牙鲆室内人工养殖试验

报道了室内养殖牙鲆的试验结果,１９９２年－１９９５年进行的小规模试验。将受精卵培育至鱼苗、成鱼直至成熟亲鱼。在水温为２－２５℃范围内,经过３６个月将全长为５．３ｃｍ鱼苗培育至全长为４６．８ｃｍ、体重为１７８０ｇ的商品鱼,成活率为５０．６％。１９９７年－１９９８年进行的生产性养殖试验,在水温为１０－３３℃范围内。经过１０个月将全长为５．４ｃｍ鱼苗养至全长为３３．４ｃｍ、体篝为３５６ｇ的商品鱼、成活率     

生态因子对条斑紫菜自由丝状体生长的影响

报道了生态因子对条斑紫菜自由丝状体生长的影响,结果表明,条斑紫菜自由丝状体生长的最适宜盐度范围为２０￣３０,低于１０的盐度不能生长,最适宜温度范围为１５℃￣２５℃,高限为３０℃,适宜光辐射照度１５μＥｍ％－２Ｓ＾－１￣６０μＥｍ＾２Ｓ＾－１,添加的适宜Ｎ浓度２０ｇ／ｍ＾３￣６０ｇ／ｍ＾３,Ｐ为１．５ｇ／ｍ＾３￣５ｇ／ｍ＾３。     

中草药防治河蟹溲苗病害的研究

用中草药防治溲苗病害的试验,育苗水用ＣｕＳＯ４处理,用黄芩和五倍子配合使用,可保证后期天然海水育苗的顺利进行,黄岑浓度为１．５－２ｇ／ｍ＾３,五倍子浓度为１．－１５ｇ／ｍ＾３。     

中华鳖皮肤溃烂病的病原研究

从病鳖肝脏,颈,腿部皮肤溃烂处分离得到菌株ｍ－３,ｍ－６,Ｊ－８,Ｊ－１０株细菌,经人工感染试验证明这四株菌为鳖皮肤溃烂病的病原菌,对菌体形特征,培养特性和生理化反应的鉴定证明了Ｊ－８,Ｊ－１０,为温和气单胞菌（Ａｅｒｏｍｏｎａｓｓｏｂｉｒａ）Ｍ－３,Ｍ－６Ｏ为摩根氏菌（Ｍｏｒｇａｎｅｌｌａｍｏｒｇａｎｉｉ）。     

一例欧洲鳗小瓜虫病的诊断与治疗

安化县马路鳗鱼场，养殖鳗池２０个，养殖面积３１６０ｍ~２（其中大池１０个２４００ｍ~２，小池１０个７６０ｍ~２）。１９９８年３月１４日，鳗鱼因病死亡严重，病情来势十分凶猛。１８~＃池当日死鳗８ｋｇ，１６５尾，全池约有２５％的个体被感染。２０~＃池死３ｋｇ，１４５尾，约有１５％的个体被感染。针对病鳗所表现出来的一系列症状，诊断为鳗鱼小瓜虫病，并立即采取措施积极治疗，取得了满意的效果。１发病原因鳗场在日常管理中是每星期用０．４ｇ／ｍ~３鱼用强氯精和０．０６ｇ／ｍ~３的灭虫精进行细菌性鱼病和寄生虫病的防治，…     

甲基睾酮对珍珠玛丽鱼及红剑尾鱼性逆转及体色影响的初步研究

将５月龄的珍珠玛丽鱼、３月龄的红剑尾鱼各１００尾,分别平均分成二组,即各设一对照组和一处理组。在处理组的基础饲料中添加１０μｇ／ｇｍ的甲基睾酮,饲养５０多天,期间观察各组试验鱼的性逆转现象,并对其体表及肌肉中所沉积的β－胡萝卜素进行比较研究。结果表明：饲料添加１０μｇ／ｇｍ的甲基睾酮不能使５月龄的珍珠玛丽鱼性逆转,体色也无明显变化;但能使３月龄的红剑尾鱼全雄化,且其群体的体色得到加深。     

水库网箱养殖彭泽鲫试验

经过１６个月（含自然越冬期）的网箱养殖，成功地把４．５万尾体长２．５ｃｍ，尾重０．７ｇ的彭泽鲫乌仔，养成平均尾重３４６－４０５ｇ，的商品鱼，成活率为８７％，鱼产量１４９２０ｋｇ，产值２２３８００元，利润８６７７８元，每ｋｇ鱼盈利５．８２元，４ｍ＾３小网箱平均养成单产为１８６．５ｋｇ／ｍ＾３。     

嗜水气单胞菌对4种中草药和4种抗生素耐药性的比较研究

ＳＨ－９２－０２和Ｃ－９５０５０１两菌株对大黄,穿心莲,诃子,连翘、呋喃唑 酮,氟哌酸,氯霉素和土霉素的ＭＩＣ分别为１６ｍｇ／ｍＬ、２５０ｍｇ／ｍＬ、０．１２ｍｇ／ｍＬ、３．９ｍｇ／ｍＬ、０．１２μｇ／ｍＬ、０．０３４μｇ／ｍＬ、０．３１μｇ／ｍＬ、０．９７μｇ／ｍＬ和３０、５００、０．１２、３．９、０．９７、０．１２、０．９７、１．９５ｍｇ／ｍＬ。１０次药物肖工递增继代培养,共试菌株ＳＨ－９２－     

美国青蛙养殖技术研究

研究了美国青蛙的形态,生态、人工催产,孵化,幼蛙培育,成蛙养殖,配饵驯食及腐皮病,红腿病,气泡病的防治技术,结果：孵化密度４０００－８０００粒／ｍ＾２,４８ｈ出苗。幼蛙培育适宜密度为８０－１００只／ｍ＾２,幼蛙体重１５ｇ左右时,以活饵带动法或直接驯食法分３个阶段进行驯食。成蛙养殖密度以２０－３０只／ｍ＾２为宜。５２ｍ＾２土池放养幼蛙１４０４只,经１２３天养殖,成蛙平均体重２５２ｇ,每平方米蛙６．３     

养殖牙鲆弧菌病病原菌初步研究

1998年 7月自荣成市寻山水产集团总公司养鱼场养殖牙鲆病死鱼体内分离到 1株细菌 ,经人工感染试验证明是牙鲆弧菌病病原菌。该菌主要特征为 :革兰氏阴性 ,弧状 ,以极生单鞭毛运动。氧化酶阳性 ,发酵葡萄糖产酸不产气 ,不产生 H2 S,不产生色素。生长温度范围 10～ 4 2℃ ,p H范围 6～10 ,盐度范围 0 .5～ 6。经 Biolog Microstation System鉴定为河川弧菌 - 。该菌株对环丙沙星、氟哌酸、利福平、呋喃唑酮、呋喃妥因、红霉素、链霉素等药物敏感。     

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).     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

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.     

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.