Sterlet Acipenser Ruthenus Research Articles

The effect of a cortisol analogue and transport stress on the frequency of occurrence of micronuclei in erythrocytes of the peripheral blood of sterlet Acipenser ruthenus L.

The effect of a cortisol analogue and transportation on the occurrence of micronucleus in erythrocytes of the peripheral blood of sterlet was studied. Both factors increased the number of fish with micronucleus and the percentage of aberrant erythrocytes.

Preliminary results on Siberian sterlet (Acipenser ruthenus marsiglii) fries rearing under intensive conditions

In our experiments production performances of Siberian sterlet were tested under intensive tank conditions. During the 25 days long experiment effectiveness of weaning to artificial diet of the fish was investigated. Production performances of fish fed on exclusively dry diet from the beginnings were lower than the other two groups. Between the values of sterlets fed on live food also then suddenly vs. continuously were weaned to dry diet there were no significant differences. Based on our results live food feeding could be suggested for the Siberian sterlet larvae for some days but the method of the weaning to dry diet has no significant influence to the production performances.
 In 21 days long experiment four different feeding frequencies were tested in Siberian sterlet (~13 g) fingerlings. Dry feed was offered for the fish continuously, 2, 3 and 4 times per day. There were no significant differences between the values of the four treatments. Based on our results there is no high influence of feeding frequency in case of this size group of Siberian sterlet.
 During the nursing in two different size groups of Siberian sterlet the optimal daily amounts of feed were aimed to determine. In case of growth values of the group fed at 7% of the total biomass were higher than the other two groups (3 and 5%). Feeding performances of fish fed at 5% were significantly better than fish fed at 7%. Based on our results for ~20 g size of the subspecies at least 5% of total body weight could be suggested.
 In case of ~150 g size of the fish the production performances of fish fed at 1% were lower than the other two groups (2 and 3%). Between the values of stocks fed at 2 and 3% there were no significant differences. Based on these results 2% of total body weight of dry feed could be suggested for the Siberian sterlet with ~150 g body weight.

Influence of environmentally relevant concentrations of vinclozolin on quality, DNA integrity, and antioxidant responses of sterlet Acipenser ruthenus spermatozoa

The effects of vinclozolin (VIN), an anti-androgenic fungicide, on quality, oxidative stress, DNA integrity, and ATP level of sterlet (Acipenser ruthenus) spermatozoa were investigated in vitro. Fish spermatozoa were incubated with different concentrations of vinclozolin (0.5, 2, 10, 15, 20 and 50μg/l) for 2h. A dose-dependent reduction in spermatozoa motility and velocity was observed at concentrations of 2–50μg/l. A dramatic increase in DNA fragmentation was recorded at concentrations 10μg/l and above. After 2h exposure at higher test concentrations (10–50μg/l), oxidative stress was apparent, as reflected by significantly higher levels of protein and lipid oxidation and significantly greater superoxide dismutase activity. Intracellular ATP content of spermatozoa decreased with increasing concentrations of VIN. The results demonstrated that VIN can induce reactive oxygen species stress in fish spermatozoa, which could impair the sperm quality, DNA integrity, ATP content, and the antioxidant defense system.

Developmental structure of the vertebral column, fins, scutes and scales in bester sturgeon, a hybrid of beluga Huso huso and sterlet Acipenser ruthenus

In the larval bester, a hybrid sturgeon of beluga Huso huso and sterlet Acipenser ruthenus, development of cartilage around the notochord began 7 days post hatch (dph) (14.0 mm, total length, L(T)). The vertebral cartilage develops in the following sequence: basidorsals and basiventrals, neural canals, neural spines and ribs. The development of ribs remained incomplete in the largest specimen (181 dph, 179 mm L(T) ) that was examined. Endoskeletal development of the fins began 4 dph for the dorsal and anal fins, 6 dph for the pectoral fin and 10 dph for the caudal and pelvic fins. Complete elements of all fins were observed by 91 dph and complete ossification of fin rays was observed by 122 dph in the double-stained specimens. Observation of the histological sections, however, suggested that ossification occurred soon after the formation of the organic matrix in the fin rays. Dorsal scutes were first visible by 25 dph, followed by the lateral and ventral scutes, which were visible by 37 and 44 dph, respectively. The number of scutes was fixed at 44, 59 and 91 dph and ossification was complete by 59 (dorsal) and 91 dph (lateral and ventral scutes) in the double-stained specimens. Ossification occurred soon after the formation of the scute organic matrix in the histological sections. Four types of scales were observed in the H. huso×A. ruthenus hybrid. Median predorsal, preanal and small scales on the anterior section of the head were visible by 59 dph. Scales on the caudal fin were visible by 91 dph and a variable assemblage of scales anterior to the anal fin was visible by 122 dph. Both the scutes and scales developed in a process that is similar to that of intramembranous ossification.

Comparison of Protein Fractions in Seminal Plasma from Multiple Sperm Collections in Sterlet (Acipenser ruthenus)

Seminal plasma of sterlet Acipenser ruthenus was evaluated using comparative proteomics to characterize its protein fractions and to determine any influence of multiple sperm collections on these proteins. An experimental group of fish was used, in which sperm was collected three times at 5 h intervals. Protein fractions of seminal plasma were determined by SDS-gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis high-resolution gels (2D). At all stripping times, five protein bands with molecular weights of 93, 53, 48, 33 and 28 kDa were identified using SDS-PAGE. No significant differences (p > 0.05) in relative mass of protein bands among collections were observed. At the third collection, 20 protein spots were detected from the two-dimensional gels, compared to 17 found at the first and second collections. Ten protein spots, from the third stripping, were analysed. Screening of these spots by mass spectrometric analysis showed positive results for spot 10. Direct comparison across public databases revealed sequence similarity with two hypothetical proteins, MCAG_00854 and IscW_ISCW011489. Differences in the seminal plasma protein fractions were found at the third stripping compared to the first two. It is hypothesized that these extra proteins after the third collection could be involved in some step of intracellular mechanism which is responsible for regulating of spermatozoa motility. However, protein identification revealed no significant distinction for any protein spot and protein sequences available in public databases. These results highlighted the need for a complete genome sequences for sturgeons.

Spermatozoa motility, cryoresistance, and fertilizing ability in sterlet Acipenser ruthenus during sequential stripping

We describe spermatozoa characteristics from sequential collections in sterlet, Acipenser ruthenus, following a single dose of carp pituitary extract (CPE). Sperm production and spermatozoa fertilizing ability, percent motility, and curvilinear velocity (VCL) were investigated in fresh and frozen/thawed sperm. Sperm was collected by two procedures: (A) stripping 3 times per 24h at 3h intervals on 3 consecutive days beginning 12h after CPE treatment, and (B) stripping 3 times over 6h beginning 36h after CPE treatment. Spermatozoa motility and VCL were evaluated by video microscopy, and sperm production was measured as volume and concentration. Sperm samples were frozen by a conventional freezing procedure in a cryoprotective medium containing 10% methanol. Fertilization was conducted using a ratio of 105 spermatozoa/egg. Both sequential stripping procedures yielded larger volumes of viable spermatozoa than did a single collection. Sperm parameters such as density and volume varied widely depending on collection time. The highest numbers of spermatozoa per individual were collected 15–42h post-CPE treatment in (A) and at 42h post-CPE treatment in (B) (85±4% and 64±5% of total spermatozoa count, respectively). Median percent motility in spermatozoa before cryopreservation was 26–100% and 5–67% post-thaw. Fertilization rates obtained with frozen/thawed spermatozoa were 13–76% (median value). A significant increase in spermatozoa motility parameters and fertilizing ability at the second collection on each day was observed. Sequential stripping and spermatozoa cryopreservation in combination could improve the efficiency of sturgeon aquaculture.

Feeding of juvenile sterlet (Acipenser ruthenus, Acipenseridae) in the Danube River midstream

The present paper provides the results of the study on feeding of juvenile (underyearlings and age 2+) sterlet (Acipenser ruthenus) caught in the Danube River in 2002–2003. The full spectrum of food items found in the fish stomachs was identified. The seasonal patterns of food composition are revealed. It is shown that juvenile sterlet in the Danube feeds mainly on larvae of chironomids and trichopterans, amphipods, and leeches. The organisms typical for lithophilic and lithorheophilic biocenoses play considerable role in the feeding of sterlet. Mean daily gains of body length and weight in the sterlet underyearlings are calculated.

Effect of dexamethasone on activity of glycosidases and proreinases of intestine of sterlet Acipenser ruthenus

Effect of dexamethasone (2.0 mg/kg) on activity of enzymes hydrolyzing proteinaceous and carbohydrate food components in the intestine of the starlet Acipenser ruthenus is studied. Dexamethasone modifies the activity of proteinases more than of glycosidases. As a rule, the hormone significantly decreases the level of proteolytic and general amylolytic activity of the intestinal mucosa and chyme in comparison with intact fish on the first day into the experiment and increases it on the 7th or 14th day. The dynamics of activity was different in enzymes of different chains (glycosidase and proteinase) and preparations (the mucosa and chyme).

Potential role of the acrosome of sturgeon spermatozoa in the fertilization process

Sturgeon gametes are unique in that their spermatozoa possess acrosome containing acrosomal enzymes whereas their eggs are perforated by numerous micropyles. Thus the function of acrosome, which undergoes acrosomal reaction and filament formation, is unclear. The acrosomal reaction of sterlet Acipenser ruthenus spermatozoa was induced by sperm exposure to the solution containing Ca2+ and high pH. The rate of affected spermatozoa was evaluated using Soybean Trypsin Inhibitor-Alexa conjugate fluorescent staining. Fertilization and hatching test using sperm of this way disrupted acrosome and non-treated sperm as a control proofed necessity of acrosome integrity for fertilization. Increasing percentage of spermatozoa with disrupted acrosome highly decreased percentage of hatching, in spite of electron microscopy verification that the spermatozoa bearing such disrupted acrosomes were able to reach the micropyle. In addition the significant positive correlation between the ability of spermatozoa to induce acrosomal reaction by activation solution and sperm fertilizing ability suggested that spermatozoa, which are able to activate the acrosomal reaction, are more successful in fertilization.

Feeding ecology of sterlet Acipenser ruthenus L. in the Hungarian section of the Danube River

The aim of the study was to describe the feeding habits of sterlet, Acipenser ruthenus L., in the mid section of the Danube (km 1676-1694). The fish were caught in the summers of 1991 and 1992. The food composition of 85 sterlets (mean body length BL = 37.1 cm; body weight W = 540 g) was analyzed. Most of the fish analyzed (98.8%) had full digestive tracts. Sterlet is considered to be a typical benthic feeder. The food analyzed contained insect larvae and pupae (Trichoptera, Chironomidae), amphipods (Corophium sp., Gammarus sp.), bivalves (Bivalvia), polychaetes (Annelida) and barbel, Barbus barbus (L.). The dominant food items in the digestive tracts were larval caddisflies (Trichoptera), Corophium (Amphipoda), and larval Chironomidae. Regardless of sterlet body size, the fish consumed Chironomidae followed by Trichoptera. The remaining components were noted in the food rarely and in small quantities. One exception were bivalves that were a considerable dietary component of the largest sterlet size group.

Image cytometric measurements of diploid, triploid and tetraploid fish erythrocytes in blood smears reflect the true dimensions of live cells

Comparative image cytometry of erythrocytes of diploid and triploid tench Tinca tinca L. and evolutionary tetraploid sterlet Acipenser ruthenus L. was performed on whole live unstained cells, live cells with stained nuclei and on stained fixed whole cells and their nuclei to test if erythrocyte measurements made from blood smears reflect the true dimensions of live cells. Nuclear area and perimeter were the best ploidy level predictors distinguishing accurately among live and fixed diploid, triploid and tetraploid cells, without significant differences between live and fixed cells within a ploidy level. Redundancy analysis revealed insignificant marginal effect of fixation (explained 2.3% of variation, F = 0.804), whereas the effect of ploidy level was highly significant (explained 50.6% of variation, F = 34.874). The erythrocyte measurements of diploid, triploid and tetraploid fish erythrocytes and their nuclei made from blood smears reflect the true dimensions of live cells, and the fixation procedure did not substantially affect their predictive value for ploidy level determination.

Buffer and respiratory properties and ion surrounding of hemoglobin of the sterlet Acipenser ruthenus

Buffer and respiratory properties and ion surrounding of hemoglobin of the sterlet Acipenser ruthenus

Size determination of Acipenser ruthenus spermatozoa in different types of electron microscopy

In this study three types of scanning electron microscopes were used for the size determination of spermatozoa of sterlet Acipenser ruthenus – high vacuum scanning electron microscope (SEM, JEOL 6300), environmental scanning electron microscope (ESEM, Quanta 200 FEG), field emission scanning electron microscope (FESEM, JEOL 7401F) with cryoattachment Alto 2500 (Gatan) and transmission electron microscope (TEM, JEOL 1010). The use of particular microscopes was tied with different specimen preparation techniques. The aim of this study was to evaluate to what degree the type of used electron microscope can influence the size of different parts of spermatozoa. For high vacuum SEM the specimen was prepared using two slightly different procedures. After chemical fixation with 2.5% glutaraldehyde in 0.1 M phosphate buffer and post-fixation by 1% osmium tetroxide, the specimen was dehydrated by acetone series and dried either by critical point method or by means of t-butylalcohol. For ESEM fresh, unfixed material was used, which was dropped on microscopic copper grids. In FESEM working in cryo-mode the specimen was observed in a frozen state. Ultrathin sections from chemically fixed and Epon embedded specimens were prepared for TEM observation. Distinct parts of sterlet spermatozoa were measured in each microscope and the data obtained was statistically processed. Results confirmed that the classical chemical procedure of specimen preparation for SEM including critical point drying method led to a significant contraction of all measured values, which could deviate up to 30% in comparison with values measured on the fresh chemically untreated specimen in ESEM. Surprisingly sperm dimensions determinated on ultrathin sections by TEM are comparable with values obtained in ESEM or FESEM.

Migrations and resources of sterlet Acipenser ruthenus (Acipenseridae) from the lower reaches of the Volga River

Based on long-term materials, spawning, postspawning, and downstream migrations of the Lower Volga sterlet Acipenser ruthenus were studied. The dates, extent, pattern (two-step and one-step) and main parameters of the spawning and postspawning migrations of the previously separated three populations of the Lower Volga starlet—Volgograd and eastern and western delta ones were established. The main differences of the downstream migration of this potanadromous species from that of anadromous species of acipenserids were revealed. It was found that, after downstream migration, juveniles of sterlet form a continuous chain of aggregations from the dam of the Volgograd Hydraulic Power System to the Caspian Sea. Each link of this chain acts as a center of formation of local groups of sterlet that are components of the distinguished populations. It is shown that the observed distribution of sterlet in the lower reaches of the Volga is determined by the location of the spawning grounds of individual populations and the extent of downstream migrations of prolarvae and larvae. The total extent of migrations of sterlet is small (it does not exceed 250 km), which is a cause of the relative isolation of the previously distinguished populations. The stocks of Volgograd sterlet are exhausted at the present time; the recovery of its stock is possible, first of all, at the expense of a decrease in illegal fishing. The resources of the eastern and western delta populations of sterlet are in a satisfactory condition.

The reaction of leukocytes of sterlet Acipenser ruthenus to hormone-induced stress

The influence of cortisone on the part of leukocytes in the differential leukocyte count of peripheral blood of sterlet is described. The changes in particular groups of leukocytes are characterized quantitatively. To the hormone, the fish reacted by a decrease in leukocyte count, blastic (juvenile) cells, and eosinophils and an increase in neutrophils and monocytes. It is concluded that the stress hormone suppresses lymphopoiesis by the hormone-induced apoptosis of lymphocytes while, on the contrary, myelopoiesis activates it.

On the populational structure of sterlet Acipenser ruthenus (Acipenseridae) from the Volga Lower reaches

Trawl surveys made in the Lower Volga and the Caspian Sea revealed that the full life cycle of the Lower Volga sterlet is confined to fresh water and only single specimens living in the Volga-Caspian canal can live in the canal and swim to weakly saline and stagnant waters. Therefore, the sterlet living in the Volga-Caspian canal with its expressed current should be attributed to potamodromous forms. In consideration of the data on distribution, the variation of the complex of plastic characteristics, growth rate, and infestation with the parasite Amphilina foliacea it is concluded that within the Lower Volga population of sterlet three populations of the lower rank may be discerned: the Volgograd population living from the Volgograd Hydroelectric Complex dam to the Kamennyi Yar settlement; the eastern population living in the top of the Volga Delta and Buzan channel; and the western population in the Volga-Caspian canal. These populations differ in some plastic characteristics, linear growth rate, the part of fish infested with the parasite A. foliacea, and in the occurrence of anomalies in the structure of mature ovicells.

The ontogenetic development of the digestive tract and accessory glands of sterlet (Acipenser ruthenus L.) larvae during endogenous feeding

The process of differentiation of digestive tract structures in the sterlet Acipenser ruthenus (L.) larvae was studied from hatching to the beginning of exogenous feeding [9 dph (day post hatching)] using histological procedures. On the day of hatching the digestive tract was closed and completely filled with nutrients (the yolk platelets) that were successively utilized during development. A liver primordium was present in the ventral region of the yolksac. The pancreas was observed on the 2 dph. At the same time, the mouth opening took place. Glandular and nonglandular stomach and anterior and intermediate intestine developed from the yolksac walls. Gastric glands became visible on the 7 dph. The primary intestine developed into the spiral intestine. At the moment of onset of exogenous feeding the yolk material was completely exhausted and there was not mixed feeding observed in sterlet larvae. The fish started exogenous feeding on the 9 dph, which was accompanied with evacuation of melanin plug. At the end of endogenous feeding the digestive tract of sterlet larvae was developed and functional, so they could properly utilize food.

Rare species of cyclostomata and fish in the Upper Oka basin and within Kaluga oblast

The species list of fish of the Upper Oka basin is verified. Data on biology of rare species are presented (western brook lamprey Lampetra planeri, sterlet Acipenser ruthenus, bystryanka Alburnoides bipunctatus rossicus, asp Aspius aspius, undermouth Chondrostoma variabile, bitterling Rhodeus sericeus, and fresh-water sculpin Cottus gobio koshewnikowi). Their morphological characters, distribution in the Upper Oka basin relative abundances of these species, and its changes during recent decades are also commented.

Dynamics of species composition of fish and some results of ichthyomonitoring in the middle course of the Oka (Ryazan oblast)

The dynamics of species composition of fish from the middle course of the Oka is considered. A total of 53 species of Cyclostomata and fish was previously recorded; however, only 43 species have been found at the present time. Due to different causes, ten species have disappeared, and ten new species have emerged. The species composition and structure of aboriginal fish population are characterized by relative stability; however, the total abundance of fish during the current decade, as compared to the 1970s, has considerably decreased. The sterlet Acipenser ruthenus, lake minnow Phoxinus precnurus, Volga zander Sander volgensis, and freshwater sculpin Cottus gobio belong to rare fish.

Fine structure and morphology of sterlet ( Acipenser ruthenus L. 1758) spermatozoa and acrosin localization

Ultrastructure of sterlet Acipenser ruthenus L. 1758 sperm was examined by scanning and transmission electron microscopy, which allowed us to use various methods for visualizations of different parts of sterlet spermatozoa. Sperm cells possess a head with a distinct acrosome, a midpiece and a single flagellum surrounded by the flagellar plasma membrane. The average length of the head including the acrosome and the midpiece was estimated as 5.14 ± 0.42 μm. Nine to 10 posterolateral projections were derived from the acrosome. Three inter-twining endonuclear canals bounded by membranes traversed the nucleus in its whole length from the acrosome to the implantation fossa. Acrosin was located in all the three parts (acrosome, endonuclear canals and implantation fossa). The proximal and distal centrioles located in the midpiece compacted of nine peripheral triplets of microtubules. One cut of the midpiece contained from two to six mitochondria with area of 215 ± 85 nm 2 in average. The flagellum was 42.47 ± 1.89 μm in length with typical eukaryotic organization of one central pair and nine peripheral pairs of microtubules. It passed through a cytoplasmic channel in the midpiece, which was formed by an invagination at the plasmalemma. The flagellum gradually developed two lateral extensions of its plasma membrane, so-called “fins”. Detected morphological variation can be described by four principal component axes corresponding to groups of individual morphometric characters defined on the sperm structures. Correlations among the characters indicate that the sperms are variable in their shape rather than size. Significant variation among examined fish individuals was found only in flagellum and nucleus length. Comparison between the present and previous studies of morphology of sturgeon spermatozoa confirmed large inter- and/or intra-specific differences that could be of substantial taxonomic value.