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The study examined how chitosan nanoparticles loaded with folic acid (FA/CNPs) and/or folic acid impact on growth performance and immune response of juvenile beluga sturgeon (Huso huso). Fish weighing an average of 15.3±0.7 g were placed in 15 fiberglass tanks with 25 fish per tank and given diets with varying levels of FA/CNPs and/or folic acid: 0 (control), treatment 1 (T1: 1 mg of FA/CNPs per kg of feed), treatment 2 (T2: 1 mg of folic acid per kg of feed), treatment 3 (T3: 1 mg of FA/CNPs + 1 mg of folic acid per kg of feed), and treatment 4 (T4: 2 mg of FA/CNPs + 1 mg of folic acid per kg of feed) for 8 weeks. The findings demonstrated notable improvements in various growth indicators, including daily growth rate, body weight gain, specific growth rate (SGR), feed conversion ratio (FCR), and immune indices (total serum protein, levels of immunoglobulin M, total immunoglobulin, and complement C3). Additionally, antioxidant parameters such as catalase, superoxide dismutase, and glutathione peroxidase also showed significant improvements with T3 and T4 treatments that incorporated both FA/CNPs and folic acid compared to the control group (P < 0.05). Furthermore, these treatments resulted in lower serum cholesterol and triglyceride levels compared to other treatments, particularly the control group (P < 0.05). The study found that incorporating FA/CNPs and folic acid into the diet resulted in notable improvements in red and white blood cell counts, lymphocytes and neutrophils percentages, hematocrit, and haemoglobin concentration, as well as reduced levels of triglycerides, cholesterol, ALT and AST enzymes, and cortisol in the blood. It is recommended to use a combination of 1–2 mg/kg of FA/CNPs with 1 mg/kg of folic acid to improve growth and general immune status of juvenile great sturgeon.

Sturgeon species hold significant commercial and ecological value, with many listed as endangered. Understanding their genetic structure is crucial for developing effective conservation strategies. The main aim of this study is to examine the genetic structure of sturgeon, which can provide a foundation for creating strategies to conserve these species. A total of 121 sturgeon individuals were analyzed using microsatellite molecular markers (STR) to conduct the study on the genetic structure of sturgeon fish species. DNA was extracted from fin tissues using a commercial kit, and genotyping was conducted using seven microsatellite loci. Cluster analysis and principal coordinates analysis (PCoA) were performed to identify genetic differentiation among populations. The analysis showed differences in genetic diversity between the Siberian sturgeon, Russian sturgeon, and beluga samples. A deficiency of heterozygotes was discovered in artificial samples of sturgeon, indicating possible inbreeding. Genetic analysis has also revealed genetic differentiation between populations, possibly due to geographic structure or other factors. The study allows us to recommend increasing genetic diversity by introducing individuals from natural environments into sturgeon populations in aquaculture. Regular monitoring of genetic parameters in aquaculture populations and monitoring diversity dynamics are also crucial for the conservation and sustainability of sturgeon populations. The findings could help shape conservation strategies, especially in managing genetic diversity in aquaculture and reducing the risks associated with inbreeding and genetic drift. [ABSTRACT FROM AUTHOR]

Sturgeon farming is rapidly expanding in Europe, where Italy ranks first in farmed caviar production. A major threat to sturgeon health in captivity is infection with Acipenser European Iridovirus (AcIV-E), a viral disease definitively identified in 2016. Here we present data on the occurrence of AcIV-E in 482 sturgeons (age ≤ 12 months, species of the genus Acipenser and the species Huso huso) collected from sturgeon farms in northern Italy between January 2021 and December 2023. The health status of each specimen was determined by necroscopy and virological assay. Virological analysis was performed on gill samples and real-time PCR specific to the MCP gene of the iridovirus viral capsid. Molecular analysis revealed positivity to the virus in 204 samples (42.68% of the total), while anatomopathological examination of nearly all fish with positive real-time PCR disclosed swollen abdomen, hepatic steatosis, splenomegaly, and increased gill volume. Two challenges to timely diagnosis are the absence of pathognomonic symptoms and the inability to isolate the virus on cell monolayers. Continuous and widespread health monitoring is therefore crucial for disease management and to effectively control spread of the virus. [ABSTRACT FROM AUTHOR]

Abstract Background The sturgeon group has been economically significant worldwide due to caviar production. Sturgeons consist of 27 species in the world. Mitogenome data could be used to infer genetic diversity and investigate the evolutionary history of sturgeons. A limited number of complete mitogenomes in this family were sequenced. Here, we annotated the mitochondrial Huso huso genome, which revealed new aspects of this species. Results In this species, the mitochondrial genome consisted of 13 genes encoding proteins, 22tRNA and 2rRNA, and two non-coding regions that followed other vertebrates. In addition, H. huso had a pseudo-tRNA-Glu between ND6 and Cytb and a 52-nucleotide tandem repeat with two replications in 12S rRNA. This duplication event is probably related to the slipped strand during replication, which could remain in the strand due to mispairing during replication. Furthermore, an 82 bp repeat sequence with three replications was observed in the D-loop control region, which is usually visible in different species. Regulatory elements were also seen in the control region of the mitochondrial genome, which included termination sequences and conserved regulatory blocks. Genomic compounds showed the highest conservation in rRNA and tRNA, while protein-encoded genes and nonencoded regions had the highest divergence. The mitochondrial genome was phylogenetically assayed using 12 protein-encoding genes. Conclusions In H. huso sequencing, we identified a distinct genome organization relative to other species that have never been reported. In recent years, along with the advancement in sequencing identified more genome rearrangements. However, it is an essential aspect of researching the evolution of the mitochondrial genome that needs to be recognized.

The effect of inclusion of Nanoselenium to the commercial diet on the growth indices, liver enzymes and immune system of juvenile Acipenser stellatus was investigated. Individual 120 juveniles with an average weight of 21.93±1.03 g were fed with diets A, B, C and D (containing 0.1, 0.2, 0.3 and no Nanoselenium) for 8 weeks. At the end of the rearing period, blood samples were prepared from fish to evaluate liver enzymes and immune system indices. The final weight and daily growth in fish fed with diet A (0.1 mg /kg) were significantly higher than those fed with diet C (0.3 mg/kg). But there was no significant difference with fish fed with diet D (non Nanoselenium). The condition factor and protein efficiency ratio of fish fed with diet containing 0.1 mg/kg Nanoselenium was significantly higher than fish fed with diets C and D. There was no significant difference in the of total immunoglobulin (IgM) and complement (ACH50) in different groups, But the secretion of lysozyme in fish fed with diet B was significantly higher than other groups. There was no significant difference in the activities of alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase enzymes in fish fed with diets containing Nanoselenium compared to the treatment without Nanoselenium. It seems that inclusion of 0.1 and 0.2 mg of Nanoselenium per kilogram has a positive effect on the growth indices and immune system of Acipenser stellatus in growth stage. [ABSTRACT FROM AUTHOR]

Sturgeon farming is rapidly expanding in Europe, where Italy ranks first in farmed caviar production. A major threat to sturgeon health in captivity is infection with Acipenser European Iridovirus (AcIV-E), a viral disease definitively identified in 2016. Here we present data on the occurrence of AcIV-E in 482 sturgeons (age ≤ 12 months, species of the genus Acipenser and the species Huso huso) collected from sturgeon farms in northern Italy between January 2021 and December 2023. The health status of each specimen was determined by necroscopy and virological assay. Virological analysis was performed on gill samples and real-time PCR specific to the MCP gene of the iridovirus viral capsid. Molecular analysis revealed positivity to the virus in 204 samples (42.68% of the total), while anatomopathological examination of nearly all fish with positive real-time PCR disclosed swollen abdomen, hepatic steatosis, splenomegaly, and increased gill volume. Two challenges to timely diagnosis are the absence of pathognomonic symptoms and the inability to isolate the virus on cell monolayers. Continuous and widespread health monitoring is therefore crucial for disease management and to effectively control spread of the virus.

The amount of lysine required in the diet of juvenile Beluga Huso huso with an average initial weight of 2.45 g was evaluated based on growth response in 12 aerated aquariums in four treatments each with three replications for 40 days. Four diets were prepared based on fish meal with the same protein (39.32%), fat (15.78%) and carbohydrate (21.19%) with different levels of lysine (0, 0.75, 1.5 and 2.25% of dry weight). The diet without lysine was considered as the control diet. Each ration was given in proportion to 4% of body weight, in three equal portions, to groups of three with 10 fish in each replicate. The mean water temperature, dissolved oxygen and pH during the test period were 23.8 ºC, 6.27 mg/L and 7.32, respectively. The results showed a significant difference in the growth performance between the treatments. The maximum weight obtained (31.95 ± 0.84 g) and specific growth rate (7.01 ± 0.09%/day) were observed in the treatment with 2.25% lysine. Apart from the decreased growth in the fish fed the lysine-deficient diet, no signs of growth deficiency were observed in the other fish. Codition factor, food conversion ratio, protein efficiency ratio and survival rate were not significantly different among treatments. Finally, the optimal amount of lysine for this weight group of juvenile Beluga was estimated to be 2.25 g per 100 g of the dry weight of the diet.

The aim of the current study was to investigate the beneficial effects of dietary thiamine supplementation on physiological, immunological and antioxidant responses in juvenile beluga, Huso huso. The juvenile fish (∼ 3 g) were fed four times a day with diets containing 0 (control), 5 (5 T), 10 (10 T), and 20 (20 T) mg kg−1 thiamine for 12 weeks. Significant increases were observed in growth performance indicators of the fish fed different levels of thiamine, compared to the control group and the best performance was observed in 10 T treatment. The carcass protein content significantly increased in the thiamine-treated fish and the highest protein content was observed in the 10 T treatment. Digestive enzymes’ activities (pepsin, trypsin, lipase, and amylase) significantly increased in the fish fed the thiamine-supplemented diets. The serum alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase activities significantly decreased in the 10 T and 20 T treatments, compared to the control group. Dietary thiamine supplementation significantly increased the serum lysozyme, alternative complement activities, and IgM level, compared to the control diet and the highest lysozyme activity and IgM level were observed in the 10 T and 20 T treatments. The hepatic superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione-s-transferase, transketolase activities of 10 T and 20 T treatments were significantly higher than those of the control treatment. The hepatic catalase activities in the thiamine-treated fish were significantly higher than that of the control fish. Contrastingly, the hepatic malondialdehyde contents of the 5 T, 10 T, and 20 T treatments were significantly lower than the control treatment. Although all the dietary thiamine levels (5–20 mg kg−1) showed beneficial effects on different tested parameters, 10 mg kg−1 was the most beneficial level and is recommended for dietary inclusion to improve the growth and health of juvenile beluga.

Copyright of Journal of Fisheries is the property of University of Tehran and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study was performed to evaluate the effects of two types of powdered extract Echinacea purpurea and Allium sativum on growth indices and survival rate of Huso huso during a two-month period. For this purpose, 210 juvenile with an average weight of 27.74 ± 0.26 g were randomly placed in 21 half-ton fiberglass tanks in seven different treatments with three replications, including a control group and three experimental groups of different amounts of E. purpurea powder extract (T1, T2 and T3: 250, 500 and 1000 mg kg-1) and three experimental groups of different amounts of garlic powder extract (T4, T5 and T6: 250, 500 and 1000 mg kg-1). At the end of the experiment, a statistically significant difference was observed between the treatments in the mean final weight, mean final length, final biomass, final production, fish weight gain, mean daily growth, body weight gain increase, specific growth rate and daily growth rate (p0.05). The results showed that addition of 1000 mg turmeric powder extract per kg of food is more effective in improving growth indices.

In this study, the effects of mixture of dietary nano-selenium, vitamin C and E on growth indices, liver enzymes and nonspecific immune response of juvenile Huso huso were investigated. One hundred and twenty individuals juvenile Huso huso with average weight of 77.77 ± 2.3 g were fed with four diets including treatment A (TA by adding 0.1, 30 and 100 mg/kg), treatment B (TB by 0.2, 60 and 200 mg/kg), treatment C (TC by 0.3, 90 and 300 mg/kg) and control group (without adding nano-selenium, vitamin C and E) for 10 weeks. At the end of the rearing period, blood samples were taken from fish to evaluate liver enzymes and immune system indices. No significant differences were observed in growth indices, feed conversion ratio and protein efficiency ratio (p>0.05). The lowest activities of ALT and AST were found in TA and TB (p>0.05). However, IgM and ACH50 levels were significantly higher in TB and TA than in control group, respectively (p

Sturgeon gelatin hydrolysates combined with epigallocatechin‐3‐gallate (SGH + EGCG) were incorporated in fat‐free set‐type yogurt stabilized using sturgeonish (Ysg) or bovine gelatin (Ybg). Sturgeon gelatin hydrolysates in combination with epigallocatechin‐3‐gallate increased yogurts probiotics growth during refrigerated storage. In Ysg with SGH + EGCG at 0.1 g/dL the flow behavior index (n) was decreased, and the values of consistency coefficient (k), complex viscosity (η*), and yield stress (τ0) increased. Ysg and Ybg had higher acidification rates during fermentation compared to control (Yc). However, the higher SGH + EGCG (0.3 g/dL) led to an increased syneresis and weaker hardness. Results indicated the enhanced fermentation rates, textural, and gelation of Ysg with SGH + EGCG at 0.1 g/dL. [ABSTRACT FROM AUTHOR]

Fish is one of the most important and valuable sources of protein, fat and energy, but it is very corruptible and will be corrupted faster than other meat dishes. The present study was carried out to determine the effect of Spirulina algae chitosan coating on maintaining the quality of Huso huso fresh fillet during storage in refrigerator. Fresh fillets of chitosan solution (1%) containing 1% algae extract, treated and stored in a refrigerator. Microbial and chemical tests including total bacterial count and psychrophilic bacteria, pH, TBA as well as sensory evaluation were performed periodically forallspecimens and measured for DPP Heagla. For algae - containing coatings, the total bacterial load was 2.56×106 cfu/ml and on the fifth day it was still in acceptable range for human consumption, but in control samples, 3.81×107cfu/ml it was five days that exceeded the limit. Serum bacterial levels for control treatment were significantly higher than that of extract containing chitosan coatings and TBA values were significantly higher in the control fillets than in the first treatment, while the pH values in the control sample with the treated sample, there was no significant increase. Current study showed that using algae extract containing chitosan coating can prevent bacterial growth in fresh fish fillets and maintain its sensory properties including texture, smell, color and general acceptance. And increased the fish storage period in the refrigerator. [ABSTRACT FROM AUTHOR]

In the present study, the effect of various feeding strategies during 60 days and subsequent re-feeding over the next 60 days was evaluated to achieve the compensatory growth on growth performance and biochemical parameters in great sturgeon Huso huso. For this purpose, two hundred and forty fish with a mean individual weight of 67.10 ± 1.10 g (Mean ± SD) were divided into four feeding strategies groups: satiation feeding (100%), 75% satiation feeding (75%), 50% satiation feeding (50%), and 25% satiation feeding (25%). In the second phase, all groups were fed to satiation. Blood sampling was performed at the end of feeding trial (120 days) to measure biochemical parameters. At the end of first phase, final weight in the satiated group (100%) was higher than the other groups while it decreased with increasing dietary restriction (p < 0.05). Specific growth rate and mean individual weight increased significantly in 75% and 100% satiation feeding compared to the other treatments (p < 0.05). At the end of second phase, there was not significant differences in the final individual weight, total length, weight gaine and specific growth rate among treatments (p > 0.05). Hematocrit was affected by dietary strategies and in the treatment with 25% satiation feeding was lower than the other treatments (p <0.05). Total protein and triglyceride in 100 and 75% treatments were higher than the other treatments (p < 0.05). Based on the present study, feeding, at the rates of 75 and 50% satiation and subsequent re-feeding lead to a high growth rate and reducing the feed costs without negative impact on physiological conditions of the great sturgeon fish, and this methods can be considered as an appropriate strategy for culture of this fish. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of Ultra-Amax commercial prebiotics on the hematologic, biochemical and serum steroid hormones levels of Huso huso blood at the Ashoradeh catchment processing center. The experiment was conducted using a completely randomized design in the control group (without any additive) and two experimental treatments including 1g / kg of prebiotics in per kg of diet were supplemented. Each treatment was carried out with 3 replicates and 10 fish per cage per 120 day breeding period with an average weight of 4.55 ± 0.37 kg.The results showed a significant improvement in serum levels of steroid hormones in fish fillets in experimental treatments compared to control group (p

This study was carried out regarding the effects of cyclopoid copepod Acanthocyclops trajani on first feeding of beluga larvae (Huso huso). The treatments comprised a control diet containing Artemia naupli and Daphnia magna and a combined diet containing Artemia naupli, Daphnia magna and A. trajani. The results of this study indicated that the average length, body weight and specific growth rate in larvae of control and combined diets were not significantly different. In spite of the fact that, A. trajani was significantly different in the amount of n-3 fatty acids in comparison with the other live feeds in this study, but indicated more effectiveness in survival rates (80%) of beluga larvae, as a supplement. Furthermore, the combined diet was significantly different in DHA, in comparison with control diet. This study indicated that freshwater copepod is potential supplemental live food, to increase nutritional value from the point of view in terms of essential fatty acids and survival rate of valuable fish larvae such as beluga.

To determine the effect of coriander on beluga, Huso huso, a total of 150 fish (250 ± 2 g) were fed a diet containing 0, 5, 10, 15, or 20 g kg−1 of coriander for 60 days (Phase 1). The fish were then subjected to 1 mg L−1 of heavy metal exposure (lead, cadmium, and copper) for 7 days (Phase 2). The best growth performance before exposure to heavy metals was observed in beluga fed 5 or 10 g kg−1 coriander and after exposure in fish fed 10 or 15 g kg−1 coriander. While mortality occurred only in fish fed 20 g kg−1 coriander before heavy metal exposure, 100% survival was only observed for sturgeon fed 10 g kg−1 coriander after exposure. Enzyme activities and level of biochemical parameters in blood were better before heavy metal exposure in fish fed 5, 10, or 15 g kg−1 coriander, while for postexposure, fish fed 10 or 15 g kg−1 coriander showed superior biochemical responses. Carcass protein and lipid declined for all coriander treatments after exposure, but fish fed 10, or 15 g kg−1 coriander exhibited the highest levels of carcass protein and lipid in both exposure phases. Carcass ash and moisture both increased as coriander increased in diet, and levels of both proximates declined after heavy metal exposure. Furthermore, in both experimental phases, the highest and lowest amounts of cadmium, copper, and lead in carcass were measured in the control group and fish fed 15 or 20 g kg−1 coriander respectively. Based on these results, addition of 10 g kg−1 coriander to beluga diet is recommended for optimal growth and health regardless of whether rearing water is contaminated with heavy metals. [ABSTRACT FROM AUTHOR]

This study was performed to evaluate the effects of two types of powdered extract Echinacea purpurea and Allium sativum on growth indices and survival rate of Huso huso during a two-month period. For this purpose, 210 juvenile with an average weight of 27.74 ± 0.26 g were randomly placed in 21 half-ton fiberglass tanks in seven different treatments with three replications, including a control group and three experimental groups of different amounts of E. purpurea powder extract (T1, T2 and T3: 250, 500 and 1000 mg kg-1) and three experimental groups of different amounts of garlic powder extract (T4, T5 and T6: 250, 500 and 1000 mg kg-1). At the end of the experiment, a statistically significant difference was observed between the treatments in the mean final weight, mean final length, final biomass, final production, fish weight gain, mean daily growth, body weight gain increase, specific growth rate and daily growth rate (p<0.05). These indices in the treatments had an increasing trend compared to the control and in T6 (1000 mg of E. purpurea powder extract per kg of food) which was significantly higher than in the other treatments (p<0.05). The feed conversion ratio in this treatment was also decreased significantly compared to other treatments (p<0.05). There was a significant difference in levels of ALP and LDH enzymes between treatments and control group (p<0.05). The highest level of ALP enzyme was in control group and T6, while the lowest level was in T4 (250 mg of E. purpurea powder extract per kg of food) (p<0.05). The highest level of LDH enzyme was observed in the control group and T6, however, the levels of ALT and AST enzymes were not significantly different between treatments and control group (p>0.05). The results showed that addition of 1000 mg turmeric powder extract per kg of food is more effective in improving growth indices. [ABSTRACT FROM AUTHOR]

Taurine is one of the most studied amino acids in aquaculture over the last decade. This study was conducted to investigate the taurine requirements in terms of growth, immune system, antioxidant enzyme activities and stress response of beluga (Huso huso) (209.1 ± 23 g) in both fresh water (FW) and brackish water (BW: 15 ppt). Twelve experimental tanks with six taurine levels (2.1 g/kg_21.8 g/kg), for FW (Tau2.1, Tau4.3, Tau7.1, Tau12.3, Tau16.7 and Tau21.8) and BW (BwTau2.1, BwTau4.3, BwTau7.1, BwTau12.3, BwTau16.7, and BwTau21.8), were designed to feed and farm fish for eight weeks. Generally, fish farmed in BW had better growth and immune response performance compared with FW. The quadratic relations for pooled data determined taurine requirements in terms of weight gain (12.1 g/kg), lysozyme (13.5 g/kg), IgM (12.7 g/kg) and osmolality (15.1 g/kg) (p<0.05). Furthermore, taurine requirements to obtain the minimum cortisol before and after stress were 10.4 g/kg and 14.3 g/kg, respectively. When we exposed fish to high stock density stress (12 kg/m3 for 4 hours), those fed dietary 16.7 and 21.8 g/kg had more stable glucose, cortisol and lactate before and after stress in both FW and BW. In conclusion, beluga fed diets with 12.3 g/kg and 16.7 g/kg taurine in both FW and BW groups had the best performance regarding growth and health status, respectively. [ABSTRACT FROM AUTHOR]

This research evaluated the influences of two autochthonous probiotics Lactococcus lactis and Weissella confusa, on growth performance, feed conversion efficiency, haematological parameters, immune status and intestinal morphology of Huso huso fingerlings. Fingerlings (N: 480; initial weight, 2.92 ± 0.01 g) were randomly dispersed in four treatments (three replicates) and fed with the diet (crude protein 47%) that fortified by autochthonous probiotics Lactococcus lactis and Weissella ciberia (PB0: control; PB1.5: 1.5 × 107; PB3: 3 × 107; PB4.5: 4.5 × 107) for 56 days. The results revealed that growth in fish fed probiotics diets were increased compared with the control group. Haematological and blood biochemistry indices did not show any differences between groups (p > 0.05). The highest value of complement 3 was observed in the PBP4.5 group (p < 0.05), while other immunological indices were not significant between treatments (p > 0.05). Foregut villi height of fish fed with PB4.5 diet revealed notable differences compared with those of other groups (p < 0.05). The villi height of PB3 and PB4.5 groups were significantly higher than that of the other treatments (p < 0.05). Taken together, the results of this study showed that the optimum range of autochthonous probiotics were 2.5–2.61 × 107 CFU/g in H. huso fingerlings based on broken‐line regression analysis. [ABSTRACT FROM AUTHOR]

To characterize the effects of a poultry by‐product (PBM) on the gonadosomatic, physiometabolic indices, digestibility and digestive enzymes of juvenile Huso huso (28.42 ± 0.17 g), we procured six experimental diets with 0 (control), 20%, 40%, 60%, 80% and 100% PBM to replace fishmeal. After an 8‐week feeding trial, results confirmed that the weight gain, the specific growth rate of fish fed the 80% and 100% diets were markedly inferior to other groups (p < 0.05). Also, the highest feed conversion ratio and the lowest protein efficiency ratio were observed in dietary of full replacement of fishmeal by PBM (p < 0.05). Triglyceride and cholesterol significantly increased in the PBM100 than the control and PBM20 (p < 0.05). Gastrointestinal enzyme activities were notably decreased in fish fed the diets of more than 60% substitution of fishmeal by PBM (p < 0.05). No statistical difference was observed in the digestibility of protein, dry matter, lipid and gross energy in fish fed up to 300 g/kg (PBM60) of PBM, while beyond this level, all of ADCs value reduced (p < 0.05). Taken together, the optimum range replacement by PBM was 235.9–251.8 g/kg in juvenile Huso huso diet based on the broken‐line regression analysis. [ABSTRACT FROM AUTHOR]

Effects of diets containing microwave-irradiated canola meal were evaluated on growth, nutrition performance, carcass composition and digestibility of nutrients in Huso huso fry with 31.18 ± 1.43 g in initial weight during 8-week experiment in a factorial design 4 × 2 with 8 treatments, each with 3 replications. Treatments included T1: %20 canola meal without irradiation; T2, T3 and T4: 20% irradiated-canola meal at 800 watts for 5, 10 and 15 min respectively; T5: 40% canola meal without irradiation; T6, T7, and T8: %40 800 watt – radiated canola meal at 5, 10 and 15 min respectively. At the end of the experiment, according to the results, the effects of diet containing microwave-irradiated canola meal on the final weight, weight gain, specific growth factor, feed conversion ratio and daily growth in H. huso fry were significant (p0.05), but showed significant effect on the carcass ash content (p0.05). So, it can be added to the diet up to 40% without any unfavorable effect on protein digestibility and growth rate.

Purpose. Forming a thematic bibliographic list of English-language publications on certain issues of vital activity of sturgeon (Acipenseridae), both in natural conditions and in aquaculture. Particular attention was given to species that are not common in aquaculture of Ukraine. Methods. The complete and selective methods were applied in the process of the systematic search. The bibliographic core was made up of literary sources from electronic archives of world-renowned specialized scientific journals. In particular: Journal of Applied Ichthyology, Environmental Biology of Fishes,Conservation Biology, Lake and Reservoir Management, Estuaries,Freshwater Fisheries, Aquaculture, North American Journal of Fisheries Management, Canadian Journal of Fisheries and Aquatic Sciences, Copeia & others. Results. A thematic list of main publications including thematic scientific collections, materials of international scientific and practical conferences, scientific articles and abstracts of dissertations was composed. It consists of 187 English-language papers. Presented publications cover the time interval for the last thirty years. The literary sources are arranged in alphabetical order by author or title, and described according to DSTU 8302:2015 “Information and documentation. Bibliographic reference. General principles and rules of composition”, with the amendments (code UKND 01.140.40), as well as in accordance with the requirements of APA style ‒ international standard of references. Practical value. The prepared list may be useful for scientists, practitioners, students, whose sphere of interests is related to issues of questions breeding sturgeon in aquaculture and conservation of populations of rare species of fish.

The aim of this study was to investigate the effects of different levels of Celmanax commercial prebiotic on growth performance, nutritional efficiency, blood and plasma biochemical indices in beluga, Huso huso (Linnaeus, 1758) in a 120-day feeding period. So that, 120 individuals of beluga with the average weight of 4.66 ± 0.26 kg were transferred to 12 holding cage nets, 1.20 × 1 × 2 m in size at a depth of 1.5 m with a completely randomized design as four treatments with three replications including control (without prebiotic) and three experimental treatments fed by diets containing 0.5, 1, 1.5 g/kg prebiotic. The results exhibited that adding Celmanax to the diet, especially 0.5 g/kg, significantly enhanced relative weight, daily growth rate, specific growth rate, feed conversion ratio and relative eating (p0.05). There were also no significant differences between the treatments fed by prebiotic compared to control with respect to hemoglobin, mean corposcular volume and mean corpuscular hemoglobin (p>0.05). Analyses on biochemical indices indicated that there were significant differences in total protein, glucose and triglyceride in blood plasma levels. Totally, according to the results, 0.5 g/kg Celmanax in diet can effectively enhance growth performance, nutritional efficiency and blood indices in cultured beluga.

Hematological parameters are useful indicators for assessing the physiological conditions of Sturgeon in response to stress, pollutants and physiological and ecological changes. The aim of this study was to investigate the effects of nitrosomonase and nitrobacter in removing ammonia and on blood and serum indices of Huso huso .Four treatments were designed with densities of bacteria (0, 101, 103, 105) in 100 ml with three replications were performed using 120 sturgeon fish with an average weight of 200 ± 800 g and a length of 55±2 cm in 12 fiberglass tanks (4000 liters per each 10 fish) for 12 weeks and two weeks of initial compatibility. Based on the results, the highest amount of ammonia was observed in treatment 1 (control) with significant difference (p≤0.05) with treatment 3 and no significant difference with other treatments. Ammonia levels were not significantly different (p≥0.05) between the hours measured in each treatment. Among the blood parameters, only neutrophil was significantly different in treatments (p≤0.05). Serum blood parameters such as aspartate aminotransferase (AST), alkaline transferase (ALP), keratin phosphatase (CP), total protein and alanine aminotransferase (ALT) were not significantly different (p≥0.05). Lactic dehydrogenase (LDH) had a significant difference with other treatments (p

Citrus peel is a natural source of antioxidants and the use of its natural extracts to improve the quality of fish is increasing. The effect of orange peel extract on the chemical and sensory properties of Huso huso fillet when refrigerated (4±1 °C) was investigated. In this study, fish fillets with aqueous solutions of ethanolic extract of orange peel (w / w 5%) or (5 ml of extract in 100 ml of solvent), orange peel extract (w / w 6%) and orange peel extract (w / w 7%) were tested as natural preservatives for 30 minutes. Control samples were immersed in distilled water for 30 minutes. Control and treated samples were packed with ethanolic extract of orange peel and stored for 15 days. Samples are then taken at regular intervals for chemical properties of pH, free fatty acid (FFA), peroxide (PV), thiobarbituric acid (TBA), total volatile nitrogen bases (TVB-N) and sensory evaluation (texture, color, odor and acceptance) were studied. Analysis of the results of chemical tests and sensory evaluation showed that orange peel extract maintains good quality characteristics and increases the shelf life of fish samples during storage at refrigerator temperature. 7% orange peel extract and then 6% and 5% orange peel extract significantly (P <0.01) delayed the oxidation and hydrolysis of fat in the samples treated with the Orange peel extract. [ABSTRACT FROM AUTHOR]

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The subject of this study was the development of midbrain in beluga sturgeon (Huso huso) larvae. To this end, 36 larvae (6 larvae of each age) were fixed in 10% buffered formalin, dehydrated in an etha-nol series, cleared in xylene and embedded in paraffin. The larvae brain were very small in size, total head was fixed and sited in paraffin blocks. Serial sections (6 µm thick) were stained with haematoxy-lin & eosin, Luxol fast blue, cresyl echt violet and PTAH Mallory for histological studies by light microscope. A stereological study was done by the Cavalieri principle to estimate the different areas of the midbrain, about 10 sections from each specimen were selected and photographed by a camera attached to the light microscope Olympus CX22. From 1 day of age, the two parts of midbrain, optic tectum and tegmentum were obvious. There was an area between these parts called Torus semicircu-laris. In 6-day-old larvae, the optic tectum cell layers were partially observed and in 54-day-olds, the optic tectum occupied the largest volume of midbrain (12.16±0.07 mm3). Tectal ventricle in H. huso larvae was observed from the first day. The tegmentum was located in the ventral part of the midbrain and in its dorsal part joined the hindbrain and contained some nuclei. Stereological results showed significantly distinctive regional differences in midbrain volume (P

We evaluated the stocks of Huso huso in the south Caspian Sea along Iranian coasts using data on different population parameters such as length, age, weight, catch and catch per unit effort changes. The study covered data from 1971 to 2003. The stocks and catch rate of H. huso shows a decrease during the last three decades. The recorded catch for the years 1971-1972 was 74 tons with 5.55kg catch per unit effort which was decreased to 38 tons with 0.26kg per unit effort in 2003 in gillnet fishery and the same trend was observed in beach seine fishing. The data shows that during 1990 to 2003, the average length of the fish has increased from 192.8 to 216.2 centimeters and the average weight has improved from 73 kg to 116.3 kg. Age frequency comparison between the catch of the years 1990 and 2003 showed that with time, older age classes replaced the younger ones, hence the increase in the length and weight of the fish. Due to the decrease in the younger fish and the increase in illegal fi.....

Fish gelatin, by benefiting the lower melting point, quicker mouth melting and presenting elastic characteristics is considered as the most proper substitute for mammalians gelatin and as a Halal food item. The aim of this study was to evaluate the effects of temperature at three levels of 30, 40 and 50 ºC, enzyme at 0.055%, 0.01% and 0.1% (w/w) levels and pH at 2, 3 and 4 levels on the quality of extracted gelatin from Huso huso fish skin. Accordingly, the gel strength in form of breaking force and distance, yield and color (L*a*b*) and whiteness of resultant gelatin were determined. According to the results, the highest gelatin yields as 21.65% was related to the enzymatic assisted method at 50 ºC, 0.01% enzyme at pH=2, whereas it was obtained as 10% at the chemical extraction method. Based on the results, despite from temperature, by increasing of pH and enzyme percentage, the firmness of gelatin was increased (p

The objective of the present study was to investigate the effects of dietary supplementation with zinc oxide (ZnO) and chitosan–zinc nanoparticles (chitosan–ZnO NPs) on biochemical, immunological, and antioxidant biomarkers in blood of juvenile belugas (Huso huso). The beluga juveniles with initial weight of 287 ± 46 g were fed with eight experimental diets containing 0 g kg−1 ZnO (the control diet); 10, 20, and 40 mg kg−1 ZnO; and 10, 20, and 40 mg kg−1 chitosan–ZnO NPs and 36 mg kg−1 chitosan. After 28 days of culture, the fish were fed with ZnO and chitosan–ZnO NP–supplemented diets showed a more significant increase in total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPX), and glutathione S-transferase (GST) activity (p < 0.05) compared to the control group. There were no significant differences (p > 0.05) in malondialdehyde (MDA) and glucose level in all treatment groups. The results showed that with increasing levels of ZnO and chitosan–ZnO NPs, alternative complement activity (ACH50), and total immunoglobulin, total protein, albumin, and lysozyme had a significant increase in fish fed with ZnO and chitosan–ZnO NP–supplemented diets compared to the control group (p < 0.05). ALP, ALT, and AST enzyme activities showed significant difference between control and treatment groups (p > 0.05), while the levels of LDH enzyme activity, urea, and creatinine decreased by increasing both ZnO and chitosan–ZnO NP levels. These results demonstrated that dietary chitosan–ZnO NPs could improve the health status, immune function, and antioxidant capacity of the cultured beluga juvenile. [ABSTRACT FROM AUTHOR]

The effects of different extraction methods (I, II, III, and IV), including two levels of acetic acid (0.2–2.0 N) and sodium hydroxide (0.2–2.0 N), on the skin gelatin extracted from Caspian Sea Huso huso skin was investigated. Furthermore, the gelatin extraction yield, melting point, viscosity, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) electrophoresis pattern of the solutions was studied. Based on preliminary experiments, thawed skins (weight, 50 g) were added to a flask containing four volumes of different sodium hydroxide solutions for 60 min at 7°C. Treated skins were washed thoroughly with excess cold water, rinsed with cold-distilled water, and then, treated with acetic acid. Skins were drained using cheesecloth. Afterward, the extraction of gelatin was performed in four volumes of distilled water in a water bath for 16–18 h. Results showed that the higher melting point belonged to method II, while the uppermost amount of yield and viscosity could be observed in method III. Method III had the highest level of acetic acid (2 N) and the lowest level of sodium hydroxide (0.2 N) among the other samples. High acetic acid concentration caused greater degradation of collagen cross-links, which resulted in the extraction of more protein compounds than sodium hydroxide; therefore, an increase in extraction yield and viscosity was observed. The gelatin viscosity decreased with increasing sodium hydroxide concentration (methods II and IV), while it increased with smaller amounts (methods I and III). Modelling results showed that the power-type model described the influence of soluble solids better than exponential-type model on the viscosity of the mentioned polymer. [ABSTRACT FROM AUTHOR]

In order to determine the chelating effect of activated charcoal, a total of 150 beluga (270 g) were fed for 60 days with a diet containing 0 (control), 5, 10, 15 and 20 g activated charcoal per kg. Afterwards, the fish were subjected to challenging with 1 mg/L of each of heavy metals including lead, cadmium and copper during seven days. As results, the highest percentage of body weight gain, specific growth rate, condition factor, protein efficiency ratio and the lowest feed conversion ratio before and after challenging with heavy metals were obtained in 15 g treatment with significant differences comparing to other treatment (p < .05). In all treatments, considerable differences were observed between two experimental stages of all parameters except condition factor and feed conversion ratio (p < .05). No mortalities were observed during the experiment. Before challenging with heavy metals, 15 g treatment showed the lowest activities of AST and ALT enzymes, and uric acid, protein, albumin and cholesterol amounts. The minimum amounts of creatinine and glucose were recorded in the control and 20 g treatments respectively. The highest levels of these parameters, except for creatinine and uric acid, were measured in the control group. After challenging with heavy metals, the lowest levels of AST and ALT enzyme activities, uric acid, creatinine, and glucose, and the highest amounts of protein, albumin and cholesterol belonged to 15 g, whereas the results in the control group were almost opposite. In all treatments, significant differences were observed between two experimental stages of all parameters except AST, uric acid, glucose and cholesterol (p < .05). In the pre‐challenge stage, the maximum amount of carcass protein was observed in 15 g while the differences in lipid content were not significant (p > .05). Moreover, the highest contents of moisture and ash were measured in the control group and 20 g respectively. After the challenge, the highest values of protein and lipid were quantified in 15 g, while the maximum values of ash and moisture were observed in 20 g and control group respectively. Also, significant differences were observed just in ash and moisture amounts in both stages (p < .05). Accumulations of cadmium, copper and lead were maximal in the control group in both stages, and their amount were decreased in sample with 15 g of activated charcoal until they reached to their lowest value in sample with 20 g of activated charcoal. The only different parameter between two treatments was copper amount. Also, significant differences were observed in all treatments in both stages (p < .05). Although activated charcoal at 20 g/kg diet yielded the best results in metal chelation, it is recommended to add 15 g/kg of activated charcoal to the diet of beluga because of other parameters. [ABSTRACT FROM AUTHOR]

Aims The objective of the current study was to investigate the effects of three commercial prebiotics including A-Max, Celmanax, and A-Max Ultra (each of them 0.5, 1, and 1.5g/kg diets) on growth, feed performance, and blood biochemical compounds of beluga juvenile. Materials & Methods 900 fish with an average weight of 21.5±0.89g were feed in 9 treatments (with three replicate) for 60 days. Control treatment was without supplementation. Fish were fed to satiation triple daily of 5% body weight. At the end of this period, the feed and growth performance were measured. Findings There was a significantly higher final body weight in A-Max ultra 0.5g/kg (90.00±21.78g) compared with control (37.50±9.60g). The highest and the lowest of food conversion were in control and A-Max ultra 0.5g/kg treatments, respectively. The results showed that the highest fat and protein efficiency ratio was obtained in prebiotic treatment (A-Max ultra 0.5g/kg) as 2.19±0.77 and 7.37±2.60 and the lowest was obtained in control. Generally, the best treatments were in groups of Celmanax (dose of 0.5g/kg), A-Max (dose of 1.5g/kg), and A-Max Ultra (0.5g/kg). In addition, after determining the proper dose, blood samples of fish were collected in the above-mentioned treatments. Based on the results of blood biochemistry parameters, there were no significant differences AST, ALP, and ALT activity, so that the highest amount was obtained in the control. Also, there were no significant differences in protein and cortisol experiment groups. Conclusion The use of prebiotics in juvenile sturgeon diet has positive effects on feed performance, liver enzymes, and blood biochemical parameters. [ABSTRACT FROM AUTHOR]

Current knowledge about sturgeon behavior is incomplete and certain aspects of it are completely unknown, despite tremendous conservation efforts. This paper describes aspects of annual recruitment, fitness distribution and genetic diversity of the offspring of two sturgeon species – Huso huso (beluga sturgeon) and Acipenser stellatus (stellate sturgeon). To ensure a step forward in understanding their behavior in general and offspring ethology in particular, we conducted a pilot study on the 2016 sturgeon offspring diversity in the Lower Danube River, on the rkm 123 feeding area community. Our approach allowed us to draw a hypothesis about offspring behavior that can also be applied in other feeding areas on the Danube River. Namely, from the convergence of the morphological and genetic data, we found that the two studied sturgeon species have distinct and complex downstream migration behavior. Overall, the present paper presents a pilot study in sturgeon behavior that reveals several traits of offspring ethology. However, further analyses are needed to decode the cryptic behavior of sturgeons

This study designed to evaluate blood parameters of 3-4 years Huso huso on pen in the center of the fishing and processing Ashuradeh (Chalasht) from the Gorgan Bay in different seasons.Blood samples from 10 Huso huso withaverage weight2698.01 ± 757.32 g and length 77.98 ± 5.53 cm were collected in each season (autumn 2014 to summer 2015) and activity of alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and variation in hematological parameters such as hemoglobin, erythrocyte count, leucocytes count, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) in the blood samples of fish were measured in each season. There is significant difference in the enzymes levels were observed. (P

This experiment was conducted to examine the effect of dietary alphamion probiotic on growth, hematological indices and body composition of Huso huso fingerlings. A basal diet supplemented with 0 (control), 0.5, 1, 1.5 and 2 percent probiotic to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish with initial average weight of approximately 192±3.2 g. After 8 weeks of feeding trial, fish fed diets with probiotic showed the highest final weight and SGR, and lowest in fish fed the control diet (p

In this study, in order to investigate the effect of Caraway (Carum carvi) on growth parameters and body approximate composition of Huso huso (Linnaeus; 1758) fingerlings, 3 diet containing 10%, 15% and 20% of Caraway with control diet that had not Caraway in its composition was utilized for feeding the Huso huso fingerlings. Fishes with initial mean weight of 10 g were fed with control diets in 7 weeks and growth parameters including total length, total weight, protein efficiency ratio, feed conversation rate and body approximate compositions were measured and analyzed. Results showed that the diet with 15% Caraway has the best effect on growth parameters of Huso huso fingerlings and lead to more gaining weight (146.60±1.85 g) than other diets. Moreover, between body approximate compositions, only the protein and moisture level were affected by diets containing Caraway. Maximum protein was observed in fingerlings fed with diets containing 10% and 20% Caraway. According to obtained results, using the diet with 15% Caraway recommend in order to enhance growth of Huso huso fingerlings.

This study investigated the effects of dietary Sargassum ilicifolium on growth performance, hematological parameters, immune responses, and protection against Yersinia ruckeri challenge in great sturgeon, Huso huso. The fish (56.8 ± 4.1 g) were fed diets containing four concentrations of S. ilicifolium (0 (basal diet), 5, 7.5, and 10%) for 8 weeks. Growth parameters were significantly (p < 0.05) higher in 10% S. ilicifolium fed group after 8 weeks of feeding trial. The same group contained significantly higher serum immunological activities such as serum total protein, lysozyme, immunoglobulin M, respiratory bursts, and complement activities. Among hematological parameters, hemoglobin levels, red blood cells, and white blood cells were significantly higher in group supplemented with 10% of S. ilicifolium. Administration of S. ilicifolium had no significant effects on blood biochemical parameters such as triglycerides, lactase dehydrogenase, aspartate aminotransferase, and alanine aminotransferase activities. However, 10% S. ilicifolium supplementation significantly lowered blood cholesterol levels. Furthermore, fish fed 10% S. ilicifolium supplemented diet exhibited the highest (p < 0.05) relative post-challenge survival (75.2%) against Y. ruckeri infection. Overall, these results suggest that dietary supplementation of S. ilicifolium (at 10%) can promote growth and strengthen immunity of great sturgeon. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the past decades, medicinal plants were used to enhance the specific and non-specific defense mechanism and to increase resistance to disease. OBJECTIVES: This study was performed to evaluate the effect of Curcuma longa L. on the hematological factors of Huso huso. METHODS: In this study, 90 beluga with average weight of 2.403± 0.006 Kg were kept on Shahid Rajai reproduction, culture and rehabilitation of sturgeon for 20 days. This number of fish were distributed in the three groups with the names curcumin, control (+) and control (-) with three replicates. After one week adaptation with experimental environment fish were injected intraperitoneally. In curcumin group 400 mg/kgbw curcumin extract at the maximum volume of 0.5 ml was used. In control (+)and in control (-) without injection 0.5 ml of physiological serum was kept just to check fish experimental conditions. Blood was taken at 0, 3, 6, 9 and 12 days post injection. RESULTS: The results of this study showed that the amount of red blood cells, white blood cells, hematocrit, hemoglobin and blood indices such as MCV, MCH, MCHC in the curcumin group was higher than the control group (control (+) and control (-)). CONCLUSIONS: The result of this study showed that use of curcumin in beluga has high impact on increasing Hematology parameters. [ABSTRACT FROM AUTHOR]

In this research, acute toxicity (LC) of zinc oxide nanoparticle on Beluga (Huso huso) and common carp (Cyprinus carpio) was studied. The experiment was conducted using the Organization for Economic Co-operation and Development (No. 202) method. For both species, 96hLC10 was determined to be more than 200 mg/l. To assess the effects of zinc oxide nanoparticles on blood factors, leukocyte index count (Lymphocyte, Monocytes, Neutrophils, Eosinophil, and Basophils) was performed, and the results were analyzed using IBM SPSS software version. According to the results and based on the ANOVA test, there is no significant difference among mean values of leukocyte index responses (p>0.05), and one should note that the amount of lymphocyte had decreased while that of neutrophils and monocytes had increased. Furthermore, with regard to concentration levels, this decrease or increase has not followed a systematic trend. In Beluga based on ANOVA test, there is a significant difference between mean values of lymphocytes and neutrophils (p

The effects of orally administered purple cone flower Echinacea purpura and garlic (Allium satvium) on the non-specific immunity and growth condition of beluga weighing 1.15 ± 0.02 kg were evaluated for a period of 60 days. The tree groups of fish were fed two diets containing 0.5% purple coneflower and 1% garlic and a control diet containing no supplemented herb. The growth performance was positively affected by both dietary herbal supplementations (p < 0.05). Among the humoral factors, serum alternative complement, lysozyme and respiratory burst activity increased significantly in all supplemented groups when compared to the control (p < 0.05). These findings demonstrate that dietary Echinacea and garlic can modulate some of the innate defense mechanisms, hematological and growth parameters in Huso huso.

To compare the reproductive performance of the wild and cultured stocks of beluga, Huso huso males, some spermatological parameters were measured including: sperm motility, sperm density, spermatocrit and also fertilization rate, hatching rate and larval growth and survival rates. The semen samples were sampled from 11 wild spawners and 12 cultured brooders. A half of each semen sample was allocated for spermatological analysis and remaining were used for artificial propagation. In wild beluga, sperm motility time was 339.09  23.11 s; spermatozoa motility rate 83.64  2.01%; sperm density 15.22  3.46 ×109 and spermatocrit 5.88  1.36% while in cultured beluga, sperm motility time was 199.35  29.02 s; spermatozoa motility rate 74.22  2.4 %; sperm density 8.37  0.24 × 109 and spermatocrit 3.21  0.29 %. The fertilization rate (%), hatching rate (%), larval growth (% g.day1), and survival rate (%) in wild beluga were 61.72  14.16, 43.33  11.13, 12.28  0.33 and 52.66  7.77, while in cultured beluga were 49.98  6.55, 31.47  8.49, 12.28  0.62 and 57.37  7.89, respectively. The spermatozoa motility (the ratio and duration of motility) were significantly different between wild and cultured brooders (P 0.05).

Background: Polycyclic aromatic hydrocarbons (PAHs) are a predominant group of contaminants that have been shown to accumulate and persist in marine organisms. We evaluated the dose-dependent induction of the cytochrome P4501A (CYP1A) system in the Sturgeon fish, Huso huso after after exposure to PAHs, beta-naphthoflavone (BNF) and 3- methylcholantheren. Methods: The fish were treated by i.p. injections of beta–naphthoflavone and 3- methylcholantheren dissolved in corn oil at three doses 35, 70 and 105 mg/kg wet-body weight respectively for 72 h every day. Similarly, the control fish received injections of only corn oil. Microsomal fraction was prepared and ethoxy resorufin-O-deethylase activity (EROD) was measured in the fish liver. Cytochrome P4501A1 (CYP1A1) content was estimated by ELISA based on monoclonal anti-cod P4501A1. Results: Beta-naphthoflovone and 3-methylcholantheren treated-fish developed 15-32 fold increase in Ethoxyresorufin-O-deethylase activity in liver microsomes. The results of ELISA showed higher levels of cytochrome P4501A content in treated fish as compared to controls. Conclusion: A parallel increase of the CYP1A immunochemically assay and an increase in EROD activity could be recorded for beta –naphthoflavone and 3- methylcholantheren in injected fish. Dose-response relationships on the induction of EROD and CYP1A immunodetectable protein were recorded. Therefore, EROD activity and CYP1A content can be used as a biomarker of polycyclic aromatic hydrocarbons.

This investigation focused on an episode of chronic mortality observed in juvenile Huso huso sturgeons. The examined subjects underwent pathological, microbiological, molecular, and chemical investigations. Grossly severe body shape deformities, epaxial muscle softening, and multifocal ulcerative dermatitis were the main observed findings. The more constant histopathologic findings were moderate to severe rarefaction and disorganization of the lymphohematopoietic lymphoid tissues, myofiber degeneration, atrophy and interstitial edema of skeletal epaxial muscles, and degeneration and atrophy of the gangliar neurons close to the myofibers. Chemical investigations showed a lower selenium concentration in affected animals, suggesting nutritional myopathy. Other manifestations were nephrocalcinosis and splenic vessel wall hyalinosis. Septicemia due to bacteria such as Aeromonas veronii, Shewanella putrefaciens, Citrobacter freundii, Chryseobacterium sp., and pigmented hyphae were found. No major sturgeon viral pathogens were detected by classical methods. Next-generation sequencing (NGS) analysis confirmed the absence of viral pathogens, with the exception of herpesvirus, at the order level; also, the presence of Aeromonas veronii and Shewanella putrefaciens was confirmed at the family level by the metagenomic classification of NGS data. In the absence of a primary yet undetected biological cause, it is supposed that environmental stressors, including nutritional imbalances, may have led to immune system impairment, facilitating the entry of opportunistic bacteria and mycotic hyphae.

We examined the relationships between a number of sperm characteristics (motility, concentration and pH) and sperm fertility (egg fertilisation and hatching rate) in 10 mature females and four mature males of the beluga sturgeon, Huso huso. The fish were treated with luteinising hormone-releasing hormone agonists (LHRH-A2), at a dose of 5-10 µg/kg of body weight (BW) by injection into the muscle between the dorsal and lateral scutes. Significant linear relationships were found between sperm pH and fertilisation rate (R2 = 0.82, P < 0.01) and sperm pH and hatching rate (R2 = 0.75, P < 0.05). Highly negative relationships were also observed between sperm concentration and fertilisation rate (R2 =-0.71, P < 0.05) and sperm concentration and hatching rate (R2 = -0.83, P < 0.01). We suggest that understanding these correlations is critical in the evaluation of sperm quality and for the preparation of media (extender) for use in sperm dilution to improve sperm motility/fertility and therefore increase fertilisation success in beluga sturgeon production.

By decreasing sturgeon stocks in the Caspian Sea, rearing different sturgeon species especially Huso huso was increased in Iran. Under stress conditions the sturgeon can easily be infected by several opportunistic pathogens. In June 2011, mortality happened in 25 - 28°C water temperature, in one of the most important cultured sturgeon farms in Mazandaran province, north of Iran. The mortality rate was 15%. The first clinical signs in moribund fish were lethargy and anorexia. A total of 20 moribund fish was transferred to a central laboratory for more bacteriological examination. Clinical signs including several deep ulcers on body surface, around the head, under operculum, ulcers at the base of the pectoral fins, hemorrhage around the anus, operculum, and pale gills were observed in moribund fish. The main internal signs were hepatomegaly and splenomegaly, liquid accumulation in the intestine and diffuse visceral hemorrhage. The results of morphology and microscopic characterizations and also biochemical tests indicated that Vibrio vulnificus (biotype 2) was the etiological agent of mortality in infected fish. This study was the first report of V. vulnificus in cultured H. huso in Iran.

The development of proteolysis digestive enzymes from the stomach and pancreas were studied in Beluga, Huso huso from hatching up to 50th day post hatching (dph). Larvae were obtained from ShahidMarjaniSturgeonRearingCenter, Gorgan province, Iran. Sampling was carried out immediately after hatching, 7, 14, 19, 24, 29, 35, 42 and 50 dph. The results showed that at the onset of exogenous feeding, gastric glands were already functional, which was indicated by an increase in proteolitic activity of stomach. In contrast, proteolitic activity of pancreas decreased after the onset of exogenous feeding, showing the importance of these types of enzymes in the cleavage of yolk proteins during the endogenous feeding phase. The present study indicated that larvae of Beluga at the onset of exogenous feeding had an advanced digestive system to accept exogenous food and to digest the formulated diets.