鲤科骄子——建鲤(Cyprinus Carpio Var.jian)

<正> 建鲤是采用荷元鲤F_4长型品系与两个同型的雌核发育系相结合,经选择横交固定,六代定向选育,首次育成,遗传性状稳定(达99％以上)并能自繁自育的鲤鱼优良品种。建鲤的乳酸脱氢酶、同工酶、酯酶同工酶和血清蛋白电泳分析结果表明:它具有独特的生化遗传特征。建鲤生长优势非常显著。其体重增长较荷包红鲤、沅江鲤和荷元鲤分别高58.2～71.3％、44.5～49.1％和28.5～29.3％;群体增重分别高60.1～71.8％、49.1～50％和29.4～30.8％,并显著地高于其它鲤鱼和杂交鲤,能增产30％以上。     

建鲤夏花当年育成商品鱼的试验

将建鲤夏花放在池塘内进行集约化养成，给人工驯养养并投喂全价颗粒配合饲料，１７８天后尾均重由０．９ｇ增长到５７０ｇ，增重数６３３．３，成活率７９．６％，单产１１４０ｋｇ／１００ｍ＾２，蛋白利用率为２７．５％，饲料系数１．４６投入与产出比为１：２．４２。     

丰鲤在稻田中生长的试验观察

本文报道了丰鲤在稻田生态条件下的生长情况和生产效果。结果表明，当年丰鲤比杂交鲤(散鳞镜鲤8×本地江鲤早，未定名)、禾花鲤、长鳍鲤个体增重分别快29.45%、42．38％、88．87％；群体增重分别快51．98％、48．33%、115．39％。     

鱼用中草药饲料添加剂开发研究

在９２１号鱼用中草药添加剂研究的基础上，进行９３１号、９３２号、９３３号和９３４号鱼用中草药复方筛选试验。在网箱中养殖鲤，观察其生长、饵料系数以及血液指标。其结果表明，９３４号组生长效果最好，９３２号组其次，日增重率两组分别较对照组高３０．６％和１５．３５％，饵料系数则分别低１８．９１％和６．０１％，并且血液指标也高。本文对该鱼用中草药饲料添加剂的试验结果和意义，进行了分析和探讨。     

建鲤FABP3基因分离及其多态性与增重的相关分析

为获得与建鲤增重相关的分子标记进行建鲤分子育种,实验在建鲤心肌型脂肪酸结合蛋白(FABP)基因上筛选了与增重相关的SNP位点.首先使用PCR扩增到2个建鲤FABP3基因,jlFABP3a和3b基因,两个基因均有4个外显子和3个内含子组成,3a和3b阅读框相似性为93％,编码133个氨基酸,相似性为94％,内含子长度和序列存在着明显差异.jlFABP3的系统进化和传统的分类地位一致.通过序列比对,在3a和3b上分别找到26和25个SNP位点.构建PCR-RFLP法检测了其中3个SNPs在建鲤群体中的分布,并与增重进行相关分析,结果显示,C30G与检测群体雌、雄鱼鱼种阶段和雌鱼成鱼阶段增重显著相关(P＜0.05),CC型个体增重显著快于CG型个体.G267T在5个家系中与雌鱼成鱼增重相关,在7个家系中不同基因型个体增重虽呈相同趋势但差异不显著(P＞0.05).同时考虑G267T和C30G位点,则发现GGCC个体在雌、雄鱼增重均最大,在雌、雄鱼中分别比GGCG个体快17％和12％.GGCC个体在实验样本中占约9％,存在着较大的选育空间.     

用RNA/DNA比率评定鲤的生长及其配合饲料的营养价值

投饲不同动物蛋白源，不同蛋白质含量的配合饲料养殖鲤鱼种，在环境条件和投饲率相同的情况下，测定鱼体的增重率、肌肉、肝脏中脱氧核糖核酸（ＤＮＡ）和核糖核酸（ＲＮＡ）的含量。结果表明：Ａ、Ｂ、Ｃ三组饲料蛋白质含量分别为１８．１７％、１７．８６％、３１．５６％时，其个体平均增重率分别为１０６．８７％、９４．６５％、１２９．４８％；平均饲料系数分别为２．０４、２．３０、１．５２时，ＲＮＡ／ＤＮＡ平均比率分别     

江口水库网箱投饵养建鲤,团头鲂试验

网箱养殖建鲤及团头鲂,投喂颗粒饲料及青饲料、建鲤平均产量41．25kg／m~2,增重倍数7．44;团头鲂平均产量30．56kg／m~2,增重倍数5．43。     

丰鲤在稻田中的生长观察

在稻田生态条件下,当年丰鲤比杂交鲤(散鳞镜鲤(?)×本地江鲤♀,未定名),禾花鲤、长鳍鲤个体增重分别快29.45％、42.38％、88.22％,群体增重分别快51.98％、48.33％、115.39％。     

不同体色瓯江彩鲤生长率和存活率的差异研究

要用同池比较法，研究了一龄和二龄阶段“全红”，“大花”，“麻花”，“粉玉”及“粉花”五种不同体色瓯江彩鲤生长率和存活率的差异，结果表明：（1）在一，二龄阶段，麻花存活率均最高，分别是98．8％和96．3％，但各体色彩鲤间差异不显著（P＜0．05），（2）不则体色彩鲤的生长率在不同阶段表现不同，一龄阶段，不同体色彩鲁的绝对增生率，瞬时增生率均依次为大花＞麻花＞粉花＞全红＞粉玉，差异极显著（P＜0．01），二龄阶段，不同体色彩鲤的绝对增重率，瞬时增重率均有显著差异（P＜0．05），但次序和I龄阶段不完全相同。（3）一龄阶段，“大花”和“麻花”始终保持较快的增长，二龄阶段，则是“粉玉”和“大花始终保持较快的增长。     

氨基酸螯合盐对罗非鱼促生长作用的研究

本文报道了氨基酸螫合盐与无机盐添加剂在罗非鱼饲养中的对比试验结果，以及在螯合盐中添加稀土对罗非鱼生长的影响，测定了各组试验鱼的耗氧率以及肌肉中蛋白质、脂肪和水分的含量，结果表明，添加螯合盐的四个试验组鱼的增重效果均优于添加无机盐的对照组，四个试验组分别比对照组多增重７５．７％、８６．５％、１０８．５％．８９．０％，饵料系数下降率分别为２９．２％．３３．４％，４２．５％，３３．７％。ｔ检验表明，四个试验组与对照组差异显著。     

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.