虾塘中新生残饵的N、P营养物质溶出速率及其变化规律研究

通过实验模拟的测定结果,估算了新生残饵对虾塘养殖环境的可能影响程度.结果表明,两种新生残饵的N、P营养物质溶出速率及其TN与TP、IP与TP比值,随其生成时间的延长均有较大幅度变化,且变化趋势相近.贻贝新生残饵因其分解速率较快,故对养殖水体短期影响较大,但其总体影响却并不大于配合饵料.新生残饵是对虾养殖水环境及其临近浅海环境的主要污染源.     

对虾行为生态学研究进展Ⅱ.环境因子对对虾行为习性的影响

综述了近年来国内外关于外界环境因子对对虾行为习性影响的研究进展.着重介绍了光、水流和潮汐、溶解氧、底质及水温等环境因子对对虾摄食、运动、产卵、蜕皮及潜底和浮现等行为习性的影响,并探讨了对虾对环境因子变动的行为调节.提出了对虾行为生态学研究中存在的问题以及今后的研究方向,即对虾的行为习性和疾病传播间的关系、对虾的行为习性对养殖生态系统的影响和高密度工厂化养殖环境对对虾行为特征的综合影响等.     

高亚硝酸盐环境下不同生长速率凡纳滨对虾肠道微生物多样性研究北大核心

【目的】高亚硝酸盐环境中饲养的凡纳滨对虾(Litopenaeus vannamei),在养殖结束时其生长速率和体重往往差异较大。本研究旨在探讨在高亚硝酸盐环境下饲养的对虾生长速率与肠道菌群结构和功能的相关性。【方法】本研究通过收集高亚硝酸盐条件下快速生长对虾(rapidly growing,RG)、正常生长对虾(normally growing,NG)和缓慢生长对虾(slowly growing,SG)的肠道和海水样品,通过16S rRNA基因测序、线性判别分析[line discriminant analysis(LDA)effect size,LEfSe]等进行分析。【结果】发现SG的细菌群落多样性与RG和NG不同。主坐标分析(principal coordinate analysis,PCoA)分析表明,NG的群落组成与RG比SG更相似。通过LEfSe差异分析发现,RG中火色杆菌科(Flammeovirgaceae)、黄杆菌科(Flavobacteraceae)和浮酶菌科(Planctomycetaceae)的丰度较高,而SG中脱硫弧菌科(Desulfovibrionaceae)、希瓦氏菌科(Shewanellaceae)和弧菌科(Vibrionaceae)的丰度显著增加。【结论】本研究发现,在高亚硝酸盐环境下,肠道微生物群落的氮代谢能力是造成对虾不同生长速度的原因。该研究将为虾的工业化养殖提供指导。     

周期性断食对凡纳滨对虾摄食、生长和排粪的影响

凡纳滨对虾(Litopenaeus vannamei)具有生长快、环境适应力强、适合进行集约化养殖等优点,现已成为我国沿海甚至内陆地区对虾养殖的主要品种.     

斑节对虾血淋巴免疫指标变化与其养殖池塘理化因子的关系

2009 年8 月至9 月期间, 在广东粤西选择2 口斑节对虾养殖土池(303、501 号池), 每14 天一次定期采集养殖对虾和水样, 检测了对虾血清的PO、SOD、Ua、AKP、ACP 等免疫酶活力和水温、DO、氨氮、亚硝氮等环境因子, 探讨养殖对虾免疫指标与环境因子的相关关系。结果发现, 较高的COD、BOD、pH 与较低盐度的303 号池对虾血清SOD、Ua、AKP、ACP活力大体上低于501 号池, PO 活力高于501 号池; 8 月25 日到9 月8 日, 501 号池氨氮、亚硝氮和硝氮浓度由高于303 号池转变为低于303 号池, 其对虾血清PO、SOD 活力由低于303 号池转变为高于303 号池。本实验中COD、BOD、pH 与盐度的耦合作用对斑节对虾血淋巴免疫指标的影响是明显的, 氨氮、亚硝氮和硝氮为影响斑节对虾血淋巴PO、SOD 等活力的关键因子。     

凡纳对虾淡化养殖池浮游纤毛虫研究

在对虾养殖环境,纤毛虫能摄食大量的腐质和藻类,促进对虾养殖水体的自身净化;但缘毛类 Peritrichida 和吸管虫类Suctorida纤毛虫能大量固着生活在对虾的附肢、鳃等部位,是对虾养殖的重要危害生物。在我国,对海水、盐碱池和淡水养殖环境的浮游动物(包括纤毛虫)有较多的研究,对河口区斑节对虾淡化养殖环境浮游生物也有报道,本文报道了珠海市斗门区某凡纳对虾 Litopenaeus vannamei(南美白对虾)养殖基地44口淡化养殖虾池浮游纤毛虫种类及数量组成, 并对其中 1-5号虾池养殖过程中的纤毛虫种群的动态变化进行了研究,以期为凡纳对虾淡化养殖提供参考。       

沙蚕移植在对虾养殖中的应用及生态效益

日本刺沙蚕属广盐性种 ,在我国 3～ 4月生殖 ,生殖时亲体群浮 ;其幼虫在 6刚节之前营浮游生活 ,以后随海流漂至河口低盐区开始下沉营底栖生活。对虾养殖可利用这一生活习性选择有利的海区和潮汐时间纳苗或移植亲体 ,使沙蚕在虾池中大量栖居 ,既为对虾提供动物性活饵 ,带动对虾生产过程 ;又可以净化底质 ,保持虾池良好的物质循环和水质     

两种微藻改善虾池环境增强凡纳对虾抗病力的研究

人工引入波吉卵囊藻和微绿球藻于凡纳对虾养殖环境中,检测与凡纳对虾抗病力有关因子变化和测定主要水质因子,研究微藻生态调控对凡纳对虾抗病力的影响。结果表明,引入波吉卵囊藻和微绿球藻能改善养殖水体的水质,凡纳对虾的血细胞数目,血清蛋白的含量以及酚氧化酶、超氧化物歧化酶,溶菌酶,抗菌酶的活性都较对照组显提高。因此,微藻生态调控是防止对虾疾病的重要技术措施。     

尖山蟹养殖塘叶绿素a与环境因子的通径分析

本试验以通径分析的方法来研究尖山蟹养殖水体环境因子变化对Chl.a的影响,通过相关性分析和逐步回归分析剔除了对Chl.a影响不大的盐度、pH和NO2--N,并在此基础上根据偏回归系数建立尖山蟹养殖池塘Chl.a与环境因子的回归方程。重点进行了通径分析,计算得出TP、TOC、氨态氮、硝态氮和TN变化对Chl.a影响的直接通径系数分别为0.169、0.262、-0.627、0.676、0.228,间接通径系数总和分别为-0.155、-0.325、-0.166、0.606和0.271,说明在尖山蟹养殖塘中影响Chl.a的优势因子依次为TP、TOC、NH4+-N、NO3--N和TN,各环境因子通过其它环境因子对Chl.a起正作用或副作用。研究表明,通径分析能够更科学地了解尖山蟹养殖塘水体系统的影响结构,为更合理的水环境控制及健康养殖提供科学依据。     

虾-鱼-贝-藻养殖结构优化试验研究

本研究建立了一种虾、鱼、贝、藻优化养殖结构及水质调控系统,该系统包括对虾养殖、鱼类养殖、贝类养殖、大型海藻栽培等4个功能不同的养殖区,1个益生菌及微藻培养区和1个水处理区以及1条应急排水渠。通过在封闭循环水养殖系统内不同池塘中放养生态位互补的对虾、口孵非鲫、牡蛎、江蓠等经济动植物,对虾池水质环境进行生物调控与自我修复。结果表明,循环水养殖系统内虾池水层悬浮物数量、COD值、氨态氮和总氮含量比对照组对虾单养池明显降低。养殖后排放水不处于富营养化状态(E<1)。投入每千克对虾饲料生产0.667kg对虾,同时生产0.037kg口孵非鲫、0.738kg牡蛎、0.437kg江蓠,相当于净增产值2.01元。投入与产出比,对虾单养为0.671,优化生态养殖为0.235,明显降低。该养殖模式不仅实现了虾池水质环境的自我修复与调控及养殖期间用水的零排放,而且饲料利用率大幅度提高,经济效益显著增加,还具有防病性、环保性、高效性等优点。     

虾塘底质的总耗氧量及其季节变化

虾塘底质的总耗氧量及其季节变化孙耀（中国水产科学研究院黄海水产研究所,青岛２６６０７１）Ｔｏｔａｌｏｘｙｇｅｎｃｏｎｓｕｍｐｔｉｏｎｏｆｓｅｄｉｍｅｎｔｉｎｓｈｒｉｍｐｐｏｎｄｓａｎｄｉｔｓｓｅａｓｏｎａｌｖａｒｉａｔｉｏｎ￥．ＳｕｎＹａｏ（Ｙｅｌｌ...     

Exploring the role of large predators in marsh food webs: evidence for a behaviorally-mediated trophic cascade

The influence of large predators on lower trophic levels in oligotrophic, structurally complex, and frequently disturbed aquatic environments is generally thought to be limited. We looked for effects of large predators in two semi-permanent, spikerush-dominated marshes by excluding large fish (>12 mm body depth) and similarly sized herpetofauna from 1 m² cages (exclosures) for 2 weeks. The exclosures allowed for colonization by intermediate (in size and trophic position) consumers, such as small fish, shrimp, and crayfish. Exclosures were compared to control cages that allowed large fish to move freely in and out. At the end of the experiment, intermediate-consumer densities were higher in exclosures than in controls at both sites. Decapod crustaceans, especially the riverine grass shrimp (Palaemonetes paludosus), accounted for the majority of the response. Effects of large fish on shrimp were generally consistent across sites, but per capita effects were sensitive to estimates of predator density. Densities of intermediate consumers in our exclosures were similar to marsh densities, while the open controls had lower densities. This suggests that these animals avoided our experimental controls because they were risky relative to the surrounding environment, while the exclosures were neither avoided nor preferred. Although illuminating about the dynamics of open-cage experiments, this finding does not influence the main results of the study. Small primary consumers (mostly small snails, amphipods, and midges) living on floating periphyton mats and in flocculent detritus (“floc”) were less abundant in the exclosures, indicative of a trophic cascade. Periphyton mat characteristics (i.e., biomass, chlorophyll a, TP) were not clearly or consistently affected by the exclosure, but TP in the floc was lower in exclosures. The collective cascading effects of large predators were consistent at both sites despite differences in drought frequency, stem density, and productivity.     

Influence of peat substrate on the distribution and behaviour patterns of sand shrimp, Crangon septemspinosa, under experimental conditions

Peat harvesting is a lucrative industry in New Brunswick, Canada, and is for the most part located along the coast. Current methods of mining peatlands are such that high levels of peat fibers are transported by runoff into fresh and marine waters. To understand better the influence of peat substrate on aquatic organisms living in peat‐impacted habitats, the sand shrimp (Crangon septemspinosa) was used as a bioindicator. A series of laboratory experiments was conducted in which shrimp were provided with a choice between sand and peat. Long‐term studies on starved shrimp confirmed that whereas foraging activities took place on both substrates, shrimp display an overall preference for sand (73% of all shrimp observed were on sand, n=60). When food was deposited on each of the substrates, shrimp generally opted to feed on sand (75% of all shrimp observed were on sand, n=60). After all food on sand was consumed, shrimp tended to move to peat. This was followed by a short period of foraging on both sand and peat with an eventual return to sand in most instances. The presence of food on both substrates did not influence their preference for sand. However, shrimp will move onto a peat substrate to forage if food is present only there. This observation suggests that, although there is a marked preference for sand, peat is not completely repellent to them. Finally, histological investigations of the shrimp digestive system revealed that peat was ingested with food particles and processed in the gastric mill. There was, however, no discernible discrimination between the two substances during ingestion. Finally, starved shrimp on peat substrate did not ingest peat fibers, suggesting that peat is not perceived as an alternative food source.     

对虾转基因研究的现状和展望

随着生物技术的发展,通过基因工程手段获得对虾新品种成为可能,然而经过十几年努力,目前对虾转基因研究依然处于初级阶段。各国科学家正在加紧研究,争取有所突破。综述了近年来国内外对虾转基因研究的进展以及目前面临的技术和安全问题,同时对未来对虾的转基因技术发展和应用前景进行了讨论 。     

Diet influence on growth-characteristics of the shrimp Crangon Crangon L., estimated by the evolution of nucleic acid content (author's transl)]

1. Young sand-shrimps having an initial weight of 63 mg were reared for 4 months with a natural diet (A) and a compounded diet (B). 2. Growth is studied, both by the evolution of the fresh weight and the variation of cell-number and cell-size; these are estimated from total DNA and fresh-weight/DNA ratio evolution. 3. With diet A, the mean weight increment is a linear function of time, the daily weight-gain being equal to 2.8 mg/day. The increase in total DNA content per shrimp is a linear function of fresh weight; its value goes up from 187 to 1020 micromoles. The fresh-weight/DNA ratio, initially equal to 337.9 (mg/micromoles) ,remains constant. For the whole experiment, growth is only a result of cellular multiplication. 4. With diet B, the weight gain is inferior to that observed with diet A. The fresh weight gain curves show two visibly homogenous steps, each with a distinct growth-rate; the mean daily weight gain is equal to 1.7 mg/day during the first two months, and equal to 2.6 mg/day for the two following months (fig. 1). In reality, from the total DNA and fresh-weight/DNA ratio evolution, 3 successive steps can be discerned (fig. 2, fig. 3). During the first month, total DNA increases from 187 to 418 micromoles and fresh-weight/DNA ratio falls down to 273.9, a-19% decrease. For this period, growth is only the result of cellular multiplication, and the decrease of the weight-gain in comparison with diet A is attributed to a decrease in cellular size. During the second month, as the fresh weight increases from 114.5 to 161.2 mg, total DNA increases from 418 to 519 micromoles and the fresh-weight/DNA ratio returns to its initial value. Two thirds of the growth is the result of cellular multiplication, and the rest being due to cell-size enlarging. For the last two months, as the mean fresh weight increases from 161.2 to 296.7 mg, the DNA per shrimp, hence the cell-number, remains constant; but the fresh weight/DNA ratio, or the cell-size, is multiplied by 1.93. 5. By the method used for this study, it is possible to evidence influence of diet on the growth mechanisms themselves (cellular multiplication and cell enlarging). 6. The influence of diet on the growth of the shrimp could be explained by, either a diet qualitative deficiency, or a food-intake decrease. The possibility of a hormonal control has been suggested.     

Gene-culture waves of advance

Major genetic and cultural changes may have been coupled during hominid evolution. Since hominids have had a wide geographical distribution for about one million years, any mutant gene or cultural innovation that became established had to spread from its origin. A pair of nonlinear diffusion equations is derived which models the propagation of a mutant gene and a cultural innovation. Both are assumed to originate in the same locality along a linear habitat. The mutant gene and its allele are semidominant, and the two cultural choices are transmitted according to what I call the logistic attraction-repulsion model. The genes influence cultural choice, and the two interact to determine fitness. Of particular interest is the case in which mutant gene and cultural innovation are mutually dependent, neither being able to spread without the other. Each equation of the pair is similar in form to Fisher's equation, with a linear function of the other dependent variable replacing the constant coefficient in the reaction term. The partial differential equations are solved numerically to obtain the asymptotic speeds. Their form also suggests an heuristic argument which has proved useful, but I have been unable to obtain any analytic results. The waves of the system are shown to be of two types, synchronous and asynchronous. When genes and culture are mutually dependent, synchronous travelling waves can exist. However, their existence is dependent on initial conditions, and the speed of propagation is slow.     

Cloning and expression analysis on a homolog of spermatogonial stem-cell renewal factor in Fenneropenaeus chinensis

The spermatogonial stem-cell renewal factor (SSRF) was named since its function in spermatogonial mitosis was reported in Japanese eel. Our previous study showed that a homolog of SSRF was highly expressed in the ovary of triploid shrimp, but not expressed in the ovary of diploid shrimp. To understand the function of SSRF in shrimp, the full-length cDNA of ssrf gene was cloned from Chinese shrimp Fenneropenaeus chinensis (Fcssrf) and its expression was analyzed. The full length of Fcssrf cDNA was 2588?bp and it contained an open reading frame encoding 450 amino acids. The predicted tertiary structure of FcSSRF was very similar to that of SSRF/eSRS34 from Anguilla japonica and TP/PD-ECGF from Homo sapiens. RT-PCR analysis showed that the Fcssrf was highly expressed in nerve, testis, hepatopancreas, gill, and stomach rather than in ovary. Expression of Fcssrf mRNA was not detected during embryonic stages and larval stages, from the nauplii to the post-larvae stage, in diploid, and triploid shrimp. However, it began to be expressed in juvenile stages (June–September) in diploid and triploid shrimp. Immunohistochemical analyses showed that FcSSRF was identified in both the diploid testis and triploid ovary. We inferred that the Fcssrf might be related to testis development.     

Molecular mechanisms of the shrimp clotting system

Shrimp, like other invertebrates, relies solely on its innate immune system, to combat invading pathogens. The invertebrate immune system has ancient origins that involve cellular and humoral responses. The clotting system of the humoral immune response is the first line of defense against pathogens and also serves to prevent blood loss during injury and wound healing. Tranglutaminase and clotting protein are molecules involved in the blood clotting system of crayfish and shrimp. Studies have shown that the shrimp clotting system is linked with the activation of antimicrobial peptides, similar to that of the horseshoe crab. Unlike the horseshoe crab and crayfish blood coagulation which are well studied systems, blood clotting in shrimp remains poorly understood. Here we review the shrimp clotting system and its involvement in innate immunity.