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1.
Among the strategies being developed to improve survival and harvest yields in the farming of Pacific white shrimp Litopenneus vannumei is breeding domesticated family lines and the selection for further development of those lines that demonstrate resistance to Taura syndrome virus (TSV) challenge in the laboratory. A standardized laboratory challenge method for measuring TSV resistance by per os exposure to the virus, relative to a reference stock of L. vannamei , was developed and used to screen a total of 176 family lines provided by five different companies over a period of several months. All challenged shrimp were exposed to TSV per os by feeding minced TSV-positive shrimp carcasses at ∼10% of the shrimp biomass once per day for three consecutive days. Studies were carried out for a minimum of 14 d from the first day (day 0) of exposure to TSV. The survival rates obtained following TSV challenge of the selected L. vannamei families ranged from 0% to 100%, with a mean of 31%. The reference line of L. vannamei ("Kona line") gave survival rates of 0% to 37% with a mean of 13%. The results of the present study demonstrate that the use of a relatively simple laboratory challenge procedure provides a mechanism to evaluate and compare resistance to TSV among selected L. vannamei families and to predict the performance of selected stocks in farm environments where TSV is enzootic.  相似文献   

2.
A specially designed recirculating system was used to maintain P. vannamei broodstock for maturation, mating and spawning in the same tank. Two groups of different size shrimp were stocked in this system in Phase I (8 May to 5 September 1989) and Phase II (5 September to 5 December 1989). Results showed that this recirculating system was able to maintain good water quality keeping broodstock maturing, mating and spawning with high stocking density (10 shrimp/m2) and low mortality (6%). Seventy-eight percent of spawned eggs were collected by a submerged egg collector. Mating success was very poor (3.4%) in Phase I even though there was normal spawning frequency. Mating success and nauplii production were much improved in Phase II. During Phase II 104 male and female broodstock housed in a 6 m3 tank produced 1.6 ± 106 nauplii (with 70% mating success) in three months. This study illustrated that broodstock size was a critical factor of successful mating and fertilization for P. vunnamei , and also, reduction of handling stress and lowered disturbance of the shrimp greatly enhanced the mating success.  相似文献   

3.
为提高凡纳滨对虾种苗质量,探索群体选择育种和杂交育种方法在凡纳滨对虾大规模人工育苗生产中的应用,对1个经过人工选择的凡纳滨对虾群体A的自交和杂交子代的抗逆性和生长性状进行了比较。群体A是2008年来自美国种虾的子一代,并经过2个世代的人工选择和自交传代。群体B为2010年来自广东的繁育群体。A群体自交,及其与B群体的正、反杂交,产生3组不同交配组合的子代。对3个组合后代仔虾幼体的抗低温、低盐能力及养成期的生长性状进行比较分析,结果表明,以A群体为母本的杂交组AB抗逆性最强,以B群体为母本的杂交组BA抗逆性次之,而A群体自交组抗逆性最弱。在低温(13.0±0.9) ℃和低盐4.7条件下,AB组存活率分别比AA组高27.6%和64.4%。3个组合养成期的体质量生长速度为AB组(253±55) mg/d、 BA组(208±52) mg/d、AA组(219±36) mg/d,AB组比BA组快21.6%,比AA组快15.5%。研究表明,凡纳滨对虾的杂交优势与亲本的提纯、选优密切相关。  相似文献   

4.
王佳佳  王琼  秦桢  陈耀辉  李健  李吉涛 《水产学报》2023,47(6):069606-069606
为了探究SSR标记对凡纳滨对虾养殖群体的遗传多样性和群体遗传结构的影响,为凡纳滨对虾种质资源的遗传改良提供基础信息。实验利用MISA软件对凡纳滨对虾全基因组SSR位点进行搜索,通过聚丙烯酰胺凝胶电泳获得多态性高的SSR标记,基于POPGENE 1.32、PIC-CALC和Mega 6.0软件分析6个不同来源的凡纳滨对虾养殖群体的遗传多样性和群体结构特征。在凡纳滨对虾全基因组数据中共鉴定出10 453 975个微卫星,约占基因组序列总长度的18.56%,其中,二碱基微卫星最丰富,占总数的82.15%。利用具有多态性的14个SSR标记分析3个国内群体[桂海1号(CG)、海兴农2号(CH)和山东养殖群体(CT)],及3个国外群体[厄瓜多尔1号(FO)、厄瓜多尔2号(FT)和墨西哥群体(FM)]的遗传特征。结果显示,14个SSR标记在6个群体中共检测到208个等位基因变异,等位基因数、观测杂合度、期望杂合度和多态性信息含量的范围分别为6～25、0.112～0.994、0.234～0.925和0.226～0.918;遗传多样性丰富程度为CH>FO>FM>CT>FT>...  相似文献   

5.
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6.
应用RT-PCR技术,对福建南部养殖南美白对虾(Litopenaeus vannamei)自然暴发的急性传染病病原进行了检测。结果检出桃拉综合征病毒。对231bp的扩增产物进行了测序,并与Genbank桃拉综合征病毒相应序列进行比较,其同源性超过97．O％。临床观察也表明,虾体表发红、有的虾体表散布有一些灰白色病灶,附肢及尾扇发红,还有一些病虾体表散布大量黑色不规则病灶,为桃拉综合征病毒感染引起的典型症状。组织病理学检查表明,病虾体表、附肢、鳃等组织的表皮上皮有许多坏死病灶,结缔组织细胞与相邻横纹肌纤维基底部也有病变。病变细胞嗜酸性颗粒增多,细胞核固缩或破裂。部分病虾肝胰腺出现脂肪化和空泡变性。  相似文献   

7.
In Mexico, the capture of wild broodstock of Penaeus vannamei or P. stylirostris for hatchery production of postlarvae is a common practice. During September 1995 and March-April 1996, high mortalities were observed in the wild broodstock captured in the Platanitos area, on the coast of San Blas, Nayarit, Mexico. As a result of these mortalities, many hatcheries closed down their facilities. Because early histological analysis had shown that some of these animals were infected with different pathological agents, such as bacteria and viruses, the present study was carried out to determine the prevalence and severity grade of infectious diseases affecting these shrimp. During March 1996, a total of 28 female and 28 male shrimp were randomly selected from a recently captured stock of 600 breeders of P. vannamei . A second sampling (28 females and 28 males) was performed from a stock of 800 breeders captured in April 1996. On this occasion, the shrimp were sampled after 10 d of acclimation in a hatchery. The animals selected for examination were those with necrosis in the cuticule, red coloration in the telson and uropods, soft cuticle, empty gut, and erratic swimming. All of the specimens were subjected to histological analysis and dot blot hybridization with a gene probe specific for Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV). The results showed that both stocks were infected with at least three different viruses (Infectious Hypodermal and Hematopoitetic Virus, Taura Syndrome Virus and Hepatopancreatic Parvo-Like Virus), gram-negative bacteria and other parasites such as gregarines. It is likely that the high mortalities observed are due to the recent introduction of TSV in the wild population of P. vannamei .  相似文献   

8.
ABSTRACT:   Five loci ( Phz2 , Phz6 , Phz7 , Phz12 , and Phz14 ) of microsatellite DNA markers developed in a previous study for parentage assignment in the hatchery population generated by mating among 61 broodstock fish (35 females and 26 males) in a spawning tank, were selected. After natural spawning in the same tank, larvae collected at three different times were categorized into early phase (EP), middle phase (MP), and late phase (LP) groups. In the parental broodstock, the mean number of alleles per locus was 21.8 and expected heterozygosity ( H E ) was 0.813. In the progeny, the mean number of alleles per locus decreased to 11.6 (EP), 14.4 (MP), and 6.4 (LP) and H E to 0.796 (EP), 0.833 (MP), and 0.681 (LP). Parental assignment determined eight dams and six sires as major parents for the EP group. In the MP group, 13 dams and ten sires genetically contributed to spawning, but only three dams and two sires were involved in LP group progeny. In the hatchery population produced from a limited number of parental fish such as the LP group, genetic variability was apparently decreased.  相似文献   

9.
A high incidence of spontaneous triploidy was found in tench broodstock hormonally treated to induce spawning but without positive response. Triploidy was also observed in random samples of fingerlings from four tench lines. Triploidy was evaluated by counting Ag-stained NORs in erythrocyte nuclei and was confirmed in 62.5% of the broodstock and in a range from 0.00% to 34.62% in fingerlings. Discrimination of tench diploids and triploids based on differences in shape and length of pelvic fins was tested in the broodstock and also in stocks of earlier artificially induced triploid tench by means of the above-mentioned cytogenetic approach and shown to be a rapid method with a high accuracy (96.43%). Natural disposition for egg overripening is one of the possible causes of highly frequent spontaneous triploidy in the analyzed samples. Genetic predisposition, i.e. occurrence of a recessive allele responsible for the failure of the 2nd polar body extrusion when homozygous, was hypothesized as another possible cause of spontaneous triploidy, based on analysis of the relationships among the tench lines.  相似文献   

10.
Parentage analysis in aquaculture determines genealogical relationships between broodstock and progeny when the parents are unknown. Thus, parentage analysis is a useful tool to establish pedigree reports in molecular‐assisted selection programs. Here, we evaluated 10 heterologous microsatellite markers for parentage assignment in abalone hybrids produced from 43 abalone broodstocks of red abalone (Haliotis rufescens) and Japanese abalone (H. discus hannai). The allele frequencies, exclusion probabilities and broodstock contributions were calculated using CERVUS, PAPA and GERUD software. The polymorphic information content (PIC) values showed that most of the microsatellite loci were highly informative (>0.7) and more than 90% of parentage assignment was possible with a minimum of 5–6 microsatellite markers. Parentage assignment for hybrid and pure‐red progeny showed a better performance than pure‐Japanese progeny. This result could be due to the high level of allele loss in the parental genotypes. In addition, results indicated that only two sires contributed over 80% and 90% of red and hybrid progenies, respectively. This study gives a new molecular tool to support marker‐assisted selection in abalone hybrids produced in Chile.  相似文献   

11.
选用来源于鲤基因组中的鳞被相关基因(ant、eda、edar、fgfr)及其上下游序列中的155个微卫星标记,对德国镜鲤(Cyprinus carpio L.)与黑龙江野鲤(Cyprinus carpio haematopterus)杂交的F2 116尾个体的遗传多样性进行检测,以卡方检验估计群体Hardy-Weinberg平衡.结果表明,36个微卫星标记表现为多态,各标记的等位基因数在2～4个浮动,共检测到86个等位基因,平均每个标记2.388 9个;平均有效等位基因数为2.209 4;平均观测杂合度为0.624 5;平均期望杂合度为0.529 2;平均多态信息含量为0.432 1,其中23个微卫星标记表现为中度多态(0.25≤PIC＜0.5),13个微卫星标记表现为高度多态(PIC≥0.5),说明这个群体属于中度多态性水平.Hardy-Weinberg平衡检验结果显示,61％标记显著偏离平衡,人工选择压力和自交对家系造成了严重的影响.SPSS 17.0分析发现分别有10(28％)、7(19％)、7(19％)和11个(31％)标记与体质量、体长、体高和体厚存在显著相关性,并发现11个优势基因型.源于鳞被相关基因的微卫星标记与生长性状连锁的比例较高,以上结果从分子水平上提示鳞被基因与所研究4种生长性状存在一定的相关性.  相似文献   

12.
本研究对A、B两个凡纳滨对虾选育群体的亲虾形态特征及其产卵量和孵化率进行比较,结果表明A、B群体的体型性状存在一定差异,尤其是体重、体长、头胸甲长、第二腹节高和尾节长存在显著差异(P0.05),其他形态性状差异不显著(P0.05)。两个群体亲虾产卵量分别为(0.65±0.20)×104、(0.64±0.18)×104粒/体重(g),差异不显著(P0.05),但无节幼体量和孵化率差异显著(P0.05)。A群体产卵量与体型不显著相关(P0.05),亲虾产卵量(Y,×104粒)与体重(W,g)的回归方程:Y=0.010 3W1.0878(R2=0.410 3);B群体凡纳滨对虾亲虾体重与产卵量显著相关(P0.05),亲虾产卵量(Y,×104粒)与体重(W,g)的回归方程:Y=0.054 5W0.677 8(R2=0.522 8)。  相似文献   

13.
Molecular markers (PCR–RFLP and microsatellite) were used to investigate the genetic background of the only brown trout (Salmo trutta m fario) broodstock in Hungary which due to the hydrogeography of the country should theoretically belong to the Danubian lineage. PCR–RFLP (mitochondrial DNA control region and lactate dehydrogenase and somatolactin genes) as well as microsatellite (BFRO002, OMM1064, Ssa408uos, SsoSL417, SsoSL438) markers were used to distinguish between Danubian and Atlantic lineages of brown trout in the Lillafüred broodstock. Altogether 435 fish were tagged during the experimental period. Due to mortalities, fin clips were collected from 401 individuals. According to the genetic analysis of the mitochondrial DNA, the Danubian haplotype is present in only one individual (0.2 %) of the broodstock. Analysis of the nuclear markers revealed that alleles characteristic of both the Atlantic and the Danubian lineages are found in the population. However, Atlantic alleles dominate throughout the broodstock which is in Hardy–Weinberg equilibrium according to the investigated markers. Results indicate that the original broodstock that was introduced to the farm following its construction in 1933 was of the Atlantic lineage. Although later fish from a local stream were collected and added to the broodstock, the number of these was limited and they were almost exclusively males. Fish from this farm that are stocked by anglers can have a significant genetic impact on trout populations of natural streams.  相似文献   

14.
为确定越冬凡纳滨对虾亲虾黑鳃病症病因,对患病亲虾病因进行分析。结果显示,越冬后患病亲虾鳃部观察到大量线虫。虫体特征显微结构显示,雌、雄性线虫的平均体长分别为(983.6±16.69)μm和(956.9±12.14)μm,虫体表皮不均质,具有2纵列侧分化、4根头刚毛、3个口腔实齿、5个杯形肛前附器,化感器横向扁椭圆形,食道不形成食道球;经鉴定,确定该线虫隶属于色矛科(Chromadoridae)、色矛属(Chromadorella)。组织病理观察结果表明,线虫感染后亲虾鳃组织坏死、溶解,黑色素沉积,游泳足基部出现黑化层。本文报道了一种由色矛线虫引起的越冬亲虾黑鳃病症。  相似文献   

15.
本试验在一个镜鲤家系中,随机选取68尾作为实验鱼,在测量体重、体长、全长等数量性状的同时,利用15个微卫星分子标记对其进行遗传检测,共检测到40个等位基因,每个基因座的等位基因数为1～4个不等,平均等位基因2.66个,片段长度在132-551之间,有效等位基因数(Ne)为1.3721～3.8278,平均观察杂合度(Ho...  相似文献   

16.
微卫星分子标记指导镜鲤群体选育   总被引：2，自引：0，他引：2  
本文用26个扩增效果好的微卫星分子标记分析了镜鲤（Cyprinus carpio L.）养殖亲本群体的遗传结构,指导其群体选育。本研究共检测到153个等位基因,片段大小为108~400 bp,平均等位基因数（A）5.8846个,平均有效等位基因数（Ne）2.8625个,平均观察杂合度（Ho）0.5063,平均期望杂合度...  相似文献   

17.
微卫星分析四个大黄鱼群体的遗传多样性   总被引：3，自引：1，他引：2  
为保护人工养殖大黄鱼的种质资源,用15对微卫星标记对来自浙江沿海地区的四个大黄鱼养殖群体共171个个体进行了遗传多样性分析.结果显示,这些标记在四个群体中均表现出丰富的多态性;共检测到206个等位基因;各基因座观测等位基因数7～23个,平均等位基因数13.73,大小在88～318bp之间.四个群体的平均观测杂和度(Ho)为0.5981～0.6893,期望杂和度(He)为0.7319～0.7944,多态信息含量(PIC)0.7138～0.7836,表明四个养殖群体在所检测位点均具有较好的多态性.对遗传距离的计算结果表明闵粤东群体与反交群体较近,聚类结果中首先聚到一起.本研究首次选择微卫星标记评估人共选育大黄鱼群体的遗传多样性,并采用高精度的377 DNA测序仪进行检测,将对大黄鱼的种质资源保护提供科学依据.  相似文献   

18.
本文用26个扩增效果好的微卫星分子标记分析了镜鲤（Cyprinus carpio L.）养殖亲本群体的遗传结构,指导其群体选育。本研究共检测到153个等位基因,片段大小为108~400 bp,平均等位基因数（A）5.8846个,平均有效等位基因数（Ne）2.8625个,平均观察杂合度（Ho）0.5063,平均期望杂合度（He）0.5602,平均多态信息含量（PIC）0.5292,表明该繁育群体处于较高的遗传多样性水平。用χ2检验和遗传偏离指数估计Hardy-Weinberg平衡,表明群体处于平衡状态,但在多个位点表现出杂合子缺失严重,显示出人工选择的痕迹。用PHYLIP3.6软件绘制基于Nei氏标准遗传距离的UPGMA聚类图,依据亲本个体间的遗传差异,以避免近亲交配为原则,建立最佳亲本配组体系,繁育获得2个选育群体,以常规群体繁育子代群体作为对照组,对子代群体的遗传结构及数量性状分析显示,选育群体保持了较高的遗传多样性水平,群体平均期望杂合度在0.5414~0.5449之间,其生长速度较对照群体快14.81%~63.71%。连续2年的生长实验证实,微卫星标记指导群体选育技术在保持群体的遗传多样性水平,避免近交衰退,快速建立优良种群方面具有一定的优势。  相似文献   

19.
研究了1个大黄鱼F1家系150个个体22个微卫星位点的基因型分布,并分析了标记位点与生长性状的相关性。结果显示,22个位点共检测到60个等位基因,平均等位基因数为2.73,平均有效等位基因数为2.37;平均观测杂合度与期望杂合度分别为0.75和0.73,部分位点基因型分布严重偏离孟德尔定律,暗示其可能与适应性基因相连锁,其中LYC0446位点附近可能存在隐性纯合致死基因。LYC0077位点与体质量、体长和体高均呈显著相关(P<0.05),其中等位基因A(165 bp)对应的生长性状表型值最大,可以作为选育快长性状的有效分子标记;LYC0015和LYC0243与体高呈显著相关(P<0.05),与体长、体质量的相关不显著(P>0.05),LYC0015位点的等位基因C(110 bp)和LYC0243位点的等位基因A(160 bp)为有利的等位基因。对LYC0015、LYC0077和LYC0243进行不同基因型个体表型值的多重比较,找到3种对生长性状有利的基因型,分别为BC、AA和AB。同时,以体质量性状为参照,对3个位点不同基因型组合进行比较,找到一个最优基因型组合(BC/AA/AB),与3个位点单独分析对应的最优基因型完全一致,符合加性作用模型。  相似文献   

20.
A set of 49 microsatellite loci isolated from the endemic New Zealand Greenshell™ mussel, Perna canaliculus, were evaluated for inclusion in a parentage assignment marker suite by assessing their ease of PCR amplification, allele scoring and conformity to Mendelian inheritance in hatchery-produced families. Ten polymorphic loci (mean He = 0.78 and polymorphic information content (PIC) = 0.72) were identified as being suitable for parentage assignment. These 10 microsatellite loci gave a combined non-exclusion probability of < 0.001 (probability that an unrelated parent pair will not be excluded from parentage of an arbitrary offspring), based on allele frequencies from 16 broodstock mussels. Simulations predicted an assignment success rate of 99.9% with all 10 loci and > 95% with the best 5 or more loci (mean PIC = 0.84). In actual parentage assignments, 124 offspring from 8 full-sib families were assigned to the correct parent pair with 4 or more loci. We found evidence for null alleles and extensive size homoplasy in many loci, highlighting the importance of thoroughly characterizing and evaluating microsatellite markers prior to parentage assignment and other applications.  相似文献   

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