Structural development of Pacific red snapper Lutjanus peru from hatching to the onset of first feeding          下载免费PDF全文

Iram Zavala‐Leal  Silvie Dumas  Edgar O. López‐Villegas  Renato Peña  Mauricio Contreras‐Olguín  Laura Flores‐Montijo  José De La Cruz‐Agüero 《Aquaculture Research》2015,46(5):1162-1174

Successful rearing of larval fish requires culture conditions and feeding strategies matching the ontogenetic status of larvae. This study describes the external morphology and development of organs and structures involved in the feeding process (i.e. sensorial organs, mouthparts and digestive system) from hatching until first feeding in Pacific red snapper. Hatching occurred 26 h after fertilization at 26°C and total length (TL) was 2.45 ± 0.08 mm. The larvae showed an undifferentiated eye and digestive tract. At 48 hah, TL was 3.31 ± 0.12 mm. Yolk and oil globule were still present. The mouth was still closed, but the Meckel's, quadrate, hyoid and hyomandibular cartilages were present. The retina was formed by 5 layers, and a thin layer of pigment epithelium was observed in the outer nuclear layer (ONL). At 70 hah, TL was 3.44 ± 0.22 mm. A remnant of oil globule was still present. The mouth and anus were open. At 93 hah, the number of cones in the ONL of the retina have increased and there was more pigment in the pigment epithelial layer. A joint between Meckel's and the quadrate cartilage and also a joint between the hyomandibular cartilage and the skull were present. The presence of live feed was detected in the digestive tract of these larvae. Based on these observations, the Pacific red snapper larvae is functional to start ingesting live feed between the 3rd and 4th day after hatching.  相似文献   

水稻WRKY转录因子OsWRKY71的cDNA分离和表达分析     

邹克琴  汪得凯  胡东维  李素芳  陈振煌 《浙江农业学报》2014,26(6):1405

WRKY蛋白是植物中最大的转录因子家族之一,对植物的生长发育具有重要调控作用。利用SMART\|RACE\|PCR技术分离获得水稻WRKY转录因子基因（OsWRKY71）的全长cDNA序列,并进行了相关的生物信息学分析。分离到的水稻WRKY转录因子cDNA全长为1 245 bp（GenBank登录号KJ137000）,开放阅读框1 047 bp,编码348个氨基酸,分子量为3828 kDa,OsWRKY71具有WRKY转录因子家族典型的保守结构域,属于第Ⅱ组WRKY蛋白家族。系统进化分析表明,OsWRKY71氨基酸序列与禾本科作物小麦的亲缘关系最近,其中与小麦序列相似性为69%,和大麦的序列相似性为68%。荧光定量PCR检测表明,OsWRKY71在孕穗期剑叶中表达丰度最高,根中最低,具有表达的空间差异性。抗病品种‘IR28’在受到稻曲菌诱导的初期,OsWRKY71基因表达呈现先升高后下降趋势,易感品种‘甬优9号’在受到稻曲菌诱导后表达受到抑制。这些结果表明,OsWRKY71的表达对稻曲菌侵染有应答响应,很可能在水稻防御稻曲菌侵染的机制中发挥作用。  相似文献   

江苏宝应湖湿地秋冬两季鸟类区系组成及多样性调查     

马德高  宋丹红  赵强  潘达  汪霄  陈志芳 《浙江农业学报》2014,26(3):0

于2012年9月至2013年3月采用样线法对江苏扬州宝应湖湿地冬季鸟类的区系组成进行调研,调查期间共记录到鸟类56种,隶属11目28科。冬季鸟类组成中,留鸟31种,冬候鸟19种,旅鸟6种。古北界鸟类24种,东洋界鸟类20种,其余12种为广布型,鸟类的区系组成兼有古北界和东洋界过渡的特点。鸟类群落多样性的比较分析显示,湖岸生境较敞水区生境的鸟类多样性程度高。调查期间未发现大型雁鸭类。结果表明,保护区域内越冬鸟类的多样性,必须权衡满足当地居民对淡水资源的合理需求与尽可能多地保护生物多样性这两者之间的关系。  相似文献   

First isolation of hirame rhabdovirus from freshwater fish in Europe     

E Borzym  M Matras  J Maj‐Paluch  M Baud  C De Boisséson  C Talbi  N J Olesen  L Bigarré 《Journal of fish diseases》2014,37(5):423-430

A rhabdovirus was isolated in cell culture inoculated with tissue material from diseased grayling, Thymallus thymallus (L.), originating from a fish farm affected by a mortality episode in Poland. Diagnostics tests showed that the virus was not related to novirhabdoviruses known in Europe, nor to vesiculovirus‐like species, except perch rhabdovirus (PRhV) with which it shared moderate serological relations. However, RT‐PCR with PRhV probes gave negative results. To identify the virus, a random‐priming sequence‐independent single primer amplification was adopted. Surprisingly, two of the obtained sequences exhibited a high identity (>99%) with hirame rhabdovirus (HIRRV), a novirhabdovirus usually found in fish in marine Asiatic countries, for instance Japan, China and Korea. The full‐length sequence of the phosphoprotein gene (P) demonstrated a higher identity of the present isolate with HIRRV from China compared with the Korean isolate. An identical viral sequence was also found in brown trout, Salmo trutta trutta L., affected by mortalities in a second farm in the same region, after a likely contamination from the grayling farm. To our knowledge, this is the first report of HIRRV in Europe, and in two hosts from fresh water that have not been described before as susceptible species.  相似文献   

n-3 LC-PUFA deposition efficiency and appetite-regulating hormones are modulated by the dietary lipid source during rainbow trout grow-out and finishing periods     

D. S. Francis  T. Thanuthong  S. P. S. D. Senadheera  M. Paolucci  E. Coccia  S. S. De Silva  G. M. Turchini 《Fish physiology and biochemistry》2014,40(2):577-593

Largely attributable to concerns surrounding sustainability, the utilisation of omega-3 long-chain polyunsaturated fatty acid-rich (n-3 LC-PUFA) fish oils in aquafeeds for farmed fish species is an increasingly concerning issue. Therefore, strategies to maximise the deposition efficiency of these key health beneficial fatty acids are being investigated. The present study examined the effects of four vegetable-based dietary lipid sources (linseed, olive, palm and sunflower oil) on the deposition efficiency of n-3 LC-PUFA and the circulating blood plasma concentrations of the appetite-regulating hormones, leptin and ghrelin, during the grow-out and finishing phases in rainbow trout culture. Minimal detrimental effects were noted in fish performance; however, major modifications were apparent in tissue fatty acid compositions, which generally reflected that of the diet. These modifications diminished somewhat following the fish oil finishing phase, but longer-lasting effects remained evident. The fatty acid composition of the alternative oils was demonstrated to have a modulatory effect on the deposition efficiency of n-3 LC-PUFA and on the key endocrine hormones involved in appetite regulation, growth and feed intake during both the grow-out and finishing phases. In particular, n-6 PUFA (sunflower oil diet) appeared to ‘spare’ the catabolism of n-3 LC-PUFA and, as such, resulted in the highest retention of these fatty acids, ultimately highlighting new nutritional approaches to maximise the maintenance of the qualitative benefits of fish oils when they are used in feeds for aquaculture species.  相似文献   

IUCN Red List of freshwater fishes and lampreys in Flanders (north Belgium)     

H. Verreycken  C. Belpaire  G. Van Thuyne  J. Breine  D. Buysse  J. Coeck  A. Mouton  M. Stevens  T. Van den Neucker  L. De Bruyn  D. Maes 《Fisheries Management and Ecology》2014,21(2):122-132

Red Lists are used to assess the extinction risk of species. Regional IUCN criteria were applied to categorise 42 indigenous freshwater fish species in Flanders into Red List categories. As such, three species are assessed as Regionally Extinct, eight as Critically Endangered, two as Endangered and eight as Vulnerable. A further five species are considered Near Threatened, 15 species as Least Concern and one species is Data Deficient. Five species disappeared from the Regionally Extinct category compared with the previous Red List (1988) as a consequence of improved water quality of estuaries and reintroduction programmes. In total, 62% of the freshwater fish species in Flanders was considered extinct or threatened. This is higher than neighbouring regions and Europe as a whole (44%). This new Red List of freshwater fishes in Flanders can be used to inform conservation actions.  相似文献   

以科学的视角揭开作物转基因的神秘面纱     

崔德周  李永波  樊庆琦  隋新霞  黄承彦  楚秀生 《中国种业》2018,(8):26-28

转基因技术是近现代农业史上发展最为迅猛的作物遗传改良技术。1996年首例转基因作物开展商业化种植,截至2016年转基因作物种植面积已呈百倍增加。人们从转基因作物的大面积推广应用中获得了巨大的经济效益与社会效益。目前转基因在我国被"妖魔化",甚至出现"谈转基因色变"的局面。为使公众对转基因有科学全面的认识,对转基因的基本概念、国内外发展现状、安全性评价等内容进行了阐述,同时展望了转基因作物在我国产业化的发展趋势。  相似文献   

Molecular identification of arbuscular mycorrhizal fungal spores associated to the rhizosphere of Retama raetam in Tunisia     

Mahdhi Mosbah  De Lajudie Philippe  Mars Mohamed 《Soil Science and Plant Nutrition》2018,64(3):335-341

ABSTRACT

Arbuscular mycorrhizal fungi (AMF) are found in the soil of most ecosystems where they form mutualistic associations that affect plants growth. We have investigated the community structure of AMF associated to Retama raetam growing in five regions of Tunisia. The total number of spores was significantly different across sites, ranging from 633 to 1062 spores per 100 g dry soil. A dominance of small spores was revealed. The large subunit region of the rDNA of AMF spores associated to the rhizosphere of R. raetam was sequenced. Sequences clustered into 13 operational taxonomic units. Phylogenetic analysis revealed that the majority of sequences were grouped within Glomeraceae and Claroideoglomeraceae families. Only two sequences were affiliated to the Scutellospora genus. These results suggest the dominance of the genus Glomus in the soil rhizosphere of R. raetam. A correlation between phylogenetic analysis, soil chemicals properties, and AMF community richness was also detected.  相似文献   

Development of the polysaccharidic matrix in biocrusts induced by a cyanobacterium inoculated in sand microcosms     

Gianmarco?Mugnai  Federico?RossiEmail authorView author&#;s OrcID profile  Vincent?John?Martin?Noah?Linus?Felde  Claudia?Colesie  Burkhard?Büdel  Stephan?Peth  Aaron?Kaplan  Roberto?De?Philippis 《Biology and Fertility of Soils》2018,54(1):27-40

Soil inoculation with cyanobacteria (cyanobacterization) is a biotechnological method widely studied to improve soil quality and productivity. During their growth on soil, cyanobacteria excrete exopolysaccharides (EPSs) which glue trichomes to soil particles, in a three-dimensional extracellular polymeric matrix. EPS productivity is an important screening parameter to select proficient inoculants and is affected by growth conditions and abiotic stresses. In this study, we evaluated the capability of the cyanobacterium Schizothrix cf. delicatissima AMPL0116 to form biocrusts when inoculated in sand microcosms under stressing conditions, and the characteristics of the synthesized polymeric matrix. In parallel, we evaluated the characteristics of exopolysaccharidic exudates of the strain when grown in liquid culture, under optimal growth setting. Our results pointed out at significant differences of the exopolymers produced in the two conditions in terms of monosaccharidic composition and molecular weight distribution, and proved the capability of S. cf. delicatissima AMPL0116 to form stable bioaggregates on sandy soils.  相似文献   

Considering neighborhood effects improves individual dbh growth models for natural mixed-species forests in Mexico     

Gerónimo Quiñonez-Barraza  Dehai Zhao  Héctor M. De Los Santos Posadas  José J. Corral-Rivas 《Annals of Forest Science》2018,75(3):78

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