were characterized and identified. Prawn samples yielded mean microbiological counts of 4.92 log CFU g?1 of shell with muscle and 7.78 log CFU g?1 of intestine at 30°C. Bacterial numbers in the intestine of prawn were much higher than those in the pond water. Motile and non‐motile aerobic Gram‐negative bacteria together with Enterobacteriaceae accounted for 60–70% of the mesophiles isolated from water and prawn. However, the microorganisms isolated in significant numbers from shell with muscle and intestine of prawn were not recovered from the growing waters. Among Gram‐positive bacteria, Micrococcus, Bacillus, coryneforms, and Arthrobacter were found. Faecal coliforms and enterococci were found in significant numbers in M. rosenbergii. The rearing practices such as feeding and pond fertilization could have influenced the microflora in prawn. The commensal microflora of freshwater prawn included opportunistic pathogens such as Aeromonas spp. and Streptococcus spp. Storage of prawn at elevated temperatures can permit their survival and growth leading to quality loss. Care should be exercised during handling and processing to prevent contamination of edible meat.  相似文献   

6.
As is the case at other sites in the body (e.g. the gut, skin and mouth), the ocular microbiota plays a crucial role in their host, as disturbances of the composition and function of the ocular microbiota are known to be associated with ocular disorders. Exophthalmic disease (ED) is a significant cause of high mortality in fish species, including farmed turbot (Scophthalmus maximus). However, the relationship between alterations in the ocular microbiota and ED in turbot is unclear. In this work, we collected turbot samples from farmed ponds with ED and healthy samples to understand changes in the ocular microbiota of turbot suffering from ED. We compared the structural and metabolic differences of ocular bacterial communities from farmed turbot with exophthalmic disease and those of healthy controls. Besides less microbial diversity found in turbot with ED regarding the control group, we also found that Aeromonas was the dominant bacteria both in controls and ED samples, but the abundance of Aeromonas was significantly greater in ED individuals. Moreover, the results of correlation test further suggest that Aeromonas overgrowth was correlated with the progress of the disease and shifts in ocular microbiota functional pathways in turbot. These findings emphasize that an increased abundance of Aeromonas serves as an ocular bacterial signature associated with ED in turbot, which provide basic information useful for diagnoses, prevention and treatment of ocular diseases occurring in cultured fish.  相似文献   

7.
In this study, the effects of natural and artificial colorants on the shelf life of hot smoked garfish were investigated in terms of its chemical, microbiological, and sensory quality. Turmeric and Sunset Yellow FCF were used as the natural and artificial colorants, respectively. The amount of total volatile basic nitrogen (TVB-N) and thiobarbituric acid (TBA), counts of total mesophilic aerobic bacteria, total psychrophilic aerobic bacteria, total yeast and molds increased during the storage (p < 0.05). The results showed that turmeric and Sunset Yellow FCF had a significant effect on pH value and salt content of hot smoked garfish samples during storage (p < 0.05). According to the sensory analysis results, the shelf life of hot smoked garfish stored at 4 ± 1ºC was determined as 17 days.  相似文献   

8.
ABSTRACT

This study monitored the physical, chemical, and sensory quality of raw Pacific white shrimp (Litopenaeus vannamei) and the evolution of microbial flora under modified atmosphere packaging (MAP) with varying concentrations of CO2 (95% CO2/5% O2; 80% CO2/15% N2/5% O2; 65% CO2/30% N2/5% O2) at 4°C during 10-day storage. Plate counts on selective agars indicated that MAP had a strong inhibitory effect on psychrotrophic bacteria, mesophilic bacteria, Enterobacteriaceae, and H2S-producing bacteria. Analyses with molecular techniques (denaturing gradient gel electrophoresis, DGGE) by extracting bacterial DNA from shrimp samples showed that Vibrio spp. and Aeromonas spp. were predominant in fresh MAP samples. Shewanella putrefaciens, which dominated in samples stored in air, were found sporadically in MAP samples. Interestingly, lactic acid bacteria were not predominant in MAP samples, whose pH values were high (6.66 to 8.14) during storage. The content of total volatile basic nitrogen in MAP samples was about 10 mg N/g lower than the control at the end of storage. Higher lightness values and sensory scores were also observed in samples under MAP. However, MAP with CO2 concentrations higher than 80% did not enhance the inhibitory effect on bacterial growth but induced more severe reddening and sensory quality loss.  相似文献   

9.
Several strains of Garm-positive short rod (coccibacilli)-shaped bacteria were isolated from diseased cultured turbot, Scophthalmus maximus (L.), in the North of Spain with lesions and signs of Spain with lesions and signs of streptocecosis. The α-haemolytic streptoceoccus-like organisms from diseased turbot were identified by physiological, biochemical and 16S rRNA gene sequence analysis as Streptococcus parauberis. This is the first report of S. parauberis associated with fish disease.  相似文献   

10.
The effect of spraying microbial transglutaminase (MTGase) at various levels (1, 4, 7, and 10 units/gram) on the quality of mackerel (Scomber scombrus) fillets was investigated during refrigerated storage. The results of pH and the total volatile base nitrogen (TVB-N) revealed that 7 µ/g MTGase treatment met the best results regarding fish quality. The oxidation was hindered by increasing MTGase concentration, and the lowest totox value was recorded in the fillets treated with 10 µ MTGase. The progress in the total free amino acids was suppressed with the addition of MTGase, and the most effective concentration was found to be 7 µ/g MTGase treatment. Moreover, this concentration was the most promising in inhibition of the total mesophilic aerobic bacteria, the total psychrophilic aerobic bacteria, coliform, and yeast-mold. Panelists preferred the samples treated with 7 µ/g MTGase in terms of odor, texture, and appearance. The addition of MTGase straightened the fish muscle and helped preserve its initial texture. It is important to use the proper concentration of MTGase instead of high concentrations.  相似文献   

11.
Bacteria were cultured from a chronic skin ulceration on a shark, Carcharhinus plumbeus (Nardo), kept in the Genoa Aquarium, Italy. Sixteen out of 18 isolated strains belonged to Vibrio spp. Identification through fatty acid composition analysis and biochemical tests showed that V. carchariae, the most recently described Vibrio species, were the predominant bacteria isolated from the ulcer.  相似文献   

12.
Two bacterial strains, 4:44 and PB52, isolated from turbot(Scophthalmus maximus L.) were used during a first feedingexperiment with turbot larvae. Bacteria were either added directly tothe water on the day of hatching of the larvae (day 0), orbioencapsulated in rotifers (Brachionus plicatilis) distributedon day 2 after hatching. The two bacterial strains were found to bepresent in the water of the rearing tanks throughout the experiment. Theaddition of bacteria influenced the species-composition of themicroflora associated with intensively produced rotifers added to thetanks, and resulted in colonization of the gut of the larvae by theadded bacterial strains. The strain 4:44 showed a peak on day 9 afterhatching, and reached a mean(sem) of 2.5(1.4) × 104bacteria per larva, when added in a mixture with PB52, and 0.4(0.1)× 104 bacteria per larva, when added alone. The strainPB52, on day 12 after hatching, reached 5.2(1.5) × 104bacteria per larva when added in a mixture with strain 4:44, and12.5(0.7) × 104 bacteria per larva, when added alone.The added bacteria colonized the gut turbot larvae, whereas thebacterial land, the survival and growth of the larvae were in most casesnot influenced in a negative way by the addition of bacteria.  相似文献   

13.
Between 2007 and 2012, a variety of disease outbreaks most often characterized by skin disorders were observed among different species of freshwater fish in Poland. In most cases, the clinical signs included focally necrotized gills, necrotic skin lesions or ulcers. Internally, haemorrhages, oedematous kidney and abnormal spleen enlargement were generally noted. The disorders were accompanied by increased mortality. Most of the problems concerned cultured common carp Cyprinus carpio L. and rainbow trout Oncorhynchus mykiss (Walbaum). Fish have been examined from a number of these farms, and additionally, the wild and ornamental fish with similar clinical signs of diseases were also tested. Bacteria were isolated consistently from lesions and internal organs. They had characteristic orange-pigmented colonies which grew in pure culture or constituted 55–95% of total bacterial flora. One hundred and eighteen isolates were collected and biochemically identified as Shewanella putrefaciens group, and this was confirmed by sequencing. Challenge tests confirmed the pathogenicity of these bacteria. This is the first report characterizing and describing S. putrefaciens as a pathogen of different species of freshwater fish in Europe.  相似文献   

14.
采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)和荧光定量-聚合酶链式反应(Q-PCR)技术分析高体重(high weight,HW)和低体重(low weight,LW)斑点叉尾(鮰)(Ietalurus punetaus)皮肤、鳃和胃肠道菌群多样性,为斑点叉尾(鮰)微生态研究及筛选斑点叉尾(鮰)源益生菌提供理论依据.结果显示,斑点叉尾(鮰)菌群丰富度由低到高依次为鳃、皮肤、前肠、后肠和胃.肠杆菌科(Enterobacteriaceae)和气单胞菌属(Aeromonas)是皮肤的优势菌群;肠杆菌科(Enterobacteriaceae)、气单胞菌属(Aeromonas)和肠球菌属(Enterococeus)是水体、鳃和胃的优势菌群;肠杆菌科(Enterobacteriaceae)、拟杆菌属(Bacteroidetes)、气单胞菌属Aeromonas)和酵母菌属(Saccharomyces)是肠道的优势菌群.HW斑点叉尾(鮰)鳃菌群的香农多样性指数、均匀度和丰富度及前肠菌群的丰富度显著高于LW斑点叉尾(鮰)(P＜0.05).皮肤的黄杆菌属(Flavobacterium),胃的肠杆菌科(Enterobacteriaceae),前肠的拟杆菌属(Bacteroidetes)和双歧杆菌属(Bfidobacterium及后肠的拟杆菌属(Bacteroidetes)、双歧杆菌属(Bifidobacterium)和酵母菌属(Saccharo-myces)的拷贝数分别是101 97、107.69、106.19、103.83、106.13、103.92和104 26,均显著高于LW斑点叉尾(鮰)(P＜0.05).结果表明,斑点叉尾(鮰)皮肤、鳃、胃肠道均形成独特的菌群结构,LW和HW斑点叉尾(鮰)菌群结构存在明显差异,HW斑点叉尾(鮰)菌群多样性增加.  相似文献   

15.
两种疾病发生对养殖半滑舌鳎肠道菌群结构的影响分析   总被引：5，自引：5，他引：0  
为研究疾病发生情况下鱼类肠道菌群的结构变化,运用高通量测序方法分别对感染腹水病和皮肤溃疡病的工厂化养殖半滑舌鳎病鱼及同一养殖系统中健康鱼的肠道菌群结构进行了对比分析。结果发现,养殖半滑舌鳎肠道中的细菌种类要明显少于环境中的细菌种类,仅为养殖池进水和颗粒饲料中细菌种类总数的14.3%~44.7%。在疾病发生后,病鱼肠道中的细菌种类数量仅是同一养殖系统中健康鱼肠道细菌种类数量的45.8%和64.5%,病鱼肠道中细菌多样性下降非常明显。进一步分析肠道菌群结构的组成发现,虽然发病鱼和健康鱼肠道中超过60%的细菌种类不相同,但优势菌群的结构组成差异不明显,丰度最高的前10种细菌种类基本相同,其比例超过肠道相对总菌量的80%。不同疾病的发生对半滑舌鳎肠道菌群结构的影响也不同,腹水病会造成肠道中优势菌株的种类和相对丰度都发生比较明显的改变,而皮肤溃疡病发生前后肠道菌群结构组成几乎没有变化。研究表明,养殖半滑舌鳎的肠道菌群结构相对比较保守,而且并不是所有的疾病种类都会引起肠道菌群结构发生改变。  相似文献   

16.
In this study, the effect of edible coarse/nanoemulsions of alginate as coating containing Zataria multiflora Boiss essential oil (ZEO) on the microbial quality of fish fillets was investigated at three concentrations (i.e. 0.25%, 0.5% and 1% [w/v]) in 16 days of storage at 4°C. Moreover, a comparison was made between the fabricated coarse emulsion and nanoemulsion coatings by particle size and polydispersity index analyses. Sample analysis was performed with regard to total viable count (TVC), total psychrophilic count (TPC), hydrogen sulphide‐producing bacteria count (HSC) and Enterobacteriaceae count (ENC) on days 0, 4, 8, 12 and 16. According to the findings, all the samples showed increased microbial counts during the storage periods. The highest reduction rates of TVC (about 2 log CFU/g), TPC (about 1 log CFU/g), HSC (about 1.5 log CFU/g) and ENC (about 3 log CFU/g) were observed in the nanoemulsion of alginate containing 1% w/v ZEO (NE 1%) samples, compared with alginate and control samples. The microbial growth was significantly inhibited in all treatments, compared with that in the control (p < .05). Accordingly, it can be concluded that nanoemulsion coating was more effective than coarse emulsion to prolong the durability of fish fillets and revealed a faster and greater inhibition of microbial flora, compared with coarse emulsions during the storage time.  相似文献   

17.
The microbial diversity of culturable intestinal microflora of wild freshwater salmonid fishes salmon Salmo salar and sea trout Salmo trutta trutta juveniles (0+ years old) from the same environmental conditions were investigated by means of molecular identification techniques and analysis of diet. Significant differences in the intestinal microbial diversity were observed in different fish species. The predominant group in the intestinal tract of the salmon comprised representatives of the Enterobacteriaceae family (23%), Plesiomonas (19.2%) and Carnobacterium (15.3%). Predominant microbiota in sea trout intestinal tract were Enterobacteriaceae (52%), Aeromonas (22%) and Pseudomonas (14%). The results show that Enterobacteriaceae were predominant in the intestinal tract of the salmon and the sea trout juveniles raised on diets of different compositions. However, molecular identification of the intestinal microbiota at the species or genus level revealed differences in these fish species. Bacteria in the hindgut of salmon included Pragia and Serratia. However, bacteria in the gut contents of sea trout from the Enterobacteriaceae family were Buttiauxella, Enterobacter, Moellerella, Pantoea, Rahnella and Tiedjeia arctica. A novel phylotype of T. arctica is harbored in the intestinal tract of wild salmon, and may correspond to a previously undescribed species.  相似文献   

18.
The microenvironment of bacteria associated with the gastrointestinal tract of an animal influences the host in many ways, including the metabolism of several nutrients. Isolation, molecular characterization and enzymatic activities of culturable bacteria associated with the gastrointestinal tract of hatchery‐reared oceanic yellow seahorse, Hippocampus kuda, were investigated in the present study. 16S rRNA sequencing of bacterial isolates yielded 10 different bacterial genera belonging to two major groups: proteobacteria (62.9%) and firmicutes (37.03%). The predominant microbial flora belonged to the genera Vibrio spp., Enterovibrio sp. and Bacillus spp. Burkholderia cenocepacia, hitherto unreported from the gastrointestinal tract of marine fish, was retrieved from the seahorse gut, albeit in small numbers. Enzymatic studies indicated that the bacterial isolates possess the ability to degrade lipids, cellulose, xylan, starch and proteins. Lipase activity was exhibited by a majority of the isolates (70.4%), indicating that the bacterial flora associated with the intestinal tract of seahorses is capable of digesting foods rich in lipids. The possible implications for the role of these bacteria in the digestion and physiological processes are discussed. To our knowledge, this is the first time that the characterization and enzymatic activities of bacteria associated with the intestinal tract of farmed seahorses have been reported.  相似文献   

19.
Intestinal bacteria in marine fish may produce antimicrobial substances which inhibit pathogenic bacteria. The aim of this study was to determine the influence of a change of fish diet on the antimicrobial activity of the culturable aerobic gut microflora of Senegalese sole, Solea senegalensis. Pre‐adult 15‐month‐old fish previously fed on an artificial diet, were fed polychaetes (Hediste diversicolor), which form part of the natural diet of Senegalese sole. Samples were taken0, 3 and 6 weeks after start of the experiment from the stomach, small and large intestine of the fish. The bacterial strains isolated from these samples were sub‐cultured to pure cultures and stored at ?80°C. Several biochemical tests were run to obtain some basic phenotypic characteristics of the isolated strains. Amplification and sequencing of 16S rDNA fragments were used to identify the majority of the bacterial strains isolated. The identification by use of this molecular approach gave results in agreement to the phenotypic characterization. Feeding with polychaetes significantly increased (P<0.05) the numbers of presumptive Vibrio isolates in the gut. The number of bacterial strains with antimicrobial activity, as determined by two in vitro approaches, was significantly (P<0.05) increased by feeding with polychaetes.  相似文献   

20.
研究结果表明:随着养殖的结束,池塘水体和底泥中总异养菌数和反硝化细菌、氨化细菌、硫酸还原菌等特殊生理类群的数量均显著降低。从梭子蟹养殖环境及生物体内分离到115株细菌,经鉴定可归于9个属与肠杆菌科的部分属。通过监控养殖环境中异养细菌和弧菌的数量波动,可以预警梭子蟹病害的发生,及时采取有效的应急防治措施。  相似文献   

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