全国最大规模的鱼类种苗生产基地──广东龙发渔业总公司（即原广东省水产局外经处龙发特种养殖试验场）

全国最大规模的鱼类种苗生产基地──广东龙发渔业总公司（即原广东省水产局外经处龙发特种养殖试验场）（封面广告说明词）驰名国内外的广东龙发渔业总公司，即原广东省水产局外经处龙发特种养殖试验场，是具有十多年历史的专业生产国内外名、特、优、新、珍稀鱼类和动物...     

发展长江名特鱼类养殖打造三峡库区渔业品牌

万州地处长江上游，三峡库区腹心，境内有长江鱼类108种，其中名特经济鱼类32种。随着经济的发展和人们生活质量的提高，长江名特鱼类越来越受人们推崇。为适应新的渔业发展形势，有效地调整水产养殖品种结构，提升渔业发展质量，万州区采取切实措施，大力发展长江名特鱼类养殖，努力打造三峡库区渔业品牌。主要做法是。     

淡水养殖鱼类饲料专题讲座 第八讲 投饲技术

在鱼类养殖生产过程中,正确合理地选用饲料,采用科学投饲技术,可促进鱼体生长,降低生产成本,提高经济效益。如果饲料选用不当,投饲技术不合理,等于把钱白白扔在水里,当今随着鱼类养殖科学技术的进步,新的养殖对象和新的养殖方式不断出现,如网箱养鱼、围栏养鱼、流水养鱼、工厂化养殖和名、特、优水产动物的养殖等对投饲技术的要求都     

河鲈鱼种人工配合饲料养殖试验

正河鲈(perca fluviatilis)属鲈形目、鲈科,地方名"五道黑",为肉食性凶猛鱼类,是新疆重要经济鱼类之一。河鲈人工养殖对推进水产养殖业转变发展方式、调整养殖结构起到重要作用。河鲈人工养殖普遍采用的是投喂冰鲜野杂鱼的模式,这种养殖方式存在饵料不易获取、水体容易恶化、鱼易得病等弊端,不符合当前水产绿色健康养殖的要求,且存在产品质量安全隐患。目前,一些养殖户零星开展了人工配合饲料养殖河     

水产养殖动物摄食及其营养调控

我国水产养殖的未来发展方向就是集约化,水产养殖动物依赖于饲料。很多水产养殖动物都配备了人工饲料,但是一些水产养殖动物当前还未实现人工配合饲料的问题,例如鳜鱼是一种特殊的鱼类,通常以活鱼为食物,很难摄食人工饵料。本文主要论述了水产养殖动物摄食问题,提出营养调控措施。在水产养殖过程中,需要充分了解鱼类摄食调控,进而可以更好地研制人工饲料。     

加快推进水生动物防疫步伐

三、水生动物病害防治体系发展情况水产养殖病害防治体系为防疫体系情况的基础,水产养殖病害防治体系应包括法律法规与标准系统、队伍与机构、基础设施等内容。20世纪50年代随着我国四大家鱼人工繁殖技术的突破,为开展鱼类人工养殖奠定了基础。为保证鱼类人工养殖的顺利进行,于     

水产养殖专业中动物学课程教学改革与实践

通过在"水产养殖"专业的"动物学"课程教学过程中引入了"创新型实践教学"、"知识竞赛"及"学生自主课堂"等教学手段,这些新教学手段的引入,增加了"水产养殖"专业学生对"动物学"课程的学习热情,加强了学习效果,并且促进了具有较强创新精神和应用能力的高素养应用型人才的培养。     

养殖鱼类的防疫策略及健康管理

草、青、鲢、鳙、鲤、鲫、鳊等是我国淡水养殖渔业中的当家品种,尽管近年来迅速兴起了名特水产动物养殖的热潮,但这些当家鱼的养殖产量仍占淡水水产养殖总产量的70％左右,具有举足轻重的地位。之所以此类养殖鱼类在当今水产养殖迅速发展的情况下,仍然长盛不衰、持续发展,     

注澜湖渔场发展名特新稀水产经验

益阳县注澜湖渔场拥有水面5095亩,其中湖泊4700亩。近年来,他们积极发展名特新稀水产养殖。1992年生产鳖、鳜、乌鳢、鲶、黄颡鱼等名贵水产品5.6t,创产值达31.2万元,比上年增长2.3倍。他们的主要经验有三点: 一、揽信息,开拓生产门路。前两年名特水产品市场价格看好,销售紧俏。他们抓住机遇,采取措施,积极发展。一是人工放流鳖、鳜、乌鳢、鲶等苗种,增加名特水产资源;二是人工投喂精料、动物下脚料等,并施用化肥,为名特鱼类提供充足的食饵;三是在湖中营造假山、开辟鱼道,为名特鱼类创造良好的生态环境条     

《水产动物疾病学实验》课程教学改革与探索

《水产动物疾病学实验》是水产养殖专业必修的实验课程,针对水产动物疾病学实验教学存在的问题,河南师范大学水产学院水产动物医学系根据水产养殖专业的培养目标,探讨了水产动物疾病学实验教学的改革措施,主要围绕实验内容体系、教学方法和考核评价体系几个方面进行探索实践,充分调动了学生的学习积极性,促进创新型人才培养,取得了较好的效果。     

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.