尼罗罗非鱼与萨罗罗非鱼及其正反杂交后代的微卫星分析

微卫星（microsatellite）技术是近年来广泛应用的DNA标记,具有重复性好、较易操作和共显性的特点。在硬骨鱼类中表现出高度多态性,已在家系鉴定、遗传作图、群体遗传分析、育种以及系统发生研究等多个领域得到应用。尼罗罗非鱼（Oreochromis niloticus）是我国主要淡水养殖鱼类,生长快,耐盐能力一般;萨罗罗非鱼（Sarotherodon melanotheron）耐盐能力强,适合咸淡水养殖,但生长较慢。[第一段]     

中国罗非鱼养殖现状及发展前景

罗非鱼属热带性鱼类,具有生长快、繁殖力强、食性杂、病害少、抗病力强、适应性强等特点,适宜于淡水、海水、网箱、流水池高密度集约化养殖,我国罗非鱼养殖最近十几年中迅速发展,１９９８年产量为５３万吨,占世界产量７０%。一、我国罗非鱼养殖情况１．罗非鱼被引入中国１９５６年我国从越南首次引入莫桑比克罗非鱼（Ｍｏｓｓａｂｉｃａｔｉｌａｐｉａ）,当时称它越南鱼,又因其形状似鲫鱼,故又称为非洲鲫鱼,此后先后引入各种罗非鱼,如１９７８年由长江水产研究所从苏丹境内引进的尼罗罗非鱼（简称沙尼罗）;１９８３年、１９９２年,由淡水渔…     

奥尼罗非鱼的人工育苗技术

罗非鱼系鲈形目丽鱼科罗非鱼属,属热带性鱼类,共有100多种,多数产于非洲。罗非鱼具有生长快、食性广、繁殖力强、病害少、肉质好、产量高等特点。目前养殖的主要品种有：奥尼罗非鱼、吉富罗非鱼、吉奥罗非鱼等10多个品种。奥尼罗非鱼是奥利亚罗非鱼（6）和尼罗罗非鱼（早）杂交的后代,是中国目前主要养殖的罗非鱼种类。我国南方沿海地区适宜罗非鱼养殖的区域广阔,罗非鱼养殖具有巨大的开发潜力和有利条件。本文将奥尼罗非鱼人工育苗技术介绍如下：     

吉富罗非鱼人工催产技术研究

吉富品系尼罗罗非鱼（以下简称吉富鱼,GIFTstrainofOreochromisniloticus）是由国际水生生物资源管理中心经混合选育获得的优良品系。吉富罗非鱼具有生长快、养殖周期短、产量高、群体繁殖力强、对环境适应性强以及抗病力强等特点,目前是我国罗非鱼养殖的主要品种之一。     

罗非鱼鱼鳞提胶工艺优化研究

正罗非鱼属鲈形目、鲡鱼科、罗非鱼属。罗非鱼是一种中小型鱼,它具有广盐性、杂食性、耐低氧、不耐低温、天然抗病性强、生长快、繁殖性强等特性,具有很高的养殖经济效益。我国养殖的罗非鱼品种主要有尼罗罗非鱼、奥利亚罗非鱼、莫桑比克罗非鱼以及各种组合的杂交后代等,其养殖主要分布在广东、广西、福建、海南及云南等地区。近年来,我国罗非     

雄性化奥尼罗非鱼海水池塘养殖试验

子一代奥尼雄性化罗非鱼除具有食性广泛、适应性强、生长快等罗非鱼的一般优点外,还具有抗逆性强、品质好等特殊性状,是优良的淡水养殖品种。为拓宽其养殖渠道,我们承担了日照科委下达的“罗非鱼雄性化海水育苗与养殖”项目。现将其养殖技术报告如下：一、试验条件1．池塘为本场对虾养殖池塘,长方形,长12Om、宽72m,面积13亩,其地底为硬泥,池底四周有一条宽3m深40cm的环水沟。池塘平均水深1．3m,过排水方便,有提水设备。2．鱼苗取自本场用海水繁殖的尼罗罗非鱼雌性内奥利亚罗非鱼（雄性）杂交的子一代奥尼罗非鱼苗,雄性率为90％…     

池养彩虹鲷不同密度的对比试验

彩虹鲷俗称红罗非鱼,也称红吴郭鱼,为尼罗罗非鱼和莫桑比克罗非鱼突变型的杂交良种,具有食性广、生长快、抗病力强、耐低氧等诸多优点。体型象奥尼罗非鱼,体色粉红或橘红,头小,背高,体厚。腹膜白色,肉质鲜嫩,雄性率达98％以上。为研究彩虹鲷成鱼养殖的合理放养密度,提高养殖效益,笔者于2005年4月8日至9月30日,在广西水产引育种中心进行了彩虹鲷3种放养密度的对比试验。现将试验的结果总结如     

狠抓奥尼鱼苗质量确保提高养殖效益

1976年联合国粮农组织据罗非鱼具有食物链短、生长快、抗病力强、易养、肉质鲜美的优点，向世界推荐作为养殖对象。在许多国家及地区，罗非鱼的养殖和发展很快，产量迅速增加。但人们同时也发现罗非鱼在成鱼养殖过程中有过度种内繁殖的习性，造成密度过大，产量不高，商品率低，效益差的问题。为此，开展研究各种方法解决问题，     

吉奥罗非鱼养殖试验

本文通过进行吉奥罗非鱼养殖试验,探讨和验证吉奥罗非鱼所的优良经济性状,并获得了显著的效果。在21．45hm^2的池塘中投放平均体重60g的吉奥罗非鱼鱼种48800尾,经192d养殖,吉奥罗非鱼平均体重为0．948kg/尾（最大体重为1．201kg／尾）,吉奥罗非鱼产量为44．98t,平均产量为31．02t／hm^2总产值为32．4万元,获利7．65万元,经济效益显著。试验表明,吉奥罗非鱼集成了吉富罗非鱼生长速度快,奥尼罗非鱼雄性率高、抗病力强等优点,适合于不同地区、不同环境的池塘养殖,推广养殖前景广阔。     

广西罗非鱼产业的现状分析及提高竞争力的措施

<正>一、广西罗非鱼产业的发展现状罗非鱼属鲈形目、丽鱼科、罗非鱼属,全世界共有600余种。目前,已经产业化养殖的共有15种,养殖范围最广的是吉富罗非鱼。我国养殖的罗非鱼大部分从非洲引种,具有食性杂、生长快、抗病抗逆性好、繁殖力强、方便养殖管理、产量高等众多优势。同时,罗非鱼适合于大规模的工厂化养殖,在淡水和咸淡水都可以生长。另外,池塘、网箱、流水池、循环系统等各种水体中,养殖罗非鱼都能够获得较好的产量。近年来,我国的罗非鱼养殖产量呈急剧上升的态势,成为了罗非鱼主要生产国和消费国。广西由于     

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.