中国对虾(Fenneropenaeus chinensis)“黄海3号”新品种的培育

2006年收集中国对虾“黄海1号”保种群以及海州湾、莱州湾2个野生群体为基础群体构建核心育种群,采用群体选育技术以仔虾Ⅰ期耐氨氮胁迫成活率和收获时对虾体重为选育指标,经过连续5代选育,培育出中国对虾“黄海3号”新品种。新品种耐氨氮胁迫能力强,仔虾Ⅰ期成活率较商品苗种提高21.2%,养殖成活率提高15.2%;生长速度快,收获对虾平均体重较商品苗种提高11.8%。AFLP 技术分析获得5代选育群体的平均多态位点比例分别为42.28%、40.64%、40.32%、39.95%和38.05%。研究结果显示,随着选育世代的增加,选育群体的遗传多样性呈现下降趋势,但随着选育时间的延长,世代之间的分化逐渐降低,群体的遗传结构开始趋于稳定。     

三疣梭子蟹新品种“黄选1号”的选育

2005年收集鸭绿江口、莱州湾、海州湾、舟山4个三疣梭子蟹野生地理群体,构建核心育种群体,评估有效群体含量,制定合理保种模式;在5％留种率下,采用群体选育方法进行新品种培育.到2010年经过连续5个世代选育,形成特征明显、性状稳定的三疣梭子蟹新品种“黄选1号”.在相同养殖条件下与商品苗种进行对比测试.“黄选1号”收获时平均个体体重提高20.12％,成活率提高32.00％,全甲宽变异系数小于5％“黄选1号”新品种2010～2012年进行中试养殖200余hm2,养殖方法以“蟹、虾、贝、鱼”多品种生态养殖为主.结果显示,新品种收获时个体规格大、成活率高、整齐度好,平均单产提高30％;已推广到山东、河北及浙江等地,累计养殖面积6 000余hm2,获得较显著的经济效益和社会效益.     

中国对虾“黄海2号”新品种的培育

选取中国对虾“黄海1号”、“即抗98”2个养殖群体,朝鲜半岛南海群体、乳山湾群体、青岛沿岸群体及海州湾群体等4个自然群体,采用不平衡巢式交配方案设计,于2005年建立了中国对虾育种的基础群体。设计并建立了中国对虾的多性状复合育种技术,选育的目标性状为生长速度、白斑综合症病毒感染后的存活时间及养殖存活率。为最大限度消除环境差异对遗传方差的影响,在中国对虾家系构建过程中采用标准化程序培育苗种,经过对体长为3cm左右的幼虾进行荧光标记,每个家系标记后混合养殖测试。随机从每个家系中抽取同等数目的标记对虾分成2组,一组共同养殖在养殖池中,测试生长速度和养殖存活率,另一组在封闭的水泥池中进行WSSV感染实验,测试病毒感染后的存活时间长短。中国对虾遗传参数的估计结果表明,养殖170天收获体重的遗传力为0.22,抗WSSV存活时间的遗传力为0.14,存活率的遗传力为0.03。采用BLUP法估算个体育种值,通过百分比加权的形式,分别赋予生长速度、抗WSSV存活时间和存活率的加权值为：80%、15%和5%,并对性状育种值进行标准化,获得综合选择指数;按照每个家系及个体的综合选择指数大小进行家系间及家系内留种,并根据系谱信息,设计交配方案,将每代的近交系数控制在1%以内。选育4代后的统计结果表明,平均每代的遗传进展为：生长速度,13.56%;抗病力,6.76%;存活率,5.05%。三个性状中,收获体重的遗传力最高、加权最大,每代获得的遗传进展稳定在12%以上;抗WSSV存活时间与存活率遗传力较低,每代获得的遗传进展相对小且不稳定。实验培育的新品种“黄海2号”于2009年通过全国水产原良种委员会审定,可在适合中国对虾的养殖区进行推广养殖。为更快地培育抗病新品种,解决对虾养殖病害问题,进一步的研究需查明对虾抗病的遗传机制,提高抗病性状的选择强度,快速培育对虾抗病新品种。     

2014年全国渔业主导品种——虾

<正>A.中国对虾"黄海2号"品种来源:收集4个中国对虾自然群体及2个选育群体,由中国水产科学研究院黄海水产研究所选育。审定情况:2009年2月通过全国水产原种和良种审定委员会审定,获水产新品种证书。审定编号:品种登记号:GS01-002-2008。特征特性:生长速度快,收获体重比未经选育的野生种提高30%以上,适     

凡纳滨对虾“海兴农2号”

<正>针对当前对生长速度快、抗逆性强的凡纳滨对虾新品种需求量不断提高,广东海兴农集团有限公司、广东海大集团股份有限公司、中山大学、中国水产科学研究院黄海水产研究所联合选育出新品种凡纳滨对虾"海兴农2号"(品种登记号:GS-01-004-2016)。该品种利用从美国夏威夷、佛罗里达、关岛和新加坡等地区引进的8个亲虾群体,以生长和成活率为选育目标,采用BLUP技术经连续5代选育而成。     

凡纳滨对虾“中科1号”

凡纳滨对虾“中科1号”（品种登记号：GS-01-007-2010）,是以从美国夏威夷、佛罗里达州引进的2个群体和国内5个养殖群体为基础群体,以生长速度和仔虾淡水应激成活率为主要选育指标,经2代群体选育及5代家系选育获得的品种。     

河北省开展中国对虾“黄海5号”新品种养殖示范

正中国对虾"黄海5号"新品种(GS—01—002—2008),是黄海水产研究所在中国对虾"黄海2号"和野生群体基础上采用多性状复合育种技术,经6代选育而成。在相同养殖条件下,与未经选育的中国对虾相比,白斑综合征病毒抗性平均提高30.1%,生长速度提高26.5%。该品种是农业部2018年主推品种之一。2018年,河北省农业产业技术体系特色海产品创新     

凡纳滨对虾“正金阳1号”

正一、品种名称凡纳滨对虾"正金阳1号"二、品种来源凡纳滨对虾"正金阳1号"养殖新品种是以3个引进的凡纳滨对虾群体和凡纳滨对虾"中科1号"种虾为基础群体,以耐低温、耐低盐、生长速度和成活率为目标性状,采用家系选育和品系选育相结合的选择育种技术,经连续4代选育获得的凡纳滨对虾选育品种。三、审定情况2017年通过全国水产原种和良种审定委员会审定。审定编号为GS-01-006-2017。     

2个凡纳滨对虾群体仔虾的生长比较

以凡纳滨对虾二代群体自交、选育家系(♀)×引进SPF(♂)群体杂交,通过自然交配和人工培育获得2个仔虾群体,待仔虾长至体长0.8～1.0 cm时,随机选取60万尾放养于3口0.133 hm2的对虾养殖高位塘中,密度150万尾/hm2,其中二代仔虾2口塘,杂交仔虾1口塘.投喂"恒兴"牌饲料,相同的养殖环境和管理措施,养殖30 d后,每隔10 d进行一次生长测定.结果表明,杂交仔虾的生长速度和成活率高于二代仔虾,体质量和体长的总生长率高于二代仔虾,抗应激能力强于二代仔虾,较二代仔虾均匀;在40 d的观测期内杂交仔虾体长的绝对增长量为4.49 cm,二代仔虾为3.66 cm,提高22.68%,杂交仔虾体质量的绝对增长量为3.73 g,二代仔虾为2.20 g,提高69.55%,杂交仔虾生长优势明显.     

凡纳滨对虾群体杂交与自交 F1低溶氧与高氨氮耐受性比较

利用6个遗传背景不同的凡纳滨对虾(Litopenaeus vannamei)群体,通过群体间自交与杂交建立了8个交配组合。对不同交配组合F1,在幼虾和成虾阶段,进行低溶氧与高氨氮48 h胁迫试验,比较不同交配组合群体在不同生长阶段的高氨氮与低溶氧耐受性。结果显示,低溶氧胁迫,YH♀×ZX♂、SS♀×SS♂、HD♀×YH♂交配组合幼虾存活率分别为76.23%、74.61%、74.38%,显著高于其他交配组合存活率(P0.05),成虾的存活率分别为83.08%、65.57%、71.12%,可作为耐低溶氧优良品系选育的候选材料;高氨氮胁迫,YH♀×KN♂、HD♀×YH♂、YH♀×ZK♂交配组合幼虾存活率分别为97.71%、86.43%、80.01%,显著高于其他交配组合(P0.05),成虾存活率分别为85.53%、74.18%、69.23%,可作为耐高氨氮优良品系选育的候选材料;HD♀×YH♂交配组合低溶氧与氨氮耐受性均较好,但不同交配组合低溶氧与氨氮耐受性间相关性检验不显著(P0.05)。研究发现,亲本中雌虾来源为YH,子代低溶氧耐受性优良,推断抗低溶氧性状为母系主导遗传;对虾低溶氧的耐受性随着生长发育的进行而降低,高氨氮耐受性随着生长发育的进行而增强;各交配组合高氨氮和低溶氧耐受性,在幼虾阶段和成虾阶段均呈极显著相关(P0.01),表明凡纳滨对虾低溶氧与高氨氮耐受性适宜在幼虾阶段进行遗传评估。     

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.