中国东南沿海青蟹线粒体COI基因部分序列分析

对我国东南沿海5个地区的72个青蟹个体的线粒体细胞色素氧化酶亚基I (COI)部分序列序列进行了测定和分析。获得的72个细胞色素氧化酶亚基I (COI)序列可分为12个单倍型，与GenBank中已知的Scylla paramamosain COI序列的相似性达到98%以上，与其它3种 青蟹的差异为7.36%～15.54%。这些序列与S. paramamosain的遗传距离仅为0.00783，但是与S. serrata、S. olivacea和S. tranquebarica〗的遗传距离却分别达到0.11659、0.17812和0.08423。序列特征、遗传距离和系统进化等分析结果都表明本文研究的青蟹为S. paramamosain。结果提示，在进行青蟹属相关研究应当仔细鉴别采集样本的种类。     

Mitochondrial DNA sequence variation of Japanese anchovy <Emphasis Type="Italic">Engraulis japonicus</Emphasis> from the Yellow Sea and East China Sea

Sequence variation of a fragment of the mitochondrial cytochrome b (cyt b) and cytochrome c oxidase subunit I (COI) gene was examined using polymerase chain reaction and direct sequencing among three populations of Japanese anchovy Engraulis japonicus from the Yellow Sea and East China Sea. A total of 24 and 47 nucleotide sites were detected variable defining 29 and 32 haplotypes in cyt b and COI data, respectively. All variable sites except one in COI were silent in the two sets of sequences. The Ewens-Watterson test indicated that the observed allelic configurations in both data sets were in full agreement with neutral expectations. The variation level was high, with h=0.957±0.018, π=0.644±0.387 (%) in cyt b data set and h=0.958±0.021, π=0.640±0.386 (%) in COI data set, respectively. However, at the population level, Fst values between pairs of populations were not significantly different from zero (P>0.05) in both data sets. The analysis of haplotype frequency distribution showed no significant differences among populations. Similarly, the analysis of the partitioning of molecular variance indicated that all or almost all of the genetic variation was distributed within populations. Based on the data from this study, the existence of separate genetic stocks in this area were not detected. Mixing of stocks to some extent in migration cycle and dispersal capacity of anchovy’s planktonic larvae could be the reasons for genetic homogeneity in this species in the Yellow Sea and East China Sea.     

Intraspecific diversity of <Emphasis Type="Italic">Undaria pinnatifida</Emphasis> (Harvey) Suringar (Laminariales,Phaeophyta) from Japan,China and Korea,based on the <Emphasis Type="Italic">cox1</Emphasis> gene and ITS2 sequences

As a trial to develop a method of authenticating the place of origin of circulated Undaria pinnatifida products, we investigated their intraspecific genetic diversity using the mitochondrial cytochrome c oxidase subunit 1 gene (cox1) and the internal transcribed spacer 2 (ITS2) region of the nuclear ribosomal DNA (rDNA) sequence. Four dried U. pinnatifida products labeled with their origins (one from Japan, one from China and two from Korea), natural plants collected from three locations (two from Japan and one from China), and cultivated plants collected from two locations (one from Japan and one from China) were used in the present study. The amplified fragments of cox1 were 664 bp in length, and the aligned sequences were highly homologous. Among the nine sequences, no insertions or deletions were found and six substitution positions were detected, and they were classified into five haplotypes. In contrast, multiple highly variable regions were found in ITS2, and some of them carried a restriction site for Mbo II. Polymerase chain reaction-restriction fragment length polymorphism analysis showed different restricted profiles among the tested samples. The availability of molecular markers for authenticating food products of U. pinnatifida is discussed.     

一种免疫诱导型鲤启动子的克隆与功能分析

为发掘适用于基因工程抗病育种的鱼类启动子,通过实时荧光定量PCR实验对鲤Rab GTP酶(Ras-associated binding-GTPases 1a3,Rab1a3)基因的表达模式进行了分析,证实该基因在鳃、头肾等与机体免疫防御功能密切相关的组织内转录水平较高,且免疫激活后转录显著增强,符合基因工程抗病育种所需的外源免疫基因转录模式。从鲤细菌人工染色体文库中,使用Rab1a3基因特异引物筛选获得包含该基因区域的文库克隆,测序获得该基因完整序列,以及上下游调控序列。通过生物信息学手段,预测到长度为1014 bp的鲤Rab1a3基因启动子序列,该启动子不具有典型的TATA盒或CpG岛特征,存在多个免疫相关转录因子结合位点。在草鱼肾组织细胞系内验证该启动子活性,结果显示,绿色荧光蛋白基因和萤火虫荧光素酶基因都能够在该启动子驱动下表达,证实该片段具有启动子活性,且启动子活性在受到免疫诱导后增强,双荧光素酶报告基因检测结果显示,该启动子活性在免疫刺激后增强至免疫刺激前的8.67倍。研究表明,鲤Rab1a3基因启动子有望被开发成为免疫诱导型的基因工程元件,驱动外源免疫基因在鱼体内适时表达,抵御外界病原感染,同时避免非必要条件下的过度表达形成生长负担。     

西伯利亚鲟海豚链球菌和鲟疱疹病毒Ⅱ型混合感染的诊断与病理损伤

2018年8月,四川彭州与邛崃的养殖西伯利亚鲟发生一种以出血为临床特征,高死亡率的传染病,为明确其病因,本研究对发病鲟的肝脏、肾脏进行病原菌分离、鉴定和鲟疱疹病毒Ⅱ型(AciHV-2)的PCR检测。从患病鲟体内分离到2株G+链状球菌,其16S rRNA序列(MN416231、MN416230)与GenBank中海豚链球菌16S rRNA序列同源性达99%,在以16S rRNA序列构建的系统发育树上,分离菌与海豚链球菌聚为一支;同时基于海豚链球菌lctO基因的特异性PCR检测为阳性,鉴定2株分离菌为海豚链球菌。提取患病鲟肝脏、肾脏组织DNA进行AciHV-2特异性PCR检测,扩增出501 bp的特异性条带,在以AciHV-2 polymerase基因序列构建的系统发育树上,检测样本与AciHV-2聚为一支。病理组织学上,患病鲟的多组织器官发生明显损伤,尤其是肝脏、肾脏、鳃、脾脏和肠的损伤较为严重,表现为明显的变性、坏死、出血以及炎症细胞浸润;电镜下,观察到肝脏、肾脏组织内大量直径200～220 nm的疱疹病毒样颗粒与0.7～0.8μm的链球菌入侵细胞,并导致细胞损伤。综上,诊断患病西伯利亚鲟的病因是海豚链球菌与AciHV-2混合感染。     

A simple method to distinguish two commercially valuable eel species in Japan <Emphasis Type="Italic">Anguilla japonica</Emphasis> and <Emphasis Type="Italic">A. anguilla</Emphasis> using polymerase chain reaction strategy with a species-specific primer

In order to distinguish the two eel species Anguilla japonica and A. anguilla irrespective of unprocessed and processed samples, a quick, convenient method using polymerase chain reaction (PCR) with a species-specific primer was established. The comparison of partial sequences of the mitochondrial 16S ribosomal RNA gene between A. japonica and A. anguilla facilitated designing of a primer pair common to both A. japonica and A. anguilla and a primer specific to A. japonica. PCR was carried out with the three primers for total 110 specimens of A. japonica and A. anguilla. PCR products with the species-specific primer showed two bands for A. japonica and one band for A. anguilla in an agarose gel electrophoresis. This analytical procedure required only a short period and is more convenient than PCR-restriction fragment length polymorphism, one of the standard methods employed for fish species identification.     

Molecular divergence and application of the ITS-5.8S rDNA and RUBISCO spacer in <Emphasis Type="Italic">Porphyra haitanensis</Emphasis> Chang et Zheng (Bangiales,Rhodophyta)

To select a reliable and sensitive method for discriminating strains of Porphyra haitanensis, the nucleotide sequence of the internal transcribed spacer 1 to internal transcribed spacer 2 regions (ITS-5.8S) of nuclear ribosomal DNA and the intergenic spacer region of RUBISCO were compared in five wild and five cultivated Porphyra haitanensis strains. Based on molecular analyses, sequences of ITS-5.8S (about 1,210 bp) could be divided into three regions: ITS1, 5.8S, and ITS2. The ITS1 and ITS2 sequences of each strain differed, even between individuals collected from the same site. In contrast, 5.8S rDNA and RUBISCO spacer sequences were identical among the ten P. haitanensis strains, although differences were found among different Porphyra species. Phylogenetic analysis also supported these conclusions. These sequence features of highly conserved regions and diversified regions that occurred repeatedly in ITS-5.8S could be useful in discriminating germplasm of P. haitanensis strains or Porphyra species. In contrast, the RUBISCO spacer is only suitable for identifying Porphyra species. New coupled primers were designed to amplify only the 5.8S rDNA and ITS2 region of Porphyra. The sequences of these amplified fragments can be readily used to identify germplasm or to perform phylogenetic analysis of Porphyra spp.     

凡纳滨对虾肠道内产消化酶益生菌的分离与筛选

为获得具有消化酶活性且安全的益生菌,从凡纳滨对虾肠道中初步分离得到576株细菌,对菌株进行产蛋白酶、淀粉酶和脂肪酶能力的定性及定量测试,筛选出产酶种类多且产酶能力强的菌株11株。对筛选出的11株菌进行了幼虾浸浴实验、药敏性实验和溶血性实验,以评价其生物安全性。将11株菌的菌悬液添加到凡纳滨对虾幼虾的养殖水体中进行浸浴实验,浸浴结束后用鳗弧菌进行刺激,测定不同浸浴组幼虾相关免疫基因的相对表达量,以确定其对幼虾的保护效果。综合消化酶活性、菌株对幼虾的保护效果及生物安全性,筛选得到4株效果较好的菌株。菌株的16S r DNA分子鉴定结果表明,细菌1号、2号和4号分别与芽孢杆菌(Bacillus sp.PCSAS2-38,GQ284495.1)、蜡样芽孢杆菌(B.cereus strain N419,JN400121.1)及苏云金芽孢杆菌(B.thuringiensis strain EA26.1,KC758847.1)的相似性均为100%,9号菌株与荚膜红细菌(Rhodobacter capsulatus strain PSB-03,FJ866782.1)相似性达到99%,为后续益生菌制剂的开发奠定了前期基础。     

A comparative account of the structure of the growth hormone encoding gene and genetic interrelationship in six species of the genus <Emphasis Type="Italic">Labeo</Emphasis>

The growth hormone (GH) gene isolated and cloned from various Labeo species (L. rohita, L. calbasu, L. fimbriatus, L. gonius, L. bata, and L. kontius) is shown to contain a single copy in the haploid genome, with an overall size of ∼2.5 kb. The GH gene in all the Labeo species studied has five exons and four introns of various sizes with the exon/intron boundary sequence of GT/AG. The length variation of the GH gene between the species is found to be due to length variation in the form of several deletions in the third intron. The length of individual exons is the same in all the species with an open reading frame (ORF) of 630 bp (210 amino acids) except in L. rohita, which has a 9 bp deletion in the fourth exon, resulting in a shorter GH of 621 bp (207 amino acids). The similarity in the nucleotide and amino acid sequences between the different Labeo species is greater than 97%, in spite of eight amino acids being altered in the GH protein of Labeo that reside outside the conserved domain sequence required for its function. Nucleotide substitutions are seen in the form of 20 transitions and three transversions in the ORF of the GH gene. Both types of transitions (A–G; T–C) and only one type of transversion (A–C) are detected in the GH gene. Codon preference in GH gene shows a strong preference for G and C in the wobble position of the codons. Genetic interrelationships determined between Labeo and other species of fishes using nucleotide sequence of GH cDNA supports the overall teleost classification of Nelson (Fishes of the World. Wiley, New York, 1984) with separate clades for Ostariophysi, Protacanthopterygii, and Acanthopterygii. Besides, the unweighted pair group method with arithmetic means (UPGMA) analysis clearly distinguishes between the species having five exons and four introns in the GH gene from the species having six exons and five introns in the same gene. The Labeo species analyzed in the present study could be clustered into two groups using the maximum-parsimony method on the intron sequences data of the GH gene.     

基于16SrDNA分析的浒苔外生细菌多样性研究

为研究浙江近海浒苔Ulva spp.(Enteromorpha spp.)外生细菌多样性,采用传统的形态学和16S rDNA测序分析的方法,从舟山朱家尖、宁海国华电厂和奉化南沙3个地区分离到可培养的浒苔外生细菌及其周围海水细菌65株。根据细菌菌落特征和革兰氏染色结果等将分离到的细菌分为26种表型。16S rDNA序列测序比对发现:菌株与不动杆菌属(Acinetobacter)、交替单胞菌属(Alteromonas)、弧菌属(Vibrio)、假交替单胞菌属(Pseudoalteromonas)、微小杆菌属(Exiguobacterium)、芽孢杆菌属(Bacillus)、赤细菌属(Erythrobacter)、微球菌属(Micrococcus)、假单胞菌属(Pseudomonas)、深海杆菌属(Idiomarina)、Phaeobacter、Roseivirgaj和Silicibacter等23个属相应菌株具有较高同源性。对不同地区浒苔外生细菌进行了Shannon-Wiener多样性指数分析。研究表明:(1)宁海国华电厂的浒苔外生细菌多样性最丰富,多样性指数为93.98%;(2)浒苔外生细菌与其生活地区密切相关,其群落组成具有地域差异,其优势类群也不尽相同,但均归属于变形菌门。     

鲤和草鱼IL17受体基因家族的全基因组识别、起源进化及表达分析

为了研究鲤科鱼类最具代表性的二个物种—鲤和草鱼IL17受体基因家族的起源进化,实验采用比较基因组学和生物信息学的方法,分别在鲤和草鱼基因组数据库进行序列比对和注释,然后对得到的基因进行结构域和系统发育学分析,最后在12个不同组织中进行基因表达分析研究。结果显示,在鲤和草鱼中分别注释得到9个和5个IL17受体基因家族成员。系统发育分析显示,该基因家族不存在鱼类特有的基因,在硬骨鱼类中具有一定的保守性。比较基因组学结果显示,与四足动物相比,大多数硬骨鱼类中IL17受体基因没有明显增多。鲤与草鱼等其他硬骨鱼类相比,除IL17RB以外,其余IL17受体基因家族成员均加倍。不同组织的表达分析结果显示全基因组复制后不同基因拷贝的功能发生了分化。研究表明,虽然硬骨鱼经历第三轮全基因组复制,但是由于复制发生时间久远,大多数基因已经发生改变或退化,进而在基因组中丢失。而鲤第四轮基因组复制时间发生在820万年前,复制发生时间较近,故复制后的基因基本得以保留。但是对于一些具有特殊功能的高度保守基因(例如IL17RB),也会发生在极短时间内出现丢失现象。鲤和草鱼健康组织的表达谱分析结果同样表明,鲤IL17受体基因的不同拷贝之间已经发生了快速进化及亚功能化,并且这种现象在鲤四倍体基因组中普遍存在。     

鳖源柠檬酸杆菌属新种的分离鉴定与多位点序列

为确定2020年10月湖北一中华鳖发病的病原体及病原特征，实验从该养殖场患病中华鳖个体肝脏中分离获得1株优势菌A3，经理化性状及16S rRNA序列鉴定，表明菌株A3属于柠檬酸杆菌。进一步通过recN序列鉴定，发现A3与布氏柠檬酸杆菌recN碱基一致性为95.58%～96.01%，与柠檬酸杆菌属其他种的recN碱基一致性均低于93.72%，表明菌株A3为柠檬酸杆菌属潜在新种。人工回归感染实验证实菌株A3是引起本次中华鳖患病的病原菌。与嗜水气单胞菌相比，A3感染病程偏慢但致死率较高。药敏实验结果显示，菌株A3对美罗培南等10种抗生素敏感，对氟苯尼考等9种抗生素耐药。多位点序列分型(MLST)鉴定显示，菌株A3属于新序列型(ST)。对柠檬酸杆菌多位点序列分型的7个管家基因序列进行级联并构建系统发育树，结果显示，柠檬酸杆菌的进化与菌株的分离源及分离地点没有明显关系；菌株A3与分离自欧洲人源的ST120型菌株Citfre2580亲缘关系最近。本研究对中华鳖的病原进行了分离鉴定，并阐述了一种更可靠的柠檬酸杆菌鉴定方法，旨在引起人们对柠檬酸杆菌致病性的重视，为水产品健康养殖提供一定的参考依据。     

Susceptibility of corkwing wrasse Symphodus melops, goldsinny wrasse Ctenolabrus rupestis, and Atlantic salmon Salmo salar smolt, to experimental challenge with Vibrio tapetis and Vibrio splendidus isolated from corkwing wrasse

The virulence of two Vibrio strains, previously isolated from diseased corkwing wrasse Symphodus melops and identified as V. tapetis and V. splendidus, to corkwing and goldsinny wrasse Ctenolabrus rupestris and to Atlantic salmon Salmo salar, was studied under laboratory conditions. Both bacteria were shown to be opportunistically pathogenic to corkwing wrasse, causing significantly higher mortality in the challenged groups than in the controls. Bacterial cultivation of kidney samples and re-isolation of V. tapetis and V. splendidus from most mortalities confirmed the two strains as the probable cause of mortality in the challenged groups. The control group also suffered relatively high mortality, but no specific pathogens that were suspected to be the main cause of death were isolated, other than a mixture of Vibrio spp. and, in the case of one individual, atypical Aeromonas salmonicida. Following injection challenge with both bacterial strains, no mortality was recorded in Atlantic salmon. In bath challenge trials with goldsinny wrasse, only slight mortality was observed in the challenged groups and the unchallenged control group. Bacterial examination showed that atypical Aeromonas salmonicida was the probable cause of death in both bath challenged and control groups of goldsinny wrasse, and no indication of infection by any Vibrio sp. was found.     

基于黄河鲤新品系IGF2b基因SNPs获取体系的建立及在该品系选育中的应用

为了建立鲤 IGF2b (insulin-like growth factor 2)基因全基因组信息 SNPs (single nucleotide polymorphism)的获取体系,并验证该获取体系在黄河鲤新品系选育中运用的适用性,本研究首先对 10个不同鲤品种的 33个鲤个体重测序数据进行分析,整体上了解 IGF2b 基因的单核苷酸位点及其在基因组上的分布情况。然后在基因组 DNA 水平上分段获取 IGF2b 基因的 SNPs 信息,并以不同的鲤品种验证引物的适用性,最后在黄河鲤新品系中检测其应用。研究结果:获得 8 对聚合酶链式反应(polymerase chain reaction, PCR)引物进行分段克隆的结果,并通过直接测序和限制性片段长度多态性来获取相应的 SNPs。经过直接测序,本文对黄河鲤、建鲤、黄河鲤和建鲤的正反交后代进行 PCR 检测发现条带单一,目地片段正确;结合黄河鲤新品系的体重数据,本文又以 IGF2b3#引物检测到一个与体重明显相关的 SNPs,同时检测到一个与该基因表达量相关的另一个 SNPs。本研究的方法能够在该基因全基因组范围内开展鲤分子育种中 SNPs 的检测,并验证发现黄河鲤新品系 IGF2b3#引物 227 号位点处,出现的突变位点使体重降低,且有一处 SNPs 与其表达量有关。这将为其他物种、其他功能基因的多态性分子标记研究提供思路。     

Identification of Stress Sensitive Genes in Hyperthermic Atlantic Salmon (Salmo salar) Embryos by RAP-PCR

Deformities of skeletal structures, the heart, and other organs are a recurrent problem in species used in intensive aquaculture. Elevated egg incubation temperature appears to be a high risk factor in the development of these malformations, but the causal relation has not been established. Our aim was to identify candidate genes involved in the development of heat induced deformities in Atlantic salmon (Salmo salar). Temperature sensitive genes were isolated by RNA Arbitrarily Primed (RAP)-PCR. A total of 33 RAP-PCR products were successfully sequenced, and the expression of eight identified genes was further examined by RT-PCR from pooled samples of heat exposed embryos. Five of these genes were demonstrated to be temperature sensitive, of which four were shown to be up-regulated and one was down-regulated at elevated water temperatures. The atrial natriuretic peptide (ANP) gene, which is a promising candidate for heart deformities, showed the highest level of heat induction. Three additional RAP-PCR products identified as heterogeneous nuclear ribonucleprotein (hnRNP) A0, acyl CoA binding protein (ACBP) and mitochondrial (mt)-HSP70 showed up-regulated mRNA expression in response to elevated water temperature. The single down-regulated gene was identified as an Atlantic salmon (Salmo salar) homolog of the cysteine and tyrosine-rich 1 (CYYR1) gene. This study demonstrated that a temperature elevation of only 4 °C during the early stages of the organogenesis in Atlantic salmon induce altered expression of a number of genes, which are candidates for the development of heat induced deformities.     

Pathological and PCR detection of mycobacteriosis in pond-cultured Chinese soft shell turtles, Trionyx sinensis

Mycobacteriosis due to infection of Mycobacterium marinum is a common disease in pond-cultured Chinese soft shell turtles, especially in those surviving beyond their first year. The infected turtles independently showed either heterophilic or histiocytic granulomas in various organs such as the spleen, liver, lungs, intestine, kidneys, stomach and pancreas. The heterophilic granuloma contained many acid-fast unbranching bacilli intracellularly in macrophages and extracellularly in the necrotic center. The histiocytic granuloma had only a few bacteria, mainly in the cytoplasm of Langhan's giant cells. The organisms were rarely observed in the advanced lesions of both types. Based on PCR assays for partial hsp65 gene of Mycobacterium spp., all of our strains were identified as M. marinum which can be divided into two groups. The strains of the first group induced heterophilic granulomas and had very high nucleotide sequence identities (99.8%-100%) to the reference strains of M. marinum (AF456471) and M. pseudoshottsii (AY550226). Those strains of the second group caused histiocytic granulomas and also showed very high identities (99.8%-100%) to the reference strains of M. marinum ATCC 927 (AF456470) and M. shottsii (AY550225). However, when we compared the partial sequence of the hsp65 gene from group one and two strains the identities between the two groups range from 98.8% to 99.3%, therefore we can not assert that these two belong to the same species.     

Production of bactericidal substances by a marine vibrio isolated from cultures of the scallop Argopecten purpuratus

A marine vibrio (strain C33) having inhibitory effects on the growth of the pathogen Vibrio anguillarum-VAR was isolated from seawater used in mass culture of the north-Chilean scallop Argopecten purpuratus. This bacterial isolate demonstrated broad inhibitory activity on several bacterial strains, including some pathogenic vibrios. Ethyl acetate extracts of extracellular products of strain C33 were separated by thin layer chromatography (TLC), and three fractions thus obtained were found to have antimicrobial activity when tested using microplate bioassays. One of the fractions (A2) having marked antimicrobial activity, was further purified using TLC and analyzed by IR spectrophotometry and NMR'H and was characterized on a preliminary basis as an aliphatic hydroxyl ether. This compound demonstrated bacteriostatic activity against the important marine pathogens Vibrio parahaemolyticus and V. splendidus, and as discussed in the paper, may be useful in developing natural strategies for the control of pathogens in mass cultures of Argopecten purpuratus and possibly other molluscs affected by these bacteria.     

团头鲂tf和tfr1a基因启动子克隆及转录调控分析

为探索鱼类转铁蛋白基因tf和转铁蛋白受体基因tfr1a的转录调控机制,本实验以团头鲂为研究对象,在其全基因组数据库中获取tf和tfr1a基因序列,对2个基因候选启动子区转录因子结合位点及CpG岛进行预测,通过PCR方法克隆得到tf和tfr1a基因近端启动子区不同长度片段,连接至pGL3-Basic/pEGFP-1载体,瞬时转染入Hela细胞,并采用双荧光素酶报告基因检测系统进行检测。结果发现,团头鲂tf基因启动子区无CpG岛位点,而tfr1a基因启动子区有2个CpG岛位点。成功构建9个tf和10个tfr1a不同长度启动子片段的重组质粒,经双荧光素酶报告基因系统检测发现,tf启动子核心区域为-268^+56 bp,且-1 308^-1 102 bp片段可能存在正调控该基因表达的转录因子结合位点;tfr1a启动子核心区域为-224^+48 bp,且+48^+92 bp可能存在抑制该基因转录的负调控元件,而-1 229^-1 219 bp区域可能存在促进tfr1a基因表达的正调控转录因子结合位点。     

Natural food and artificial,dry starter diets: effects on growth and survival in intensively reared European grayling

Four artificial, dry feeds and two diets consisting of natural, live food were evaluated for use as starter diets in the intensive rearing of European grayling (Thymallus thymallus). Long-term effects of the different diets were also studied. The investigation was divided into two parts: a 14 day starter period and the subsequent 115 days, during which the long-term effects were studied. Diets differed between the different treatment groups during the initial 2 weeks, whereafter all fish were offered a single diet. At the end of the starter period, significant differences in weight (p<0.001) were obtained between natural (control) feed groups and three of the artificial feed groups. The highest growth rate (9.6% day^–1), and length increase (9 mm) as well as the lowest mortality rate (6.0%) were obtained with one of the artificial diets. Growth rate, length increase and mortality of grayling in the other diet groups varied from 3.6 to 7.7% day^–1, 5 to 7 mm and 7.0 to 9.1%, respectively. The switchover to a different dry diet resulted in an increase in mean daily mortality for all groups previously fed a dry diet. For the fish previously fed live food the mortality rate remained about the same. Groups of fish growing slowly during one period seemed to compensate for their initially low growth by increasing their growth rates during the next period. The highest mean daily mortality for all groups during the experiment was observed during the period with the highest water temperature. It was concluded that European grayling can be intensively reared during the start-feeding phase on artificial as well as natural diets, and that artificial dry diets can be used exclusively throughout the first summer.