The present study was conducted on a large number of oocytes collected from 36 female Acipenser stellatus brood fish caught from fishing grounds in the Guilan province and transferred to the Shahid Behesti STURGEON Breeding Center during 1997-1998. Physiological assessments were carried out on the microscopic sections prepared from these oocytes.Under normal conditions, 9 distinguishable layers were observed in the sections prepared from A. stellatus oocytes that included the follicle, the outer most layer, followed by a jelly coat, an external zona radiata, internal zona radiata, fat layer, pigments, cytoplasm, nucleus and nucleoli. The presence of erythrocytes and micropyle canal in the oocytes indicate normal embryognesis among them.

Motility of spermatozoa was studied on 12 and 7 specimens of Acipenser persicus and A. stellatus, respectively. The density measured to be 2.22±0.65x109ml-1 in A. persicus and 2.21±0.55x109ml-1 in A. stellatus. Semen samples were diluted with two extenders containing tris 118mM, sucrose 23.4mM, pH=8, egg yolk (20%), dimethyl sulfoxide (15%) and penicillin potassium (500IU/ml) and biociphus extender containing glycerol as a cryoprotectant at a ratio of 1:1 and then transferred to 0.5ml straws and frozen in a computer controlled low temperature apparatus and stored in liquid nitrogen for one week. To study fertilizing ability, the spermatozoa were then used to inseminate eggs after thawing. Mean sperm motility in fresh spermatozoa was 86.6% in A. persicus and 73.75% in A. stellatus which decreased to 32.2% (P<0.001) and 37.5% (P<0.001) in frozen spermatozoa, respectively. Also mean fertilization rate decreased from 90.4% to 30.7% in A. persicus and from 72% to 36.8% in A. stellatus.

In this study the effects of LHRHa, a mixture of common carp and STURGEON pituitary extracts (CCP+SPE), Thyroxin hormone (T3) with commonly method used in hatcheries were compared. The experiments were conducted using different doses of hormones with several replicates in order to determine the most effective dose. Total number of brood stocks were 58 females and 22 males. Prior to injecting the fishes, the Germinal Vesicle (GV) situation of all broodstocks were determined. The results showed that broodstocks has been injected with LHRHa were very satisfactory and the percentage of response; fertilization and hatching of them had significantly different. The least effective dose of LHRHa that induced maturation was 250µg/fish for single injection and 350-375µg/fish for double injection. Thus it was determined that under the experimental conditions, 20.0 to 31.2 µg/Kg of body weight of brood stock was the most effective dose. In the case of male broodstocks LHRHa was the most effective hormone and the sperms collected from these broodstocks were better in quality and quantity.

In the last three decades, several ecological factors were changed and affected the most important commercial fish stocks in the Caspian Sea. This paper aims to assess the effects of these pressures on the population structure, stock status and the vulnerability risk of stock extinction of the STELLATE STURGEON (Acipenser stellatus Pallas, 1771) in the Southern Caspian Sea, in the years 1990-2011. For this period, we estimated growth parameters, the age structure of catch, sexual maturity, age at first capture, natural and fishing mortality, biomass and risk of stock extinction of STELLATE STURGEON by IUCN Red List categories. Fork lengths of individuals ranged from 82 to 206 cm and ages from 4 to 29 years. The growth parameters were L∞ =215. 0 cm, K= 0. 064 year − 1, t0=− 3. 2 years. The majority of the catch (67. 4-90. 1%, averaged 80. 0%) belonged to 913 years old. The biomass had a descending trend from 4983. 5 mt in 1990-91 declined to 10. 6 mt in 2011-12. The generation length was 16 years. Stock status indicators showed that 89% of catch were mature individuals, mature and optimum fish length comprised 74% and 10% of the fish captured comprise mega-spawners. This study revealed that the stock of the STELLATE STURGEON is being overfished for the whole years and critically endangered.

STURGEON species are commercially important species in finfish aquaculture industry. Till now, a small number of studies have been reported on the immune responses in STURGEON species against infectious diseases. Monoclonal and polyclonal antibodies in fish immunoglobulins (Igs) are essential to evaluate the humoral immune response. This study aimed to produce, characterize, and evaluate the polyclonal antisera against STELLATE STURGEON Igs. For the production of polyclonal antibodies against fish Igs, STELLATE STURGEON serum Igs was isolated using the ammonium sulfate precipitation method. The purified Igs with the Freund adjuvant was injected subcutaneously in to sheep (Ovis aries). Then, anti- STELLATE STURGEON Ig antibody titer and specificity were determined using ELISA and Western blot techniques. STELLATE STURGEON Ig antibodies were detected in the immunized animals and were significantly higher in the immunized group compared to the non-immunized group. The polyclonal antisera showed a high specificity to the immunoglobulin heavy )H( chain of STELLATE STURGEON and moderately cross-reacted with the immunoglobulin H chain in Siberian (Acipenser baerii) and ship (A. nudiventris) STURGEONs but did not show reactivity with rainbow trout (Oncorhynchus mykiss) serum Igs. It was indicated that the produced polyclonal antisera should be further investigated to be used for immune-diagnostic purposes in STURGEON species upon exposure to various infectious diseases.

In order to determine the optimum feeding rate in rearing of STELLATE STURGEON, Acipenser stellatus, based on feed consumption, an experiment was conducted in three groups of low, medium and high weights of 11. 71 ± 0. 68, 41. 2 ± 1. 87 and 421. 76 ± 15. 88 g, respectively, in a completely randomized design in concrete tanks. The fish were fed based on appetite for seven months with 2 to 6 times daily feeding frequencies. The amounts of consumed feed and daily temperature were recorded. During the experiment, the temperature range was 13. 5 ± 5. 5 ° C. At the end of the experiment, nutrition and growth parameters were measured. The results exhibited that the body weight gain, daily growth rate, specific growth rate and feed conversion ratio of fish in the low-weight group were significantly different from the other two groups (p<0. 05). The maximum growth rate and lowest food conversion ratio were also observed in low-weight group. Furthermore, according to results, the average feed consumption rates in fish with 11-183 g and 41-173 g in weights were 1%, while 0. 88% in those with 421 to 553 g in weight. No mortality was observed during the experiment in the studied groups. Moreover, according to the amount of feed consumed, a table was designed to determine the appropriate feeding rate in STELLATE STURGEON at different weights and temperatures, which can be a guideline for rearing of this species.

Acipenser stellatusis one of the most invaluable species of STURGEON fishes in the world.The purpose of this study was to identify the resident microbial community from the gastrointestinal tract (GIT) ofAcipenser stellatus. One hundred and twenty three fungi were isolated from the GIT of 7Acipenser stellatus samples including Aspergillus spp (45.5%), Trichodermaspp (8.9%) and Cladophialophora spp (8.1%). Among different Aspergillus isolates, A.niger was the predominant species. Although, fungi were predominantly isolated from stomach (36.6%), but with respect to frequency of fungal isolates there were no significant differences between stomach and other parts of GI. In general, the bacterial isolates recovered were mostly gram negative and related toEnterobacteriaceae family such asAeromonas, Pseudomonas and Salmonella species. The most bacterial species were isolated from intestine and pre stomach region (88.2%). It is concluded thatA. niger and Aeromonasspecies were predominant fugal and bacterial microbes isolated from understudy fish GIT, respectively.

In this study, the effect of 17-b estradiol on hematological indices in juvenile STELLATE STURGEON (AciPenser stellatus) was investigated. For this, 180 five-month juvenile STELLATE STURGEONs with an average weight of 11.7 ± 0.2 g were divided to 3 treatments (20 fish/tank). The treatments were included 0, 25 and 50 mg E2/kg diet. The duration of the exPeriment was considered for 7 months and fish were fed according to their satiation. At the end of the exPeriment, 5 fish were randomly samPled for measuring hematological indices including number of red (RBC) and white blood cells (WBC), hemoglobin (Hb), hematocrit (Hct) and differential leukocyte count. Results showed that significant decrease of WBC, RBC, Hb and HCT with increasing of hormone dosage (P<0.05), but there were no significant differences between control and fish fed 25 mg/kg in those Parameters (P>0.05). Also, no significant different (P>0.05) were found among the treatments in other hematological indices including MCV, MCH, MCHC and differential leukocyte counts (neutroPhil, lymPhocyte, monocyte and eosinoPhil). The results of this study demonstrated that E2 could cause an anemia in fish which fed by dietary E2 and the intensity of anemia is directly dePended on hormonal dosage, but it seems that the diversity of leukocyte was not affected by hormonal treatment.

Background: Chondroitin sulfates (CS) is an important glycosaminoglycan’ s which is found in STURGEON fishes which are present in cartilage of these fishes. This compounds, in addition to application in food and cosmetic industries, they have clinical significant in arthritis treatment and wound healing. Materials and Methods: In present study, the chondroitin sulfate extraction was performed by using pepsin and trypsin digestions with 12 and 18 h interval times followed by cationic salt, cetylprydinium chloride (CPC) treatment. MTT assay at different incubation time (24, 48 and 72 h) was used in order to study of Chondroitin sulfate effect on induction of proliferation of fibroblasts isolated from human skin. In order to determine the proper time and enzymatic digestion, after temperature treatment of samples using pepsin and trypsin enzymes, the SDS-PAGE electrophoresis was used. And the FT-IR analysis was performed to characterize the type of CS. Results: The maximum yield of enzymatic digestion was observed for trypsin digestion at 18h, according to electrophoresis patterns. the amount of CS yield was estimated at 4. 76% in this situation. FT-IR analysis revealed that, the CS belongs to the C4S type. Chondroitin sulfates extracting from cartilage showed concentration-dependent incremental impact on fibroblast cell proliferation so that the dose-response results have shown 167% proliferation at 10 μ g/ml dose of CS compared to the control in fibroblast cells. Conclusion: Extracted CS has a positive stimulatory effect on fibroblast cells proliferation in a dose dependent manner. So it can be used for wound healing and some fibroblast related diseases.