用RAPD技术鉴定荷包红鲤抗寒品系

本利用RAPD技术对荷包红鲤抗寒品系的基因组DNA进行分析。通过对50个引物，150次的RAPD分析，找出了用RAPD技术从分子生物学角度对荷包红鲤抗寒品系进行鉴定的方法。     

提高抗寒鲤鱼的起捕率

鲤鱼起捕率低是多年来淡养的一个很难解决的问题。我所为了搞清抗寒和高起捕率的遗传规律，先后进行了柏氏鲤与黑龙江鲤、德国镜鲤、荷包红鲤等的正反杂交。从中选出一组双杂交种 [(柏氏鲤×镜鲤 )F1× (黑龙江鲤×红镜鲤 )F1]，此组种系具有较强的抗寒能力，起捕率却不很高，其起捕率高者为两网 40％左右，为提高起捕率，又以此组鲤鱼与柏氏鲤原种进行回交，得到一组抗寒能力强且高起捕率鲤鱼新品系。 　　1983年我所从云南引进 58尾柏氏鲤亲鱼，采用杂交技术分别与黑龙江野鲤、江鲤和散鳞镜鲤进行正反交，并对其亲和力及后代的抗寒能力…     

黑龙江野鲤的主要经济性状及其遗传资源

本文通过三年试验,测定了黑龙江野鲤的生长、饲养成活率、越冬成活率、抗病力、繁殖力、含肉率、鱼肉成份等主要经济性状。松花江下游野鲤群体生长快于镜泊湖、达赉湖和嫩江的群体。嫩江野鲤(♀)与兴凯湖野鲤(♂)杂交F_1,表现出生长的杂交优势。从鱼苗到性成熟野鲤的饲养成活率明显高于荷包红鲤和德国镜鲤。黑龙江野鲤具有极强的抗寒能力和抗病能力,它的这两个特性可以通过杂交转移给后代。野鲤的繁殖力很高,因此在黑龙江水系中保持较大的群体数量。野鲤的含肉率比其它鲤鱼高:在鱼肉成份中,有较高的蛋白质含量和较低的脂肪,含水量较小,鱼肉品质高。黑龙江野鲤的这些优良经济性状,是鲤鱼遗传改良的重要遗传材料,开发利用后必将产生巨大的经济效益。     

二个鲤鱼优良新品系和一个杂交种通过鉴定

中国水产科学研究院黑龙江水产研究所承担的“六五”国家重点科技攻关项目——鱼类繁育体系和杂交育种两个课题,经过4年的辛勤研究和克服了各种困难,终于初步选育出荷包红鲤抗寒品系(二代)和蓝色鳞鲤(二代)2个鲤鱼新品系和获得了一个高起捕率的杂交种。荷包红鲤是一个优良的杂交亲本,与沅     

鲤野生和养殖群体遗传多样性分析中的微卫星(SSLP)分析

采用7个微卫星标记,研究了鲤(Cyprinus carpio)、高寒鲤和荷包红鲤抗寒品系(Cyprinus carpio var.wananensis)三个群体的遗传变异。结果显示,鲤野生群体、高寒鲤、荷包红鲤抗寒品系的平均杂合度分别为0.276、0.147、0.0952,平均无偏倚杂合度期望值为0.431、0.355、0.305。鲤野生群体的杂合度明显高于其他两个养殖品种,说明其较其他两个养殖品种的遗传多样性丰富。     

选育中的高寒鲤

从１９７９年至１９８８年，为培育适合于北方地区养殖的鲤鱼新品种，我所选用遗传差异大的黑龙江野鲤和荷包红鲤进行了正反杂交（单交）。结果两个亲本具有很强的配合力，正反交Ｆ＿１都有明显的生长优势，优势率在１５－３０％；反交组Ｆ＿１的抗寒、抗病力很强，并完成了单组的选型。由于原种荷包红鲤在，黑龙江不能过冬，越冬成活率为零，为保证新品种的培育，根据杂支分离的遗传学原理，从上述组合Ｆ＿２中筛选出一个越冬成活率已达７０％以上、基因型与原种相似的抗寒品系。１９８５年至１９８８年，又用上述单交Ｆ＿１与散鳞镜鲤进行正反三杂交，通过池塘生长对照，抗寒力试验，结果正反三杂交Ｆ＿１的生长相似，比单交Ｆ１更具生长优势，优势率在３０～５０％之间，成活率、抗寒、抗病力都提高５％以上。并已进行了推广应用。     

鲤鱼种间、种内杂交中杂种优势强度表现的某些规律的初步研究

从1986年至1990年于我所松浦试验场,用黑龙江野鲤、荷包红鲤、兴国红鲤、红镜鲤、散鳞镜鲤、德国镜鲤和柏氏鲤进行了种间、种内14个组合的杂交,系统观察了不同组合亲本和杂种F_1在鳞被、体色、体型、生长、成活率、抗寒力、抗病力和起捕率等8个性状的遗传传递规律及其杂种优势强度,结果是.(1)鲤鱼种内异源杂交几乎所有的杂交组合的杂种F_1都表现出生长优势和对环境抗性的增强,其大小随亲本的亲缘远近和鳞被、体色、体型等性状间的差异而不同。一般品系间杂交,杂种生长的优势率在10％左右;品种间杂交,单交种的生长优势率在15—30％,三杂交种的生长优势率在30％以上。在抗寒、抗病、成活率等抗性上,表现出受其中一个亲本的影响,且有明显的母本效应,并可遗传传递给杂种后代。鳞被、体色、体型的基因效应,对杂种的生长有明显的促进作用。(2)鲤鱼种间杂交几乎不表现杂种优势,其特点:是柏氏鲤和黑龙江野鲤两个野生种间杂交,成活率、抗寒力强烈的表现不亲和性;而柏氏鲤与家养种间的杂交,表现一定的亲和性。亲本和杂种F_1的鳞被、体色仍表现显隐性关系,而体型、抗寒、抗病、成活率、起捕率等受柏氏鲤种质的强烈影响。获得抗寒力的杂种,在第二代时抗寒力明显消失,说明基因转移和整合的不稳定性。用柏氏鲤与散鳞镜鲤杂交的杂种F_1与另一抗寒很强的杂种F_1(黑龙江野鲤♀×红镜鲤♂)的双杂交种F_1,抗寒明显增强。     

江西省鲤生物遗传多样性调查和 DNA指纹分析↑（*）

采集样本１０种，经生物学调查和ＤＮＡ指纹分析鉴定为６个品种（品系），其中３个样本是荷包红鲤、另外的５个品种（品系）是兴国红鲤、玻璃红鲤、野鲤、建鲤和锦鲤。它们在形态、生态分布、染色体组型及ＮＯＲｓ、肉质肉量、电泳同工酶、ＰＣＲ、对基因探针的反应等方面具有明显的多态性和差异。ＤＮＡ指纹分析还查明，一种来源不清的鲤是荷包红鲤、南昌的一种所谓兴国红鲤的一种混杂了的鲤。江西鲤较印度尼西亚和菲律宾的鲤遗传多     

黑龙江地区锦鲤的饲养和抗寒研究

通过引进的日本原种锦鲤在黑龙江地区土池（富营养）饲养,采用与食用鲤鱼相同的养殖条件,对锦鲤一龄鱼,二龄鱼,三龄鱼,四龄鱼和亲鱼的成活率测定,分别达77％,85％,95％,94％,100％,得出锦鲤适合黑龙江地区的土池养殖。进行原种锦鲤,杂交种锦鲤一龄鱼,二龄鱼和三龄鱼室内和自然条件下赵冬成活率的比较,原种锦鲤在水温11℃的室内越冬成活率较高。在高寒地区自然越冬条件下成活率接近0,抗寒能力极差,但与荷包红鲤抗寒品系交的杂交种锦鲤,一龄鱼,二龄鱼和三龄鱼和在自然条件下越冬成活率分别达56．6％,86％和81．1％。抗寒性状可通过与荷包红鲤抗寒品系杂交遗传给杂交种锦鲤,并对自交种,杂交种的后代较好体色的锦鲤进行了统计,自交后代为35％,同荷包红鲤抗寒品系的杂交种后代为6％,杂交种后代体色较好的锦鲤明显低于自交种。     

适宜我国推广的水产优良养殖品种简介

全国水产原良种审定委员会第一届第三次会议审(认)定了适宜在我国推广的水产优良养殖品种,经农业部审核通过。 第一届第三次会议审(认)定通过了33个品种(品系)、杂交种和引进种。 荷包红鲤、兴国红鲤、彭泽鲫、建鲤、松浦银鲫、荷包红鲤抗寒品系,德国镜鲤选育系为适宜推广的水产优良品种(品系)。     

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.     

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.     

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.     

Effects of cortisol on hepatic carbohydrate metabolism and responsiveness to hormones in the sea raven,Hemitripterus americanus

The sea raven, Hemitripterus americanus, is a sit-and-wait, low metabolic rate, marine teleost. The objective of this study was to determine i) whether cortisol implantation (50 mg. kg^-1) for 7 days altered hepatocyte metabolism, and hepatocyte responsiveness to epinephrine, glucagon and insulin, and ii) whether 8 weeks of food-deprivation modified the above response. Cortisol implantation significantly increased hepatocyte total glucose production and oxidation from alanine compared to the sham group. There was no cortisol effect on glycogen breakdown, suggesting that the activation of other pathways, including gluconeogenesis, are required to account for the increased glucose production. Epinephrine-mediated (10^-5M) glycogen breakdown and insulin-mediated (10^-8M) total glucose production were enhanced in hepatocytes of cortisol implanted sea ravens, but there were no change in any glucagon (10^-7M) effects. The enhanced glycogen breakdown in the absence of similar increases in total glucose production with epinephrine indicates mobilization of carbohydrate reserves for endogenous use by the liver. Food-deprivation for 8 weeks significantly decreased condition factor, plasma cortisol concentration and liver glycogen content in the sea raven, but had no effect on plasma glucose concentration. Hepatocyte total glucose production and flux rates from alanine increased significantly with food-deprivation. Moreover, food-deprivation increased responsiveness of total hepatocyte glucose production to the actions of glucagon and insulin, but not to epinephrine; none of these effects were modified by cortisol implantation. Our results indicate that cortisol in the sea raven exerts both a direct and an indirect or permissive effect on hepatocyte metabolism by modifying hepatocyte responsiveness to epinephrine and insulin stimulation. Cortisol implantation did not modify the effects of glucagon or food-deprivation in this species.     

Simulation and quantification of enrichment and retention processes in the southern Benguela upwelling ecosystem

Important environmental processes for the survival and recruitment of early life stages of pelagic fishes have been synthesized through Bakun's fundamental triad as enrichment, concentration and retention processes (A. Bakun, 1996, Patterns in the Ocean. Ocean Processes and Marine Population Dynamics. San Diego, CA, USA: University of California Sea Grant). This conceptual framework states that from favourable spawning habitats, eggs and larvae would be transported to and/or retained in places where food originating from enrichment areas would be concentrated. We propose a method for quantifying two of the triad processes, enrichment and retention, based on the Lagrangian tracking of particles transported within water velocity fields generated by a three‐dimensional hydrodynamic model. We apply this method to the southern Benguela upwelling ecosystem, constructing putative maps of enrichment and retention. We comment on these maps regarding main features of the circulation in the region, and investigate seasonal variability of the processes. We finally discuss the results in relation to available knowledge on the reproductive strategies of two pelagic clupeoid species abundant in the southern Benguela, anchovy (Engraulis encrasicolus) and sardine (Sardinops sagax). Our approach is intended to be sufficiently generic so as to allow its application to other upwelling systems.     

Effects of capture,loading density and transport stress on the mortality,physiological responses,bacterial density and growth of rohu <Emphasis Type="Italic">Labeo</Emphasis><Emphasis Type="Italic"> rohita</Emphasis> fingerlings

This study evaluated the effects of three levels of loading density (200, 300 and 400 g L⁻¹) and four levels of duration (1, 3, 6 and 9 h) on the mortality, plasma cortisol and chloride levels and growth of rohu Labeo rohita fingerlings in a transport simulation. While total immediate mortality was low (4–12%), delayed mortality was high (27–49%). Initial capture and handling were found to constitute the most stressful phase as indicated by elevated plasma cortisol. The levels of cortisol continued to rise at 6 and 9 h after transport, with the highest level observed at 9 h after transport. The level of plasma chloride fell after transport across all density levels and treatment durations. Specific growth rate (SGR, %/day) and total bacterial density (cfu/g) were not different between and within treatments, and between treatments and the controls. This study demonstrates that transport has a profound effect on the stress responses of rohu fingerlings. Although the level of immediate mortality was low, the higher level of delayed mortality has serious implications in terms of production inefficiency for grow-out farmers.     

The effects of introduced tilapias on native biodiversity

• 1. The common name ‘tilapia’ refers to a group of tropical freshwater fish in the family Cichlidae (Oreochromis, Tilapia, and Sarotherodon spp.) that are indigenous to Africa and the southwestern Middle East. Since the 1930s, tilapias have been intentionally dispersed worldwide for the biological control of aquatic weeds and insects, as baitfish for certain capture fisheries, for aquaria, and as a food fish. They have most recently been promoted as an important source of protein that could provide food security for developing countries without the environmental problems associated with terrestrial agriculture. In addition, market demand for tilapia in developed countries such as the United States is growing rapidly.
• 2. Tilapias are well‐suited to aquaculture because they are highly prolific and tolerant to a range of environmental conditions. They have come to be known as the ‘aquatic chicken’ because of their potential as an affordable, high‐yield source of protein that can be easily raised in a range of environments — from subsistence or ‘backyard’ units to intensive fish hatcheries. In some countries, particularly in Asia, nearly all of the introduced tilapias produced are consumed domestically; tilapias have contributed to basic food security for such societies.
• 3. This review indicates that tilapia species are highly invasive and exist under feral conditions in every nation in which they have been cultured or introduced. Thus, the authors have concluded that, despite potential or observed benefits to human society, tilapia aquaculture and open‐water introductions cannot continue unchecked without further exacerbating damage to native fish species and biodiversity. Recommendations include restricting tilapia culture to carefully managed, contained ponds, although exclusion is preferred when it is feasible. Research into culture of indigenous species is also recommended.

Copyright © 2005 John Wiley & Sons, Ltd.