Siberian Sturgeon Acipenser Baeri Research Articles

Regulation of 14-3-3β/α gene expression in response to salinity, thermal, and bacterial stresses in Siberian sturgeon (Acipenser baeri).

The 14-3-3 proteins are a family of widely expressed acidic proteins, which are involved in the regulation of many biological processes of animals. However, no research regarding 14-3-3 has been described in sturgeon to date, one of the most primitive Actinopterygii species. Here, we identified the first 14-3-3 gene from Siberian sturgeon (Acipenser baeri), named Ab14-3-3β/α (GenBank Accession No. KY094076.1). The cDNA of Ab14-3-3β/α is 1212bp in length, containing a 5'-untranslated region (UTR) of 82bp, a 3'UTR of 392bp, and an open reading frame (ORF) of 738bp, encoding a polypeptide of 245 amino acids which contains a 14-3-3 homologs domain (PF00244). Phylogenetic analysis showed that the 14-3-3 gene product from Acipenser baeri is a counterpart of vertebrate 14-3-3β/α. The deduced Ab14-3-3β/α protein shares high identities of 46.5-95.5% with the homologs of other species. Ab14-3-3β/α mRNA was constitutively expressed in all examined tissues, with high expression levels in the blood and gill. Furthermore, the expression level of Ab14-3-3β/α mRNA increased significantly in the gill at 1h under acute salinity shock by transfer of Siberian sturgeons from fresh water (FW) to 15ppt. In fish subjected to a high temperature (31°C), Ab14-3-3β/α showed a significant upregulation in the liver at 3h compared with the control group (24°C). A 4.85-fold increase of Ab14-3-3β/α expression in the spleen of Siberian sturgeon was observed at 24h following Aeromonas hydrophila challenge. Collectively, these results indicated that Ab14-3-3β/α might play a certain role in sturgeon in response to some environmental stresses and bacterial challenge.

Comparative study on the effects of different feeding habits and diets on intestinal microbiota in Acipenser baeri Brandt and Huso huso

BackgroundSiberian sturgeon (Acipenser baeri Brandt) and Beluga sturgeon (Huso huso) are two important commercial fish in China, and the feeding habits of them are very different. Diets and feeding habits are two significant factors to affect the gastrointestinal microbiota in fish. The intestinal microbiota has been reported to play a key role in nutrition and immunity. However, it is rarely reported about the relationship between the intestinal microbiota and feeding habits/diets on different Acipenseridae fish. This study is to comparative analysis of gut microbial community in Siberian sturgeon and Beluga sturgeon fed with the same diet/Beluga sturgeon fed with different diets in order to determine the effects of different feeding habits/diets on the fish intestinal microbiota.ResultsAccording to the experimental objectives, BL and BH groups were Beluga sturgeon (Huso huso) fed with low fishmeal diet and high fishmeal diet, respectively. SH group represented Siberian sturgeon (Acipenser baeri Brandt) fed with the same diet as BH group. After 16 weeks feeding trial, the intestinal microbiota was examined by 16S rRNA high-throughput sequencing technology. On the phylum level, Proteobacteria and Bacteroidetes were significantly higher in BL group than BH group, and Cyanobacteria showed the opposite trend. Compared with BH group, Proteobacteria and Firmicutes were significantly increased in SH group, whereas Cyanobacteria were clearly decreased. At the genus level, Pseudomonas and Citrobacter in BL group were significantly higher comparing with BH group, while Bacillus, Luteibacter, Staphylococcus and Oceanobacillus was lower in BH group than SH group.ConclusionsAlpha and beta diversities indicated that the intestinal microflora were significant difference between Siberian sturgeon and Beluga sturgeon when they fed with the same diet. Meanwhile, Beluga sturgeon fed with low fishmeal diet can increase the species diversity of intestinal microbiota than it fed high fishmeal diet. Therefore, feeding habits clearly affected the gastrointestinal microbiota of sturgeons. Moreover, the impact of changes in food on the gut microbiota of sturgeons should be taken into consideration during the process of sturgeon aquaculture.

Transcriptomic analysis reveal an efficient osmoregulatory system in Siberian sturgeon Acipenser baeri in response to salinity stress

Sturgeons are euryhaline fish species that have developed specific mechanisms of osmotic and ion regulation to adapt to waters of varying salinity. For the aim to elucidate the osmoregulation strategy behind its high salinity tolerance of sturgeons, the transcriptomes of gills in Siberian sturgeon Acipenser baeri under salinity stress (30 ppt) were sequenced using deep-sequencing platform Illumina/HiSeq-2500 and differential expression genes (DEGs) were identified. A total of 167, 501, 278 clean reads were obtained and 280, 238 unigenes were composed of those clean reads with the mean length of 520nt, and the N50 of 630 bp. Unigenes Sequence alignment was implemented via KEGG, KOG, NT, NR, PFAM, Swiss-Prot, and GO databases. 62, 242 unigenes (22.21%) were annoated in at least one database. 11380 significantly differentially expressed unigenes were found, 6969 of which were up-regulated and 4411 were down-regulated by salinity stress. Amongst the top 20 KEGG pathways with the most amount of annotation sequences, some pathways such as glycerophospholipid metabolism, fatty-acid biosynthesis, glycolysis/gluconeogenesis, oxidative phosphorylation have been comprehensively proved to be relevant to osmoregulation. Despite of these, three possible osmoregulation-related signaling pathways as lipid metabolism related pathways, tight junction pathway and thyroid hormone signaling pathway have been widely analyzed in the current study. In all DEGs, some of the typical genes involved in osmoregulation, including calcium-transporting ATPase 4 (ATP2B4), Na+/K+-ATPase alpha subunit (α-NKA), potassium-transporting ATPase alpha chain 1 (ATP4A) and Ras GTPase-activating protein (RasGAP) etc were also identified. RNA-seq results were validated with quantitative real-time PCR (qPCR), the 12 selected genes showed a consistent direction in both DGE library and qPCR analysis, proving that the RNA-seq results are reliable. The present results would be helpful to elucidate the osmoregulation mechanism of aquatic animals adapting to salinity challenge.

Subyearling Siberian Sturgeon Acipenser baeri Fed a Diet Supplemented with ImmunoGen: Effects on Growth Performance, Body Composition, and Hematological and Serum Biochemical Parameters.

In this research, the effect of ImmunoGen (IMNO) on the growth indices, hematological parameters, and carcass composition of Siberian Sturgeon Acipenser baeri was investigated. After acclimation, fish (274.8±16.2g) were allocated into 12 tanks (10 fish per tank) and triplicate groups were fed a control diet (0%) or diets containing 0.5, 1.0, or 1.5% IMNO for 75d. At the end of the experiment, final length, final weight, and weight gain were significantly higher in the fish fed the diet containing 1.0% IMNO, though no significant differences were observed between the control and experimental diets containing 0.5% and 1.5% IMNO. In addition, there were no significant differences among diets in terms of hematological parameters and carcass composition. However, dietary IMNO significantly affected the serum biochemical parameters of Siberian Sturgeon, such as cholesterol, triglycerides, and IgM, with the highest level of IgM occurring in the 1.0% IMNO treatment and the lowest levels of cholesterol and triglycerides in the 1.5% IMNO treatment. The findings of this study thus indicate that the administration of 1.0% IMNO in diet positively affects the growth factors and some serum biochemical parameters of Siberian Sturgeon.

The effect of four C21-steroids on oocyte maturation in Siberian sturgeon (Acipenser baeri Brandt)

The effect of four C21-steroids, progesterone (P4), 17,20β-dihydroxy-4-pregnen-3-one (17,20βP), 17,20β,21-trihydroxy-4-pregnen-3-one (20βS) and 11-desoxycortisol (S), on in vitro oocyte maturation in Siberian sturgeon (Acipenser baeri Brandt) females was demonstrated using short-term (5 and 30 min) exposures of ovarian follicles to steroid solutions followed by incubation in steroid-free medium. The study aimed to find out which of the four candidates for a maturationinducing steroid (P4, 17,20βP, 20βS or S) induces a fastest germinal vesicle breakdown (GVBD) in oocytes of Siberian sturgeon. Dissolution of the oocyte nucleus or GVBD was taken as a criterion of oocyte maturation. Dose-response profiles of hormone activities as well as effects of the hormones under short-term exposures of follicles to their equal doses were compared. P4 was found to be a most active GVBD inducer compared to other C21-steroids, S was the second in its activity, whereas 17,20βP and 20βS were less efficient. A comparison of the present and previously obtained data on the dynamics of C21-steroids in vivo and their effect on ovarian follicles in vitro indicates an important role of the above hormones, particularly P4 and 20βS, in the regulation of the final stage of oocyte maturation in sturgeons.

Effect of Exhaustive Exercise on the Swimming Capability and Metabolism of Juvenile Siberian Sturgeon

AbstractThis study investigated the effect of exhaustive exercise on the swimming performance of Siberian Sturgeon Acipenser baeri and on the time required for recovery. Critical swimming speed (Ucrit), maximum metabolic rate (MMR), speed coefficient (c), and excess postexercise oxygen consumption (EPOC) were measured on three groups of juvenile sturgeon by stepped velocity tests at 20°C in a fish respirometer. After a recovery period of 1 h (group 1), 1 d (group 2), or 1 week (group 3), the four parameters were determined a second time and the results compared. The Ucrit of the sturgeon was 3.26 ± 0.11 body lengths per second (mean ± SE). After a 1 h recovery period, Ucrit was 78% of its initial value and complete recovery required slightly more than 1 d. Recovery of MMR followed the same pattern. The speed exponent (c) was approximately 1.0, indicating that the Siberian Sturgeon is an efficient swimmer; swimming efficiency decreased after exhaustive exercise and the effect appeared to last for at least 1 week. Exhaustive exercise strongly hindered anaerobic swimming in Siberian Sturgeon for more than an hour.

Comparing Ultrasonography and Endoscopy for Early Gender Identification of Juvenile Siberian Sturgeon

AbstractEarly gender identification is economically advantageous in sturgeon aquaculture to facilitate the targeting of food and spatial resources to females for caviar production. In addition, many species of free‐ranging sturgeon are threatened or critically endangered, and the ability to identify gender and evaluate gonads can reveal pertinent biological information that can lead to better management and recovery plans. We compared the speed and accuracy of ultrasonography and endoscopy in identifying gender in 143 juvenile Siberian Sturgeon Acipenser baeri using gonadal histology as the gold standard. The age‐3 and age‐4 sturgeon were anesthetized with buffered tricaine methanesulfonate and evaluated using ultrasonography and endoscopy; endoscopic gonadal biopsy was then done for histologic confirmation. All fish recovered normally, and there was no postprocedural morbidity or mortality. Histology confirmed the gender for 128 of the 140 (91.4%) fish. Histology and endoscopy agreed on the gender of 124 of the 128 (96.9%) fish, while histology and ultrasonography agreed on 113 of the 128 (88.3%) fish. Ultrasonography (mean time, 11.2 s) was significantly faster than endoscopy (22.3 s), while endoscopy was more accurate but more invasive. Diagnostic accuracy, speed, and invasiveness are factors to consider when selecting a method of gender identification for commercial and free‐ranging populations.

Antioxidant response versus selenium accumulation in the liver and kidney of the Siberian sturgeon (Acipenser baeri)

The aim of this study was to examine the effects of selenium on concentrations of metabolites and enzyme activities acting as antioxidant markers in liver and kidney of Siberian sturgeon Acipenser baeri. Sturgeons were fed selenium cysteine for 30 and 60d at 1.25, 5, 20mg Sekg−1. Selenium level in the control feed was 0.32mgkg−1. Se concentration was measured in liver, kidney and muscle of every specimen. Sturgeon accumulated Se in tissues with a clear dose-response relationship and the highest Se concentration was recorded in liver. This outcome is lined up with the findings obtained on the antioxidant markers evaluated in both tissues, and in which a dose-response for several biomarkers was recorded in liver. The superoxide dismutase activity in Se-treated fish was generally induced, while catalase activity was lower in liver or unaltered in kidney. The concentrations of glutathione S-transferase, glutathione reductase and total glutathione responded differently for both tissues and were induced in a different way at both endpoints. No changes of glyoxalase I activity were noted for both Se-treated tissues, while for glyoxalase II enzyme in liver a dose-related pattern was found showing a reversible effect (decreased and increased counteractive response) only in the 5mgkg−1 group. Moreover, the highest Se concentrations did not cause marked changes in malondialdehyde levels of liver and kidney. The enhancement of glutathione peroxidase activity in Se-treated sturgeon might have prevented the lipid peroxidation in both tissues, providing to the Siberian sturgeon a great defense ability versus the prooxidant effect of selenium.

Pathologic and Physiologic Effects Associated with Long‐Term Intracoelomic Transmitters in Captive Siberian Sturgeon

AbstractIntracoelomic transmitters are commonly used to evaluate migratory patterns, distribution, and habitat use of many species of fish. Currently, transmitter implantation relies mostly on the assumption that transmitters do not cause any adverse physiological or pathological effects on the animal. To investigate these effects, we surgically implanted 60 Siberian Sturgeon Acipenser baeri with transmitters that weighed less than 2% of their body weight. Postoperative assessments were conducted at 1, 2, 8, 12, 26, and 55 weeks to evaluate surgical healing and transmitter retention. Blood samples were collected before and after the 55‐week study for serum cortisol analysis. Overall transmitter loss was 32%. Minor to moderate adhesions were noted at necropsy but did not appear to affect organ function. One fish was noted to have an intraintestinal transmitter at necropsy, but the fish was in overall good health. Long‐term transmitter presence does not appear to increase serum cortisol levels or affect overall growth more than nontransmitter fish. Although long‐term telemetry studies can be undertaken with minimal concern for negative physiological or pathological effects from transmitters, researchers should be aware that transmitter loss rates may be higher than previously thought. Mechanisms for transmitter loss may include expulsion through the surgical incision, expulsion through the mucocutaneous junction between the large intestine and the vent, or intraintestinal capture and expulsion through the vent.Received February 10, 2013; accepted June 10, 2013

Effects of dietary bovine lactoferrin on growth, physiological performance, iron metabolism and non-specific immune responses of Siberian sturgeon Acipenser baeri

The present experiment was carried out to investigate the effects of different levels of dietary lactoferrin (LF) on growth performance, physiological status, iron absorption and innate immune response of juvenile Siberian sturgeon Acipenser baeri. Fish were fed with six different rations including 0, 100, 200, 400, 800 and 1600 mg LF kg−1 diet for 8 weeks. At the end of the experiment, samples were collected for estimating the physiological and immunological parameters. Dietary LF did not change the fish growth performance, hematological parameters, serum proteins or hepatic enzymes. Moreover, stress indicators (plasma cortisol, glucose and lactate) were not affected by dietary LF. The iron absorption of fish was considerably affected by LF; thus, plasma iron in LF-treatments greatly declined and the total iron binding capacity (TIBC) significantly increased in fish fed with 800 mg LF kg−1. In addition, the liver iron content markedly increased in some LF-treatments, but the variation of muscle iron concentration in treatments was insignificant. The amount of mucus secretion and serum bactericidal activity rose in fish fed on dietary LF, although other non-specific immune responses such as mucus bactericidal activity, serum and mucus lysozyme activity, serum peroxidase, serum natural hemolytic complement activity and serum IgM were not influenced by LF. This study revealed the ability of dietary LF to sequester iron, which is an essential nutrient required for the growth of bacteria. LF was also shown to improve some physiological and immunological parameters of Siberian sturgeon, to some extent.

Anatomical relations between neuropeptide Y, galanin, and gonadotropin-releasing hormone in the brain of chondrostean, the Siberian sturgeon Acipenser baeri

We investigated the immunohistochemical localization of immunoreactive (ir) cell bodies and fibers of neuropeptide Y (NPY) and galanin (GAL), and the anatomical relations between these neurons in the brain of the Siberian sturgeon Acipenser baeri to clarify the interactions between these neuropeptides. Furthermore, the anatomic relations between NPY and gonadotropin-releasing hormone (GnRH) in the brain were also examined. NPY-ir cell bodies were observed in the ventral part of the ventral telencephalon (Vv). NPY-ir fibers were observed throughout the brain, primarily in the ventral telencephalon, hypothalamus, optic tectum, and midbrain. GAL-ir cell bodies were observed in the Vv, nucleus anterioris tuberis (NAT), nucleus lateralis tuberis (NLT), and nucleus recessus posterioris (NRP). GAL-ir fibers were also observed throughout the brain. Neither NPY-ir fibers nor GAL-ir fibers were detected in the pituitary. Dual-label immunohistochemistry revealed that some GAL-ir fibers were in close contact with NPY-ir cell bodies in the Vv, and some NPY-ir fibers were in close contact with GAL-ir cell bodies in the NAT. Furthermore, some NPY-ir fibers were in close contact with GnRH-ir cell bodies in the preoptic area, and some GnRH-ir fibers were in close contact with NPY-ir cell bodies in the Vv. These findings suggest that reciprocal connections exist between the NPY and GAL neurons and between the NPY and GnRH neurons in the brain of the Siberian sturgeon.

Viable gynogenetic offspring of siberian sturgeon Acipenser baeri Brandt (Pisces, Acipenseridae) obtained from in vitro ovulating eggs

Viable gynogenetic offspring of siberian sturgeon Acipenser baeri Brandt (Pisces, Acipenseridae) obtained from in vitro ovulating eggs

First detection of a viral agent causing disease in farmed sturgeon in Russia

A virus was isolated from Siberian sturgeon Acipenser baeri and bester (beluga Huso huso x sterlet A. ruthenus hybrid) fingerlings in SSO-2, SSF-2 and WSSK-1 cell lines during an acute epizootic on a large fish farm producing fertilised sturgeon eggs and fry. Transmission electron microscopic examination of samples from both inoculated cell cultures and skin of affected fish revealed viral particles with a herpesvirus-like morphology. The etiological role of the Siberian sturgeon herpesvirus (SbSHV) was confirmed by fulfilment of Rivers' postulates. Experimental immersion of healthy Siberian sturgeon fingerlings in a suspension of SbSHV resulted in 100% mortality with signs of focal epidermal hyperplasia, skin necrosis and multiple skin haemorrhages. While infecting different organs and tissues, the virus showed clear integumentary tropism. Carp fry and rainbow trout fingerlings were neither susceptible to the virus nor did they transmit it to healthy Siberian sturgeon.

Application DNA Fingerprint Analysis for Identification of Mixed Groups of Siberian Sturgeon (<i>Acipenser Baeri</i> Brandt)

DNA finferprinting analysis based on microsatellites was applied for separation of mixed gynogenetic offspring of Siberian sturgeon (Acipenser baeri) and individuals from commercial production. Variation at 11 microsatellite DNA loci was surveyed for parent of gynogenetic offspring. Thus microsatellite DNA profiles in studied loci were known and this key-point was aplied in segregation analysis of mixed fish. In results 108 individuals of 281 studied were verified as gynogenetic offspring. The present survey of microsatellite variation demonstrated a reliable tool for separation of mixed group of fish.

Verification of meiotic gynogenesis in Siberian sturgeon (Acipenser baeri Brandt) using microsatellite DNA and cytogenetical markers

Diploid gynogenesis was induced in Siberian sturgeon Acipenser baeri using ultra violet (UV)‐irradiated bester (Huso huso ×Acipenser ruthenus) sperm. The higher survival rate of meiotic diploids was noted after 1350 ergs mm−2 UV irradiation. A total of 80 meiotic diploids of known parentage from two different experimental treatments were screened using microsatellite DNA and cytogenetical analysis, and uniparental transmission in meiotic diploids was confirmed.

Alteration of thermoregulation behavior in juvenile fish in relation to satiation level

Thermoregulation behavior of satiated and hungry juvenile sterlet Acipenser ruthenus, the Siberian sturgeon Acipenser baeri, and the goldfish Carassius auratus was studied. Significant alterations of thermoregulation behavior appear in juvenile fish one day after food deprivation. Hungry fish preferred, on average, lower temperatures, their temperature range was broader, and the locomotor activity was higher than in satiated fish.

Influence of Storage Duration of Ovulated Eggs Prior to Fertilisation on the Early Ontogenesis of Sterlet ( Acipenser ruthenus ) and Siberian Sturgeon ( Acipenser baeri )

The influence of short-term storage (0, 2, 4, 6. 9 and 12 h) in coelomic fluid at 15 °C of ovulated eggs of mature females from sterlet (Acipenser ruthenus) and Siberian sturgeon (Acipenser baeri) was studied. The percentage of fertilization, embryonic survival, abnormally developing embryos, hatching and larvae with malformations at hatching was measured. The results showed that ovulated eggs from A. ruthenus retained their fertilizability during 2-4 hours after ovulation depending on the maternal origin (83.5-43.7%, P 0.05). The results showed that ovulated eggs of A. ruthenus and A. baeri stored in coelomic fluid at 15 °C lost their fertilizability and viability. and became over-ripe between 2-4 and 6 hours after ovulation. respectively.

Evaluation of a Gastric Lavage Method for Sturgeons

Because of their threatened status, sturgeons (Acipenseridae) can no longer be sacrificed for stomach content analysis. We tested a nonlethal method of gastric lavage on Siberian sturgeon Acipenser baeri. The efficiency and harmlessness of the method were tested with four different volumes of food (10, 20, 30, and 40 cm3), each composed of brown shrimp Crangon crangon, Chironomidae, earthworm Lumbriscus terrestris, and sand goby Pomatoschistus minutus. The Siberian sturgeons were force-fed before the gastric lavage was performed. Some prey were recovered from all the sturgeons, and the average food item recovery rate from stomach contents was 67.5%; recovery of brown shrimp and sand goby (78.2%) was greater than that of vermiform items (51.4%). The volume of food had no significant influence on the prey recovery rate. No mortality resulted from the gastric lavage. However, the method is not totally benign because the fish that had undergone gastric lavage averaged significantly greater weight loss than the control fish during the 60-d follow-up period.

Effect of Modificators on the Process of Membrane Digestion in the Siberian Sturgeon Acipenser baeri

Effect of Modificators on the Process of Membrane Digestion in the Siberian Sturgeon Acipenser baeri

Identification of the river blenny, Salaria fluviatilis, as a host to the glochidia of Margaritifera auricularia

Laboratory experiments to control glochidial infestations of fishes are particularly interesting when considering the conservation of endangered freshwater mussels. The few species of the family Margaritiferidae for which hosts have been identified have specific fish gill filament glochidia. Margaritifera margaritifera (L.), M. laevis (Haas) and M. falcata (Gould) glochidia seem to be specific to salmonids, 1,2 and recent results suggest specificity between the ictalurid Noturus phaeus (Taylor) and the North American Margaritifera hembeli (Conrad). 3 In the critically endangered M. auricularia (Spengler), controlled experiments in aquaria have demonstrated the suitability of the Siberian sturgeon Acipenser baeri Brandt for successful metamorphosis of the glochidium 4 , suggesting a possible historical relationship between M. auricularia and the endangered native Atlantic sturgeon A. sturio L. Recent studies in the Ebro River using both drift nets and electrofishing have demonstrated that none of the fish species currently living with M. auricularia can host their glochidia for complete metamorphosis 5 . The absence of juveniles in the habitat of the known population also supports this fact. To discover more about possible suitable fish hosts of M. auricularia, we attempted to infest several native fishes that historically cohabited with M. auricularia. Experiments were carried out in aquaria at the Museo Nacional de Ciencias Naturales in February, March and April (M. auricularia glochidia release period 5 ) 1999 and 2000. Numbers and species tested were: 2 Salaria fluviatilis (Asso) the river blenny, 12 Barbus spp. (includying B. haasi Mertens and B. graellsii Steindachner), 1 Rutilus arcasii (Steindachner) and 3 Anguilla anguilla (L.). The river blenny, an endangered species, was directly collected at the Canal de Lodosa (La Rioja, Spain). Eels, a historically common species in the Ebro River, were purchased from a fish hatchery. The other species were collected by electrofishing in River Ebro tributaries. Eleven and ten gravid specimens of M. auricularia were collected at the Canal Imperial de Aragon (Zaragoza, Spain) in February 1999 and 2000, respectively, and maintained in aquaria until mature glochidia emerged. Mussels and fishes were kept in aerated tanks with average room and water temperatures of 19°C and 17.5°C, respectively. Prior to infestation, fishes were fed with red mosquito larvae. For induced infestation, glochidia were obtained with a pipette from the exhalant apertures of the mussels and rinsed with aerated water into glass jars each containing a fish. After infestation, each fish was isolated in an aerated aquarium without substratum and with a 5 mm-mesh plastic net on the bottom and regularly inspected for glochidium