基于26个微卫星标记的三江水系草鱼遗传多样性分析

选取26个微卫星标记对来自长江(监利、邗江)、黑龙江、珠江3个水系的4个野生草鱼(Ctenopharyngodon idellus)群体的遗传多样性进行了检测。结果表明,26个微卫星位点均为高度多态位点,草鱼4个地理群体的多态信息含量(PIC)平均值为0.581 3~0.638 6;共检测出141个等位基因,其中有102个为共有等位基因;每个位点有等位基因2~11个,平均等位基因5.46,平均有效等位基因3.455 6。4个地理群体野生草鱼的平均杂合度在0.711 4~0.804 5之间。群体间遗传固定指数(FST)及AMOVA分析表明,群体间遗传分化并不显著(FST=0.031 73)。基于DA遗传距离构建的UPGMA聚类树表明,监利群体与邗江群体这两个长江水系野生地理群体聚为一支,然后与珠江群体聚为一支,黑龙江群体单独聚为一支。长江群体是原始群体。综上所述,三江水系野生草鱼具有较高的遗传多样性,4个群体之间遗传分化并不明显。     

Probiotic bacteria effects on growth and bacterial composition of black tiger shrimp (Penaeus monodon)

The effects of Bacillus probiotic forms on growth performance and microbiota were examined in black tiger shrimp (Penaeus monodon). Shrimp were fed for 120 days with one of three diets; a control diet alone or supplemented with either probiotics consisting of live‐sprayed Bacillus (LS) or freeze‐dried Bacillus (FD). Culturable bacteria counts in the hepatopancreas, intestine and culture water of the three treatments were relatively constant during the experiment. Bacillus numbers in the hepatopancreas and intestines of probiotic‐treated groups increased significantly (P < 0.05) after 30 treatment days and remained relatively constant afterwards while no appreciable changes occurred in the control. Shrimp supplemented with LS and FD contained significantly lower concentrations of Vibrio (P < 0.05) in the hepatopancreas, intestine and culture water, compared to those in the control group. Shrimp treated with LS and FD probiotic bacteria showed a significant improvement (P < 0.05) in specific growth rate (SGR) and feed efficiency (FE), compared to those of control group. Probiotic bacteria have the potential to enhance shrimp culture by reducing Vibrio and improving growth performance.     

三疣梭子蟹快速生长品系核心种质有效群体含量

三疣梭子蟹是我国海水养殖的重要种类之一,良种选育核心种质的繁衍与更新是制约品种选育成功的技术瓶颈。根据Doyle和Talbot提出的计算有效群体含量的计算公式,对2008年三疣梭子蟹快速生长品系核心育种群有效群体含量进行估算,得出实际群体有效含量为213,实际近交系数为0.002 3,其近交系数较小,近交衰退控制在较低的水平。但三疣梭子蟹保种数量和留种方式仍然困扰育种群体控制,因此,借鉴畜禽的保种模式,从留种方式、雌雄比例、保种数量等方面对三疣梭子蟹快速生长品系核心基础群进行保种研究。结果表明,采用随机留种,雌雄1∶1比例交尾,雌雄数量各131只,此保种模式既能保证三疣梭子蟹快速生长品系核心基础群遗传多样性处于较高水平,使其具有较大的选育潜力,又能使保种成本维持在一个合理水平。此研究模式也为理论保种模式,需要在以后的实际群体选育过程中逐步完善。     

黄鳝体内新棘衣棘头虫的种群生态学研究

通过野外取样调查研究 ,揭示了新棘衣棘头虫种群生态学的一些特点。结果表明 ,新棘衣棘头虫寄生在黄鳝的肠道内 ,多集中于前肠 ;其感染率和感染强度都有随宿主体长的增加而逐渐增加的趋势 ;种群的平均丰度随宿主体长的增加呈指数增加 ,其回归方程为M =7.6× 10 -9L3 .3 83 0 ;随着黄鳝体长的增加 ,棘头虫种群在宿主中的频率分布的尾不断增长 ,即感染较多棘头虫的黄鳝所占比例增加 ;棘头虫种群在宿主不同体长组的分布类型为聚集分布 ,且聚集强度随棘头虫的种群平均丰度增加而增加。     

大连沿海野生鼠尾藻种群生态调查

2009年7月至2010年7月对大连沿海4个采样点潮间带野生鼠尾藻种群的生长发育情况进行了生态学调查.结果显示,鼠尾藻种质资源的生态分布受海域地貌特征、自然环境条件、人为干扰等多方面因素的影响.藻体长度和质量增长受海水表面温度的影响最为显著,与盐度的季节变化无相关性.7-10月各种群生物量和长度达到最高值,5-7月出现...     

Differential response to disturbance factors for the population of sympatric crocodilians (Gavialis gangeticus and Crocodylus palustris) in Katarniaghat Wildlife Sanctuary,India

相似文献   

Conservation needs for the endangered New Zealand sea lion,Phocarctos hookeri

相似文献   

循环水养殖系统生物滤池细菌群落的PCR-DGGE分析

通过模拟实验对循环水养殖系统中不同初始NH ₄N浓度的生物滤池中生物膜上和水中的细菌数量及群落种类组成进行了研究。对成熟生物膜及水体样品中的异养菌、氨氧化菌、亚硝酸盐氧化菌的培养计数结果表明,随着生物滤池初始氨氮浓度增大,除异养细菌数量逐渐下降外,生物膜上的氨氧化菌和亚硝酸盐氧化菌数量呈逐渐增加趋势,且均高出水样3~4个数量级;同时对上述样品的16S rRNA基因片段的PCR扩增产物进行变性梯度凝胶电泳(DGGE)分析及其序列同源性分析的结果表明,生物膜和水中都有较高的细菌多样性,同一初始氨氮浓度的滤池中生物膜上的细菌多样性高于水中的。生物滤池中的细菌主要由拟杆菌门的黄杆菌纲和变形菌门的α-、β-、γ-变形菌纲的15种细菌组成。生物膜上的优势菌包括奥雷氏菌属、湖饲养者菌属、泥滩杆菌属、沉积杆菌属、雷辛格氏菌属、冷蛇形菌属和亚硝化单胞菌属等;水体中的优势菌则有明显差异,主要有蛋黄色杆菌属、Nautella,玫瑰杆菌属和一种硫氧化菌等。初始氨氮越高的滤池中,亚硝化单胞菌属的细菌在生物膜上所占比例越高,逐渐成为优势菌之一。实验证实,挂膜初期,提高水体中初始氨氮浓度,有利于硝化细菌的富集和固着,提高生物滤池的除氮效率。     

Stock structure of blue threadfin Eleutheronema tetradactylum across northern Australia as inferred from stable isotopes in sagittal otolith carbonate

Abstract Stable isotopes of δ¹⁸O and δ¹³C in sagittal otolith carbonates were used to determine the stock structure of the polynemid Eleutheronema tetradactylum (Shaw) across tropical northern Australia, where this species is an important component of inshore commercial and recreational fisheries. Stable isotopes from the sagittal otolith carbonate of 470 fish from 11 discrete locations across western, northern and eastern Australia were sampled between 2007 and 2009. Analysis of these stable isotopes revealed different location‐specific signatures, indicating strong population subdivision. The significant differences in the isotopic signatures of E. tetradactylum demonstrated that there is unlikely to be substantial movement of fish between these locations. The spatial separation of these populations indicates a complex fine spatial scale stock structure across northern Australia, with at least 11 stocks or management units present. The population subdivision of E. tetradactylum was evident along expansive stretches of open beach systems and within coastal embayments with no physical barriers such as headlands. These results indicate that optimal fisheries management will require a review of the current spatial arrangements, particularly the potential for localised depletion of stocks on small spatial scales.