野生和养殖大鲵群体遗传多样性的微卫星分析

中国大鲵是世界上最大的两栖动物并且为我国特有,现在该物种野生种群急剧下降, 而人工养殖种群逐渐增多。为了对大鲵(Andrias davidianus)群体进行遗传多样性的本底调查, 本文用10对微卫星引物对28尾野生大鲵和16尾人工养殖的大鲵样本进行了遗传多样性分析。结果表明, 在10对引物中有7对检测到多态位点, 野生群体和养殖群体的观察等位基因数分别为5–8和4–6, 期望杂合度分别为0.81和0.75, 说明本实验中研究的大鲵的遗传多样性水平较高。通过人工养殖群体和野生群体的比较发现, 人工养殖群体存在较大的等位基因丢失现象, 并且遗传多样性水平低于野生群体。以上结果将为大鲵的人工繁育和遗传多样性的保护、利用提供一定的理论依据。     

池养成年大鲵体重和性别发育与水温的相关性研究

本研究以人工养殖大鲵为研究材料,控制水温于最适生长温度范围内,实时监测水温变化,收集对应温度下成年大鲵体重变化数据,利用方差分析等,得到体重和不同性别生长发育与水温的相关关系。结果显示,大鲵个体的生长速度随温度的升高而加快,水温与大鲵个体月均体重符合:y=3.938 4e0.01923x(y=个体月均体重,x=积温/月,R2=0.967 47,p0.05)。雌、雄群体间增重有显著性差异(p0.05)。雌性个体总增重量在0.45 kg以上个体占雌性群体的66.7%,而在雄性群体中,该比例仅为33.3%。同时发现雌、雄个体生长速度除了两性间的差异外,还与其自身初始的体重绝对值相关。随着池养水温的升高,雌、雄群体月均体重均有不同程度的增长,雌性群体增重率略偏高。因此,我们认为适当提高养殖水体温度,有利于成年大鲵个体,尤其是雌性个体的增重。本研究对于提高大鲵的人工养殖效益具有重要意义。     

中国大鲵子二代适应能力及生长优势的研究

2002年成功孵化出大鲵子二代1260尾,经过8个月生长,随机抽取172尾全长13～15 cm、体重25～35 g子二代与172尾全长14～16.5 cm、体重30～40 g野生代进行环境适应能力和生长速度的对比试验.结果表明,子二代在耐高温、耐低氧、耐不良水质、耐盐度、耐酸碱性、耐苦味饵料方面比野生代有明显优势,说明子二代适应能力更强,易于饲养.从生长优势方面,表现出大鲵子二代生长速度快,生长指标为4.4928,而野生代生长指标为3.4714.     

湖南张家界市大鲵资源调查

为科学确定张家界大鲵国家级自然保护区境内大鲵Andrias davidianus资源状况,2006～2008年对该保护区大鲵资源的分布区域和数量进行了调查.结果表明,近年该保护区野生大鲵呈不连续点状分布,约为0.2万尾,资源量仍有衰退趋势,人工养殖资源量增加较大,约3.21万尾.需要加强野生大鲵保护管理,增加人工放流数量与效益,以逐步恢复野生大鲵资源,同时继续发展大鲵人工养殖,不断增加大鲵的资源总量.     

卢氏县大鲵种群年龄结构和性比的初步研究

对大鲵种群样本(n=252)及观察到的当年孵化的幼鲵进行测量,样本采自河南省卢氏县大鲵自然保护区。以大鲵体长、体重为指标,用重心法聚类划分出8个年龄组(不含当年孵化幼鲵)。在此基础上结合大鲵的生长发育特点,同时与人工养殖条件下的生长情况进行对照,根据样本聚类情况推断出大鲵5个个体年龄组及相应的体长和体重指标,对卢氏县大鲵20世纪90年代初的种群年龄结构和性比进行了分析,探讨了以大鲵体长和体重为生长指标、用聚类分析法划分大鲵年龄组的可能性。     

大鲵食性分析

大鲵Andrias davidianus是我国分布较广、体型较大的有尾两栖类,是国家Ⅱ级保护动物。分析大鲵的食性可为人工养殖和保护大鲵提供资料。1985年10月—1988年3月,作者对大鲵的食性做了观察和分析,现整理报道如下。 方法 1985年—1988年,共采集大鲵标本71尾。每年除1—2月气温低河水冻结,无法采集标本外,其余3—12月份每月均可采到标本3—5尾。把采到的大鲵立即用福尔马林溶液浸泡,并在腹腔内注射福尔马林液。然后解     

大鲵的身体测量

大鲵(Ａｎｄｒｉａｓｄａｖｉｄｉａｎｕｓ)系国家二级保护野生动物。笔者于1993年夏、秋两季,在安徽省黄山市祁门县凫峰乡和休宁县流口乡收集到105尾大鲵活体,体重70～4450ｇ。饲养在人工建造的大鲵饲养场内,开展人工繁殖研究。现将自野外收集时测得的大鲵身体各部位数据分析结果报道于后。1　测量的数据(1)体重(ｇ):大鲵身体离开水后10分钟左右测得;(2)全长(ｃｍ):吻端至尾尖长度;(3)头长(ｃｍ):吻端至左右颈褶中间点长度;(4)头宽(ｃｍ):头最宽处长度;(5)尾长(ｃｍ):肛孔后缘至尾尖长度;(6)前肢长(ｃｍ):前肢基部至指尖长度;(7)后肢长(ｃ…     

繁殖前期中国大鲵雄性成体的冲凉行为及其意义

为揭示和探讨中国大鲵(Andrias davidianus)繁殖前期的冲凉行为及其意义,在仿生态养殖环境条件下,采用定时定点观察法和全事件记录法,对雄性成鲵的冲凉行为过程及姿势进行了观察记录,并分析了冲凉行为与年龄、求偶行为、繁殖成功率之间的关系.繁殖前期雄性成鲵表现出冲凉行为,冲凉行为与求偶行为之间存在极显著的正相关,表现出求偶行为的6尾雄性成鲵有4尾成功参与了繁殖.冲凉行为可能促进了雄性成鲵精巢的发育,引发求偶行为,最终达到成功繁殖.     

封闭式循环水养殖7月龄四指马鲅幼鱼形态性状对体质量的影响

为了解封闭式循环水养殖四指马鲅(Eleutheronema tetradactylum)主要形态性状对体质量的影响效果, 对204尾同一批次封闭式循环水养殖7月龄四指马鲅的体质量(Y)与尾柄高(X1)、尾柄长(X2)、体高(X3)、体长(X4)、全长(X5)等5个主要形态性状进行测量, 并进行相关性分析、通径分析及多元回归分析。结果显示, 四指马鲅体质量(Y)与各形态性状间均呈正相关, 且相关性均达极显著水平(P<0.01), 全长(X5)与体质量(Y)的相关性系数最大(0.973), 尾柄长(X2)与体质量(Y)的相关性系数最小(0.745)。通径分析发现全长(X5)对体质量(Y)的直接作用最大(0.609), 其次为尾柄高(X1) (0.247)、体高(X3) (0.168)。决定系数分析表明, 尾柄高(X1)和全长(X5)对体质量(Y)的共同决定系数最大(0.233), 表明尾柄高和全长可以较好地表征体质量; 尾柄高(X1)、体高(X3)和全长(X5) 3个性状共同决定系数的总和Σd =0.924, 表明这3个性状是影响体质量的主要性状; 通过逐步回归分析建立多元回归方程: Y = -254.360 + 34.385X1 +13.082X3 + 10.042X5。结果表明, 在四指马鲅养殖及选育过程中, 全长、尾柄高和体高等性状可作为主要测量指标。     

白鲢的鳞长与体重及外部形态性状的关系

为了全面地了解鱼类鳞片在鱼类生长及鱼类学的研究中的作用,本文研究了白鲢的鳞片生长与体重及形态可量性状生长的关系。结果表明:白鲢的鳞长与体重、鳞长与24个形态可量性状都呈显著的相关关系,可以从鳞片材料上反映出白鲢体型的基本特征和生长情况。在每尾鱼体上,只要测得体长、全长及鳞长便可预测此尾鱼其它可量性状及体重的数值。这将给鱼类数量分类学及鱼体生长的研究提供简捷方便的途径。 本文还讨论了白鲢的长度与体重关系的表达式,建议应根据具体情况,对鱼体长度指标——全长与体长进行选用。     

患病大鲵中弗氏柠檬酸杆菌的分离与鉴定

【目的】确定导致大鲵(Andrias davidianus)细菌性感染死亡的病原。【方法】从大鲵肝脏中分离细菌,通过Biolog微生物自动鉴定系统及分子生物学方法对纯培养的细菌进行鉴定,再用大鲵和鲫鱼分别进行人工感染试验,以确定分离菌的致病性,同时对分离到的病原菌进行药物敏感试验。【结果】从患病大鲵肝脏中分离到一株致病菌JZ01,经人工感染健康大鲵,可复制与自然发病相同的症状,且从人工感染病鲵体内再次分离到相同的病原菌。该致病菌对健康鲫鱼也有致病性。经Biolog微生物自动鉴定系统的鉴定,以及进一步的16S rDNA基因序列和系统发育分析都表明,此致病菌为弗氏柠檬酸杆菌。药物敏感性试验表明,该菌株对氨曲南、头孢三嗪、先锋噻肟等9种药物高度敏感。【结论】弗氏柠檬酸杆菌是大鲵的一种致病菌。本文在国内外首次报道了该菌对大鲵具有致病性。     

配合饲料和鲢鱼肉对大鲵生长的比较试验

为探讨人工配合饲料和鲢鱼肉对大鲵生长、消化和抗氧化能力的影响, 试验选取初始体重为(20.99±0.15) g的大鲵幼体48尾, 随机分成2组, 每组3个重复, 每个重复8尾, 分别投喂人工配合饲料(粗蛋白55.67%, 粗脂肪6.83%)和鲢鱼肉(粗蛋白18.03%, 粗脂肪4.11%)共92d。结果显示: (1)饲料组大鲵的增重率(WGR)、特定生长率(SGR)、蛋白质沉积率(PRR)和肌肉蛋白质合成能力均显著高于鱼肉组, 饲料系数(FCR)和存活率(SR)在两个试验组之间无显著差异(P>0.05)。(2)在大鲵摄食人工配合饲料后, 全鲵粗蛋白、皮肤胶原蛋白及粗灰分含量均显著高于鱼肉组(P<0.05), 而全鲵水分、粗脂肪与肌肉的粗脂肪和粗灰分含量显著低于鱼肉组(P<0.05)。(3)饲喂鲢鱼肉的大鲵胃蛋白酶活性显著高于饲料组(P<0.05), 而两个试验组的胃H+-K+-ATP酶和肠道消化酶活性均无显著差异(P>0.05)。(4)饲喂人工配合饲料的大鲵肝脏总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)活性显著高于鱼肉组(P<0.05), 而肝脏丙二醛(MDA)含量低于鱼肉组(P<0.05), 两个试验组的肠道抗氧化指标差异不显著(P>0.05)。研究表明, 在实验条件下, 大鲵可主动摄食人工配合饲料, 而且相比于投喂新鲜鲢鱼肉, 人工配合饲料饲喂大鲵, 在提高生长性能、促进大鲵合成皮肤胶原蛋白和肝脏抗氧化能力等方面更具优势, 说明人工配合饲料可以替代新鲜饵料成为大鲵的主要饵料。     

中国大鲵研究概况

中国大鲵(Andrias davidianus)为我国特有物种, 也是国家二类保护水生野生动物。野生大鲵多栖息在山区溪流里, 喜穴居, 怕光怕声, 以鱼蟹等水生动物为食, 从数量上看, 以陕西秦岭山区居多。大鲵经济价值极高, 在美食、保健、医药、观赏等方面均具有广泛开发利用的前景, 因而颇受社会各界关注。近年来对大鲵的科学研究涉及多个方面, 包括疾病方面, 如病毒性疾病、细菌性疾病、真菌性疾病、寄生虫性疾病等; 生理与发育方面, 如生长、发育、应激反应等; 遗传与进化方面; 保护与开发方面, 如开发药品、食品、保健品等。综上, 围绕大鲵从不同角度所展开的研究非常丰富。大鲵基因水平的研究仍是未来研究的热点和趋势, 其成果将为日后更深层的探究奠定基础。     

大鲵细菌性败血症病原分离及生物学特性研究

利用湖南润孚生物工程公司大鲵人工养殖场10尾具有典型症状的患病大鲵,从体表病灶和体内器官肠、胃、肝、脾、肾等共分离得到9株细菌。通过人工感染试验、细菌形态观察和生理生化实验对其进行鉴定,结果显示引起该养殖场大鲵发病的病原为嗜水气单胞菌。通过回归感染试验发现,其中一菌株对大鲵的致病力很强,死亡率达到100%。药物敏感性试验结果显示,菌株对环丙沙星、头孢曲松、头孢他啶、头孢孟多、头孢哌酮、庆大霉素、头孢西丁药物相对比较敏感,而对克林霉素、头孢唑林、甲硝唑和复方新诺明具有耐药性。     

Response of stream‐breeding salamander larvae to sediment deposition in southern Appalachian (U.S.A.) headwater streams

1. Increased fine sediment deposition is a prevalent threat to stream biodiversity and has been shown to impact stream‐breeding salamanders negatively. However, their complex life histories make it difficult to determine which stage is affected. 2. We conducted field experiments from 26 August to 11 September 2010 and 11 October to 11 November 2010 in two southern Appalachian headwater streams (U.S.A.) to examine the response of larval salamanders to increased fine sediment deposition. Fine sediment was increased in artificial stream channels by 0, 33 and 67%. The number of larvae observed at the end of the experiments was used to determine whether larval microhabitat selection was influenced by fine sediment deposition. A concurrent survey of aquatic larvae in three nearby streams complemented this experiment. Stream substratum composition at survey sites was quantified to examine the effects of fine sediment on larval salamander abundance. 3. Increases in fine sediment deposition failed to explain the number of larval salamanders detected in stream channels. Similarly, a negligible effect of fine sediment was observed on abundance estimates. 4. These results suggest that fine sediment deposition has a minimal impact on aquatic salamander larvae. Therefore, the effects of increased fine sediment loads on stream‐breeding salamanders may not be the result of deleterious effects on the aquatic larvae but instead may be the result of effects on other stages. Management efforts that consider these other stages are therefore needed to protect stream‐breeding salamander communities.     

Eradication of the chytrid fungus Batrachochytrium dendrobatidis in the Japanese giant salamander Andrias japonicus

The purpose of this study was to establish a method for eradicating a chytrid fungus (Batrachochytrium dendrobatidis; Bd) from the Japanese giant salamander Andrias japonicus. The emerging agent (Bd) has a high rate of detection in this endangered amphibian species, which is designated as a special natural monument in Japan. Four Japanese giant salamanders with Bd confirmed by PCR assay were bathed in 0.01% itraconazole for 5 min d-1 over 10 successive days. PCR assays were conducted prior to treatment, on Days 5 and 10 of treatment, and on Days 7 and 14 post-treatment. By treatment Day 5, all individuals tested negative for Bd and remained negative until the end of the experiment. No side effects associated with itraconazole were observed. The present method appears to be a safe and effective approach for Bd eradication and may contribute to reducing the threat and spread of Bd among endangered amphibians. Notably, this study represents the first reported Bd eradication experiment involving Japanese giant salamanders.     

Macro- and micromorphological remodeling of olfactory organs throughout the ontogeny of the fire salamander Salamandra salamandra (Linnaeus, 1758)

This article studies the morphological remodeling of olfactory organs in the fire salamander (Salamandridae, Caudata), from the larval stages of ontogeny to the adult and throughout the course of the annual cycle. The fire salamander exhibits adaptations to the aquatic environment during premetamorphic life and terrestrial adaptations after metamorphosis. During adulthood, the annual activity of this species is divided into three seasonal periods: a breeding period, a nonbreeding period, and hibernation. We observed significant differences in morphology of olfactory organs between developmental stages as well as between each period within the annual cycle. For the first time in caudates, we examined the morphology of olfactory organs during the winter period (wintering larvae, hibernating adults). The results show that the remodeling of olfactory organs during the life of the fire salamander occurs both on macro- and micromorphological levels. Macromorphological ontogenetic variability includes the shape of the main olfactory chamber (MOC) and the distribution of olfactory epithelium (OE) in the MOC and in the vomeronasal organ (VNO). In larvae, the vomeronasal epithelium (VNE) is in a separate cavity, while in the post-metamorphic stages of ontogeny, the VNE occurs in the diverticulum of the MOC. In adult fire salamanders, both olfactory organs are most developed during the breeding season and reduced during hibernation. The VNE and OE in the MOC are also reduced during hibernation. Micro-morphological changes included different types/subtypes of olfactory receptor neurons (ORNs) in the OE in particular stages of ontogeny and periods within the annual cycle, for example, ciliate ORNs are present in the VNE only in the larval stages and giant ORNs occur only in nonbreeding adults. Also, there was a variable set of types of olfactory supporting cells in the VNO of the fire salamander during pre- and postmetamorphic life stages.     

Heterogeneous Vesicles in Mucous Epithelial Cells of Posterior Esophagus of Chinese Giant Salamander (Andrias Davidianus)

The Chinese giant salamander belongs to an old lineage of salamanders and endangered species. Many studies of breeding and disease regarding this amphibian had been implemented. However, the studies on the ultrastructure of this amphibian are rare. In this work, we provide a histological and ultra-structural investigation on posterior esophagus of Chinese giant salamander. The sections of amphibian esophagus were stained by hematoxylin & eosin (H&E). Moreover, the esophageal epithelium was observed by transmission electron microscopy (TEM). The results showed that esophageal epithelium was a single layer epithelium, which consisted of mucous cells and columnar cells. The esophageal glands were present in submucosa. The columnar cells were ciliated. According to the diverging ultrastructure of mucous vesicles, three types of mucous cells could be identified in the esophageal mucosa: i) electron-lucent vesicles mucous cell (ELV-MC); ii) electron-dense vesicles mucous cell (EDV-MC); and iii) mixed vesicles mucous cell (MV-MC).Key words: Amphibian, esophagus, ultrastructure, mucous cells, heterogeneous vesicles     

Genetic diversity of Chinese giant salamander (Andrias davidianus) based on the novel microsatellite markers

Chinese giant salamander (Andrias davidianus) is a rare amphibian species in the world. Microsatellite markers are a promising tool for accurate estimation population structure and genetic diversity. In this paper, we isolated novel microsatellite marker for Chinese giant salamander using fast isolation by AFLP of sequences containing repeats (FIASCO) method. More than 50% sequences in 132 clones had repeat number over ten times with di or trinucleeotide repeat except of (GA)₁₂. Seventy pairs of primers were designed and eleven polymorphic microsatellite loci were characterized for wild and cultivated Chinese giant salamander populations. The allele number was from 3 to 9 in different loci. Polymorphism information content was from 0.544 to 0.702 in cultivated population. The results implied more alleles and PIC were in the wild population than cultivated population. The observed heterozygosities in two populations were higher than 0.553. The data analysis suggested that the cultivated population has lower genetic diversity than wild population, which it??s perhaps owing to inbreeding in artificial breeding. To our knowledge, it??s the first time to isolated microsatellite markers for Chinese giant salamander. The result indicated that the markers were suitable for the population genetic analysis of Chinese giant salamander.     

Polymorphic tetranucleotide microsatellites for Cope's giant salamander (Dicamptodon copei) and Pacific giant salamander (Dicamptodon tenebrosus)

We present primers and amplification conditions for 15 microsatellite loci developed for the Cope's giant salamander (Dicamptodon copei), 14 of which are tetranucleotide repeats. Cross-species amplification revealed 10 of these loci to also be polymorphic in the Pacific giant salamander (Dicamptodon tenebrosus). Several loci produced nonoverlapping allelic ranges between the two species and may be useful in species identification. These polymorphic microsatellite loci are potentially useful for future studies of population genetics in dicamptodontid salamanders.