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Global aquaculture production has more than tripled during the last 15 years, and aquaculture is expected to account an increasing share in global seafood production. There are large differences among countries in the rate of growth and development of aquaculture. This review tries to explain the progress and problems of aquaculture during three last decades in Iran. The total production of Iran from aquaculture was 25,800 tons in 1994, approximately 8 percent of the total fisheries production. However, by 2008 it increased to more than 154,000 tons; 27% of total fisheries production. During the last decade, production share of different species in Iran has been variable. In the years 1998 and 2008 the highest percentage of aquaculture production was belonged to silver carp Hypophthalmichthys molitrix (50%) and rainbow trout (Oncorhynchus mykiss; 40%), respectively. The results showed that culture of rainbow trout has grown noticeably in the past two decades. At present, Iran has been acquired the first rank of rainbow trout culture in fresh water of the world. But in contrast, in recent decade shrimp aquaculture industry has failed due to white spot syndrome. Coastal and inland waters of Iran have more potential for aquaculture development. Recently, great sturgeon Huso huso and some species of barbus family have aroused interest from government and private enterprises for potential aquaculture use. Although aquaculture of Iran has shown a significant growth in the last decade, but it is concluded by introducing new species and overcome to present aquaculture problems in the country, the aquaculture production will be increased to several times.

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In order to understand the importance of particle size and agglomeration for nano-eco-toxicological studies in aquatic environments, the acute toxicity of two different types (suspended powder and colloidal) of silver nanoparticles (AgNPs) were studied in alevin and juvenilerainbow trout. Fish were exposed to each type of AgNPs at nominal concentrations of 0.032, 0.1, 0.32, 1, 3.2, 10, 32, and 100 mg/L. Lethal concentrations (LC) were calculated using a Probit analysis. Some physical and chemical characteristics of silver nanoparticles were determined. In the case of colloidal form, particles were well dispersed in the water column and retained their size; but in the case of suspended powder, particles were agglomerated to large clumps and precipitated on the bottom. In alevins, the calculated 96 h LC50 values were 0.25 and 28.25mg/L for colloidal and suspended powder AgNPs respectively. In the case of juveniles, the 96h LC50 of colloidal form was 2.16mg/L, but suspended powder did not caused mortality in fish even after 21 days. The results showed that both in alevin and juvenile stages, colloidal form is much toxic than suspended powder; this shows increase of nanoparticles size due to agglomeration, will reduce the toxicity. Silver nanoparticles are toxic materials and their release into the water environment should be avoided.

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The effect of nonylphenol on vitellogenin and zona pellucida 3.1 expressions in the liver, spleen, gill and muscle tissues of the juvenile Persian sturgeon were investigated. The fish were initially injected per kilogram of their body weights with 100mg nonylphenol, 5mg 17 beta estradiol, and 2ml peanut oil carrier agent (respectively, for the main treatment, positive and negative controls), and had the extracted RNA of their tissues converted into cDNA. Afterwards, RT-PCR reaction for each tissue sample was done separately. Results showed vitellogenin gene was expressed only in the liver, but zona pellucid 3.1 gene was expressed in the liver as well as the spleen of the fish exposed to nonylphenol and 17 beta estradiol. No vitellogenin gene in the spleen, gill and muscle was expressed; no gene for zona pellucida 3.1 was either observed in the gill and muscle. The expression rate of vitellogenin gene was 9.95±2.48 for the treatment with 17 beta estradiol and 2.85 ± 0.35 with nonylphenol; the expression rate of zona pellucida 3.1 was 9/98 ± 2/51 for exposed treatment with 17 beta estradiol and 3.37±0.35 for the treatment with nonylphenol. In conclusion, considering the meaningful effect of nonylphenol on vitellogenin and zona pellucid 3.1 expression in liver and spleen, it could be used for detection of xenoestrogen biomarker in the Persian sturgeon.

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Morphological changes of the chloride cells and the α_1b subunit gene expression of Na⁺-K⁺-ATPase in triploid rainbow trout (70.6 g average weight) were studied upon direct transferring to 6, 12 and 18 ppt salinities. Changes in abundance, distribution pattern, and the sectioned area of the chloride cells was studied through classic histology and Na⁺ K⁺-ATPase localization was performed through immunofluorescence light microscopy using a mouse monoclonal antibody IgGα5. Gene expression of Na⁺-K⁺-ATPase α_1b subunit was studied by semi-quantitative gene expression methods.No mortality occurred among the fish in all salinities during the 10-days experimental period and treated fish kept their plasma osmolality at standard physiologic levels. All the fish also showed similar distribution pattern in their chloride cells that were distributed on filaments, between and over lamella. Histological studies confirmed some abnormal morphological changes such as lamella interruption. Immunohistochemical studies showed the highest number of the chloride cells on lamella and between lamella in 18 ppt and the maximum sectional area of the chloride cells in freshwater. Gene expression of Na⁺-K⁺-ATPase α_1b subunit had direct correlation with increasing trend of salinity. In conclusions, triploid rainbow trout was found to be adaptable to the various experimented salinities and could be recommended for rearing in brackish water.

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Silver nanoparticles (AgNPs) are widely used in consumer products mainly due to their antimicrobial action. The rapid increase in the use of nanoparticles has driven more attention to their possible ecotoxicological effects. In this study: first, acute effects of colloidal AgNPs during embryonic stage of Persian sturgeon and Starry sturgeon were investigated and then in Starry sturgeon, their short-term effects during early life stages (before active feeding commences) were analyzed. Based on the obtained results from the acute toxicity tests, AgNPs induced a dose-dependent toxicity in both species during early life stages. The short-term toxicity test was performed using 0, 0.025, 0.05 and 0.1 mg/l of colloidal AgNPs. Silver accumulation in larvae exposed to 0.1 mg/l AgNPs was recorded significantly higher than the control treatment (P<0.05). However, the obtained survival rate data did not indicate any significant differences among treatments.

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Spermatogonial stem cells (SSCs) are unique with an important role in the transmission of genetic information to the next generation. Thus, they play an important role for the production of interspecies germ line chimeras. Therefore, the objective of this study was to produce chimera through the intraperitoneal transplantation of Caspian brown trout SSCs into newly-hatched rainbow trout. Spermatogonial cell were isolated from the testes of 8-month-old Caspian brown trout through enzymatic digestion. The spermatogonial cell suspension was enriched using differential plating technique to remove testicular somatic cells. After culturing for 48 h in L15 supplemented with 10% serum, suspended cells were collected and stained with the fluorescent membrane dye PKH26. The stained cells were intraperitoneally transplanted into triploid rainbow trout hatchlings. At 15 and 30 days after transplantation, the recipients were investigated under a fluorescent microscope. The gonads of recipients were dissected for molecular analysis at 180 days after transplantation. Transplanted spermatogonial cells migrated toward and incorporated into recipient genital ridges. The presence of the Caspian brown trout genetic material was confirmed by PCR in 41.4% of the rainbow trout testes. These results demonstrated for the first time that the interspecies spermatogonial transplantation was successful in rainbow trout and that the somatic microenvironment of the rainbow trout gonad can support the colonization and survival of intraperitoneally transplanted cells derived from a fish species belonging to a different genus. Therefore, the SSCs transplantation can be used as a tool for conservation of Caspian brown trout genetic resources.

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The indirect application of silver nanoparticles (AgNPs) in controlling the common fungal infection during the incubation period of Persian sturgeon -saprolegniasis - was investigated in this research. Filters containing 0.2%, 0.5% and 1% of AgNPs in two states without agent and with aminopropyltriethoxysilane (APTES) coupling agent along with the control treatment (without filter) were the treatments investigated in the present study. The results showed that in the first 48 hours of incubation, which corresponds to embryonic growth before the start of neurulation, despite the start of contaminating the water in the incubators with Saprolegnia fungus, fungal infection was not seen in any of the investigated treatments. The results of measuring the amount of silver released from the studied filters at the end of the first 12 hours of incubation showed that the amounts of silver released in the water in the treatments of 1% AgNP filters without APTES and with APTES were significantly higher than other filters containing AgNPs. This trend was repeated at the next sampling rounds (48 and 96 hours) with the difference that the release rate was significantly higher only in the 1% AgNP-APTES filter treatment. In the treatment of AgNP-APTES filters, the percentage of hatching showed a significant increase compared to the control filter treatment.

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The main objective of this study was assessment of hormonal treatments effects on sperm quality improvement in Barbus sharpeyi. Results showed differences in effects of treatments with LHRHa2, LHRHa2 combined with a dopamine antagonist (MET), and CPE (Carp Pituitary Extract) on parameters of sperm volume, motility, spermatocrit, biochemical indices of seminal plasma and sperm efficiency on artificial propagation, incubation survival, and deformities. Biochemical analysis of seminal plasma showed that the majority of parameters were affected by different hormonal treatments. In conclusion, the highest sperm quality of Benni fish could be achieved by application of LHRHA2 (10 µg kg^-1+MET), LHRHA2 (5 µg kg^-1+MET) and LHRHA2 (5 µg kg^-1) at 8, 12, and 16 hours PHS, respectively.