The objectives of the present study were to evaluate the yolk-sac and oil globule absorption and point of no return (PNR) of pikeperch ( Sander lucioperca L.) larvae. Artificial propagation of pikeperch was performed at (15±2)°C. Yolk-sac absorption, oil globule absorption, larval growth and the first initial feeding rate were observed to analyze the early growth and to determine the PNR of pikeperch larvae. The total length of newly hatched (0 day after hatching, DAH) pikeperch larvae was (4.25±0.22) mm and the volume of the yolk-sac and the oil globule was (0.30±0.12) mm 3 and (5.14±2.28) 10 -2 mm 3 respectively. The yolk-sac and the oil globule were exhausted at 11 DAH and 14 DAH, respectively. Pikeperch larvae began feeding at 8 DAH with an initial feeding rate about 10.0%. From 9 to 14 DAH, the initial feeding rate increased rapidly, and reached its highest (about 82.7%) at 14 DAH. It declined thereafter, 48.9% at 15 DAH and 35.6% at 16 DAH, thus the pikeperch larvae reached PNR by 15–16 DAH. The appropriate first feeding time for the pikeperch larvae is 11–12 DAH, when the initial feeding rate is higher than half of the maximum initial feeding rate.

The pikeperch (Sander lucioperca L.) is one of the most economically important freshwater species and has been recently explored as a potential candidate for aquaculture. To facilitate pikeperch research, we sequenced its transcriptome and developed a set of microsatellite markers. We conducted Illumina RNA-sequencing and obtained over 50 million reads from a pooled cDNA library of different tissues. The clean reads were de novo assembled into 56,746 transcripts, with an average length of 1474 bp. The annotation analysis demonstrated 37,386 transcripts (65.9%) with homologous sequences in the NCBI Nr protein database. Of these annotated transcripts, 18,576 sequences were successfully assigned into Gene Ontology (GO) terms, 23,566 transcripts into the Cluster of Orthologous Groups (COG), and 12,081 transcripts to 322 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Totally, 16,368 SSRs (≥10 bp) were detected from 11,921 unigenes. The validation of randomly selected 300 SSR markers demonstrated 87.0% of the markers can be successfully amplified, suggesting RNA-Seq is an efficient tool for the development of molecular markers. This study provides not only a valuable transcriptomic resource, but also a set of SSR markers for basic as well as applied research in pikeperch.

红草鲫又名金鲫.其体质健壮,抵抗力与适应性强,食性广、饲养简便.体色艳丽,主要有红色、白色和五花等.红草鲫既能在公园及天然水域大面积饲养,也可以在庭院水池内及水族箱中饲养,已成为一种深受人们青睐的观赏鱼.我们在苏州沙家浜东湖现代渔业科技发展有限公司进行了红草鲫规模化人工繁殖和鱼种培育,总共催产了1600组鱼,获得鱼苗500万尾,育成夏花270万尾.催产率、出苗率以及夏花培育率均较高.现将生产操作要点介绍如下.

The pedigree method is one of the main methods for genetic breeding of fish because it reduces inbreed-ing and maintains gene diversity.An understanding of the genetic structure of Paramisgurnus dabryanus guides the breeding of this species.20 microsatellite markers were used to investigate the genetic diversities and kinship of five Paramisgurnus dabryanus families (AB2013F-7,AB2013F-81,AB2013F-27,AB2013F-74,AB2013F-77)and the results provided technical parameters for selective breeding.The pectoral fins of 142 individuals from the five fami-lies were sampled and preserved with 95% ethanol.Genomic DNA was extracted from the pectoral fins using the phenol-chloroform extraction technique.PCR was performed in 20 μL solution (2 ×Mix 10 μL,H2 O 7 μL,DNA 1 μL)and the PCR products were analyzed using Popgene 32 software.A total of 53 alleles were detected in the five families of P.dabryanus in 20 simple sequence repeats (SSRs).The mean number of alleles was 2.65 with the number of alleles per locus ranging from two to four.The average observed heterozygosity (Ho ),average expec-ted heterozygosity (He)and average polymorphic information content (PIC)for the five families ranged,respec-tively,from 0.3117 to 0.5542 and 0.3261 to 0.4371,0.3459 to 0.4538.The average fixed coefficient (Fis)was-0.0472 (<0)and the genetic differentiation coefficient (Fst)was 0.2703.Cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA)showed the kinship of families AB2013F-7 and AB2013F-81 is the most distant.The results of this study indicate genetic differentiation among the five P.dabryanus families is sufficient for good breeding potential.

通过人工催产、孵化获得金鲫仔鱼,对初孵的仔鱼进行饥饿试验和正常投喂试验,通过观察卵黄囊的吸收、仔鱼生长变化以及初次摄食率的变化,分析饥饿对金鲫仔鱼生长、形态的影响,确定其不可逆点.结果表明:①出膜后的第一天,卵黄囊的消耗率最大,达到45.98％;而仔鱼体长增长率也最大(14.2％).②7日龄的仔鱼卵黄囊全部吸收完毕.饥饿组的仔鱼体长开始出现负增长,部分饥饿组仔鱼出现身体畸形.③仔鱼从孵出后第4天开始摄食,摄食率为6.67％,第7天初次摄食率到达100％,第8天到第9天这段时间内到达最高初次摄食率的50％,到达不可逆点.

The large-scale loach (Paramisgurnus dabryanus, Cypriniformes) is a bottom-dwelling freshwater species of fish found mainly in eastern Asia. The natural germplasm resources of this important aquaculture species has been recently threatened due to overfishing and artificial propagation. The objective of this study is to obtain the first functional genomic resource and candidate molecular markers for future conservation and breeding research. Illumina paired-end sequencing generated over one hundred million reads that resulted in 71,887 assembled transcripts, with an average length of 1465bp. 42,093 (58.56%) protein-coding sequences were predicted; and 43,837 transcripts had significant matches to NCBI nonredundant protein (Nr) database. 29,389 and 14,419 transcripts were assigned into gene ontology (GO) categories and Eukaryotic Orthologous Groups (KOG), respectively. 22,102 (31.14%) transcripts were mapped to 302 KEGG pathways. In addition, 15,106 candidate SSR markers were identified, with 11,037 pairs of PCR primers designed. 400 primers pairs of SSR selected randomly were validated, of which 364 (91%) pairs of primers were able to produce PCR products. Further test with 41 loci and 20 large-scale loach specimens collected from the four largest lakes in China showed that 36 (87.8%) loci were polymorphic. The transcriptomic profile and SSR repertoire obtained in this study will facilitate population genetic studies and selective breeding of large-scale loach in the future.

To promote the protection of Paramisgurnus dabryanus germplasm resources, and to select the base breeding population, 400 Paramisgurnus dabryanus SSRs were developed through next generation sequencing platform and 400 primer pairs were synthesized. After validation, 17 polymorphic EST-SSR markers were randomly selected out of400 SSR markers for genetic diversity analysis in four P. dabryanus populations from Lake Taihu, Lake Hongze, Lake Dongting and Lake Chaohu in China. The average observed allele number and effective allele number of all markers were 9. 5 and 5. 5. The average heterozygosity was 0. 566 5, and mean Fst value was 0. 219 4(>0. 2), indicative of the high differentiation in four populations. The mean Nm was 0. 889 4 (<1), suggestive of a low ge-netic exchange in four populations. The allele number of all four populations ranged from 5. 4 to 6. 2 (mean 5. 8), and the observed and expected heterozygosities ranged from 0. 273 2 to 0. 386 4 and 0. 562 9 to 0. 589 3, respectively. The polymorphism information content (PIC) was 0. 550 3-0. 575 4, indicating a high genetic diversity in all populations. The genetic relation ship of Lake Taihu population and Lake Chaohu population was the closest with lowest distance of 0. 528 3, while the populations of Lake Taihu and Lake Dongting showed the farthest relationship. Lake Taihu and Lake Hongze populations were clustered togegher and Lake Dongting and Lake Chaohu populations were clustered together in phylogenetic tree, which was consistent with the distribution of their living regions. Among the four natural P. dabryanus populations, Lake Hongze population and Lake Taihu populantion had higher levels of genetic diversity and could be con-sidered as the base populations for further breeding.

大鳞副泥鳅是鳅科重要经济鱼类,通过Illumina HiSeq 2000测序平台对2个大鳞副泥鳅样本的转录本进行了高通量测序,其中AB2011M-1是群体中生长较快的10尾鱼的混合转录本,AB2011M-2是生长较慢的10尾鱼的混合转录本。通过对以上2个混合转录本的测序,分别获得了65536和80786个单核苷酸多态性( single nucleotide polymorphisms,SNP)突变；对2个测序样本进行表达差异的比较,获得了39个表达差异基因。随机选取120个位点设计引物,进行验证分析,共获得16个有效的多态性标记。