日本鳗鲡肌肉中风味氨基酸的多组学研究

鳗鱼是辐鳍鱼纲、鳗鲡目、鳗鲡科、鳗鲡属鱼的总称,又名河鳗、鳗鲡.全球约有鳗鱼20余种,比较常见的有欧洲鳗鲡(Anguilla anguil-la)、美洲鳗鲡(Anguilla rostrata)、日本鳗鲡(Anguilla japonica)、鲈鳗(Anguilla mormora-ta)和澳洲鳗鲡(Anguilla ...     

日本鳗鲡健康养殖技术

日本鳗鲡俗称鳗鱼、白鳝,是世界性的优质养殖鱼类,其营养价值和经济价值都相当高,素有“水中人参”之称,在分类学中属鳗鲡科（Anguillidae）、鳗鲡属（Anguilla）,自然界广泛分布于我国江河沿海,是中国长江及以南地区淡水养殖的主要名贵品种之一,以其肉质鲜美,营养丰富,深受人们的喜爱,素有“水中人参”之称。     

Hg2+对5种鳗鲡白仔急性毒性影响的研究

以日本鳗鲡（Anguilla japonica）、欧洲鳗鲡（A.anguilla）、印尼鳗鲡（A.bicolor pacifica）、菲律宾鳗鲡（A.mormorata）和美洲鳗鲡（A.rostrata）5种鳗鲡白仔为试验对象设计急性毒性试验,研究了汞离子（Hg2+）对5种鳗鲡白仔的致死作用和种间差异,试验时间为96 h。结果表明,Hg2+对5种鳗鲡白仔的24 h半致死质量浓度（24 h LC50）依次为日本鳗鲡（0.408 mgL-1）欧洲鳗鲡（0.179 mgL-1）美洲鳗鲡（0.111 mgL-1）菲律宾鳗鲡（0.052 mgL-1）印尼鳗鲡（0.018 mgL-1）。而48 h、72 h和96 h的半致死质量浓度依次为日本鳗鲡美洲鳗鲡欧洲鳗鲡菲律宾鳗鲡印尼鳗鲡。日本鳗鲡和美洲鳗鲡表现出较强的耐受性,养殖水体应严格限制Hg2+的输入。     

鳗鲡脂肪酸组成和胆固醇含量分析

对日本鳗鲡（Anguilla japonica）、欧洲鳗鲡（Anguilla anguilla）及其制品烤鳗进行胆固醇、脂肪含量和脂肪酸组成分析。结果表明，鳗鲡的胆固醇含量与其他鱼类接近，日本鳗鲡和欧洲鳗鲡及其烤鳗制品的胆固醇质量比分别为0.852、0.832mg/g和1.15、1.12mg/g。鳗鲡各食用部位中除腹部的胆固醇较高外，其他部位没有明显差异。鳗鲡的脂肪质量分数16％-24％，日本鳗鲡和欧洲鳗鲡高度不饱和脂肪酸质量分数分别为18.9％和19.0％，EPA DHA质量比分别为22.66mg/g和29.27mg/g。     

欧洲鳗鲡“狂游病”的血液学判别

利用聚类分析和判别分析方法，对患“狂游病”的和健康的欧洲鳗鲡（Anguilla anguilla)各30尾，53项血液指标，共3180个参数进行综合分析，建立了区别“狂游病”欧洲鳗鲡和健康鳗鲡的判别公式，并介绍了其血液学判别方法。     

Hg（2＋）对5种鳗鲡白仔急性毒性影响的研究

以日本鳗鲡（Anguilla japonica）、欧洲鳗鲡（A.anguilla）、印尼鳗鲡（A.bicolor pacifica）、菲律宾鳗鲡（A.m orm orata）和美洲鳗鲡（A.rostrata）5种鳗鲡白仔为试验对象设计急性毒性试验,研究了汞离子（Hg2＋）对5种鳗鲡白仔的致死作用和种间差异,试验时间为96 h。结果表明,Hg2＋对5种鳗鲡白仔的24 h半致死质量浓度（24h LC50）依次为日本鳗鲡（0.408 mg.L-1）〉欧洲鳗鲡（0.179 mg.L-1）〉美洲鳗鲡（0.111 mg.L-1）〉菲律宾鳗鲡（0.052 mg.L-1）〉印尼鳗鲡（0.018 mg.L-1）。而48 h、72 h和96 h的LC50依次为日本鳗鲡〉美洲鳗鲡〉欧洲鳗鲡〉菲律宾鳗鲡〉印尼鳗鲡。日本鳗鲡和美洲鳗鲡表现出较强的耐受性,养殖水体应严格限制Hg2＋的输入。     

鳗鲡常见疾病及其防治

鳗鲡作为我国特种养殖主要种类之一,包括日本鳗鲡（Anguilla japonica Temminck et Schlegel）、花鳗鲡（A．marmorata）、欧洲鳗鲡（A．anguilla）、美洲鳗鲡（A．rastrata）等,其中后两种为引进品种。目前苗种的来源主要靠汛期的捕捞,因其产卵孵化需要特殊的盐度压力条件,全世界还未能实现人工育苗。     

三唑磷对5种鳗鲡幼鳗的急性毒性实验

以5种鳗鲡的幼鳗为实验对象[日本鳗鲡（Anguilla japonica）、欧洲鳗鲡（A．anguilla）、印尼鳗鲡（A．bicolor Pacifica）、菲律宾鳗鲡（A．mormorata）和美洲鳗鲡（A．rostrata）],选择常见的环境污染物有机磷农药三唑磷开展了急性毒性研究。5种鳗鲡对三唑磷的毒性反应类似,但致死浓度区间有差异。三唑磷的的毒性大小顺序为欧洲鳗鲡〉菲律宾鳗鲡〉日本鳗鲡〉美洲鳗鲡〉印尼鳗鲡,其安全浓度分别为1．22×10^-4、4．12×10^-4、6．16×10^-4、2．24×10^-3、7．53×10^-3mg·L^-1,美洲鳗鲡和印尼鳗鲡对三唑磷的耐受能力显著强于其他3种鳗鲡。5种鳗鲡对三唑磷均表现出显著的时间效应和计量效应,呈显著正相关。三唑磷对于5种幼鳗的毒性评价均为剧毒。     

5种鳗鲡幼鳗极限温度的耐受性初步研究

以日本鳗鲡（Anguilla japonica）、欧洲鳗鲡（A.anguilla）、美洲鳗鲡（A.rostrata）、印尼鳗鲡（A.bicolor pacifica）和菲律宾鳗鲡（A.mormorata）5种鳗鲡的幼鳗为试验对象,探讨其对极限高、低温的耐受性及种间差异。以自然水温为试验起始温度（日本鳗鲡、欧洲鳗鲡、印尼鳗鲡为27℃;美洲鳗鲡、菲律宾鳗鲡为24℃）,高温试验过程中每4h升1℃,低温试验每4h降1℃,直至全部受试个体死亡。试验结果表明,不同种的幼鳗对环境温度的耐受范围具有种间差异。日本鳗鲡、美洲鳗鲡、欧洲鳗鲡、印尼鳗鲡和菲律宾鳗鲡高温＂死亡高峰温度＂分别为39、38、37.5、39和38℃,日本鳗鲡对高温的耐受性最强,欧洲鳗鲡最弱,但种间差异不显著;日本鳗鲡、美洲鳗鲡对低温的耐受性最强,能在冰和水混合液中生存,欧洲鳗鲡、菲律宾鳗鲡和印尼鳗鲡对低温耐受性依次减弱,低温＂死亡高峰温度＂分别为2、5和10℃。     

养殖鳗鲡鳃的寄生虫——细体似指环虫寄生数的季节变化

1969年以后，由於日本鳗鲡(Anguilla iaponica)的种苗不足，输入了欧洲鳗鲡的种苗之后，马上就得到了养殖业的使用，因在各地养殖场发生了似指环虫(Pseudodactylogyrus)的鱼病，尤其是欧洲鳗鲡亦免不了遭到生命的危害。似指环虫原来就已经寄生在我国的鳗鲡(日本鳗鲡)的体上，     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Influence of the antibacterial herbs, Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia on the survival, growth and bacterial load of Penaeus monodon post larvae

The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 10³ to 3.76 × 10⁵ cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 10⁵ cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.