水泥池精养金鱼技术

我市观赏渔业起步于上世纪70年代初,大都是一些金鱼爱好者利用鱼盆、鱼缸或家前屋后零星场地开展的金鱼养殖。到90年代,开始出现小规模的露天水泥池养殖。从2000年起我们建立了观赏鱼养殖示范园,使观赏鱼养殖规模逐年扩大。现将观赏金鱼水泥池精养技术介绍如下:一、放养前的准备1.水泥池的结构鱼池采用保水节水的砖混水泥抹面结构,按用途分为蓄水池和养殖池。蓄水池与养殖池的面积比为1:12。蓄水池的规格为10米×10米×1.5米,养殖池为5米×5米×0.5米,底面向排水口稍微倾斜,进排水管用无毒聚乙烯塑料管,规格为直径150毫米,两排池为一单元,在…     

3种药物对黄鳝源胃瘤线虫幼虫的体外杀灭效果

为筛选杀灭胃瘤线虫幼虫的有效药物,应用伊维菌素、阿维菌素和氰戊菊酯药物进行黄鳝源胃瘤线虫幼虫体外杀灭试验。结果显示:浓度2.5×10-3 mg/L伊维菌素,1.5×10-3mg/L阿维菌素,0.42 mg/L氰戊菊酯的体外杀灭胃瘤线虫幼虫的最短时间分别为20 h,(156±16.97)h和(108±16.67)h。2.5×10-3 mg/L伊维菌素可体外杀灭黄鳝胃瘤线虫幼虫。     

养殖水体与贝类体内大肠杆菌(Colibacillus)含量的关系研究

通过观察贝类在海水中对大肠杆菌的富集情况分析养殖水体与贝类中大肠杆菌含量的关系,发现海水中的大肠杆菌含量在<1.4×101个/100ml的条件下贝类体内富集的大肠杆菌<3.0×102个/100g,符合欧盟和美国一类养殖水域要求,可直接上市;海水中的大肠杆菌含量在1.4×101～7.0×101/100m1之间的条件下贝类体内富集的大肠杆菌为4.2×103个/100g,符合欧盟二类养殖水域要求。     

氰戊菊酯对鲤科鱼类致突变效应的研究

通过统计草鱼(C tenopharyngodon idellus)外周血红细胞的微核率和斑马鱼(Brachydanio rerio)胚胎致畸率,研究了氰戊菊酯对鱼类的致突变效应。结果显示:氰戊菊酯对1龄草鱼的96 h半致死浓度(LC50)为60.62μg/L;1.2μg/L以上的氰戊菊酯能显著提高草鱼的微核率、核异常率以及总核异常率,三者的变化趋势均是随着暴露时间的延长先升高,达到峰值后再缓慢下降;微核率与空白对照组比较呈显著性差异。表明氰戊菊酯对草鱼染色体畸变有明显影响。在2～32μg/L的氰戊菊酯中,随着浓度的升高,斑马鱼的胚胎死亡率升高、出膜率降低、80%胚胎出膜时间延长,仔鱼畸形率升高,说明氰戊菊酯对斑马鱼胚胎及仔鱼有致畸作用。     

提高出口金鱼经营效益的建议

近年来 ,我国的金鱼出口数量逐步上升 ,但遗憾的是 ,到目前为止国内经销商、行业协会、研究会等均没有制订出一套较完整的金鱼出口质量标准。上世纪 90年代初 ,江苏无锡的许祺源先生曾在首届无锡中国金鱼展评会上提出了《金鱼评比标准》的意见 ,这一建议对规范养殖生产 ,提高产品质量很有现实意义。根据境外客户对中国出口金鱼的反映和评价 ,笔者试述提高出口金鱼经营效益的若干建议 ,与同行们交流商讨。一、出口金鱼的规格目前国际市场上对出口金鱼的规格要求 ,大体上从体长 6～ 1 4ｃｍ比较受欢迎。有些国家和地区也进口体长 5ｃｍ的金鱼 …     

草金鱼黏孢子虫病诊治一例

<正>一、发病情况济宁曲阜市观赏鱼养殖户王先生多年来一直从事草金鱼养殖,共有5口池塘,其中发病塘为3号塘,面积30亩,平均水深4.5米,主要进行草金鱼网箱精养和大水面粗养两种模式。塘内共投放网箱20只,网箱规格2米×2米×1.5米,每只网箱放草金2000尾,同时箱外大水体粗放草金鱼1.6万尾和鲢鳙鱼500尾。据王某回忆,2018年9月3日就发现部分草金鱼出现鼓包囊肿症状,并且网箱内比网箱外发病重,但症状较轻、发病率也低,每天有几尾死亡,没引起太大重视。2019年2月中下旬,3号塘有部分草金鱼出现体表皮肤出现瘤状囊肿形成鼓包的现象,症状加重,发病率和死亡率也大幅增加。发现这种情     

提高金鱼养殖效益的关键环节

1 瞄准市场需求,强化质量意识,制定合理的生产计划 市场瞬息万变,不同时期、不同层次的消费群体,对金鱼的品种和规格需求不尽一致。但是对金鱼的质量要求却是不变的。质量是产品的生命。作为观赏鱼类的金鱼更是如此。首先要强化质量意     

话说鲫鱼的文化价值

正如果说鱼类中也有"既上得了厅堂、也下得了厨房"者,那应该非鲫鱼莫属。先说这上得了厅堂,金鱼作为观赏鱼在厅堂的地位之高尽人皆知。在中国漫长的历史长河之中,富贵之家的厅堂之上,金鱼始终处于最抢眼的位置。金鱼又称金鲫鱼,是世界著名三大观赏鱼之一,发源于中国,至今已有1 700多年历史。金鱼由野生红黄色鲫鱼演化而来,远在晋朝就有"赤鳞鱼"的文字记载,堪称中国的国粹。金鱼也素有"宫廷金鱼"之称,据说明神宗朱翊钧酷爱养金鱼,这位不务正业的皇帝处理国事不专心,但对养金鱼却情有独钟,堪称"金鱼鉴赏家"。     

几种常见农药对胭脂鱼幼鱼的急性毒性研究

本文采用胭脂鱼幼鱼作为测试生物,开展了氰戊菊酯、三唑磷、敌百虫对胭脂鱼幼鱼的急性毒性研究。通过试验获得了这3种农药对胭脂鱼幼鱼24h、48h、72h和96h的LC50值。其中氰戊菊酯、三唑磷、敌百虫对胭脂鱼幼鱼96h的LC50值分别为2．0μg／L,0．049mg／L,16．0mg／L。胭脂鱼幼鱼对氰戊菊酯、三唑磷、敌百虫96h安全质量浓度分别为0．2μg／L,4．9mg／L,1．60mg／L,3种农药对胭脂鱼幼鱼的毒性大小依次为氰戊菊酯、三唑磷、敌百虫。     

北方大棚养殖金鱼四季管理要点及常见病害防治方法

<正>我国是金鱼的故乡,是金鱼的原产地,远在唐朝就开始将金黄色的野生鲫进行"家化"养殖,这是金鱼人工养殖的起源[1]。金鱼在我国具有悠久的文化与养殖历史,也是我国观赏鱼的主要养殖品种,深受人们喜爱。金鱼的活动、摄食、生殖、生长和发育等一切生命活动都是随季节的变化而存在着一定的差异。因此,根据不同的环境条件,对金鱼的养殖管理进行适时的调整显得非常重要。同时,近年来     

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).     

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.     

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.