三种饵料模式对中华绒螯蟹蟹种早期养殖性能、非特异免疫性能及抗病力的影响

为评估不同投喂模式对中华绒螯蟹(Eriocheir sinensis)蟹种质量的影响,采用养殖实验、非特异性免疫指标分析和攻毒实验方法,比较了配合饲料、传统饵料和混合投喂模式培育扣蟹在成蟹养殖早期的养殖性能、免疫性能和攻毒后死亡率的变化。所检测的非特异性免疫指标包括碱性磷酸酶(ALP)、酸性磷酸酶(ACP)、γ-谷氨酰转移酶(γ-GT)、总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)、酚氧化酶(PO)、过氧化物酶(POD)、丙二醛(MDA)、一氧化氮(NO)、谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽还原酶(GR)及血蓝蛋白(Hc)活性或含量。采用毒力较强的嗜水气单胞菌(Aeromonas hydrophilia)Y-2-L-1菌株进行攻毒实验。结果显示:(1)无论雄蟹还是雌蟹,配合饲料组第一次蜕壳间期均短于传统投喂和混合投喂模式,且配合饲料组增重率(WGR)及体重特定增长率(SGR)均显著高于另外两组(P0.05);(2)就肝胰腺中非特异性免疫指标而言,无论雄蟹还是雌蟹,配合饲料组γ-谷氨酰转移酶(γ-GT)、总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)活性均高于另外两组,其中γ-谷氨酰转移酶(γ-GT)差异显著;传统投喂组酸性磷酸酶(ACP)、丙二醛(MDA)、一氧化氮(NO)和过氧化物酶(POD)含量均高于另外两组,其中酸性磷酸酶(ACP)和一氧化氮(NO)含量差异显著;(3)就血清中各免疫指标而言,配合饲料组谷胱甘肽过氧化物酶(GSH-Px)和总抗氧化能力(T-AOC)活性高于另外两组,但差异均不显著(P0.05),传统投喂组碱性磷酸酶(ALP)、酸性磷酸酶(ACP)、丙二醛(MDA)及血蓝蛋白(Hc)等指标含量均高于另外两组,其中丙二醛(MDA)差异显著;(4)无论雄蟹还是雌蟹,传统投喂组扣蟹攻毒后12~96 h的累计死亡率一直高于配合饲料组和混合投喂组,配合饲料组和混合投喂组雄体攻毒后的累计死亡率接近,混合投喂组雌体累计死亡率居于传统投喂组和配合饲料组之间。综上,投喂配合饲料可以提高扣蟹在成蟹早期的养殖性能、免疫性能和攻毒后的成活率,有利于提高蟹种质量。     

中华绒螯蟹(Eriocheir sinensis)肌肉中不饱和脂肪酸含量与越冬死亡、产卵关系

本文报道了中华绒螯蟹越冬时和越冬后不同性别,不同生活状态粗脂肪中不饱和脂肪酸及肌肉中不饱和脂肪酸含量及变化,分析了不饱和脂肪酸含量与越冬死亡,越冬后交配,产卵和孵化关系。越冬前雌,雄河蟹粗脂肪中不饱和脂肪酸碘（I2）值为57和48。越冬（越冬时,越冬后）死亡雌,雄河蟹粗脂肪中不饱和脂肪酸I2值分别低于28和10;而其肌肉中不饱和脂肪酸的I2值分别低于1．25和0．83。越冬后能成功交配的雄河蟹粗脂肪中不饱和脂肪酸I2值高于33。越冬后交配产卵雌河蟹粗脂肪中不饱和脂肪酸I2值高于42,抱卵并使卵正常孵化的雌河蟹粗脂肪中不饱和脂肪酸I2值大于47。脂肪酸在河蟹的细胞内氧化分解,为越冬提供了能量。     

养殖中华绒螯蟹肠道内优势细菌群组成分析

采用荧光染色计数法对养殖中华绒螯蟹(Eriocheir sinensis)肠道内微生物进行定量分析。结果表明肠道内细菌数量为(2.5±0.9)×106/μL。同时采用分离培养与16S rDNA基因克隆测序相结合的方法对其进行多样性分析,旨在揭示其中可培养细菌的组成结构。结果发现,分离自养殖中华绒螯蟹肠道内的49株代表性细菌均属于γ-变形菌纲(Gammaproteobacteria),其中假单胞菌属(Pseudomonas)、气单胞菌属(Aeromonas)和肠杆菌科(Enterobacteriales)为优势菌群。     

Development and characterization of new microsatellite loci from Chinese mitten crab (Eriocheir sinensis)

A set of new microsatellite loci were isolated from Chinese mitten crab and characterized in two Chinese mitten crab populations. The number of the alleles ranged from 3 to 8 and observed and expected heterozygosity varied from 0.0870 to 0.9565 and 0.3092 to 0.8367 in each population, respectively. Loci HLJEsin1, HLJEsin4, HLJEsin30 in CLN population and HLJEsin6 in CJS population presented significant deviation from Hardy–Weinberg equilibrium (PHWE < 0.001). These markers will be useful for population studies.     

饥饿胁迫对中华绒螯蟹(Eriocheir sinensis)仔蟹的影响

在26.2 ～28.4℃水温条件下,研究了饥饿对中华绒螯蟹(Eriocheir sinensis)仔蟹的形态、行为、存活及体重损失的影响,同时确定了仔Ⅱ的营养饱和储存点(PRS)和不可恢复点(PNR).结果表明:饥饿胁迫下中华绒螯蟹仔Ⅰ、仔Ⅱ、仔Ⅲ的初次死亡时间(T1)分别为8.0、14.0和20.3 d,50％死亡时间(Ts0)分别为11.4、16.0和25.5 d,100％死亡时间(T100)分别为15.0、22.0和32.3 d,耐饥饿能力为仔Ⅲ＞仔Ⅱ＞仔Ⅰ;饥饿期间中华绒螯蟹体内水分含量持续升高,干重量降低显著,干重损失速率也随时间延长逐渐减小;先饱食后饥饿的给饵模式中仔Ⅱ蜕皮率随初始饱食时间延长而升高,50％个体完成蜕皮所需饱食时间(PRS50)为2.10d,各处理组仔Ⅱ的蜕皮周期与持续饱食组均无显著差异(P＞0.05),但只有饱食3d以上才能达到持续饱食饲养蟹的增重率;先饥饿后饱食的给饵模式中,仔Ⅱ的蜕皮率随着初始饥饿时间的延长而下降,其中仔Ⅱ50％不能蜕皮的初始饥饿时间(PNR50)和100％不能蜕皮的初始饥饿时间(PNR100)分别为10 d和14 d,并且蜕皮周期相对延长,延长时间约等于初始饥饿时间,不存在额外的摄食时间来弥补饥饿期间损失的能量,各处理组蜕皮后仔蟹与对照组体重无显著差异(P＞0.05).     

Microsatellite analysis of genetic diversity and population structure of Chinese mitten crab （Eriocheir sinensis）

Chinese mitten crab (Eriocheir sinensis) has higher commercial value as food source than any other species of Eriocheir in China.To evaluate the germplasm resources and characterize the genetic diversity and population structure of the crabs in different water systems,two stocks and two farming populations were assessed with 25 polymorphic microsallite loci available in public GenBank.Basic statistics showed that the average observed heterozygosity (Ho) amongst populations ranged from 0.5789 to 0.6824.However,a remarkable presence of inbreeding and heterozygote deficiencies were observed.To analyze population structure,pairwise FST coefficients explained only ～10.3% variability from the subdivision of mitten crab populations,the remaining variability stems from the subdivision within subpopulations.Although the four populations had slight differentiation,different allelic frequencies resulted in distinct population structures.Two stocks and one farming population were clustered together to the phylogenetic branch of Yangtze crab,with an approximate membership of 95%.Whereas,another fanning population was clustered singly to the phylogenetic branch of the Liaohe crab,with a membership of 97.1%.The tests for individual admixture showed that Yangtze crab had probably been contaminated with individuals from other water systems.Genetic relationships between populations also supported the conclusion that Yangtze crab and Liaohe crab had different gene pools in spite of the origins of the same species.     

中华绒螯蟹（Eriocheir sinensis）肌肉中粗脂肪含量与死亡,产 …

本文报道了中华螯蟹越冬时,越冬后不同性别、不同生活状况肌肉中粗脂肪含量及变化。越冬时、越冬后死亡的♂♀河蟹肌肉中粗脂肪的含量均不到８％,而同时越冬成活的♂♀蟹肌肉中粗脂肪含量均高于１０％。顺利越冬并能产卵的雌蟹肌肉中粗脂肪含量为４．９６％,顺利越冬并交配的♂性肌肉中粗脂肪含量为４．１８％。产卵并抱卵孵化的♀蟹肌肉中粗脂肪含量为５．８５％,产卵但♀蟹中途死亡的其肌肉中粗脂肪的含量为５．４７％。交配不     

A set of new microsatellite loci isolated from Chinese mitten crab,Eriocheir sinensis

Eriocheir sinensis has higher commercial value as food source than any other species of Eriocheir in China. To protect its germplasm resources and evaluate impact on local ecology, molecular tools to characterize the population structure and identify kinships from different water systems are highly needed. We have newly identified a set of 18 microsatellite markers with the observed number of alleles at each locus ranges from 8 to 30, the observed heterozygosity ranges from 0.140 to 0.900. These newly isolated markers increase the available molecular resources that can be used to analyse population structure of Chinese mitten crab.     

Phylogenetic analysis of intestinal bacteria in the Chinese mitten crab (Eriocheir sinensis)

AIMS: To identify the dominant intestinal bacteria in the Chinese mitten crab, and to investigate the differences in the intestinal bacteria between pond-raised and wild crabs. METHODS AND RESULTS: The diversity of intestinal bacteria in the Chinese mitten crabs was investigated by denaturing gradient gel electrophoresis (DGGE) fingerprinting, 16S rRNA gene clone library analysis and real-time quantitative PCR. The principal component analysis of DGGE profiles indicated that substantial intersubject variations existed in intestinal bacteria in pond-raised crab. The sequencing of 16S rRNA genes revealed that 90-95% of the phylotypes in the clone libraries were affiliated with Proteobacteria and Bacteroidetes. Some genera were identified as unique in wild crabs and in pond-raised crabs, whereas Bacteroidetes was found to be common in all sampled crab groups. Real-time quantitative PCR indicated that the abundance of Bacteroides and the total bacterial load were approximately four-to-10 times higher in pond-raised crabs than in wild crabs. A significant portion of the phylotypes shared low similarity with previously sequenced organisms, indicating that the bacteria in the gut of Chinese mitten crabs are yet to be described. CONCLUSIONS: The intestinal bacteria of pond-raised crabs showed higher intersubject variation, total diversity and abundance than that observed in wild crabs. The high proportion of the clones of Proteobacteria and Bacteroidetes in the clone library is an indication that these bacteria may be the dominant population in the gut of the Chinese mitten crab. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated obvious differences in the intestinal bacterial composition of pond-raised crabs and wild crabs. This knowledge will increase our understanding of the effects of aquaculture operations on bacterial community composition in the crab gut and provide necessary data for the development of probiotic products for crab cultivation.     

Gait selection and the ontogeny of quadrupedal walking in squirrel monkeys (Saimiri boliviensis)

Locomotor researchers have long known that adult primates employ a unique footfall sequence during walking. Most mammals use lateral sequence (LS) gaits, in which hind foot touchdowns are followed by ipsilateral forefoot touchdowns. In contrast, most quadrupedal primates use diagonal sequence (DS) gaits, in which hind foot touchdowns are followed by contralateral forefoot touchdowns. However, gait selection in immature primates is more variable, with infants and juveniles frequently using LS gaits either exclusively or in addition to DS gaits. I explored the developmental bases for this phenomenon by examining the ontogeny of gait selection in juvenile squirrel monkeys walking on flat and simulated arboreal substrates (i.e., a raised pole). Although DS gaits predominated throughout development, the juvenile squirrel monkeys nonetheless utilized LS gaits in one-third of the ground strides and in one-sixth of pole strides. Multiple logistic regression analyses showed that gait selection within the juvenile squirrel monkey sample was not significantly associated with either age or body mass per se, arguing against the oft-cited argument that general neuromuscular maturation is responsible for ontogenetic changes in preferred footfall sequence. Rather, lower level biomechanical variables, specifically the position of the whole-body center of mass and the potential for interference between ipsilateral fore and hindlimbs, best explained variation in footfall patterns. Overall, results demonstrate the promise of developmental studies of growth and locomotor development to serve as "natural laboratories" in which to explore how variability in morphology is, or is not, associated with variability in locomotor behavior.     

Reproductive function of Selenoprotein M in Chinese mitten crabs (Eriocheir sinesis)

Selenoproteins are present in all major forms of life, including eukaryotes, bacteria and archaea. In eukaryotic animals, selenoproteins often function as antioxidants, but rare or absent in other phyla, such as plants and fungi (except for the green alga Chlamydomonas). Selenoprotein M (SelM) is a selenocysteine containing protein with redox activity, which is involved in the antioxidant response. However, information remains limited about SelM physiology and function in marine invertebrates, particularly in crustaceans. Hence, we investigated the reproductive functionality of SelM in the Chinese mitten crab (Eriocheir sinensis), which is a commercially important yet disease vulnerable aquaculture species. The full-length SelM cDNA (928bp) strand was cloned by using PCR, based on an initial expressed sequence tag (EST) that was isolated from a hepatopancreatic cDNA library. The SelM cDNA contained a 390bp open reading frame (ORF) that encoded a putative 129 amino acid (aa) protein. SelM mRNA expression in E. sinensis was (a) tissue-specific, with the highest expression observed in the hepatopancreas, testis, ovaries and intestines. Based on this information, we then detected the different stages of tissue expression for SelM in the testis, ovary, and male crab hepatopancreas and hemolymph, and the enzyme activity of SelM in the testis. Overall, SelM was isolated successfully from the Chinese mitten crab, and its involvement in the regulation of reproduction during the period of rapid development in E. sinensis was confirmed.     

Mating behaviour and chemical communication in the invasive Chinese mitten crab Eriocheir sinensis

Mating in the Chinese mitten crab (Eriocheir sinensis) was examined; in particular the nature of mating and the role of sex pheromones. A semi-lunar periodicity (16.8 days and 14.5 days, respectively) was observed in the mating frequencies in two consecutive breeding seasons (2001-2002 and 2002-2003). This semi-lunar rhythm coincided with spring tides (full and new moon), and activity peaked in November. Observation of the progression of specific behaviour types in mating and non-mating pairs revealed that pairs which would go on to complete mating progressed from fighting to mating behaviour significantly faster than non-mating pairs. These findings indicate that mate recognition occurs only after physical contact. Reproductively active pairs (ascertained from mating experiments) were then used for several bioassays aiming to assess under which conditions pheromones may be released by females. Firstly, male E. sinensis were exposed to female smell in an actograph experiment and secondly, male antennule flick rate was recorded before and after exposure to the urine of a sexually active female. In both cases no change in male E. sinensis behaviour was observed. Both experiments used females which had not had immediately prior exposure to males. However, in further experiments using water where mating had occurred, a significant response in antennule flick rate was triggered. Finally, a sponge assay was used in order to test the male attraction to a sponge injected with a water sample of varying concentrations (0.5×, 1×, 3×, 4.5×, 9×) of female smell. These samples were conditioned using a female immediately following a mating attempt. Males tried to grasp the sponge at 3× increased concentrations or higher. In conclusion, this study found no indication that E. sinensis females release a distance pheromone, but instead that mate recognition occurs after physical contact between male and female, most likely via a contact pheromone.     

Invasion biology of the Chinese mitten crab Eriochier sinensis: A brief review

The Chinese mitten crab Eriocheir sinensis is a native of freshwater and estuarine habitats along the east coast of Asia. Invasive populations have existed in northern Europe since the early 20th century, and more recently a breeding population has become established in the San Francisco Bay system along the west coast of North America. Ballast water is the most probable vector for both invasions, although there is also potential for escape from ethnic markets and from the ornamental aquarium industry. Invasive populations of mitten crabs have caused millions of dollars in economic and ecological damage. Economic impacts center largely on the burrowing activity of the crabs, which damages stream banks and levees, and the annual spawning migration, which interferes with fishing activities and irrigation projects. Chinese mitten crabs have recently appeared in the Chesapeake and Delaware Bays on the east coast of the USA, and there are confirmed reports of breeding females in both estuaries. The potential for large populations of mitten crabs in these estuaries has not been determined. This paper presents a review of the biology and ecology of native and invasive populations of the species and provides recommendations for research relevant to the prediction of future mitten crab invasions.     

Experimental alteration of limb posture in the chicken (Gallus gallus) and its bearing on the use of birds as analogs for dinosaur locomotion

Extant birds represent the only diverse living bipeds, and can be informative for investigations into the life‐history parameters of their extinct dinosaurian relatives. However, morphological changes that occurred during early avian evolution, including the unique adoption of a nearly horizontal femoral orientation associated with a shift in center of mass (CM), suggest that caution is warranted in the use of birds as analogs for nonavian dinosaur locomotion. In this study, we fitted a group of white leghorn chickens (Gallus gallus) with a weight suspended posterior to the hip in order to examine the effects on loading and morphology. This caused a CM shift that necessitated a change in femoral posture (by 35° towards the horizontal, P < 0.001), and resulted in reorientation of the ground reaction force (GRF) vector relative to the femur (from 41° to 82°, P < 0.001). Despite similar strain magnitudes, an overall increase in torsion relative to bending (from 1.70 to 1.95 times bending, P < 0.001) was observed, which was weakly associated with a tendency for increased femoral cross‐sectional dimensions (P = 0.1). We suggest that a relative increase in torsion is consistent with a change in femoral posture towards the horizontal, since this change increases the degree to which the bone axis and the GRF vector produce mediolateral long‐axis rotation of the bone. These results support the hypothesis that a postural change during early avian evolution could underlie the allometric differences seen between bird and nonavian dinosaur femora by requiring more robust femoral dimensions in birds due to an increase in torsion. J. Morphol. 240:237–249, 1999. © 1999 Wiley‐Liss, Inc.