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The Chinese longsnout catfish (Leiocassis longirostris Gunther) is a semi-migratory freshwater species. Leiocassis longirostris is mainly inhabiting the main stream of the Yangtze River and rarely found in lakes due to over fishing, environmental pollution and other human disturbances. Novel single nucleotide polymorphisms (SNPs) were screened based on high-throughput sequencing in Leiocassis longirostris. In this study, 40 SNP markers were developed successfully with 30 individuals from the Yangtze River segment of Nanjing, China. The observed heterozygosity (Ho) ranged from 0.0003 to 1.0000, while the expected heterozygosity (He) varied from 0.3367 to 0.9390. The minor allele frequency ranged from 0.0167 to 0.2500. Thirty-four SNPs have been confirmed to fit Hardy–Weinberg equilibrium after Bonferroni correction (P

Background：Traditional Chinese medicines (TCMs) had been proven to stimulate digestion, promote growth, boost immune response, and reduce inflammatory potential in aquaculture, but its action mechanism was still lack of holistic interpretation. Results: The UPLC-Triple-TOF-MS/MS based platform was developed to investigate the serum metabolic profile associated with the growth performance and immunity in Pelodiscus sinensis fed with the diet added with TCMs feeding additive. The final weight and specific growth rate of TG2 groups was significantly the highest (p ˂ 0.05), and the feed conversion ratio of TG2 groups was significantly the lowest (p ˂ 0.05) compared to the CG group. In the metabolomics assay, a total of 795 (VIP > 1) out of 3089 variable ions were significantly different between the TG2 group and CG group. 43 potential biomarkers between TG2 and CG groups were finally screened out on the basis of VIP > 1 and p < 0.05. Based on the analysis of MetPA, eleven potential biomarkers and six involved metabolic pathways were significantly regulated with treatment of TCMs. Phenylalanine, tyrosine and tryptophan biosynthesis and Arginine and proline metabolism were the two most heavily affected pathways (Impact >0.2), while Tyrosine metabolism, Cysteine and methionine metabolism and Arginine biosynthesis were relatively lightly affected pathways. Conclusions：The dietary supplementation nineteen TCMs as feed additives could influence the growth performance of the healthy juvenile P. sinensis, and the optimal dose of TCMs for juvenile turtles was 2% TCMs. The UPLC-Triple-TOF-MS based metabonomics may be a useful tool for elucidating the efficacy and mechanism of complex TCM prescriptions.

The Channa argus (Ophicephalus argus Cantor) is an endemic freshwater species which is widely distributed in the lower Yellow and Yangtze river systems in eastern China. The Ophicephalus argus is a high commercially valuable aquaculture fish in China. Due to river fragmentation, over-fishing, and water pollution, the wild population of Ophiocephalus argus suffered a dramatic decline. In the present study, 38 novel single nucleotide polymorphism (SNP) markers were developed based on high-throughput sequencing. Genetic diversity analysis revealed that the values of observed heterozygosity and expected heterozygosity varied from 0.1024 to 0.7033 and from 0.3638 to 0.8266, respectively, and the minor allele frequency ranged from 0.1911 to 0.6422. Only three loci showed significant deviation from Hardy–Weinberg equilibrium. These SNP markers will serve as a valuable tool for further population genetics, genetic breeding, and resource conservation in this species.

Northern snakehead

Northern snakehead, Ophiocephalus argus Cantor, is an endemic freshwater fish in China. However, wild stocks of O. argus are dwindling sharply. Further, water conservancy projects, environmental pollution and human activities have caused the decrease of wild stocks, which has attracted much attention. Here, we have investigated the genomic information of O. argus using IlluminaHiseq 4000 sequencing. The transcriptomes of O. argus were sequenced by Illumina technology. A total of 67,564 sequences from 79,500,964 paired-end reads were generated, 33,710 unigenes were annotated based on protein databases (NCBI nonredundant (NR) databases). In total, 7182 unigenes had the clusters of orthologous group (COG) classifications, 33,710 unigenes were assigned to 59 gene ontology (GO) terms. Further, a total of 21,464 simple sequence repeats (SSRs) from 67,564 unigenes and 113,518 single nucleotide polymorphism (SNP) sites among 335 Mclean reads were yielded for O. argus based on a transcriptome-wide search. The new transcriptome data which is presented in this study for O. argus will provide valuable information for gene discovery and downstream applications, such as phylogenetic analysis, gene-expression profiling and identification of genetic markers (SSRs andSNP).

Genetic variability and population genetic structure of the yellow catfish Pelteobagrus fulvidraco Richardso in the Huaihe river and the Yangtze river was examined with a 810-bp of the mitochondrial DNA control region. A total of 70 haplotypes were identified from 145 samples, which were characterized with high haplotype diversity (h = 0.9832 ± 0.0041) but low nucleotide diversity (π = 0.0415 ± 0.0201). The analysis of molecular variance and phylogenetic reconstructions detected significant geographic structure between Huaihe river and Yangtze with FST = 0.1183 (P = 0.0000). Neighbor-joining (NJ) phylogenetic analyses identified two distinct clades (bootstrap support 99 %). The medium joining network drawn using the complete data set was reticulated and also distinctly split the 70 haplotypes into two groups corresponding to those of the NJ tree. Departures from neutrality were not significant for the Huaihe river and the Yangtze river Pelteobagrus fulvidraco, concordant with the observed multimodal mismatch distributions (P > 0.05), which suggested that the effective size of this species has been large and stable for a long period. The question about the existence of significant genetic differentiation for Pelteobagrus fulvidraco in the Yangtze river and Huaihe river basins remains to be further studied with molecular nuclear markers and larger sample sizes from throughout the river basins.

Genetic variability and population structure of the Chinese longsnout catfish Leiocassis longirostris Günther in the Yangtze River was examined with mitochondrial control region sequences and nuclear microsatellite markers. A 705-bp segment of the mitochondrial DNA control region was sequenced from 132 samples, which identified a total of 61 haplotypes. The Chinese longsnout catfish in the Yangtze River was characterized with high haplotype diversity (h = 0.9770 ± 0.0041) but low nucleotide diversity (π = 0.0081 ± 0.0043). Median-joining network analysis revealed a star-shaped pattern and mismatch distribution analysis found a smooth unimodal distribution, which suggested that this species in the Yangtze River underwent a population expansion following bottlenecks and/or they originated from a small size of founding population. It was estimated that the possible time of population expansion was 139,000-435,000 years before present, a time period in the middle Pleistocene. The analysis of molecular variance and phylogenetic reconstructions did not detect significant geographic structure between different river sections. This pattern of genetic variation was further evidenced with nuclear microsatellite markers. The genetic differentiation between above and below the Gezhouba Dam and Three Gorges Dam is very small at mitochondrial and nuclear levels, which suggested that these recently developed dams might have not significantly resulted in population genetic fragmentation in the Chinese longsnout catfish. However, the potential exacerbation of genetic structuring by the dams should not be overlooked in the future.

Silurus asotus is a high commercially valuable aquaculture fish in some regions of China. In this survey, the first set of 14 polymorphic microsatellite loci for S. asotus was developed and characterized. The number of alleles per locus ranged from 9 to 15 and the observed and expected heterozygosities ranged from 0.593 to 0.931 and from 0.833 to 0.926, respectively. Four loci were found deviated from HWE in the sampled population after Bonferroni correction. These microsatellite loci will be useful for revealing population structure, and conservation genetics of S. asotus.

We describe the isolation and development of 17 polymorphic dinucleotide microsatellite loci for the Chinese longsnout catfish (Leiocassis longirostris). All loci were polymorphic in the 30 individuals tested. The number of alleles per variable locus ranged from 6 to 18, with a mean of 11.71. Observed and expected heterozygosities ranged from 0.467 to 1.000 and from 0.540 to 0.929, respectively. Eight loci were found to have deviated from HWE in the sampled population after Bonferroni correction. Linkage disequilibrium tests revealed significant linkage between two loci (LLW5 and LL27). These microsatellite loci will be useful for revealing population structure, genetic diversity, and phylogeography of the Chinese longsnout catfish.

Digital watermarking is a kind of technique that can be used for protecting and enforcing the intellectual property (IP) rights of the digital media like the digital images containting in the transaction copyright. There are many kinds of digital watermarking algorithms. However, existing digital watermarking algorithms are not robust enough against geometric attacks and signal processing operations. In this paper, a robust watermarking algorithm based on chaos array in DCT (discrete cosine transform)-domain for gray images is proposed. The algorithm provides an one-to-one method to extract the watermark.Experimental results have proved that this new method has high accuracy and is highly robust against geometric attacks, signal processing operations and geometric transformations. Furthermore, the one who have on idea of the key can't find the position of the watermark embedded in. As a result, the watermark not easy to be modified, so this scheme is secure and robust.