黑龙江野鲤、散鳞镜鲤良种选育技术

本文报道选育黑龙江野鲤和散鳞镜鲤良种的研究。根据对不同水域野鲤的遗传分析,发现不同自然品系之间在形态、生化遗传结构和生长都存在阴显差异,试验采用品系选育方法,筛选出一个生长比其他野鲤快10％的松花江野鲤品系。对已高度强化选育的镜鲤品种,试验采用已选育30年的散鳞镜鲤和由德国引进的纯系镜鲤进行杂交,获得一个比亲本生长快20％的杂交种。     

建鲤网箱养殖饲料管理的探索(上)

正建鲤(Cyprinus carpio var.jian)是中国水产科学研究院淡水渔业研究中心人工育成的我国第一个遗传性状比较稳定的优良鱼类养殖新品种。它是选择母本荷包红鲤与父本元江鲤杂交后代作为育种基础群,选育出F4长型品系与两个原始亲本相同、选择指标一致的雌核发育系相结合,并进行横交固定,其子代(F5和F6)的遗传性状稳定性和一致性达到95%以上,定名为建鲤。建鲤生长快,生长速度较荷包红鲤、元     

北方地区高背鲫池塘养殖技术

高背鲫即高体型异育银鲫,是采用生化遗传标记和组织移植亲和性检测的方法,从天然雌核发育银鲫4个不同的雌核发育系中选育出来的优良品种(方正银鲫雌核发育的D系鲫鱼为母本,江西的兴国红鲤为父本)。形态特征与普通异育银鲫相比,其体色为银灰色中略带黄色。此鱼具有生长快、抗病力强、肉质细嫩、味道鲜美、营养丰     

松浦镜鲤、野鲤、建鲤网箱养殖效果的试验

用１ｍ３网箱于库湾进行松浦镜鲤（散鳞镜鲤♀×德国镜鲤♂）与野鲤，建鲤网箱养殖试验。野鲤４个网箱，平均每箱为５３１尾，平均个体重１１０．９３ｇ；建鲤２个箱一箱放４５０尾，另一箱放４４９尾，平均个体重７３．４５ｇ；松浦镜鲤１个网箱放５７８尾，平均个体重４９．５０ｇ，经１３７天饲养群体净重野鲤为７８．８ｋｇ／箱，建鲤为６０．８ｋｇ／箱，松浦镜鲤为１０６．９ｋｇ／箱，瞬时体重增长率野鲤为０．７７８；建鲤为１．１２６；松浦镜鲤为１．３３６。从群体产量及个体生长速度松浦镜鲤都高于野鲤和建鲤。     

雌核发育鲢生长、体型的研究

进行了雌核发育鲢两个品系间和雌核发育链与其半同胞鲢及普通鲢的生长对比 ,并与标准鲢(李思发等 1998)进行了生长、体型比较。结果表明 ,雌核发育鲢比半同胞鲢体长增长快 13 3% ,体重增长快5 1% ,差异十分显著 ;雌核组比普通鲢组体长增长快 3 7%～ 2 5 3% ,体重增长快 6 7%～ 90 1% ,雌核发育鲢品系间也存在明显的生长差异 ,本试验中雌核发育Ⅱ系 (GyS2 Ⅱ )比Ⅰ系 (GyS2 Ⅰ )体长增长快 8 6 % ,体重增长快 2 8%。在相同体长条件下 ,雌核发育鲢比标准鲢体重大 10 6 %～ 31 9% ,平均大 15 6 % ,雌核发育鲢具有背高、尾短、头较大的特点。     

网箱养鲤技术（三）

四、网箱养鲤的饲养管理 (一)鲤品种选择。鲤品种很多，其中杂交鲤具有最明显的生长优势。网箱养殖的杂交鲤的最理想品种为“丰鲤”。它生长快，抗病力强。其次为鳞鲤，这是从苏联引进的一种杂交鲤，这种鲤体短而宽，生长快，抗病能力也强。普通鲤即所谓野鲤，生长速度比前两种慢，但适应性强，     

散鳞镜鲤♀×兴国红鲤♂杂交一代的推广试验

我区是丘陵山区,历来有养鲤鱼的习惯,一九七三年以前,主要是搭养本地野鲤,一九七三年由于我所引进并推广了散鳞镜鲤的养殖以来,许多地方逐步开始搭养散鳞镜鲤。可是,由于本地野鲤的生长速度缓慢,而散鳞镜鲤虽是一个好品种,但近两年出现多病而死亡,给生产带来了一些急待解决的问题,就是如何培育一个生长速度快、抗病力强的新品种,来取代原来的品种。参考省水科所的资料,从一九七八年开始,我所开始进行了散鳞镜鲤早×兴国红鲤♂的杂交试验。二年共获得杂     

长丰鲢苗种培育试验

长丰鲢是长江水产研究所从长江野生鲢性成熟个体中选育个体大、体质健壮的雌性鱼为母本,用遗传灭活的鲤精子做激活源,采用极体雌核发育方法经连续2代异源雌核发育和2代生长性状为主要指标的群体选育后获得的品种。该品种生长速度快、体型较高且整齐、遗传纯度高,适合在全国淡水水域中养殖。2012年5月,在国家大宗淡水鱼类产业技术体系和长江水产研究所的支持下,我们开展了长丰鲢苗种培育试验。     

鲤鱼（建鲤）营养与配合饲料（一）

鲤鱼（建鲤）营养与配合饲料（一）鲤鱼是我国主要养殖鱼类，迄今已有二千四百多年的饲养历史。建鲤是淡水渔业研究中心张建森、孙小异教授等人以特定的荷包红鲤和元江鲤为亲本，采用家系选育、系间杂交及雌核发育等技术综合育种新方法而培育成的，经杂交定向选育成遗传性...     

酯酶和乳酸脱氢酶在人工雌核发育鲢近交F1不同组织中的表达

采用聚丙烯酰胺水平平板电泳法研究了人工雌核发育鲢近交F1Ⅰ系、Ⅱ系、野生鲢、养殖鲢和雄鲤的肝、肾、心、眼和肌肉5种组织的酯酶(EST)和乳酸脱氢酶(LDH)。比较发现:(1)雌核发育鲢近交F1Ⅰ系、Ⅱ系和野生鲢的同工酶谱基本一致,雄鲤明显区别于鲢;(2)从酯酶图谱可发现,雌核发育近交鲢F1Ⅱ系的群体内有多态现象,肝、肾、肌肉的多态位点比例分别为0·6000、0·3333、0·5000,遗传杂合度分别为0·7485、0·6622、0·1139;(3)肝脏的乳酸脱氢酶中出现C带,且C带表现出多态性;(4)没有发现能区别鲢各群体的遗传标记。     

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.