Chinese Sturgeon Research Articles

Hypothalamus-pituitary-gonad axis transcriptome profiling for sex differentiation in Acipenser sinensis

Chinese sturgeon (Acipenser sinensis), a critically endangered Acipenseridae family member, is one of the largest anadromous, native fish in China. Numerous research programmes and protection agencies have focused on breeding and preserving this endangered species. However, available information is limited on the different stages of sex development, especially on the reproductive regulation of the hypothalamus-pituitary-gonad (HPG) axis of A. sinensis. To unravel the mechanism of gene interactions during sex differentiation and gonad development of A. sinensis, we performed transcriptome sequencing using HPG samples from male and female A. sinensis in two developmental stages. In this study, 271.19 Gb high-quality transcriptome data were obtained from 45 samples belonging to 15 individuals (six in stage I, six males and three females in stage II). These transcriptomic data will help us understand the reproductive regulation of the HPG axis in the development stages of A. sinensis and provide important reference data for genomic and genetic studies in A. sinensis and related species.

Drifting with Flow Versus Self-Migrating ― How Young Anadromous Fish Move to Sea

The downriver migration process of larval or juvenile fish has a far-reaching impact on the survival rate of fish and the efficacity of hatchery-reared fish release and remains fragmented. Moreover, the quantitative mechanism of dam impact on the fish remains unclear. The Chinese sturgeon in the Yangtze River is a typical example or model organism of anadromous or dam-affected fish. Here, we propose a novel theoretical framework to reveal the downriver migration process of young Chinese sturgeons in the Yangtze River. We clarify the effects of active swimming of fish and the river’s hydrologic elements on the downriver migration, and the parametric traits of the migration stages. Then we show that the young fish migrate downriver along the inshore waters in a gradual transforming manner from passive movement to active swimming. Furthermore, we evaluate the impact of the Gezhouba Dam (GD) on the downriver migration of the young fish and achieve the lifecycles of Chinese sturgeon in the Yangtze River pre- and post-GD.

Variation in the suitability of Chinese sturgeon spawning habitat after construction of dams on the Yangtze River

The Chinese sturgeon (Acipenser sinensis) is an anadromous fish inhabiting the Yangtze River. Migration of Chinese sturgeon from the estuary to upper Yangtze River was blocked by Gezhou Dam, completed in 1981, and a new, much smaller, spawning ground was established below the dam. However, Three Gorges Dam began operating in 2003, altering hydrological conditions in the new spawning grounds and the impact on Chinese sturgeon reproduction was severe. The annual survey of Chinese sturgeon shows that both spawning scale and breeding population decreased during this period. To illustrate the impact of Three Gorges Dam on the spawning grounds and reproduction of Chinese sturgeon, the habitat suitability of spawning grounds on spawning day was simulated using River2D. Results show that the area of suitable spawning grounds positively correlates with the scale of reproduction and both have decreased sharply since 2003.

Spatiotemporal variation and source apportionment of organotin compounds in sediments in the Yangtze Estuary

BackgroundThe Yangtze Estuary is a vital habitat and breeding ground for many rare species (e.g., Chinese sturgeon, Chinese paddlefish). From the view of marine ecosystem health, organotin compounds (OTCs) should be of great concern in this area based on their broad applications and potential threats. At present study, five OTC species were determined in 28 and 26 surface sediments from the Yangtze Estuary (including the Nearshore area, Estuarine Turbidity Maxima (ETM) zone and Plume zone) in 2015 and 2016, respectively. Meanwhile, four sludge samples were collected from the adjacent Shidongkou Wastewater Treatment Plant to perform a source apportionment.ResultsThe sum of OTCs presented a decreasing trend towards the open sea, averaging 4.8 ± 6.0 ng Sn g−1 dw in the Plume zone. While OTC levels in the Nearshore area (2.9–34.6 ng Sn g−1 dw) were similar with those in the ETM zone (5.6–36.0 ng Sn g−1 dw), and the sites belonging to the Deepwater Navigation Channel showed heavier contamination in the ETM zone than the Nearshore area. There are abundant suspended particles and organic matters in the ETM zone that can effectively capture the hydrophobic compounds. Besides, OTC contamination in shoreside zone was more serious than those in channel center. High OTC loads (average 633 ± 124 ng Sn g−1 dw) were also found in sludge samples from adjacent wastewater treatment plant.ConclusionLand-based sources (e.g. sewage discharge, runoff) are probably one of the predominant pathways of OTCs entering the ocean. Combining with previous observation in 2014, OTC contamination in the same ten sites varied slightly with years. Risk assessment indicated that the concentrations of tributyltin (TBT) are sufficient to pose ecosystem threats especially in the ETM zone. Hence, OTC contamination issues in the Yangtze Estuary still can not be neglected.

Comparative study on quality characteristics of pickled and fermented sturgeon (Acipenser sinensis) meat in retort cooking

SummarySturgeon (Acipenser sinensis) meat has not been fully utilised due to quality defects which were raised by Chinese sturgeon processing industry. This study was aimed to develop a high‐quality sturgeon meat product and the effect of fermentation on qualities was studied. Results showed that fermentation with Saccharomyces cerevisiae could enhance ‘mushroom’, ‘fruity’ and ‘chocolate’ flavour by 1‐octen‐3‐ol, ethyl acetate and 3‐methyl‐butanal; and enrich flavour through mild lipid oxidation and hydrolysis. In addition, fermentation could give an attractive colour with higher a*, b* and L* value. Texture properties were also improved with higher hardness, springiness, gumminess and chewiness. Higher free amino acids, TCA‐soluble peptides and taste score in fermented sturgeon meat indicated better flavour and taste. The organoleptic evaluation suggested an overall satisfactory of wine‐aroma sturgeon meat by fermentation with S. cerevisiae.

Morphology and mechanical properties of the dorsal bony plates in the Chinese sturgeon (Acipenser sinensis).

The morphology, composition, and mechanical properties of the dorsal bony plates in the Chinese sturgeon (Acipenser sinensis) were determined in this study. Scanning electron microscopy images of the bony plates revealed a ridge-like shape similar to that of traditional Chinese architecture and displayed hierarchical microstructures whose the degree of mineralization decreased from the surface layer to the internal layer. Moreover, the crests in the central part of the bony plates displayed porous characteristics. Composition analysis of the bony plates revealed that they were primarily composed of Ca, P, O, and C, demonstrating that hydroxyapatite was the main constituent. Mechanical experiments including nanoindentation, penetration, and tension tests confirmed that the bony plates have excellent mechanical properties and present high specific tensile strength that is comparable to that of 304 stainless steel. This study may provide a new bionic design template for lightweight and high-strength body armor.

Effects of stocking density on growth, stress, and immune responses of juvenile Chinese sturgeon (Acipenser sinensis) in a recirculating aquaculture system

The present study was to investigate the effects of stocking density on the welfare of juvenile Chinese sturgeon (Acipenser sinensis) cultured in a recirculating aquaculture system (RAS) for three months. Fish (average weight 760.86 g) were reared in triplicate under three densities: low density (4.80 kg m−2), medium density (8.99 kg m−2), and high density (12.68 kg m−2). The results showed that the 12.68 kg m−2 treatment significantly suppressed fish growth, gene expression of glutathione-s-transferase (GST), and enhanced serum adrenocorticotropic hormone (ACTH), cortisol, glucose, lactate levels, and the heat shock protein 70 (HSP70) mRNA level (P < 0.05). Additionally, the 12.68 kg m−2 treatment significantly decreased serum glutathione peroxidase and superoxide dismutase activities, and increased the formation of malondialdehyde (P < 0.05). Serum immunoglobulin M (IgM), lysozyme, alkaline phosphatase, and acid phosphatase activities showed a significant decline in this group (P < 0.05). Transcriptions of immune-related genes, including lysozyme, hepcidin antimicrobial peptide 1 (HAMP1), tumor necrosis factor-ɑ (TNF-ɑ), interleukin 1β, and interleukin 8 significantly reduced in the 12.68 kg m−2 group (P < 0.05). In the somatotropic axis, both the serum values and gene expressions of growth hormone (GH) and insulin-like growth factor-I (IGF-I) resulted in a down-regulation in the 12.68 kg m−2 group (P < 0.05). Overall, these results suggest that high stocking density could negatively influence the growth, stress, and immune responses of juvenile Chinese sturgeon. Consequently, the appropriate stocking density recommended for culturing juvenile Chinese sturgeon in an RAS is between 4.80 kg m−2 and 8.99 kg m−2.

Development of 17 Novel Cross-Species Microsatellite Markers for Dabry’s Sturgeon (Acipenser dabryanus) from Chinese Sturgeon (Acipenser sinensis) via Next-Generation Sequencing

Development of 17 Novel Cross-Species Microsatellite Markers for Dabry’s Sturgeon (Acipenser dabryanus) from Chinese Sturgeon (Acipenser sinensis) via Next-Generation Sequencing

Effects of temperature on growth, hematology, and immune responses of subadult Chinese sturgeon (Acipenser sinensisGray 1835) under different ammonia nitrogen conditions in recirculating aquaculture system

Effects of temperature on growth, hematology, and immune responses of subadult Chinese sturgeon (<i>Acipenser sinensis</i>Gray 1835) under different ammonia nitrogen conditions in recirculating aquaculture system

Acoustic Target Strength of the Endangered Chinese Sturgeon (Acipenser sinensis) by Ex Situ Measurements and Theoretical Calculations

The Chinese sturgeon, Acipenser sinensis, is a large anadromous and highly endangered protected species. The assessment of its breeding population in the Yangtze River is critically important for effective management and population preservation. Currently, hydroacoustic methods have been widely used to study the adult sturgeons in the river, whereas the acoustic target strength (TS) characteristics of the species have not been studied. In this study, the TS of Chinese sturgeon was carefully evaluated both by ex situ measurements and theoretical calculations. Six Chinese sturgeons (Body Length (BL): 74.0−92.6 cm) were measured by a 199 kHz split echosounder in a 10-m deep net cage. The computed tomography of a Chinese sturgeon (BL: 110.0 cm) was conducted and the Kirchhoff ray mode (KRM) method was used to estimate the theoretical TS. As a result, the mean ex situ TS range of the six specimens was from −26.9 to −31.4 dB, which was very close to the KRM estimation (~1 dB difference). Then, the KRM method was used to predict the TS of Chinese sturgeon as a function of BL in six frequencies commonly used in freshwater environments and to estimate the TS of a representative adult Chinese sturgeon (250 cm) as a function of frequency and tilt angle. This study can provide a good basis for future hydroacoustic studies on the critically endangered Chinese sturgeon.

Growth and feeding ecology of juvenile Chinese sturgeon,Acipenser sinensis, in the Yangtze Estuary

The present study was conducted to assess growth and the feeding ecology with prey preferences of juvenile Acipenser sinensis individuals in the Yangtze Estuary from May to August, 2015. From May to August, juveniles grew from 11.65 ± 2.10 cm (10.82 ± 6.32 g) to 27.78 ± 3.36 cm (158.08 ± 60.50 g), and the length-weight relationship (b = 3.1124) indicated isometric growth. The stomach content analysis indicated the following order of dominance of prey groups: fish, crab, amphipoda, polychaeta, shrimp and other small benthic invertebrates. The main diet taxon has not changed dramatically compared with samples in 2004. Moreover, this study confirmed that changes occurred in the prey composition, which was different with the growth of length size in the Yangtze Estuary. Therefore maintaining species richness in the Yangtze Estuary and ensuring sufficient food source is crucial to species conservation of A. sinensis.

Yangtze Dams Increasingly Threaten the Survival of the Chinese Sturgeon

Dams are considered to be a serious threat to migratory fish on a global scale. Most of the world's rivers have been dammed, including those containing hotspots of fish diversity [1-3]. The mechanism by which dams affect fish is unclear and has often led to an underestimation of their cumulative and far-reaching adverse effects. Remedial measures of fish rescue for existing dams, including fish passage facilities and restocking, are insufficient or inefficient [1]. Although small and old dams are increasingly being removed, it is clearly unrealistic to demolish large, multi-section dams [4]. Hence, designing environmental flow to rescue fish is a complex challenge [5] and requires an in-depth understanding of the mechanism. Here, we propose an essential theory to reveal the relationship between dams and fish and discover novel insights into the migration behaviors, gonadal degeneration, and population dynamics of the Chinese sturgeon. We show that since1981, the Gezhouba Dam has reduced the migration distance by 1,175km, resulting in gonadal development being delayed by 37days, resulting in the effective breeding population size and environmental capacity of the new spawning ground respectively reduced to 24.1% and 6.5% of the original. Even worse, subsequently built dams, particularly the Three Gorges Dam and Xiluodu Dam, have further reduced the effective breeding quantity to 0%-4.5% by elevating the water temperature to inhibit breeding activity during the breeding season. The cumulative effect of the cascade dams has led to an ongoing decline in adult abundances in the Yangtze River and the sea.

Production of Biscuit from Chinese Sturgeon Fish Fillet Powder (Acipeneser sinensis): A Snack Food for Children

ABSTRACTMalnutrition in children is a current global burden. A common snack for children is biscuits prepared from cereals. However, these types of biscuits have low protein content. Therefore, producing healthier biscuits enriched with essential amino acids (EAAs) and other micronutrients is of great interest to researchers and manufacturers. In this study, biscuits produced from low gluten wheat flour fortified with sturgeon fillet powder (SFP) in various mixing ratios (100:0, 95:5, 93:7, and 90:10, respectively) were investigated. The results revealed that the nutritional and proximate composition of biscuits were significantly (P ≤ 0.05) improved: moisture (6.77 ± 0.06–7.65 ± 0.06), protein (13.23 ± 0.35–17.12 ± 0.02), fat (15.57 ± 0.18–15.85 ± 0.25), ash (0.84 ± 0.07–0.92 ± 0.06), spread ratio (14.0 ± 0.92–14.33 ± 0.21), and hardness (2,057.90 ± 28.33–3,089.02 ± 51.53). Total amino acids were 6.91, 9.34, 10.32, and 10.58; and EAAs were 2.43, 3.97, 4.48, and 4.22 g/100 g for 0%, 5%, 7%, and 10% SFP, respectively. Leucine was the major amino acid with 5% and 10% SFP, while methionine was the major amino acid with 7% SFP. Fungal counts were not observed, and quality indices were below the maximum acceptable limits in the products. Biscuits supplemented with 7% SFP showed the highest sensory evaluation score. Overall, the inclusion of 7% SFP could produce protein enriched cereal-based fortified biscuits with acceptable sensory and quality attributes and ultimately could insure effective fish utilization and solve malnutrition problems.

Sequence analysis and characterization of type I interferon and type II interferon from the critically endangered sturgeon species, A. dabryanus and A. sinensis

In the present study, we identify three type I interferon (IFN) genes (Ad/AsIFNe1-3) and a type II IFN gene (Ad/AsIFNγ) from the Dabry's sturgeon (Acipenser dabryanus) and the Chinese sturgeon (Acipenser sinensis). Sequence analysis revealed that Ad/AsIFNe1–3 and Ad/AsIFNγ contain several conserved characteristics, including signal peptides, interferon alpha, beta, and delta (IFabd) domains, and N-glycosylation sites. Ad/AsIFNe1-3 belongs to the type I IFN group I subgroup, possessing two conserved cysteines residues (C1 and C3), and Ad/AsIFNγ contained a conserved nuclear localization sequence (NLS) motif. Ad/AsIFNe1-3 and Ad/AsIFNγ contain signature motifs indicative of their corresponding IFN group. The Ad/AsIFNe1-3 and Ad/AsIFNγ genes were found to consist of 5 exons/4 introns and 4 exons/3 introns, respectively. These IFNs were separated by four phase 0 introns (type I IFN) and three phase 0 introns (type II IFN). The sequences of IFNe1-3 and IFNγ from the Dabry's sturgeon and the Chinese sturgeon were closely aligned, suggested that these two species are closely related. Phylogenetic analysis revealed that Ad/AsIFNe1-3 and Ad/AsIFNγ clustered together with the corresponding homologous proteins from other fish species. AdIFNe1-3 were found to be high expressed in early embryonic development, suggesting that AdIFNe1-3 might indicate maternal transmission, while AdIFNγ may not mediate embryonic development. Tissue distribution analysis revealed that AdIFNe1-3 and AdIFNγ carry out biological functions in immune and non-immune tissues compartments. AdIFNe1-3 and AdIFNγ can be stimulated by polyinosinic-polycytidylic acid (poly I:C) and lipopolysaccharides (LPS). AdIFNe1-3 have stronger antiviral activity than AdIFNγ, and AdIFNγ has a stronger antibacterial activity than AdIFNe1-3. The differential responses of these genes to poly I:C and LPS suggest differences in the mechanisms of defense against viruses and bacteria.

Monitoring seasonal distribution of an endangered anadromous sturgeon in a large river using environmental DNA.

Monitoring dynamic distribution is crucial to conservation management of anadromous sturgeons, but traditional survey methods are less efficient for low-density populations in a large river. Natural propagation of Chinese sturgeon has been monitored annually mainly at the spawning ground using netting for eggs and hydroacoustics for broodstock. However, absence of spawning was observed sporadically in recent years, indicating further crises for the declining population. We analyzed eDNA of water samples collected from 24 sites across 1360km of the migratory route of anadromous Chinese sturgeon in the middle and lower reaches of the Yangtze River. Chinese sturgeon was detected at 9 sites during the spawning season and 14 sites after the spawning season. We found that positive eDNA detection rates remained constant in the middle reaches but dramatically changed in the lower reaches, reflecting seasonal migration pattern of Chinese sturgeon. Invasive sturgeons were detected in the river, indicating their possible escape from aquaculture facilities. This study established a protocol for the use of eDNA to monitor distribution of Chinese sturgeon and could be valuable in making better policies for the conservation of this endangered species.

Isolation and identification of pathogens causing haemorrhagic septicaemia in cultured Chinese sturgeon (Acipenser sinensis )

Chinese sturgeon (Acipenser sinensis) is an endemic fish species of China listed as a critically endangered (CR) species on the IUCN Red List (since 2010). There was a recent outbreak of a novel disease characterized by haemorrhagic ascites and intestinal and renal haemorrhaging in cultured Chinese sturgeon, which clearly posed a serious threat to this species. Two kinds of pathogenic bacteria were isolated from moribund diseased Chinese sturgeon. Two isolates, AHth-1 and AVth-2, were selected as representative strains and were identified as Aeromonas hydrophila and Aeromonas veronii based on their morphology, biochemical characteristics, and a phylogenetic analysis derived from 16S rRNA, gyrB, and rpoD gene sequencing. Experimental infection tests showed that both identified isolates were pathogenic to juvenile Dabry's sturgeon (A. dabryanus) via intraperitoneal injection. Histopathology of Dabry's sturgeon infected with A. hydrophila or A. veronii revealed liver hyperaemia, hepatic, and splenic necrosis, and enteritis. Antimicrobial susceptibility tests showed that both bacterial strains were equally sensitive to fluoroquinolones antibiotics, and to third- and fourth-generation cephalosporins. These results provide a scientific reference for the diagnosis, prevention, and treatment of haemorrhagic septicaemia caused by A. hydrophila or A. veronii in cultured sturgeon.

Development and evaluation of an intelligent traceability system for waterless live fish transportation

Chinese consumers prefer to purchase fish that have only recently been killed. The supplying of live fish is routinely delivered by water. However, the traditional transportation of live fish with water results in small volume of transportation and may cost prohibitive. Therefore, cold anesthetized waterless live fish transport is considered an alternative and promising strategy, since this is likely to demand less energy with large freight volume. This paper aims to develop an intelligent traceability platform based on HACCP system that integrates wireless monitoring and quality control models to improve the quality control and safety transparency in waterless fish transportation. In this research Chinese sturgeon is taken as experiment subjects for long-distance transportation. Oxygen change model is established as a life-sustained key factor by hybrid prediction method can optimize fish survivability. Survival prediction model is also designed for improvement of live delivery quality with minimum stress accumulation under precise temperature condition. For tracing function evaluation, the QR Code combined with existing EPC traceability technology enables users to expediently query and quickly trace the safety transport information from aquaculture to markets. To demonstrate the automatic monitoring and intelligent traceable management in this platform, sturgeon delivery experiments have been evaluated and analyzed. The results illustrate this system can reduce the potential risks, implement quality control with high survival results, and improve the live fish transport volume at low-costly. In brief, application of this smart platform will provide an effective, suitable technical reference for aquatic enterprises to follow, and help them to adjust the waterless transport techniques for the other types of aquatic products.

Migration and feeding habits of juvenile Chinese sturgeon (Acipenser sinensis Gray 1835) in the Yangtze Estuary: Implications for conservation

Abstract Spatial and temporal variation in migration and feeding ecology of juvenile Chinese sturgeon (Acipenser sinensis Gray 1835) is reported for waters around Chongming Island, Yangtze Estuary, between April and August 2015. A migration survey showed that juvenile Chinese sturgeon remained within the Yangtze Estuary for a period of time preceding their onward migration to the sea; upper estuarine reaches were an important transition habitat during April and May, while nearshore coastal areas were foraging habitat during June to August. Stable isotopic analysis revealed (1) significantly lower isotope values in smaller‐sized Chinese sturgeon (≤100 mm) than larger‐ sized fish (&gt;100 mm), which indicated a dietary shift likely occurs at fork lengths greater than 100 mm; (2) the increase in values of δ13C and δ15N from May to August implied an ontogenetic dietary shift from lower to higher trophic‐level prey items; and (3) slight changes in distributional range among different coastal sites implied that individuals fed on similar food items. Coastal shallows represent major foraging areas for juvenile Chinese sturgeon in the Yangtze Estuary. In addition to the conventional conservation measures at the nature reserve, we suggest additional conservation actions to better protect juvenile Chinese sturgeon residing in the estuary; namely: (1) expanding the protected area and adding a seasonal component, from April to August, to afford better protection of juvenile Chinese sturgeon in the whole estuary, but particularly just upstream of the estuary mouth and in nearshore waters; and (2) banning all fishing activities and extending protection to the food resources (such as zoobenthos and small‐sized fishes) of juvenile Chinese sturgeon in coastal shallows.

A first attempt for genetic linkage map construction and growth related QTL mapping inAcipenser sinensisusing Specific Length Amplified Fragment Sequencing (SLAF‐seq)

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Optimal dietary lipid level promoted ovary development of Chinese sturgeon (Acipenser sinensis) broodstocks

A one-year feeding trial was conducted to determine the effects of dietary lipid level on gonad development and steroidogenesis-related gene expressions of Chinese sturgeon (Acipenser sinensis). Three isonitrogenous experimental diets (L10, L14 and L18) were compounded with different lipid levels. Results of the feeding trial showed that 2 female Chinese sturgeons in L18 group had developed the ovary to stage III. Chi-square independence test indicated that ovary development was significantly affected by dietary lipid level (P < .05). Po and d values of ovary also increased with dietary lipid level. Serum estradiol (E2) and testosterone (T) of L14 group was significantly higher than those in the other two groups (P < .05). Blood urea nitrogen (BUN) content decreased as dietary lipid level increased, while triglyceride (TG) and glucose (GLU) contents increased with dietary lipid level (P < .05). Vitellogenin receptor (vtgr) mRNA expression increased with dietary lipid level (P < .05); Gene expressions of androgen receptor (ar), cytochrome p450 17A1 (cyp17a1), steroidogenic acute regulatory protein (star), follicle stimulating hormone receptor (fshr), luteinizing hormone receptor (lhr) and cytochrome p450 aromatase (cyp19a1) were significantly higher in L14 group than in other groups (P < .05), whereas mRNA expression of leptin receptor (lepr) and DNA-binding protein inhibitor ID-1 (dbi) in L14 group were significantly lower (P < .05). Based on the gonad development, higher dietary lipid level (16.31%) would promote ovary development of Chinese sturgeon broodstocks through the elevation of vtgr expression to increase the assimilation of vitellogenin in ovary.