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The present study aimed to investigate variability in growth pattern and evaluate abundance of A. persicus based on catch data in the southern Caspian Sea water in a period of 27 years (1991-2018). The data of 72704 specimens were analyzed separately by sex (male, female and population), time (years) and region (coastal waters of Gilan, Mazandaran and Golestan provinces). The highest catch of this species was recorded in 1991 (6038 pieces of the fish) and the lowest catch was recorded in 2018 (292 pieces). During the period, the Golestan province had the highest number of catches (30851 pieces) and Gilan province had the lowest ones (11129 pieces). The maximum recorded fork length of this species was 240 cm in 2006. The results showed that the highest annual average fork length was 151 cm in 2007 and 2010 and the highest annual average total weight in 1993, 1994, 1996, 1997 and 2007, which was 26000 grams. The lowest annual average fork length was 139 cm in 2018 and the lowest annual average total weight was 600 grams in 2010 and 2012. The highest length frequency corresponded for the ranges of 136-148 and 148-160 cm in males and females, respectively. The females showed the highest catches in 1991, and the lowest in 2018, while the males had the highest in 1991, and the lowest in 2014. The females dominated the population in the period of 1991-2013, and after that this ratio was reversed. The allometric coefficient of growth (b) varied between 1.03 and 3.49 in the study period. The growth pattern was mostly positive allometric in first decade of study (1991-2001), isometric or negative allometric in the second decade of study period (2001-2011), and negative in third decade (2011-2018). During the study period, the condition factor of the fish varied between 0.61 and 0.80, and the average of the factor for the whole period of study was 0.72. Generally, the catch of A. persicus in the southern Caspian waters decreased more than 95% from 1991 to 2018 (a period of 27 catch-years). [ABSTRACT FROM AUTHOR]

The present experiment was carried out to investigate the effects of different levels of dietary magnesium on growth performance, proximate composition, and immune response of juvenile Persian sturgeon, Acipenser persicus. Fish were fed with six different rations including T1: 32, T2: 185, T3: 380, T4: 592, T5: 790, and T6: 935 mg kg-1 Mg in diet for 8 weeks. At the end of the experiment, samples were collected for estimating the proximate composition and immunological parameters. Results of the present study showed that dietary Mg level significantly influences on growth performance and proximate body composition. Body weight, BWI, and DG were increased by up to 592 mg kg-1 dietary Mg, while decreased by its higher levels. The significant increase in lysozyme activity (by 790 mg kg-1 of dietary Mg) and immunoglobulin (by 935 mg kg-1) were observed in fish fed with different levels of magnesium supplementation compared to control group, which may be due to immune enhancement. The dietary Mg level of 592 mg kg-1 was suitable for Persian sturgeon based on the growth performance.

Red seaweeds have several biomedical derivatives making them healthy additives for the aquaculture industry. Previously we reported enhanced growth performance, feed utilization, and immunity of Persian sturgeon treated with Gracilaria gracilis. Herein, we investigated the effects of G. gracilis on the intestinal microflora, thyroid hormones, and resistance against Aeromonas hydrophila in Persian sturgeon. Fish fed G. gracilis at 0, 2.5, 5, and 10 g/kg for eight weeks, then challenged with A. hydrophila for ten days. The results showed that the total bacterial count in the fish intestines had no meaningful differences among the groups of fish fed varying levels of G. persica (P˃0.05). Fish fed 10 g/kg of G. persica had a higher lactic acid bacteria (LAB) count than fish fed 0, 2.5, and 5 g/kg (P<0.05). Serum thyroid-stimulating hormone (TSH) showed higher levels in fish treated with 2.5 and 5 g/kg of G. persica than the other groups (P<0.05). Besides, fish fed 2.5 g/kg G. persica had higher thyroxine (T4) and triiodothyronine (T3) levels than the other groups (P<0.05). At the end of the challenge test, the highest mortality was seen in the fish fed the G. persica free diet. In summary, Persian sturgeon treated G. gracilis had improved intestinal microflora, thyroid hormones, and resistance against A. hydrophila. [ABSTRACT FROM AUTHOR]

The present experiment was carried out to investigate the effects of different levels of dietary magnesium on growth performance, proximate composition, and immune response of juvenile Persian sturgeon, Acipenser persicus. Fish were fed with six different rations including T1: 32, T2: 185, T3: 380, T4: 592, T5: 790, and T6: 935 mg kg-1 Mg in diet for 8 weeks. At the end of the experiment, samples were collected for estimating the proximate composition and immunological parameters. Results of the present study showed that dietary Mg level significantly influences on growth performance and proximate body composition. Body weight, BWI, and DG were increased by up to 592 mg kg-1 dietary Mg, while decreased by its higher levels. The significant increase in lysozyme activity (by 790 mg kg-1 of dietary Mg) and immunoglobulin (by 935 mg kg-1) were observed in fish fed with different levels of magnesium supplementation compared to control group, which may be due to immune enhancement. The dietary Mg level of 592 mg kg-1 was suitable for Persian sturgeon based on the growth performance. [ABSTRACT FROM AUTHOR]

ABSTRACT This study aimed to describe and validate the formation of the rings in the spine of the pectoral fin and to determine the coherence of the OTC mark with the rings of three species of Caspian Sea sturgeon, the Persian sturgeon (Acipenser persicus), the Starry sturgeon (Acipenser stellatus) and Ship sturgeon (Acipenser nudiventris). Validation was achieved by comparing the total radius of the fin spine of fish of known age after one and two years of growth with the measured radius of the first and second rings in the zone. There was no overlap between the measured radius for the first year and the increase for the second. The Ship sturgeon showed the largest width of the second ring followed by the Persian sturgeon and Stellate sturgeon. The results indicate that the highest growth parameter belongs to the juvenile Ship sturgeon. This research showed that chemically marking the fin spines of juvenile Acipenseridae leads to unbiased estimates and contributes to the knowledge of the population dynamics of these species. The study found that the combination of the dial ring of the pectoral fin spine with growth validated the age estimation in juvenile sturgeon Ship, Persian, and Starry sturgeon.

Heat shock proteins (HSPs) as stress-related factors play a fundamental role in innate and adaptive immune responses in fish, which can be considered as strong candidates for the development of new methods for fish disease prevention. It has been proven that Pro-Tex® as a heat shock protein inducer (HSPi) reduces harmful effects of cellular stress by increasing the Hsp70 protein production. We evaluated the effects of Pro-Tex® as an HSPi in a Persian sturgeon, (Acipenser persicus) exposed to a pathogenic bacterium. Therefore, A. persicus fries were pre-treated with 25.00, 50.00 and 100 mg L-1 of Pro-Tex® and then, injected with Streptococcus iniae ATCC29178. The Hsp70 gene expressions were determined in various organs including liver, gill and intestine and lysozyme (LYZ) activities along with supplemental levels of complement component 3 (C3) and immunoglobulin M (IgM) were also determined in sturgeon blood in days 3 and 7 after infection. Expression of Hsp70 gene was increased during the first three days of infection and then, it was found to be down-regulated during the infection process. Also, levels of LYZ activity, C3 and IgM increased in a concentration-dependent manner; but these parameters decreased after 7 days. Our data suggest that induction of Hsp70 is a promising approach in modulation of immune response in A. persicus and it might be employed to confer protection in fish against bacterial infections. [ABSTRACT FROM AUTHOR]

Lysozyme (N-acetylmuramide glyconohydrolase, (EC 3.2.1.17)) is a unique enzyme which cleaves the β-1,4 linkages of N-acetylmuramic and N-acetylglucosamine of the peptidoglycan, which leads to the lysis of the bacterial cell wall. Lysozyme, as a self-defense enzyme, is produced in many organs of vertebrates. The present study describes purification and characterization of lysozyme from Acipenser persicus (Borodin, 1897). After the extraction process, ion exchange chromatography was utilized to purify the enzyme. The SDS-PAGE analysis confirmed that the molecular weight was about 14 kDa. Moreover, some of the biochemical properties such as optimum temperature, pH and the effect of metal ions on the activity of purified enzyme were investigated. Based on the results the optimum activity and pH were obtained at 50 °C and 6.5 respectively. The purified lysozyme was active in the presence of different salts including NaCl (0–0.125 M), KCl (0.075–0.125 M), MgCl2, and CaCl2 (0.005 M). Kinetic parameters were also calculated.

A comparative analysis of data on the morphological, genetic and ecological features of Russian, Persian and Colchic sturgeons was carried out in order to assess their taxonomic relations, diagnostic characteristics and distribution patterns in the Ponto-Caspian basin. The results confirmed the presence of two close related and morphologically similar species in the Caspian basin—Acipenser gueldenstaedtii and A. persicus, the reproductive isolation of which was proved by genetic data. The complex of diagnostic characters of these species includes, in addition to the traditionally accepted body color and the shape of the snout, several craniological indices: Pds/Ri and W/Ri. The Colchic sturgeon remains virtually unstudied from a genetic point of view. The results obtained allow us to consider it an independent subspecies – A. persicus colchicus. It differs from the Caspian Persian sturgeon, as well as from the Russian sturgeon with a longer snout and larger values of the craniological index B/Ri. The distribution of the Colchic sturgeon in the Black Sea basin requires further research. [ABSTRACT FROM AUTHOR]

The induction of Hsps (heat shock protein) recognized as a promising approach to limiting disease and improving health in aquaculture. This investigation aimed to study the impacts of Pro‐Tex®, an extract from the prickly pear cactus (Opuntia ficus indica), on the expression of Hsp70 gene and induction of immune response parameters in Acipenser persicus infected with Aeromonas hydrophila ATCC®7966TM. Fish were pretreated with 25, 50 and 100 mg/L of Pro‐Tex and then injected in the intra‐peritoneal cavity with A. hydrophila. The expression level of Hsp70 gene, lysozyme activity (LYZ) and complement C3 (C3), and immunoglobulin M (IgM) levels were assessed in liver, gill, and intestine on the days 3 and 7 post‐infection. Tex‐OE® increased expression of Hsp70 in a dose‐dependent way in A. persicus, but this expression significantly reduced on the 7‐days post‐injection. The Hsp70 expression pattern was variable in each tissue, also, LYZ activity, C3, and IgM increased, depending on the concentration, and showed a decreasing trend in a time‐dependent way. In conclusion, our data indicated that Pro‐Tex as an Hsp70 inducer increases the resistance of sturgeon fry against fish pathogens by induction of different immunity factors. [ABSTRACT FROM AUTHOR]

Persian sturgeon (Acipenser persicus) is a critically endangered species, mainly due to overexploitation for its caviar. The permanence of populations of this species in the Caspian Sea is fully dependent on restocking programs. Accordingly, it is considered as an interesting target for aquaculture for both restocking and commercial purposes. In addition, as a Chondrostei, it exhibits one of the slowest rates of molecular evolution among vertebrates and is propounded as an excellent candidate for phylogenetic analysis and evolutionary biology. In this study, the early ontogeny of some key digestive enzymes precursors was determined at molecular level, aiming to obtain basic knowledge on the acquisition of digestive capacity of this species, and at the same time, to advance in its phylogenetic status from the point of view of digestion. For this purpose, A. persicus cDNAs for β-actin (actb; used as an internal reference gene), bile-salt activated lipase (cel), trypsinogen 1 (try1), pepsinogen (pga), and gastric proton pump (atp4a) were amplified and cloned, and their subsequent expressions were measured by quantitative real-time PCR during the first 34 days post hatch (dph). Two isoforms for pga and at least six for try1 were obtained in this study, probably due to the additional genome duplication which sturgeons suffered along evolution. Phylogenetic analysis of the deduced amino acids sequences from the studied genes demonstrated that this species has a close evolutionary distance to Holostei, coelacanths, and tetrapods, including amphibians, reptiles, birds and mammals. According to our results, expression of all the genes increased gradually over time and reached maximum levels around 18 dph. This pattern, which was comparable to length and weight data, could indicate that around 3 weeks after hatching, the digestive capacity of the Persian sturgeon changes from larval to juvenile mode. [ABSTRACT FROM AUTHOR]

Persian sturgeon (Acipenser persicus) is one of the most valuable fish species native to the Caspian Sea and Iran's waters. This study was designed to estimate the heritability of Persian sturgeon eggs and larval hatching. Six fish were caught from the southern Caspian Sea and transferred to "Shahid Beheshti Propagation Complex" during 2016. Cross-breeding was carried out using a 3 × 3 factorial plan. The result of mating among them was nine treatments. For heritability estimates, the total weight, egg size (No. 405), overall weight, and total length of 135 pieces of newly hatched Persian sturgeon larvae were examined. Features including weight and size of larvae and eggs at blastula, gastrula, and neurola stages were evaluated. Weight and length of larvae were measured. Variance components were estimated using software R linear mixed model (LMM) closed Lme 4. Weights at blastula, gastrula, and neurola stages were 0.218 ± 0.124, 0.033 ± 0.01, and 0, respectively. At these stages, heritability of egg size showed 0.375 ± 0.145, 0, and 0, respectively. The heritability of weight and the total length of larvae recorded were 0.231 ± 0.122, 0.161 ± 0.042, respectively. The result of additive genetic value prediction identified three females and three males as the best breeders in the broodstock. The phenotypic correlations between egg weight and size at blastula, gastrula, and neurola stages were 0.106, 0.44, and 0.43, respectively. However, the weight and length correlation of larvae was 0.435. The estimated heritability for these traits supports its suitability as a selection tool in aquaculture. [ABSTRACT FROM AUTHOR]

The analysis of blood parameters is a useful indicator in assessing the physiological conditions of aquatic animals in response to stress, pollutants, nutrition, and also physiological and ecological changes. In this study, some hematological parameters of Acipenser persicus in three age classes including cultured fingerlings, juveniles and broodstocks were studied in a six-month period (spring and summer 2012). The counts of red blood cells (RBC), white blood cells (WBC), hematocrit (PCV), hemoglobin (Hb), MCV, MCH, MCHC, electrolyte and non-electrolyte biochemical parameters, and also differential leucocyte count were measured in different age classes. For this reason, 30 Persian sturgeon(10 fingerlings, 10 juveniles, 5 males and 5 females) were used. Statistical results showed significant differences in Hb, RBC, MCV, MCHC, WBC, lymphocyte (%), neutrophil (%) and eosinophil (%) in different age classes of this species (P

The effect of starvation and re-feeding was investigated on growth, hematology and biochemical parameters in juvenile Persian sturgeon (Acipenser persicus). Three hundred and seventyfive fish (108±0.63 g) were divided into five feeding groups. The control group (C) was fed to satiation three times a day during the experiment. The four groups were starved for 1 (W1), 2 (W2), 3 (W3), and 4 (W4) weeks respectively, and then fed to satiation during a 4 week re-feeding period. The results indicated that some parameters including final weight, specific growth rate, body weight increase, plasma enzymes (ALT, Alanine aminotransferase, AST, Aspartat aminotransferase and ALP, Alkaline phosphatase(, hematological parameters [Mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular hemoglobin (MCH)]were significantly affected by feeding regimes. The plasma cortisol, hematocrit, lymphocytes, neutrophils, eosinophils, and monocytes were not affected by starvation and subsequent re-feeding. These findings showed that short term starvations had no significant negative effects on growth performance, most biochemical and hematological parameters in Persian sturgeon couldrecover when re-feeding resumed.

This study was aimed to examine the impact of different levels of dietary nucleotides (Vannagen) on serum biochemical and blood parameters of Persian sturgeon (Acipenser persicus). Fish (42.37± 2.12 g and 23.67± 0.61 cm) were divided into four treatments with different levels of dietary nucleotides (0, 0.25, 0.35 and 0.5 percent of diet). There were three replicates with a density of 12 fish per tank. After 10 weeks of feeding, serum biochemical and blood parameters were measured. Among the measured factors, blood glucose, triglycerides, cholesterol, erythrocyte and heterophil showed significant differences between the groups fed with nucleotides and the control group (P ≤ 0.05). By increasing the nucleotide levels, the mean heterophil and serum glucose showed significant increase and decrease, respectively. The highest and lowest values of cholesterol and triglyceride were found in groups fed with 0.25% and 0.35% nucleotides, respectively. The other measured factors had no significant difference (P≤0.05). Therefore, it could be said that with regard to the limited capacity of cells to synthesize nucleotides, external preparing of nucleotides could result in the production of needed nucleotides and an increase of its production speed, especially during stress. Such preparation can also improve fish physiology and health status.

In this study, a total of 60 juvenile Acipenser persicus (mean weight 410±267.6, mean length 39.6±19.6 cm and 1 - 2 year old) were captured by trawling method at depths of 20 to 100 meters in the Mazandran province via 7 times surveys during 2009 – 2012, and studied immunologically. Results showed that the mean of red blood cells (RBC) and white blood cells (WBC) were 585000 ± 151000 and 30300 ± 3200 per mm3 of blood, respectively. Mean percentage of lymphocyte, monocyte, neutrophile and eozynophile were 83.1 ± 12, 2.9 ± 2, 8.3 ± 6.6 and 5.6 ± 3.2 %, respectively. Mean concentration of Immunoglobin M (IgM) in blood serum was 25.6 ± 8.7 mg/dl. Samples showed no significant difference in length (P>0/05). These results showed that the fish by less than the length classes were more sensitive to environmental changes. For this reason, their immune indices improved. Therefore, any change in fish blood immunological factors can lead to the secondary response.

The morphology of the sagittal otolith of Great sturgeon (Huso huso), Persian sturgeon (Acipenser persicus) and starry sturgeon (Acipenser stellatus) species from the Iranian waters of the Caspian Sea were studied. Three otolith measurements and three shape indices were recorded from 90 sturgeon specimens. Fish biometry traits were measured and relationship between sagittal otolith length (OL)-total length (TL), and sagittal otolith weight (WO)-body weight of fish (BW) were estimated. Sagittal otolith has a triangle shape with irregular edges in great sturgeon, elongate triangle with smooth surfaces in Persian sturgeon, and relatively circular with smooth surface in starry sturgeon. The ratio of the WO/BW in starry sturgeon was significantly higher (P <0.05) than great sturgeon and Persian sturgeon. There is a direct proportional relationship between BW and WO in Persian sturgeon (r²=0.7), great sturgeon (r²=0.9) and starry sturgeon (r²=0.9). Regression line slope for these relationships in starry sturgeon were less than Persian sturgeon and great sturgeon. Furthermore, there is significant linear regression between OL-TL. Results showed that it is possible to identify Caspian sturgeon species based on body morphometry and sagittal otolith characteristics. [ABSTRACT FROM AUTHOR]

Persian sturgeon, Acipenser persicus is a native, commercially important and highly steemed fish species in the Caspian Sea. In this study, effects of Nodularin (NODLN), a cyclic pentapeptide hepatotoxin, on liver and gill tissues of A. persicus were studied. Nodularin was produced in high amounts by Nodularia spumigena, a cyanobacterium species during the algal bloom in the Caspian Sea and was accumulated in biota of the Sea. Persian sturgeon were exposed directly to NODLN as prolonged immersion containing N. spumigena in two different doses (1×104 and 1× 108 cells.ml-1) for 24, 48 and 96 hours to examine its histopathological effects on fish liver and gill. Histopathological examinations revealed loss of liver architecture, degeneration of hepatocytes, nuclear pyknosis, karyolysis and finally necrosis of the cells over the time. Observation of gill tissues following immersion in algal cells treatments showed hypertrophy, fusion of secondary lamellae due to proliferation (hyperplasia) of branchial epithelium in low dose and vacuolization of epithelial and pilar cells, tellangiectasis, fusion of secondary and primary lamellae, complete necrosis and sloughing of secondary lamellar epithelium in high dose.

Acipenser persicus is the most important sturgeon species in the south Caspian Sea, showing high mortality during larval culture. The aim of this study was to use the freshwater rotifer, Brachionus calyciflorus to feed A. persicus larvae to improve survival rates and enhance resistance. Three experimental treatments were used in this study Treatment 1, similar to the feeding protocol of the hatchery was initially fed decapsulated cysts of artemia and then fed daphnia Treatment 2, was fed a mixed diet of decapsulated artemia cysts, daphnia and freshwater rotifers and Treatment 3, was fed freshwater rotifers enriched with vitamin C (ascorbic acid 6- palmitate). A total of 45 larvae were stocked in each experimental tank (100 l capacity) filled with 30 l of water. Three replicates were used for each experimental group. Larvae were fed at the rate of 30% of body weight per day for 8 days. Mean dissolved oxygen, pH and water temperature throughout the experimental period were 9.58±0.2 mg/l, 8.5±0.1 and 22.5±0.5 ºC, respectively. Results showed significant differences in specific growth rate (SGR), percentage weight gain (WG), feed conversion ratio (FCR), and condition factor (CF) of experiment treatment 1 and treatment 3 and survival ratio were significantly different among treatment 3 and other treatments .This study demonstrated that Brachionus calyciflorus is a suitable live food for larval feeding.

The goal of this study was to analyse the population genetic structure of the Persian sturgeon (Acipenser persicus) between South Caspian Sea and Sefidrud River with mtDNA control region (Dloop gene) and DNA sequencing method during 2010 – 2012 sturgeon stock assessment project. Fish speciemns were collected by bottom trawl net. Extraction of DNA, PCR and DNA sequencing were carried out. Diversity index, the gamma distribution shape parameter for the rate heterogeneity among sites and nucleotide sequence, Fst index, exact test, the historical demographic pattern using neutrality tests and mismatch distribution analysis (D test of Tajima and Fs test of Fu) were analysed. Thirteen haplotypes were obtained, average (±SD) for haplotype diversity was 0.961 ± 0.101, nucleotide diversity was 0.038 ± 0.015, the gamma distribution shape parameter was 0.19, Fst index revealed little genetic structure between populations and the significant Fst value was seen by 10000 permutation only b.....

The physiological ionoregulatory, metabolic and immune responses of Persian sturgeon, Acipenser persicus, to acute stress were investigated. Water levels were lowered to the fish dorsal scutes, and fish were blood-sampled before stress (pre-stress), and 0, 6, 24 and 72 h after stress. Results showed that serum cortisol rapidly increased after stress, returning to initial levels at 24 h. Serum glucose significantly increased at 6 h, declining to the pre-stress levels at 72 h. Serum triglyceride and cholesterol showed significant decreases at 0 h, then increasing to higher than the initial levels at 72 h. Serum T3 and T4 significantly decreased at 0 h and recovered at 72 h. Serum chloride levels showed no significant changes while serum calcium showed a significant increase at 0 h and a further increase until 72 h poststress. Serum total protein and alternative complement activity showed a significant initial decrease and recovery at 24 h with further increase at 72 h. Serum lysozyme activity increased significantly at 24 and 72 h after stress. Serum total immunoglobulin significantly increased at 0 h and peaked at 24 h. This is the first work showing thyroid hormone and immunological responses in Persian sturgeon subjected to stress, and the results show that this species follows a classical hormonal and energetic stress response, although, in the low range among the sturgeons. Although transient and moderate, confinement stress can induce significant changes in the innate immune response. [ABSTRACT FROM AUTHOR]

Objective- Acipenser persicus is one of the most important caviar producing fishes in the Caspian Sea and one of the endangered species of the sturgeon fishes. For breeding of sturgeons, large numbers of animals have to be captured and examined to obtain sufficient numbers of mature fishes that will spawn within a few months in captivity. Design- Original study Animals- A total of 66 adult Acipenser persicus (40 female and 26 male) Procedures- In the present study the gonads of adult Acipenser persicus have been assessed by ultrasonography during artificial propagation to detect the features and changes of the ovary and testis. A total of 66 adult Acipenser persicus (40 fofemale and 26 male), during artificial propagation program, were used in this practice. They underwent ultrasonographic study using a Pie Medical 200 VET ultrasonic machine. A right and left lateral parasagittal of the fish between the pectoral and anal fins and a transverse view was taken. Results- Ultrasonographic view of ovary and testis in adult Acipenser persicus during artificial propagation (stage V of maturity) were detected. Conclusion and Clinical Relevance- Ultrasonography prepares useful data about gonad structure, echotexture, and echogenicity during the artificial breeding period. Ultrasonography can be an accurate, non-invasive, and fast technique to assess the gonads of sturgeons in propagation centers.

High mortality and labor costs are associated with first-feeding sturgeon culture, particularly during the period of dietary transition from live to formulated feed. Therefore we investigated the effects of various feeding treatments on the survival and growth of the Persian sturgeon (Acipenser persicus) larvae during a 20-day culture period. Three replicate groups (250 fish/replicate) of first-feeding larvae were fed according to four main feeding regimes: (1) live food (live nauplii of brine shrimp Artemia urmiana); (2) indirect transition (5 days live food followed by gradual transition to formulated diet); (3) direct transition (using different combinations of live and formulated diet from the start feeding onwards); (4) formulated feed (FD) from the start feeding. Results indicated that growth and survival were higher in the indirect transition feeding regime than in other regimes. Based on our study, co-feeding of A. persicus should start five days after prior feeding with live food.

Biotransformation enzymes of xenobiotics (ethoxyresorufin-O-deethylase, cytochrome P4501A1 content and glutathione-S-transferase) were investigated in the liver of Persian Sturgeon (Acipenser persicus) after a 96-hour exposure to polycyclic aromatic hydrocarbons (PAHs), premutagenic benzo[a]pyrene (BaP) and beta-naphthoflavone (BNF). The fish were injected 10 mg/kg wet-body weight in corn oil for 96 hours every days. Ethoxyresorufin-O-deethylase activity (EROD) and glutathione s-transferase activity (GST) were measured in the fish liver. Cytochrome P4501A1 (CYP1A1) content was estimated by indirect enzyme-linked immunosorbent assay (ELISA). The response appeared as early as 12 hours post exposure. A time-dependent response was observed in the EROD activity, being significantly higher at 48 hours post exposure to 10 mg/kg of BaP. The greatest induction occurred in the fish treated with 10 mg/kg BaP, in which a 32.1- fold increase in EROD activity was observed. Results showed that EROD activity in A. persicus is significantly increased by BaP and BNF treatments. Both chemicals showed higher values of EROD activity compared to the liver CYP1A content. There was a rise in glutathione-S-transferase activity in fish exposed to BNF, but no increase was observed in fish treated with BaP. The results showed that hepatic CYP1A expression in terms of induction of EROD activity might be suited as a biomarker of organic contamination in aquatic environments and led to lower sensitivity of the second phase in the detoxification enzyme.

In the present study, mitochondrial DNA polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to assess the population structure and genetic relationships among six Persian sturgeon, Acipenser persicus populations from the south Caspian Sea along the Iranian coast. The complete nucleotide dehydrogenase subunit 5 (NADH 5) region of mtDNA amplified by PCR was digested with five restriction enzymes. In total, 154 individuals from six populations including: Guilan (Zone1-2), Mazandaran (Zone 3 and 5), Golestan (Zone 4) and Sefidroud River, from the south Caspian Sea along the Iranian coast were analyzed using five restriction endonucleases (Rsa І, Hinf І, HaeIII, Mbo І and Cfr13І), yielding 17 haplotypes. Samples from Sefidroud River were clearly identified by cluster and molecular variance model (AMOVA) analyses. This collection showed dominant haplotypes that were little in populations from the other geographic areas. The mean haplotype diversity (h) and nucleotide diversity (π) were 0.739±0.038 and 0.0105±0.0043, respectively. Based on heterogeneity test haplotype frequencies of Persian sturgeon populations and Monte-Carlo with 1000 replicates in PCR-RFLP method significant differences were seen (χ2 =37.12, P< 0.0001) and these results showed that haplotype distribution in different location were significant and populations of Sefidroud River were statistically significant (P< 0.0001). This result suggests that the unique genetic structure of Sefidroud River represents a highly valuable genetic resource and should now be treated as demographically independent and managed separately.

The Persian sturgeon, Acipenser persicus (Borodin, 1897), is an economically important species, which mainly inhabits the Caspian Sea. However, little is known about its population genetic structure. In this study, variation in nucleotide sequences of the mitochondrial DNA (mtDNA) control region of wild stock Persian sturgeon was determined to assess the genetic diversity among different natural populations of this species. The fish (n = 46) were collected from four sites (Astara, Sefidrood, Noshahr and BandareTurkaman) in the south Caspian Sea. As a result 6 haplotypes and 44 variable sites were found. The average haplotype diversity (h) and nucleotide diversity (π) were 0.640±0.028 and 0.0442±0.011, respectively. Analysis of molecular variance (AMOVA) demonstrated that most variations occurred within samples, and the difference between the populations from Astara and Noshahr or Bandare- Turkaman was not significant (p

Morpho-cytological patterns of juvenile Acipenser persicus on basis of structure, size and distribution of kidney nephrons were studied. Sampling of head, body and caudal parts of the kidney in the fish aged 1 and 2 years were carried out (3 specimens of each age). Area, length and small diameter of nephron cells were measured by light microscope and Biocome Visolab software. We observed the kidney of A. persicus consisting of: Glomeruls, Bowman's capsule, Proximal, Distal and Collecting tubule. The statistical analyzes showed no significant difference in the area, length and small diameter between the two ages. Furthermore, the results showed that the average area in 1 and 2 year old fish were 4004.28±2486.63 and 4614.64±1261.69 mm in proximal cells, 2529.75±1015.51 and 4747.33±1676.03 mm in distal cells, 2220.98±1668.87 and 3253.48±1747.25 mm in collecting tubules, 4692.37±1739.79 and 9355.37±2073.92 mm in Glomeruls, 6768.23±1640.54 and 129210.07±1775.76 mm in Bowman's capsule, respectively. The average length and small diameter in 1 and 2 years old fish were 84.75±24.99, 53.52±14.03 and 82.76±7.46, 66.00±7.37 mm in proximal cells, 72.98±16.28, 51.10±15.00 and 77.95±9.43, 64.57±8.34 mm in distal cells, 60.52±13.69, 49.02±12.60 and 66.40±12.21, 57.40±14.20 mm in collecting tubules, 94.70±16.97, 72.78±12.75 and 129.04±23.59, 96.60±18.88 mm in Glomerules, 120.99±14.86, 80.77±9.78 and 144.76±21.12, 107.56±21.53 mm in Bowman's capsule, respectively. In all cases, no significant differences were found between measured cell of the 1 and 2 year old fish (P>0.05). Also, the modeling showed the kidney of A. persicus was Y shaped in which the distribution of different cells is not homogenous in all sections of the kidney.

The aim of this study was to determine the 96h LC50 of copper and cadmium, and also, to evaluate the effects of their sub-lethal dose on stress factors in Persian sturgeon, Acipenser persicus. Obtained results from Probit analysis showed 96h LC50 values of 0.502 and 14.78mg/l for copper and cadmium, respectively. Also, in single sub-lethal exposures, 72 juveniles (130±19g) were exposed to 0.026 and 0.68mg/l of copper and cadmium in semistatic conditions, and some stress-related biochemical factors were assessed in 1, 7 and 14 days. According to the obtained results, plasma glucose and cortisol were increased (P0.05) differences in plasma and liver protein contents between experimental groups and controls with the exception of copper treatment at the first day of sampling when plasma protein contents showed significant increases, but decreased significantly (P

Objective: Immunohistochemical localization and immunoreactivity of insulin-like growthfactor-I (IGF-I) were investigated during the ovarian developmental stages in Persian sturgeon.In addition, the effects of growth hormone and thyroxine were investigated on IGF-Iimmunoreactivity in vitro.Materials and Methods: Ovarian samples were taken from two brood stocks (caughtfrom the sea and from a river) during their reproductive migration and at three different developmentalstages based on their polarization index (PI). The effects of two hormones onIGF-I immunoreactivity were studied at two ovarian developmental stages (PI > 0.1 andPI < 0.07). In both experiments the immunoperoxidase method was performed in order todetect immunohistochemical localization and immunoreactivity of IGF-I.Results: Immunohistochemical localizations of IGFI were detected in the follicular layers.There was no significant immunoreactivity difference between the two brood stocks,however in the river brood stock IGF-I immunoreactivity was more intense in the ovarieswith PI < 0.07 than of PI > 0.1 (p < 0.05). Growth hormone (10 ng/ml) increased IGF-I immunoreactivityin ovarian samples from the river brood stock when their PI was less than0.07, however thyroxine had not such effect (p < 0.05).Conclusion: Our results showed that IGF-I is present in the ovaries of Persian sturgeonand its reactivity is different among their gonadal development stages. This may supporta role for IGF-I during reproductive physiology in female brood stocks of the Persian sturgeon.Moreover, growth hormone is a potential hormone to increase IGF-I immunoreactivityin the ovaries of this species.

Species composition, relative abundance, absolute abundance and biomass of sturgeon species were studied during the years 2008-2009. Eighty five stations were covered in the stratified random sampling design in depths less than 1Om using 9m bottom trawl (head line) and in depths more than 10m using 24.7m bottom trawl (head line). More than 70 specimens of Acipenser persicus were caught during the effort. CPUE decreased from 0.4 to 0.24 specimens per trawl in 2009. The mean total length of the A. persicus was 47.3±29.lcm and 61.9±28.7cm in 2008 to 2009, respectively. The smallest size of A. persicus was 9cm in 2008 and 24.5cm in 2009, while the maximum size was I 02.5cm in 2008 and 126.5±29cm in 2009. The mean total weight in 2009 in comparison with 2008 increased from 989(3- 5000g) to 1569(42-71OOg). Absolute abundance of A. persicus decreased from 2006000 specimens in 2008 to 1192000 specimens in 2009. The estimated biomass was 2010 and 1878 tons in 2008 and 2009, respectively. According to the results of study, the stock status of A. persicus is highly critical in the Caspian Sea and a timely decision has to be taken for conservation of the species.

The processing and comparison of quality of meat in farmed Acipenser persicus using two methods of dry and mix salting was carried out to provide a new formula for processing new sturgeon products. Ten fish specimens with a mean weight and length of 2 kilograms and 60cmthat were farmed for two years were used in this study. The meat of the specimens was processed using pure salt and a mixture of salt and one percent madder. Two replicates were used for each method. In the first method, dry sodium chloride was used at a rate of 250g of sodium chloride per kilogram body weight of fish (dry salting). In the second method, about 109 of madder was added to the 250g of sodium chloride (mix salting). Microbial examinations included total bacterial counts, Staphylococcus and Coli form bacteria assessment and chemical examinations included salt, protein and fat absorption, TVN, peroxide, and pH tests. Sensory tests as well as microbial and chemical experiments were carried out for the quality control of the processed samples for a period of three months. According to the results, Iranian National Standard and pure plate culture method (10-1,10-2 and 10-3) Coliform counts in the two different meat samples was lower than 10 per gram of meat. The total bacterial count and the Staphylococcus bacteria count was higher in the meat samples processed with dry salting. Besides, the rate of salt absorption and peroxide was lower in these samples. The protein, fat, pH and humidity were higher in the samples treated with dry salting. However, taste, flavor and color of the meat processed with a mixture of sodium chloride and madder was higher quality than that processed with dry sodium chloride. No significant differences were observed in chemical factors such as TVN and salt absorption for the two processing methods. This was also the case for microbial analysis including bacterial counts such as Staphylococcus and total bacterial count.

A study was conducted on the effects of egg size OR length, weight, growth and survival of prelarval and early feeding stages of 19 female breeders of Persian sturgeon. The results showed that egg size can affect the total length and weight of prelarvae and there were positive and significant correlation between egg size and total length of prelarvae at the hatching stage and at 2,4,6,8 and 10 days post hatching (P0.05). There were also positive and significant correlation between egg size and volume of yolk sac at hatching (P0.05). However, during the first feeding stage the correlation between egg size and survival was very weak.

Persian sturgeon, Acipenser persicus is a valuable species in the Caspian Sea ecosystem. For gill chloride cells localization, fish specimens 2-3g were adapted to experimental conditions for 7 days. Gill histology was observed through light microscopy using Hematoxylin-Fushin staining. Immunolocalization of gill Na+, K+-ATPase was observed through fluorescent microscopy using mouse monoclonal antibody (IgGa5) rinsed against (Na+, K+-ATPase a-subunit. Chloride cells dimensions was observed using Image Tools software.Gill chloride cells that have high densityof Na+, K+-ATPase, were found on gill arch, gill septum, filament and lamellae. No chloride cells were observed on spiracular or opercular gills epithelium. Chloride cells were spherical to egg-shaped and showed immunefluorescent activity on their baso-Iateral sides. Results showed that in each square millimeter of gill epithelia, 289 chloride cells existed and the maximum number of these cells was found on filament, lamellae, base of the lamellae and on the inter-lamellar space. We also found that the number of these cells is significantly different in all branchial states. Persian sturgeon fry weighing 2-3g have gill chloride cells where Na+, K+-ATPase gene and their activity occurred. Because of their cellular transporters (like Na+, K+-ATPase), these cells were the main sites of the ionic and osmotic regulation between the fish and the environment.

Regulation of water temperature is a major factor affecting the embryonic development of fish species. We examined effects of five temperatures, from 13°C to 23°C on three embryonic phases including cleavage, neurolation and hatching in Persian sturgeon (Acipenserpersicus) from March to May 2006. After obtaining mature Persian sturgeon (five females and three males) transport them to the Aquaculture Center of Aghghala in Golestan province. The temperature effects on the three embryonic period's cleavage, neurolation and hatching keeping other physical and chemical factors constant were examined. The maximum hatching was in 15°C and the minimum abnormality was in 15°C and 16°C and also, the maximum mortality was seen in 21.5°C. It is concluded that temperatures between 15°C to 18°C are the upper limit of the thermal optima for Persian sturgeon embryos. Abnormalities observed in this research included edema of the pericardial cavity, notochord curved downwards (lordosis) or upwards (kyphosis) which affected mobility of the hatching embryo.

Feeding behavior in Acipenser persicus and Acipenser stellatus in summer and winter was studied from 2004 to 2006 simultaneously with the marine survey for sturgeon stock assessment. Bottom trawls (9m) on board the research vessel Sisara 2 (50 hsp) were used to collect specimens at depth below 10m, while specimens at depths more than 10m were collected using bottom trawls (24.7m) on board the Guilan Research Vessel (1000 hsp). Examination of stomach contents of 135 A. persicus and 80 A. stellatus specimens revealed that the food spectrum was composed of bony fishes (Neogobius sp., Atherina sp., Clupeonella cultriventris), invertebrates belonging to the family Ampharitidae (polychaeta worms including Hypanai sp. and Nereis diversicolor), various crustaceans (Gammarus sp. and Paramysis sp.) and the bivalved mollusc, (Abra ovata). Significant differences were detected in the frequency of prey items in the different seasons studied. Also significant differences (P0.05).

We collected 100 specimens of Persian sturgeon broodstocks propagated in Shahid Marjani Fish Culture Center to study internal parasites during March, April, and May 2005. The center is located in the southeast of the Caspian Sea. Three different parasite species were recovered from digestive tract (stomach and intestine) of the fish.Cucullanus sphaerocephalus, Skrjabinopsolus semiarmatus showed the highest incidence and highest mean intensity (with prevalence of 80% and 55% respectively) but Leptorhynchoides plagicephalus had the lower prevalene 2 %. The prevalence of S. semiarmatus and C. sphaerocephalus were higher in males than in females whereas the intensity of these parasites was higher in females than in males. Statistical analysis of data showed a significant relationship between the occurrence of S. semiarmatus and the sex of the fish. There was a significant relationship between the occurrence of C. sphaerocephalus and the length of the fish (P £0.05). Forty nine percent of the fish had less than 10 worms. It was also found that the internal parasites of A. persicus in the southeast of the Caspian Sea are the same as those found in the southwest but the diversity of parasites were fewer in the former.

The impact of Sefidroud River sediments on the fingerlings of Persian Sturgeon (Acipenser persicus) was studied in 2005. The tests were done in 20 liter aquariums each containing 10 Persian Sturgeons fingerlings weighing 3-5 grams each. We devised 6 treatments and a control with 3 repetitions in the four day investigation through which the lethal concentration (LC5096h) of Sefidroud sediments were studied. During the test, physicochemical parameters of water such as pH, oxygen and temperature were measured as 8, 8.5mg/l and 25±1°C respectively. The results showed that LCso96hand LC5024h of sediments on Persian sturgeon were 15367.39mg/1 and 124882.04mg/l respectively. We determined the maximum allowable concentration (M.A.C) of sediments to be 1536.74mg/1.

A survey of parasitological infections of Acipenseridae fishes in the southern parts of the Caspian Sea were done from 2002 to 2004. Altogether, 338 brood stocks of Acipenser persicus were examined. In the laboratory, the weight and length of the fishes were measured and after dissection presence of different parasites in the fish was examined. According to the results of this study, during three years of examinations, six different parasites were detected. These parasites were Cucullanus sphaerocephalus, Skrjabinopsolus semiarmatus, Eubothrium acipenseinum, Corynosoma strumosom, Leptorhynchoides plagicephalus, and Amphilina foliaceae. The prevalence and mean intensity of infection with Cusullanus sphaerocephalus and Skrjabinopolus semiarmattlm were the most.

The normative of two Acipenser persicus broodstoks were scored during spawning season in 2002-2003. The breeders were caught from the southern part of the Caspian Sea. 158 breeders of Shahid Rajaii fish farm and 269 of Shahid Marjani were investigated. After checking egg quality and hormonal injection of fish, harvested egg were fertilized by common sturgeon hatchery method. Incubation temperature was about 17-22°C and hatchery period lasted 5-7 days (110-115 degree-days). About 55 percent of breeders had response to hypophysis injection. The range of somatic index (G.V) of spawned fish was varied from 4.4 to 9.9 in Shahid Rajaii farm and 4.73 to 10.96 in Shahid Marjani farm. In immature breeders it was more than 11. The optimum temperature spawning was from 15.5 to 18°C and 17 to 20°Cin Shahid Rajaii and Shahid Marjani farm respectively. The average weights of breeders were 28.14 in Shahid Rajaii farm and in Shahid Marjani farm were 30.31. The average of fork length, GV and fertilization rate, that are important normative factors in breeding of sturgeon were 169.96,7.58 and %75.31 in Shahid Rajaii farm, 158.83,7.93 and %64.57 in Shahid Marjanii farm respectively and there was significant difference between two station (P

Vitrification could provide a promising tool for the cryopreservation of fish embryos. To achieve successful cryopreservation, several parameters should be taken into account in the design of a vitrification protocol. In the present study, some relevant factors were investigated (choice of a proper vitrificant solutions and temperature for thawing) using neurulation-stage embryos. Six DMSO-based vitrificant solutions (V1–V6) were tested using a 6-step incorporation protocol. DMSO-based vitrificant solutions contained DMSO + permeable cryoprotectants + nonpermeable cryoprotectants. Embryos were immersed in vitrificant solutions for 7 minutes and directly plunged into liquid nitrogen. After vitrification (−196 °C for 10 minutes), the thawing was performed in a water bath at 0 or 20 °C and then embryos incubated until hatched. Our results demonstrated that some embryos vitrified in 5 of 6 vitrification solutions survived and hatched out, but none survived after vitrification in V2. The highest survival rate (45.45%) was observed in samples frozen with the best vitrificant solution (V6) and thawing combination (20 °C). These results establish that cryopreservation of Persian sturgeon ( Acipenser persicus ) embryos by DMSO-based vitrificant solutions is possible. [ABSTRACT FROM AUTHOR]

The toxic effects of the oil products Phenol and I-Naftol on fingerlings of the Persian sturgeon were studied in 2003. We carried out five treatments with three replicates and one control for each of the chemicals using the static O.E.C.D. method in 20 liter aquariums each containing 10 fingerlings. During the experiments, the average pH was recorded as 7.2, total hardness was measured to be 194 mg/l, average water temperature was 25.1 degrees centigrade and dissolved oxygen was 7.2 mg/l. Using the Probit Analysis procedure, we found that the LC50 96h of the Phenol and 1- Naftol for fingerlings of the Persian sturgeon was 36.65 and 1.32 mg/l respectively. We determined the maximum allowable concentration of the Phenol and I-Naftol for the fingerlings of the Persian sturgeon to be 3.66 and 0.13 mg/l respectively.

The Persian Sturgeon, Acipenser persicus is the most important sturgeon species in the southern part of the Caspian Sea and it provides 51% of Iran's caviar production. We were used five different age groups of the larvae (7, 17, 22, 28 and 33 days after yolk absorption) in 3 replicates. The larvae were all transferred at the same time to 27 liter aquarium holding 15 liter of water at different salinities (0.5, 7 and 9 ppt) and were provided with continuous aeration. Analysis of data showed that during early stages of life, age is an important factor for development of osmoregulatory organs. However, in later stages, weight and length play a vital role in this regard. The present study reveals that during post hatch and active feeding, in favorable environmental and rearing condition A. persicus fingerlings could be released into rivers and estuaries in Guilan province at an age of 33-35 days after yolk sac absorption and when they attain weight of 1.8-2.4g and length of 6.2-7.5cm.

Iranian Fisheries Institutes in the north of the country are involved in the reproduction, culture and release of five species of sturgeon fingerlings into the Caspian Sea. The species are Acipenser persicus, A. guldenstadti, A. nudiventris and A. stellatus and Huso huso. Shahid Beheshti Fisheries Centre as the first commercial hatchery started its activities in 1972 in Rasht, Guilan Province of Iran. The center achieved a production ceiling of 21.6 million fingerlings in 1997 and increased it to 24.5 million fingerlings in 1998. It is anticipated that the center will achieve a threshold of 45 million fingerlings in the next few years. During 1997-2002, the center has increased its extent from 377 hectares to 887 hectares. For Huso huso production, 17 specimens were caught in 1998, of which 10 were injected that produced 1.08 million fingerlings and in 2002, the number of caught and injected Huso huso were 29 and 21 respectively, that resulted in production and release of 2.4 million fingerlings. A number of 1062 A. persicus breeders were caught in 1998 of which 581 individuals were injected with hypophysis extract resulting in production and release of 22.5 million fingerlings. Of 538 injected individuals from among a total 802 breeder fish caught in 2002, a number of 12.3 million fingerlings were produced and released into the sea. The catch for Acipenser stellatus in 1998 was 193 breeders that produced 623000 fingerlings. In 2002, the catch increased to 290 breeders, of which 67 received injections to produce 1.3 million fingerlings. A total number of 0.67 million fingerlings of A. guldenstadti was produced in 1998 which was increased to 1.78 million in 2002. For Acipenser nudiventris, the number of fingerlings produced in 1998 was 0.4 which was increased to 1.56 million in 2002.

We sampled 139 specimen of Acipenser persicus and 103 Acipenser stellatus over the years 1998-1999 in five fishing zones of the southern Caspian Sea for heavy metal contamination assessment. Flame Atomic Absorption Spectrophotometry was used to determine contamination of the specimens with Zn, Cu, Cd, and Pb and cold vapor method for Hg. The mean age for A. persicus and A. stellatus was 17.6±2.6 years and 11.9±1.8 years, respectively. The mean concentrations of heavy metals assessed for dry weight of the muscle tissues and caviar in A. persicus were 26.9 and 65.9 µg/g for Zn, 1.8 and 4.2 µg/g for Cu, 0.61 and 0.111 µg/g for Pb and 0.61 and 0.005 µg/g for Cd. The wet weight concentration of Hg in the muscle tissue and caviar of the fish were 0.06 and 0.007 µg/g respectively. For A. stellatus we determined the mean concentration of heavy metals in dry weight of the muscle tissue and caviar to be 27.4 and 57.8 µg/g for Zn, 1.64 and 4.85 µg/g for Cu, 0.481 and 0.112 µg/g for Pb and 0.59 and 0.005 µg/g for Cd while the wet weight concentration of Hg were 0.05 and 0.008 µg/g. By international standards, the contamination of the muscle tissue and caviar samples with the heavy metals in the two sturgeon species are well below maximum allowable for human consumption.

We studied genetic difference and resemblance between Acipenser persicus and Acipenser gueldenstaedtii using Random Amplified Polymorphic DNA (RAPD) technique. The DNA of tail fin tissue of three A. persicus and A. gueldenstaedtii were extracted using phenol-chloroform method. After electrophoresis of the samples by agarose gel, their concentrations were regulated and Polymerase Chain Reaction (PCR) was conducted by 53 primers. PCR products were electrophoresed on polyacrylamide gel and silver staining was done to reveal the DNA bands of the samples. Among 53 primers, 17 had no site on genomic DNA of A. persicus and A. gueldenstaedtii and did not produce any bands while the remaining 36 primers showed band pattern. Analyzing the PCR products data using RAPD PLOT program showed that the maximum and minimum genetic distance between species were 73% and 65% respectively. Also, the mean difference between the species was 70% and the maximum and minimum genetic resemblance between the two species were 35% and 27% respectively. Based on the results, we conclude that A. persicus is an independent species from A. gueldenstaedtii.

The toxic effects of the herbicide Butachlor were studied using a concentration of 0.4- I.3ppm and 0/1-1ppm on fingerlings of the Persian sturgeon and Stellatus sturgeon respectively in 1999. We carried out six treatments with three replicates and used one control based on the static O.E.C. D. method. Over the experiments, pH ranged between 6.7 -8.2, total hardness was measured to be 230 mg/l, water temperature was 20±1 degrees centigrade and dissolved oxygen was above 6 mg/l. We found that the LC50 96h of the Butachlor on fingerlings of the Persian sturgeon and Stellatus sturgeon weighing 1-3 grams was 0.44 and 0.07 mg/l respectively. Also assessed the LC10,LC50,LC90 of the herbicide on the fingerlings of the sturgeons using the Probit Analysis procedure. We determined the maximum allowable concentration of the Butachlor herbicide for the fingerlings of the Persian and Stellatus sturgeons to be 0.044 and 0.007 mg/I. Based on the standards, the herbicide is considered highly toxic for the studied fingerlings.

Fungal infection during incubation of Acipenser persicus eggs claims high mortalities in the hatcheries each year. Malachite Green has been used for many years to disinfect eggs during incubation, but recent studies have shown that the compound might be toxic and potentially mutagenic. In addition, there are implications in the literature for the chemical to be teratogenic and tumor promoter in animals and humans. One of the best replacements for the chemical is Hydrogen Peroxide (H2O2) which has been categorized as a low priority regulation (LPR) drug by FDA. During a two year study, six experiments were carried out on the effectiveness of Malachite Green and Hydrogen Peroxide on the infected eggs of Persian sturgeon with fungi while keeping another group of the eggs as control in Yuschenkov incubators. The chemicals were applied to the eggs at a concentration of 750, 1000, 1500,2000,3000 and 9000 µl/l. Hatching rate and number of fungal colonies weight percentage of infected to that of healthy eggs were used to assess the usefulness of the chemicals in controling the infection. The results showed that eggs treated with 1000 and 1500µl/l of H2O2 compared to Malachite Green and other doses of the chemicals, had higher hatching rate, and were free from fungal infections. The separation and removal of the infected eggs was also easier when H2O2was used. Hence, the chemical can be introduced to the sturgeon hatcheries as an appropriate anti-fungal agent.

Histological study of alimentary canal of Persian sturgeon was conducted during early life from hatching to 56 days old by light microscope. Some hours after hatching, in anterior part, rudimentary eye and brain were visible, also in posterior part was completely filled with acidophil yolk. Mouth and anal were not clear. In 5-7 days after hatching all parts of the alimentary canal except stomach were roughly anatomically complete, as though in comparison with the hatching time the amount of acidophil yolk was less. At this stage, mouth was covered by stratified squamous epithelium in which several number of tast buds were visible and also rudimentary part of esophagus was squamous to pseudostratified columnar epithelium and in terminal part was columnar to ciliated pseudostratified columnar epithelium. In 8-9 days after hatching, the alimentary canal was structurally complete and two parts of stomach i.e. glandular stomach (cardia) and non-glandular stomach (pyloric) were more clear. The glandular stomach epithelium was simple columnar to ciliated pseudostratified columnar epithelium, while pyloric stomach had simple columnar to pseudostratified columnar epithelium. In 9 days after hatching, external food with a lot of yolk were visible in alimentary canal, which indicates endo-exogenous feeding. In I I-12 days after hatching a lot of external food i.e. daphnia were visible in alimentary canal .In 14 days after hatching pyloric caeca was appeared and in 40 days conical teeth was observed. In the primitive stages of life, the glycoprotein secretions belong to simple columnar cells (interior part of esophagus &some parts of intestine), while through age increase, this secretions belong to apical cells of simple columnar and also goblet cells. The beginning of active feeding of Persian sturgeon larvae was occurred in 9 to 11 days after hatching. Following the development, there was no special alternation except thickness increase of epithelium, muscular layer, connective tissue of lamina propria and increase of epithelial folds of intestine.

In the present study we investigated the histological changes in the ovary of 35 female Persian sturgeon. Ovarian samples were taken from the females stained with hematoxylin and eosin (H&E) staining and sexual maturity was determined by examining the sections under a light microscope. Four developmental stages of ovary including cortical alveoli formation stage (ΙΙ), vitellogenic stage (ΙII), mature stage (IV) and ovulation stage (V) were recognized during development. The gonadosomatic index (GSI) of female Persian sturgeon gradually increased during the development of ovary. The lowest GSI was recorded in stage II (2.57 ± 0.28) and the highest GSI was shown in stage V (23.58 ± 1.08). Therefore, GSI may be useful to determining maturity stages; however histological experiments of ovaries should be considered as the most accurate method for all stages. doi:10.14456/WJST.2014.80