Dietary Gracilaria persica mediated the growth performance, fillet colouration, and immune response of Persian sturgeon (Acipenser persicus).

Algal seaweeds have abundant amounts of active substances and can be used as pharmaceuticals and biomedicals in aquafeeds. In this context, the powder of red macroalgae Gracilaria persica was included in the diets of Persian sturgeon at the rate of 0, 2.5, 5, and 10 g/kg to investigate its role on the growth rate, fillet colouration, haemato-biochemical indices, serum, and skin mucus immunity. The weight gain, SGR, and FCR displayed no significant changes in fish fed varying levels of G. persica (P > 0.05). The level of total carotenoids was significantly higher in the blood and fillet of fish fed 5 and 10 g G. persica/kg diet (P < 0.05). Dietary G. persica significantly altered RBCs, WBCs, and HCT at 5, and 10 g/kg, whereas the Hb was increased in fish fed 5 g/kg (P < 0.05). The blood total protein and albumin were significantly increased in fish fed 5 and 10 g/kg (P < 0.05). No significant alterations were observed on ALT, AST, ALP, and glucose levels of fish fed varying levels of G. persica (P > 0.05). Serum Ig, lysozyme, superoxide dismutase, catalase, and respiratory burst activities were increased in fish fed 5, and 10 g/kg than fish fed 0 and 2.5 g/kg diet (P < 0.05). The level of total protein and lysozyme activity in the skin mucus were significantly higher in the blood and fillet of fish fed 5, and 10 g G. persica/kg diet than fish fed 0 and 2.5 g/kg (P < 0.05). Based on the obtained results, G. persica can be used as a feasible feed additive in the diets of Persian sturgeon at 5-10 g/kg diet.

Effects of dietary yeast cell wall on biochemical indices, serum and skin mucus immune responses, oxidative status and resistance against Aeromonas hydrophila in juvenile Persian sturgeon (Acipenser persicus).

The present study aims to shed light on the effects of yeast cell wall (ImmunoWall®) supplementation on biochemical indices, oxidative status, serum and mucus immune responses as well as disease resistance of juvenile Persian sturgeon (Acipenser persicus). For this purpose, one hundred fifty three juvenile Persian sturgeons (47.78 ± 0.39 g) were distributed into nine tanks (500 L) and fed with basal diets containing two levels of yeast cell wall (YCW) 0.5% (T1) and 1% (T2) and a diet without YCW as control (0%). As shown by the results obtained at the end of 56-day feeding trial, YCW had no significant effect on glucose, cortisol, SGOT, lysozyme and IgM in serum (P > 0.05) albeit an enhancement of cholesterol, LDH, ALP and SOD and ACH50 was observed in fish fed YCW supplemented diets. However, plasma triglyceride levels were lower in fish fed YCW compared with the control group. Also, total protein content, lysozyme and protease activities in skin mucus were unaffected by the supplemented diets (P > 0.05) and only total immunoglobulin and ALP enzyme activity were significantly increased in T1 and T2 groups (P > 0.05). The cumulative mortality of the fish fed supplemented diets at the end of disease challenge was 100% where cumulative mortality of those fed the control diet was 75% (P < 0.05). The present study shows that increasing immune parameters in serum and mucus of juvenile Persian sturgeon by YCW dietary supplementation did not improve resistance against Aeromonas hydrophila. According to the obtained results, the YCW supplementation at 0.5 and 1% in the juvenile Persian sturgeon diet is not recommended.

The effects of diazinon on the cell types and gene expression of the olfactory epithelium and whole-body hormone concentrations in the Persian sturgeon (Acipenser persicus).

The olfactory function and imprinting of odorant information of the native stream play a critical role during the homing migration in fish. Pesticides may impair olfactory imprinting by altering olfaction and hormone functions. The present study aimed to determine how diazinon impacts olfactory epithelium morphology and cell composition, as well as hormone concentrations in Persian sturgeon (Acipenser persicus) during their lifetime in freshwater and, also during diazinon-free saltwater acclimation. Fingerlings were exposed to 0, 150, 300, and 450 µg·L-1 of diazinon in freshwater for 7 days and then were transferred to diazinon-free saltwater by gradually increasing salinity up to 12 ppt. After diazinon exposure, the number of olfactory receptor cells (ORCs) and goblet cells (GCs) decreased and increased, respectively, and the expression of G-protein αolf (GPαolf) and calmodulin-dependent kinase II delta (CAMKIId) was down-regulated and up-regulated, respectively. Transferring the fish to diazinon-free saltwater (8 and 12 ppt) raised the number of ORCs, supporting cells (SCs), GCs, and GPαolf expression, and down-regulated CAMKIId without any significant differences among treatments. Exposure to diazinon increased whole-body cortisol at the high concentration, while decreased whole-body thyroxin (T4) and triiodothyronine (T3) in a dose-dependent manner. Although whole-body T4 and T3 increased in all the treatments after saltwater acclimation (8 and 12 ppt), the level of these hormones was lower in fish that had been exposed to diazinon than in the control. These results showed that diazinon can disrupt olfactory epithelium morphology and cell composition as well as hormone concentrations, which in turn may affect the olfactory imprinting in Persian sturgeon fingerlings.

1H NMR metabolic profiling of the cryopreserved spermatozoa of the wild endangered Persian sturgeon (Acipenser persicus) with the use of beta-cyclodextrin as an external cryoprotectant.

Persian sturgeon (Acipenser persicus) is an endangered species and genetic resource banking such as gametes and embryo preservation could be one of the most pursued conservation approaches. In this study, deleterious effects of the traditional cryopreservation technique and the effect of different doses of 2-hydroxypropyl-beta-cyclodextrin (HßCD) on thawed spermatozoa quality (motility duration and percentage) of Persian sturgeon (Acipenser persicus) were investigated from metabolic aspects of view. For cryopreserving, semen was diluted with Tris-HCl (100 mM) extenders containing 0, 5, 10, and 15 mM of HßCD in a ratio of 1:1 (semen/extenders). Semen-extenders were filled into 0.5-mL straws and were frozen with the vapor of liquid nitrogen, and then immersed into liquid nitrogen. Cryopreserved spermatozoa were thawed in water baths in 15 s. Two treatments with the highest and the lowest motility percentages (0 and 10 mM of HßCD) were chosen to reveal the extremes of the metabolites change range and were objected to 1H NMR spectroscopy. Univariate (ANOVA) and multivariate (PCA) analysis of the obtained metabolic profiles showed significant changes (P < 0.05) in metabolites. The use of 10 mM of HßCD was completely successful in the preservation of creatinine, glucose, guanidoacetate, O-phosphocholine, and N, N-dimethylglycine and probably their corresponding biochemical pathways, but it failed to preserve lactate, carnitine, betain, ß-alanin, and trimethylamine N-oxide. It was also partially successful in preserving acetate, creatine, creatine phosphate, and glycine, all suggesting how HßCD can be effective as a cryoprotectant.

Metabolic changes in droplet vitrified semen of wild endangered Persian sturgeon Acipenser persicus (Borodin, 1997).

Comparative quantitative metabolite profiling can be used for better understanding of cell functions and dysfunctions in particular circumstances such as sperm banking which is an important approach for cryopreservation of endangered species. Cryopreservation techniques have some deleterious effects on spermatozoa which put the obtained results in controversy. Therefore, in the present study, quantitative 1H NMR (Nuclear Magnetic Resonance) based metabolite profiling was conducted to evaluate metabolite changes related to energetics and some other detected metabolites in vitrified semen of critically endangered wild Acipenser persicus. The semen was diluted with extenders containing 0, 5, 10, and 15 µM of fish antifreeze protein (AFP) type III as a cryoprotectant. Semen-extenders were vitrified and stored for two days. Based on post-thaw motility duration and motility percentage assessments, two treatments with 10 µM and 0 µM of AFP had the highest and the lowest motility percentages respectively and they were objected to 1H NMR spectroscopy investigations in order to reveal the extremes of the metabolites dynamic range. Univariate (ANOVA) and multivariate (PCA) analysis of the resulting metabolic profiles indicated significant changes (P > 0.05) in metabolites. The level of some metabolites including acetate, adenine, creatine, creatine phosphate, lactate, betaine, sarcosine, ß-alanine and trimethylamine N-oxide significantly decreased in vitrified semen while some others such as creatinine, guanidinoacetate, N, N-dimethylglycine, and glycine significantly increased. There were also significant differences between vitrified treatments in levels of creatine, creatine phosphate, creatinine, glucose, guanidinoacetate, lactate, N, N-dimethylglycine, and glycine, suggesting how fish AFP type III can be effective as a cryoprotectant.

Effects of diazinon on adaptation to sea-water by the endangered Persian sturgeon, Acipenser persicus, fingerlings.

To replenish the depleting populations of sturgeon fishes especially Persian sturgeon, Acipenser persicus in the Caspian Sea, millions of Persian sturgeon fingerlings are farmed through artificial propagation and released into the Iranian river estuaries annually. Fish osmoregulation is a vital physiological process that can be affected during the release. Many Iranian river estuaries are under the influence of pesticides originating from farming activities that may affect osmoregulation. In this study, Persian sturgeon fingerlings were exposed to sublethal concentrations (0, 0.18, 0.54, 0.9mgL(-)(1)) of diazinon for 96h (short-term trial) and 12 days (long-term trial) in fresh water (FW) and then fish were exposed in brackish water (BW) for 24h. After 96h and 12 days of exposure in FW, the lower levels of plasma triidothyronine (T3), thyroxine (T4), Na(+), Cl(-), K(+), gill Na(+)/K(+)- ATPase activity and number of chloride cells were observed in exposed fish (0.54 and 0.9mgL(-)(1) diazinon) compared to control group and 0.18mgL(-)(1) diazinon treatment. Also, higher levels of plasma cortisol (except 0.18mgL(-)(1) diazinon treatment in long-term trial) were observed in diazinon exposed fish compared to control group. However, gill Na(+)/K(+)-ATPase activity and the number of chloride cells were higher in fingerlings exposed to diazinon compared than control. When fish were exposed in BW for 24h, the following changes occurred: (a) in short-term trial: increases in cortisol and Cl(-) levels (0.54mgL(-)(1) diazinon ), Na(+) (0.9mgL(-)(1) diazinon ) and gill Na(+)/K(+)-ATPase activity (0.18mgL(-)(1) diazinon ). In control group, cortisol, T4, Na(+), gill Na(+)/K(+)-ATPase activity and the number of chloride cells increased significantly. (b) In long-term trial: increases in K(+) levels in fish exposed to 0.9mgL(-)(1) diazinon, Na+ in all diazinon concentrations and decreases in chloride cells number in fish exposed to 0.18mgL(-)(1) diazinon. In control group, significant increases were observed in cortisol, T3, Na(+) and chloride cells number. Finally, gill showed many histopathological damages during exposure in FW and BW. Our results suggest that the contamination of river estuaries with diazinon may alter the osmoregulation ability of released Persian sturgeon fingerlings, which could lead to a failure in their restocking program in the Caspian Sea.

Salinity effects on osmoregulation and gill morphology in juvenile Persian sturgeon (Acipenser persicus).

The effect of abrupt and 5-day gradual salinity transfers from freshwater (FW) to 11 ‰ Caspian Sea brackish water (BW) was investigated in juvenile Persian sturgeon Acipenser persicus with three different weight groups: 1-2 g (1.62 ± 0.27 g), 2-3 g (2.55 ± 0.41 g) and 3-5 g (4.28 ± 0.76 g). Mortality rates, blood osmotic pressure, gill morphology and branchial Na+, K+-ATPase (NKA) activity were measured 4 and 10 days after abrupt transfer and 9 and 15 days after the initial gradual transfer (i.e. 4 and 10 days after reaching Caspian Sea salinity). Fish under 3 g could not survive increased salinity, and the blood osmotic pressure of the remaining surviving fish increased and remained elevated. However, heavier fish were able to survive and successfully acclimate, even to rapid salinity change with osmotic pressure reduced to Caspian Sea osmolality levels. At the gill level, the developmental increase in chloride cell volume and a higher NKA content most probably allow juveniles weighing more than 2 g to sharply increase NKA activity if the fish are transferred to BW. The rapid chloride cell proliferation occurring with increased salinity should strengthen this acclimation response. Therefore, a drastic physiological change occurs when fish weigh more than 2 g that allows migration to higher salinities. The triggering signal on chloride cells must be further investigated in order to optimize this functional step.

Effects of dietary ß-glucan on the growth and innate immune response of juvenile Persian sturgeon, Acipenser persicus.

The present study evaluated the effects of different levels of dietary ß-glucan (MacroGard(®)) on growth performance and innate immune parameters in juvenile Persian sturgeon (Acipenser persicus). Fish (20.1 ± 0.8 g) were allocated into 12 tanks (15 fish per tank) and triplicate groups were fed a control diet or diets containing 0.1%, 0.2% and 0.3% ß-glucan. After six weeks of daily feeding (3.0% body weight day(-1)), humoral innate immune parameters (serum immunoglobulin (Ig) levels, lysozyme activity and alternative complement activity (ACH50)) and growth parameters (final weight, weight gain, specific growth rate (SGR), food conversion ratio (FCR)) were examined. Innate immune responses (lysozyme activity and ACH50) were significantly higher in 0.2% and 0.3% ß-glucan fed fish (P < 0.05). Similarly, elevated growth performance (final weight, SGR and FCR) was observed in fish fed 1%, 2% and 3% ß-glucan compared to the control group (P < 0.05). However, dietary ß-glucan had no significant effect on survival rate of fish (P > 0.05). These results indicate that ß-glucan can be considered as a beneficial dietary supplement for improving the immune response and growth performance of Persian sturgeon.

Motility and fertility of cryopreserved semen in Persian sturgeon, Acipenser persicus, stored for 30-60 min after thawing.

We investigated the effect of storage times of frozen-thawed Persian sturgeon (Acipenser persicus) semen on the duration of sperm motility, percentage of motile sperm, and fertilization and hatching rates of fresh sperm and sperm stored for 0, 30, and 60 min at 4°C post-thawing. Frozen thawed semen analyzed immediately after thawing had similar quality characteristics as fresh semen. For cryopreserved semen stored for 30 min after thawing the characteristics did not differ to fresh semen and cryopreserved semen. For cryopreserved semen stored for 60 min a significant decline in the parameters was observed. Fertilization and hatching rates were not affected by storage times of maximally 30 min of storage.

Salinity modulates biochemical and histopathological changes caused by silver nanoparticles in juvenile Persian sturgeon (Acipenser persicus).

The objective of this study was to evaluate the effect of salinity on the acute and sub-chronic toxicity of silver nanoparticles (AgNPs) in Persian sturgeon. This was evaluated by exposing Persian sturgeon to AgNPs in three salinities: freshwater (F: 0.4 ppt), brackish water 1 (B1: 6 ± 0.2 ppt), and brackish water 2 (B2: 12 ± 0.3 ppt) for 14 days, which was followed by analysis of alterations in plasma chemistry and histopathology of the gills, liver, and intestine. Values of 96-h median lethal concentration (LC50) were calculated as 0.89 mg/L in F, 2.07 mg/L in B1, and 1.59 mg/L in B2. After sub-chronic exposures, plasma cortisol, glucose, potassium, and sodium levels illustrated no significant changes within each salinity level. In F, 0.2 mg/L AgNP caused the highest levels of alkaline phosphatase and osmolality levels. In B1, 0.6 mg/L AgNP induced the highest level of alkaline phosphatase and elevated plasma osmolality was recorded in all AgNP-exposed treatments in comparison with the controls. The B2 treatment combined with 0.6 mg/L AgNP significantly reduced plasma chloride level. The results showed elevating salinity significantly increased osmolality, chloride, sodium, and potassium levels of plasma in the fish exposed to AgNPs. The abundance of the tissue lesions was AgNP concentration-dependent, where the highest number of damages was observed in the gills, followed by liver and intestine, respectively. The histopathological study also confirmed alterations such as degeneration of lamella, lifting of lamellar epithelium, hepatic vacuolation, pyknotic nuclei, and cellular infiltration of the lamina propria elicited by AgNPs in the gills, liver, and intestine of Persian sturgeon. In conclusion, the stability of AgNPs in aquatic environments can be regulated by changing the salinity, noting that AgNPs are more stable in low salinity waters.

Droplet vitrification versus straw cryopreservation for spermatozoa banking in Persian sturgeon (Acipenser persicus) from metabolite point of view.

Persian sturgeon (Acipenser persicus), a commercially valuable and critically endangered fish species has been suffering considerable declines in populations in the nature due to over-fishing, habitat destruction and marine pollution during past decades. Since there were no achievements in artificial reproduction programs, genetic resource banking such as gametes and embryo cryopreservation can be a good strategy however, reported resulting gamete qualities were considerably low. In the present study, the metabolome content of Persian sturgeon spermatozoa was investigated during common straw cryopreservation and novel droplet vitrification by the use of 1H NMR (Nuclear Magnetic Resonance) spectroscopy. Univariate (ANOVA) and multivariate (PCA) analysis showed significant differences in the metabolic profiles between cryopreserved and fresh spermatozoa samples. Adenine, creatine, creatine phosphate, glucose, guanidoacetate, lactate, N, N-dimethylglycine, and glycine levels showed no significant differences between these two cryopreservation techniques suggesting these metabolites and their corresponding enzymes and chemical pathways are so vulnerable to the temperature changes and even higher cooling rate in droplet vitrification could not conserve them. However, significant differences were found in acetate, creatinine, betaine, ß-alanine and trimethylamine N-oxide suggesting better efficiency of droplet vitrification in protection of some metabolites associated to spermatozoa energetics, redox balance and hypoxia compensation compared to straw cryopreservation.

NMR-based metabolomic study on the toxicological effects of pesticide, diazinon on adaptation to sea water by endangered Persian sturgeon, Acipenser persicus fingerlings.

NMR-based metabolomics was applied to explore metabolic impacts of diazinon on sea water adaptation of Persian sturgeon fingerlings, Acipenser persicus. Fingerlings were exposed to sub-lethal concentrations of diazinon in freshwater (FW) for 96 h (short-term trial) and 12 days (long-term trial) and then exposed in brackish water (BW) (12 mg L-1 salinity) for 24 h. After 96 h and 12 days exposure in FW, identified metabolites (amino acids, osmolytes, energy metabolites) showed different change-patterns compared to control group (P < 0.05) as follow: (A) short-term trial: higher plasma levels of glucose, lactate (in all diazinon-exposed fish), acetate and acetoacetate (in 0.9 mg L-1diazinon treatment); lower levels of creatine (in all diazinon-exposed fish), trimethylamine-N-oxide, choline, taurine, betaine, N,N-dimethylglycine and almost all amino acids in fish exposed to high concentrations of diazinon (0.54 and 0.9 mg L-1 diazinon). (B) Long-term trial: higher plasma levels of lipid oxidation metabolites and almost all amino acids in fish exposed to 0.54 and 0.9 mg L-1 diazinon; lower levels of creatine, trimethylamine-N-oxide, N,N-dimethylglycine, betaine, choline (in all diazinon-exposed fish), glucose (in 0.54 and 0.9 mg L-1diazinon treatments) and taurine (in 0.9 mg L-1 diazinon treatment). When fish were exposed in BW for 24 h, the plasma levels of osmolytes decreased significantly in almost all experimental groups of short-term and long-term trial (P < 0.05). In short-term trial, the plasma levels of glucose in all groups and lactate in 0.18 and 0.54 mg L-1 diazinon treatments increased after salinity challenge (P < 0.05). However, a significant decrease was observed in lactate levels in 0.9 mg L-1 diazinon treatment (P < 0.05). Also, the plasma levels of amino acids decreased mostly in fish of control group than exposed fish (P < 0.05). The plasma glycerol concentration showed a significant decrease only in fish of 0.54 mg L-1 diazinon treatment (P < 0.05). In long term trial, the energetic metabolites (acetate, acetoacetate, glycerol) showed significant increases mostly in fish exposed to high concentrations of diazinon (P < 0.05). Phosphocreatine was detected only in groups exposed to 0.54 and 0.9 mg L-1 diazinon. Some amino acids decreased in control and diazinon-exposed groups while glycine (in control and 0.18 mg L-1 diazinon treatment), glutamine and alanine (in 0.9 mg L-1 diazinon treatment) elevated significantly after 24 h acclimation in BW (P < 0.05). Our results may help to understand the effects of pesticides on fish osmoregulation from a metabolic approach.

Evolutionary relations and population differentiation of Acipenser gueldenstaedtii Brandt, Acipenser persicus Borodin, and Acipenser baerii Brandt.

Russian ( Acipenser gueldenstaedtii), Persian ( A. persicus) and Siberian ( A. baerii) sturgeons are closely related 'Ponto-Caspian' species. Investigation of their population structure is an important problem, the solution of which determines measures for conservation of these species. According to previous studies, 'baerii-like' mitochondrial genotypes were found in the Caspian Sea among 35% of Russian sturgeon specimens, but were not found in Persian sturgeons. This confirms genetic isolation of the Persian sturgeon from the Russian sturgeon in the Caspian Sea. However, in order to clarify the relationships of these species it is necessary to analyze nuclear DNA markers. The amplified fragment length polymorphism (method) allows estimating interpopulation and interspecific genetic distances using nuclear DNA markers. In the present study, four samples were compared: Persian sturgeons from the South Caspian Sea, Russian sturgeons from the Caspian Sea and the Sea of Azov, and Siberian sturgeons from the Ob' River, which are close to the latter two species, but are also clearly morphologically and genetically distinct from them. For the amplified fragment length polymorphism (AFLP) method, eight pairs of selective primers were used. The analysis revealed that the Siberian sturgeon has formed a separate branch from the overall Persian-Russian sturgeons cluster, which was an expected result. In addition, the results showed that the Caspian Russian sturgeon is closer to the Persian sturgeon from the Caspian Sea than to the Russian Sturgeon from the Sea of Azov. The present DNA marker data confirm that despite the genetic isolation of the Persian sturgeon from the Russian sturgeon in the Caspian Sea, the Persian sturgeon is a young species.

Cryopreservation of Persian sturgeon (Acipenser persicus) embryos by DMSO-based vitrificant solutions.

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.

Effect of freezing rate for cryopreservation of Persian sturgeon (Acipenser persicus) spermatozoa.

This study examined the effect of freezing rate (-10 °C, -15 °C, -20 °C, -30 °C, and -40 °C/min) on motility parameters, rates of fertilization and hatching, ATP content, and indices of oxidative stress including thiobarbituric acid reactive substances and carbonyl derivatives of proteins in Persian sturgeon (Acipenser persicus) sperm. After sampling, sperm was diluted in an extender composed of 23.4-mM sucrose, 0.25-mM KCl, and 30-mM Tris-HCl, pH 8.0, containing 10% methanol and subsequently frozen in a programmable freezer. For postthaw sperm that were frozen at a rate of -40 °C/min, sperm motile duration (134 ± 27.01 seconds), sperm motile percent (60 ± 4.1%), fertilizability (72 ± 8.36% for fertilization rate and 65 ± 7.58% for hatching rate), and ATP content (4.8 ± 0.57 nmol/10(8) sperm) were significantly higher than for sperm frozen at any of the four slower rates (P < 0.05). Moreover, sperm cryopreserved using the fastest freezing rate had significantly lower levels of thiobarbituric acid reactive substances (0.5 ± 0.05 nmol/10(8) sperm) and carbonyl derivatives of proteins (41.3 ± 4.9 nmol/10(8) sperm) than sperm cryopreserved using all other freezing rates (P < 0.05). In addition, there is a significant difference (P < 0.05) between fresh sperm and the recovery of cryopreserved Persian sturgeon sperm using programmable freezing with -40 °C/min being the optimal freezing rate among those tested.

Histopathological and bacterial study of Persian sturgeon fry, Acipenser persicus (Borodin, 1897) exposed to copper sulfate and potassium permanganate.

Persian sturgeon frys were exposed to different concentrations of copper sulfate and potassium permanganate in order to the evaluation of their impacts on bacterial load of skin, gill and surrounding water and also the histopathological alternations of gill tissue. For this purpose, the sublethal doses were determined after a pre-test and then the experiment was done in 4 (for copper sulfate: 0.07, 0.14, 026 and 0.5 mg/l) and 5 (for potassium permanganate: 0.07, 0.14, 026, 0.5 and 1 mg/l) treatments with three replicates inside the glass aquaria. Also, one group without disinfecting drug was considered as control for each experiment. The microbial and histopathological investigations were done after 96 h exposure. According to our results, a range of histopathological alternations were observed in gills tissue including mucus coagulation and secretion, hyperplasia, lamellar necrosis, hyperplasia, lamellar adhesion, haemorrhage, thickening of secondary lamellae, hypertrophy of supporter cartilage, clubbing of gill lamellae and sliming of primary lamellae. The severity of these alternations increased with increasing of the doses of the copper sulfate and potassium permanganate. The bacterial load (CFU/g) of gill, skin and surrounding water was lower in 0.07 mg/l copper sulfate treatment and 1 mg/l potassium permanganate treatment (P < 0.05) than in other treatments. In conclusion, our results showed that the certain doses of the copper sulfate and potassium permanganate have disinfecting effects on bacterial load of gill, skin and surrounding water, although this is along with some histopathological alternations. Also, it seems that the copper sulfate has higher disinfecting power than potassium permanganate.

Histopathological study of gill, kidney and liver of Persian Sturgeon (Acipenser persicus Borodin, 1897) and Stellate (Acipenser stellatus Pallas, 1811) exposed to sublethal concentration of un-ionised ammonia UAN.

This study was carried out to investigate the histopathological changes of gill, kidney and liver of Persian Sturgeon and Stellate in response to various sublethal concentration of ammonia. The sublethal doses were determined after a lethal pre-test and then the experiment was done in six treatments with three replicates for both species. In Persian sturgeon, the treatments were including 5, 7, 9.7, 13.2, 18 and 25 mg/l ammonia. In stellate, the concentrations of 5, 6.23, 7.76, 9.66, 12.04 and 15 mg/l ammonia were considered as treatments. Also, one group without ammonia was considered as control for each experiment. The histopathological investigations were done after 96 h exposure. According to our observations, a range of histopathological alternations were found in gill, liver and kidney of both examined fish. The alternations of gill tissue were lamellar necrosis, hyperplasia, lamellar adhesion, haemorrhage, swelling of gill lamellae. Severity of these alternations was dose-dependent and was significantly higher in Persian sturgeon than in stellate. The degree of histopathological alternations of liver did not show a regular pattern between treatments in both species. These alternations were hyperemia, bile record, cell necrosis, cell atrophy, fatty degeneration and cloudy swelling. The signs of kidney alternations intensified with increasing of ammonia concentration in both species. The signs such as hyperemia, vision tissue degeneration, cell necrosis, dilatation of Bowman's space. In conclusion, our results showed that ammonia in concentration of more than 5 mg/l have more adverse impacts on gill, liver and kidney tissues.

Exposure of Persian sturgeon (Acipenser persicus) to cadmium results in biochemical, histological and transcriptional alterations.

Sturgeon is one of the endangered families of fish in the Caspian Sea region, where there is up to 80% of their global caching. Unfortunately, in recent years, increase of pollutants has been resulted in their total population reduction. Due to their benthic nature, sturgeons are at great risk of exposing to contaminants such as cadmium. Despite their endangered status in the Caspian Sea, there are only a few studies on characterizing the relative sensitivity of sturgeons to cadmium. Adverse effects associated with pollution on angiogenesis are mediated by hypoxia inducing factor-1 (HIF-1) and vascular endothelial growth factor (VEGF). In this investigation, gene expression of two distinct HIFs-1, HIF-1α and HIF-2α, and VEGF was investigated at the mRNA transcript levels after exposure of Persian sturgeon (Acipenser persicus) to cadmium. VEGF, HIF-1α and HIF-2α expressions in treated Persian sturgeon were greater than controls. Significant increases (P<0.05) were also observed in cortisol and glucose levels compared to the control group especially in the fish exposed to higher cadmium concentration (800 µg/L). Plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactic acid dehydrogenase (LDH) levels were increased in the cadmium-exposed fish, although the observed increases were not significant between the control and 200 µg/L cadmium treatment at some sampling time points. Gill tissues also showed histopathological changes in the cadmium treatments. Overall, results indicated that cadmium resulted in some alterations in biochemical parameters, mRNA transcript level expression of two important angiogenesis related genes as well as histological alterations in Persian sturgeon.

Interrelationships among egg, larvae and maternal characteristics in Persian sturgeon Acipenser persicus

This study was aimed to observe the correlations among egg, larvae and maternal characteristics of Persian sturgeon. A total of 41 females were used and the variables including fertilization rate, incubation survival rate, larvae survival rate during yolk sac absorption (before feeding), and larvae survival rate after first feeding were determined. As a result, fertilization rate was positively correlated with three variables: incubation survival, larvae survival during yolk sac absorption, and GSI (gonadosomatic index). Also, maternal size (age, weight, total length) did not show a significant relation (P > 0.05) with incubation survival, larvae survival during yolk sac absorption and larvae survival at first feeding stage.