Persian Sturgeon Acipenser Persicus Research Articles

Relationship between steroid hormones and maternal characteristics and larvae in Persian sturgeon Acipenser persicus

The reproductive biology of fish has been a field of wide interest. The aim of this study was to determine the correlations between sex steroid hormones and maternal characteristics and larvae in the Persian sturgeon Acipenser persicus. The blood samples were derived from 22 female specimens in reproductive stage IV (migration of nucleus) for measuring testosterone (T), 17β-estradiol (E2), and progesterone (P4). As a result, T demonstrated a significant correlation with E2 (r= 0.44) and P4 showed a significant relationship (P < 0.05) only with the larval survival rate after the feeding stage (r= 0.52), but other variables did not demonstrate any significant correlation with one another. There was not a significant relationship in female Persian sturgeon between steroid hormones and size.

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.

Serum Electrolyte and Nonelectrolyte Status in Freshwater Juvenile Persian Sturgeon Acipenser persicus

Status of serum electrolyte and nonelectrolyte variables can be used for managing sturgeon species cultured in freshwater or living in seawater. The aim of the present study was to evaluate serum biochemical variables in clinically healthy juvenile Persian sturgeon Acipenser persicus cultured in freshwater. Serum samples from 11 females and 10 males were analyzed, and levels (mean +/- SD) of the following variables were compared between sexes: glucose (Glc; 5.58 +/- 1.25 mmol/L for females and 8.56 +/- 1.80 mmol/L for males), total cholesterol (TC; 2.50 +/- 0.45 and 2.40 +/- 0.65 mmol/L), triglyceride (TG; 7.13 +/- 2.68 and 5.14 +/- 1.27 mmol/L), blood urea nitrogen (BUN; 1.28 +/- 0.2 and 1.01 +/- 0.2 mmol/L), total protein (TOP; 55.84 +/- 8.77 and 41.44 +/- 8.62 g/L), inorganic phosphate (P(i); 6.19 +/- 1.02 and 5.23 +/- 0.49 mmol/L), calcium (Ca; 2.80 +/- 0.43 and 2.63 +/- 0.32 mmol/L), magnesium (Mg; 0.9 +/- 0.23 and 0.99 +/- 0.22 mmol/L), sodium (Na; 152.80 +/- 13.81 and 156.38 +/- 12.67 mmol/L), potassium (K; 2.64 +/- 0.58 and 2.27 +/- 0.39 mmol/L), and chloride (Cl; 143 +/- 13.85 and 151.67 +/- 21.08 mmol/L). There were no differences in TC, Ca, Mg, Na, K, or Cl between sexes. The Glc value was lower in female Persian sturgeon than in males, whereas the values of TG, BUN, TOP, and P(i) were higher in females than in males. Freshwater adaptation may affect serum ion concentrations in juvenile Persian sturgeon.

Immune responses and behavior alterations of Persian sturgeon fingerlings Acipenser persicus exposed to sublethal concentrations of diazinon

Diazinon is an organophosphate pesticide widely used in agricultural areas (especially paddy fields) in Iran. Similar to other pesticides, diazinon may enter aquatic systems due to run-off and affect various organisms living in rivers and estuaries. Persian sturgeon Acipenser persicus is one of the most economically important species in the Caspian Sea, which enters Iranian rivers, such as the Sefidroud River, for breeding. Fish eggs hatch in the river and fingerlings migrate to the sea after a period of time. The International Sturgeon Research Institute in Rasht, Iran, produces and releases millions of fingerling sturgeons into the coastal area of the Caspian Sea annually and the fingerlings may thus be affected by this pesticide. This study was carried out to determine sublethal effects of diazinon on some hematological indices of Persian sturgeon under lab conditions. Fish were exposed to concentrations of 0, 0.01, 1.095 (0.25 LC50), 2.19 (0.5 LC50) or 3.285 ppm (0.75 LC50) diazinon and responses were studied after 12, 24 and 96 h. After 12 h exposure, the fingerlings exposed to 2.19 and 3.285 ppm revealed a series of abnormal responses such as muscle paralysis, change in gills and abdominal color, erratic swimming, rapid operculum movement, and loss of body balance. The exposed sturgeons also exhibited a significantly lower number of erythrocyte (RBC) and leukocyte count (WBC) after 24 and 96 h exposure. Similarly, after 96 h, there was a significant decrease in hematocrit (Htc). Results also revealed a decrease in lymphocyte numbers and an increase of meta neutrophils, band neutrophils and total neutrophils after 24 and 96 h diazinon. Data suggest that diazinon affects physiological and hematological functions of A. persicus, which may finally affect survival of the fish. Diazinon concentration of 0.01 ppm has been recorded in water of the Sefidroud River, where about five million Persian sturgeon fries are released annually by the Iranian department of fishery hatcheries. Since this level of pesticide was found to be toxic for fish fries, it is critical to avoid any toxic impact by regular monitoring of diazinon levels in the river water.

10.1007/s11489-008-1011-6

Taste preferences towards 20 free amino acids (L-isomers, 0.1–0.0001 M) were determined in juveniles of Persian sturgeon Acipenser persicus. It was found that most amino acids (16) had a positive effect on extraoral gustatory reception (increased the frequency of catching artificial pellets by fishes). The most efficient amino acids were the following: threonine, histidine, arginine, asparagine, phenylalanine, cysteine, glutamine, and glycine. Fifteen amino acids were efficient for intraoral gustatory receptors: serine, arginine, cysteine, histidine, alanine, and some others. The presence of these amino acids in pellets increased the consumption. Amino acids decreasing the frequency of catching or consumption of pellets were not found. Highly significant positive correlation was found between the amino acid ranges mediated by the extraoral and intraoral gustatory reception. The fishes demonstrated maximum sensitivity to aspartic acid, 0.01 and 0.001 M, respectively, for intraoral and extraoral gustatory systems. The threshold concentrations of arginine and glycine were higher for the intraoral gustatory system (0.01 M) than for the extraoral one (0.1 M). The comparison of Persian sturgeon with sturgeon fishes (Russian sturgeon A. gueldenstaedtii, Siberian sturgeon A, baerii, and starred sturgeon A. stellatus) studied earlier confirmed high species specificity of intraoral taste preferences in representatives of Acipenser genus. Species specificity of extraoral taste ranges was less pronounced.

Application of synthetic hormone LHRH-A2 on the artificial propagation of Persian sturgeon Acipenser persicus

For studying the effect of LHRH-A2 hormone on the induction of final maturation and ovulation of Persian sturgeon, 71 matured females and 20 matured males were used. Five groups of breeders were injected with sturgeon pituitary gland hormone (50 mg per fish) and LHRH-A2 in dosages of 3.5, 7, 8 and 10 μg kg−1 for females and 3 and 5 μg kg−1 for males. Results showed that LHRH-A2 successfully induced final maturation and ovulation in females, and there was no significant difference between five groups of breeders in ovulation proportion, fertilization rate, survival rate of incubation, survival of yolk-sac absorption period and active feeding period of larvae. It can be concluded that the LHRH-A2 is a proper alternative for pituitary gland hormone in artificial propagation of Persian sturgeon.

Diet composition of the Persian sturgeon Acipenser persicus at the coast of the Guilan Province, Caspian Sea

Sturgeons are one of the most important and valuable species in the Caspian Sea. This investigation (2000–2002) was aimed at determining the feeding habits and the main and secondary prey organisms consumed by the Persian sturgeon (Acipenser persicus Borodin, 1897) living at depths less than 10 m in the Caspian Sea (Guilan Province). The food spectrum of immature A. persicus was comprised of benthic invertebrates of seven genera and fishes of three genera. The main prey items of immature A. persicus were polychaete worms and the secondary prey were crustaceans. The study of stomach contents showed that polychaetes were the most important component of the diet of immature A. persicus of the length class up to 25 cm.

Isolation and characterization of Lactobacillus species from intestinal contents of beluga (Huso huso) and Persian sturgeon (Acipenser persicus)

Summary Lactic acid bacteria are characterized as gram-positive, usually non-motile, non-sporulating bacteria that produce lactic acid as a major or sole product of their fermentative metabolism. In this study, the presence of lactobacilli were investigated in the intestines of beluga (Huso huso) and Persian sturgeon (Acipenser persicus), inhabiting Caspian sea. The obtained data showed that various species of lactobacilli populations were found at high levels in the intestines of fishes. Total number of lactobacilli was about 10 5.3 and 10 6.4 cfu/g of intestinal content for beluga and Persian sturgeon, respectively. Physiological and biochemical characteristics of 84 strains isolated from intestines of beluga and Persian sturgeon revealed that these strains can be categorized into 2 metabolic groups; facultative and obligate heterofermentatives. The most common presumptive lactobacilli species were Lactobacillus sakei and Lactobacillus plantarum. The current study is the first report on the isolation of lactobacilli from the intestine of beluga and Persian sturgeon.

Relationship between biological characteristics of eggs and female brood stocks of Persian sturgeon Acipenser persicus: a comparison with other fish species

We have determined a number of biological characteristics of the Persian sturgeon egg (including diameter, surface-to-volume ratio, yolk sphere and perivitelline space) and of female brood stocks (including age, length, weight, condition and absolute fecundity) in 420 specimens of the migratory population of Acipenser persicus in Gorgan bay of Iran from 2001 to 2004. In the hydrated egg, the average egg diameter, yolk diameter, surface-to-volume ratio and yolk sphere-to-perivitelline space ratio values were: 3.64 +/- 0.17 mm, 3.26 +/- 0.25 mm, 1.65 +/- 0.08 and 0.75 +/- 0.01, respectively. In this chondrostean species, the egg surface and volume were found to increase with increasing egg diameter, but the egg surface-to-volume ratio decreased. In Persian sturgeon, the surface-to-volume ratio and yolk sphere-to-perivitelline space ratio is very high; therefore, the metabolic rate is low and female spawning occurs in low-temperature waters. The statistical Pearson correlation between egg diameter relative to a number of brood stock characteristics, including fork length (r = 0.059), weight (r = 0.140), age (r = 0.081) and absolute fecundity (r = 0.095), were not significantly different (P > 0.05). An extensive comparison of these results with data published on other fish species is presented and discussed.

The effect of maternal size on larval characteristics of Persian sturgeonAcipenser persicus

The objective of this work was to study the relationship between female size (weight) and variables of egg and larval stage of Persian sturgeon Acipenser persicus. In this study, 19 female breeders were captured in Caspian Sea and fertilized by routine methods. Positive significant correlations (P<0.05) were established between female weight and ovulated eggs per female, time of second mitosis division and volume of yolk-sac at hatching. There was not significant correlation (r=0.33, P=0.161) between female weight and egg diameter. Female weight was not affected weight of larvae at hatching time (r=0.37, P=0.119), as well as larval length (r=−0.14, P=0.558) and larval weight at the end of the experiment (48 hours after first feeding) (r=0.16, P=0.491). Mortality rate during yolk-sac absorption was higher with increased female weight but their correlation was not significant (r=0.40, P=0.076). During the first feeding stage, mortality rate was 13.39% and there was no significant correlation between mortality rate in this period and female weight (r=−0.12, P=0.613). Conclusively, as a result female size influenced fecundity, time of second mitosis division and yolk-sac volume at hatching time without affecting mortality rate during yolk-sac absorption and first feeding stage in Persian sturgeon. Thus, smaller female broods do not cause more mortality than larger ones in larval production and they can be used in reproduction procedure.

Correlations between egg size and dependent variables related to larval stage in Persian sturgeon Acipenser persicus

This study examined the correlation between egg size and a number of variables in the subsequent larval stages of the Persian sturgeon Acipenser persicus. Nineteen female sturgeons were fertilized and the eggs were harvested. The results showed that there were positive, significant correlations (p < 0.05) between egg size and several dependent variables including larval weight and duration of hatching time as well as the volume of the yolk sac and the hatching time. The weight of larvae at 2, 4, 6 and 8 days post hatching showed positive and significant correlation (p < 0.05) with egg size. Total length of larvae at 2, 4, 6, 8 and 10 days post hatching had significant correlation (p < 0.05) with egg size in all cases. During yolk sac absorption at 2, 4, 6, 8 and 10 days after hatching correlations gradually decreased. There was no significant correlation between egg size and mortality during the yolk sac absorption period (r = −0.24, p = 0.314) or the first feeding stage (r = −0.05, p = 0.840).

Minimally invasive surgical technique for egg collection from the Persian sturgeon, Acipenser persicus

A minimally invasive surgical technique (MIST) for the removal of ovulated eggs from Persian sturgeon Acipenser persicus was tested on broodstocks caught from the wild to determine whether it affected fecundity or hatching rates compared with the traditional stripping method of killing and removing the eggs (commonly used in hatchery). Morphological parameters of females, germinal vesicle (GV) position, weight of obtained egg, number of eggs/gram, fertilization rate, and percentage of hatching during incubation were not significantly different between the MIST and traditional stripping methods. Obtained ova were 4.8 ± 0.4 kg female−1 in the MIST and 4.6 ± 0.5 kg female−1 in traditional stripped groups, respectively; the fertilization rate was 83.4 ± 11.2% and 80.0 ± 7.2% in groups, respectively. The results of this study showed that the minimally invasive surgical technique approach is efficient, practical, and less stressful to Persian sturgeon broodstocks during artificial propagation than other reported egg collection procedures.

Helminth parasites of stellate sturgeon Acipenser stellatus Pallas, 1771 and Persian sturgeon Acipenser persicus Borodin, 1897 (Pisces: Acipenseridae) from the South–East Caspian Sea

A total of 182 specimens of two sturgeon species, stellate sturgeon Acipenser stellatus (N=112) and Persian sturgeon Acipenser persicus (N=70), from three coastal stations in the South-East Caspian Sea were examined for endohelminth parasites. Four helminth species were recorded: Cucullanus sphaerocephala (Nematoda: Cucullanidae) and Skrjabinopsolus semiarmatus (Digenea: Acanthocolpidae), found in both host species, and Leptorhynchoides plagicephalus (Acanthocephala: Rhadinorhynchidae) and Amphilina foliacea (Cestodaria: Amphilinidae), found only in A. stellatus. The most abundant parasites were C. sphaerocephala and S. semiarmatus in A. persicus and A. stellatus, respectively. Canonical discriminant analysis was applied for separating host species using parasite numbers data, Brillouin index of diversity, and species richness. By this means, 83% of the hosts were assigned to their correct a priori groups. The different feeding habits and habitat preferences of the two hosts are probably the major factors accounting for the difference in their parasite burdens.

Taste attractiveness of free amino acids for juveniles of Persian sturgeon Acipenser persicus

Taste preferences towards 20 free amino acids (L-isomers, 0.1–0.0001 M) were determined in juveniles of Persian sturgeon Acipenser persicus. It was found that most amino acids (16) had a positive effect on extraoral gustatory reception (increased the frequency of catching artificial pellets by fishes). The most efficient amino acids were the following: threonine, histidine, arginine, asparagine, phenylalanine, cysteine, glutamine, and glycine. Fifteen amino acids were efficient for intraoral gustatory receptors: serine, arginine, cysteine, histidine, alanine, and some others. The presence of these amino acids in pellets increased the consumption. Amino acids decreasing the frequency of catching or consumption of pellets were not found. Highly significant positive correlation was found between the amino acid ranges mediated by the extraoral and intraoral gustatory reception. The fishes demonstrated maximum sensitivity to aspartic acid, 0.01 and 0.001 M, respectively, for intraoral and extraoral gustatory systems. The threshold concentrations of arginine and glycine were higher for the intraoral gustatory system (0.01 M) than for the extraoral one (0.1 M). The comparison of Persian sturgeon with sturgeon fishes (Russian sturgeon A. gueldenstaedtii, Siberian sturgeon A, baerii, and starred sturgeon A. stellatus) studied earlier confirmed high species specificity of intraoral taste preferences in representatives of Acipenser genus. Species specificity of extraoral taste ranges was less pronounced.

Sperm motility and fertilizing ability in the Persian sturgeon Acipenser persicus

The motility and fertilizing ability of the Persian sturgeon, Acipenser persicus, spermatozoa were investigated. Optimum ionic content (Na+, K+, Ca2+ and Mg2+) and pH of activation solution as well as the optimum dilution rate were determined. The results show optimum motility characteristics of spermatozoa in buffered solutions containing 25, 0.2, 3 and 10 mM L−1 Na+, K+, Ca2+ and Mg2+, respectively, at dilution rate 1:50 and pH 8.0. To test the fertilizing ability of sperm, two buffered saline solutions were used as activation solution of sperm motility. The present study indicated (1) spermatozoa motility is one of key factors that influence on fertilizing ability of sperm, (2) a high fertilizing ability of sperm is obtained after dilution in saline solutions rather than in freshwater and (3) a maximum fertilization rate occurs in buffered saline solution containing 0.2 mM L−1 K+. There is also a good correlation between biochemical characteristics of seminal plasma and fertilizing ability of sperm.

A comparative study of some hematological features in young reared sturgeons (Acipenser persicus and Huso huso)

The physiological condition in fishes required for their selection as broodfish can be determined by hematological studies. The present study aims at examining the hematological indices in juvenile sturgeons at different stages of growth. The main blood features, such as total albumin content in blood, hemoglobin concentration and the erythrocyte and leukocyte count, were measured in a total of 54 specimens of 1-, 2- and 6-year old sturgeon (Persian sturgeon Acipenser persicus and beluga Huso huso), artificially produced at the Shahid Dr. Beheshti Fish Breeding and Rearing Center located in the Gilan Province.

Comparative study of biochemical and hematological features in reared sturgeons

Suitable physiological condition in fishes for the selection of broodfishes can be achieved through hematological studies. The present study aimed to examin the hematological indices in Juvenile Sturgeons at different stages of growth. Total albumin content in blood serum, hemoglobin concentration, the erythrocyte and leukocyte count of 54 sturgeon specimens (Persian sturgeon Acipenser persicus and Great sturgeon Huso huso) were determined at the age of 1, 2 and 6 years reared fish. In the Persian sturgeon specimens studied, total albumin concentration increased from 26.1 to 52.5 gL-1, hemoglobin from 42.2 to 65.8 gL-1, erythrocyte count from 240 to 452.5 thousand cells/ μL-1, and leukocyte count from 17.4 to 46.7 thousand cells/ μL-1. The total leukocyte was composed of 73.2-82.7% lymphocytes, 12.3 to 20% neutrophils, 2.2 to 6.5% eosinophils and 0.2 to 2.5% monocytes with the increase of age. In the great sturgeon specimens studied, total albumin concentrations in blood increased from 20 to 42.4 g L-1, hemoglobin from 46.3 to 78.6 g L-1, and erythrocyte count from 495 to 735 thousand cells μL-1. The total leukocyte was composed of 54.5 to 67.5% lymphocytes, 6.1 to 26.9 % neutrophils, 6.6 to 13.25% eosinophils and 0.6 to 2.5% monocytes with the increase of age. This research revealed the evolutionary trends of hematological features in the natural growth and development of sturgeons in the South Caspian Sea, reared in artificial conditions and shows that with the increase in age, the hematological indices also increased.

An investigation on the micropyle number in the ova of the strugeon species in Caspian Sea

The micropyle number in the ova of sturgeon species from the South Caspian Sea was investigated. The study was conducted on female broodfishes of three species of sturgeon (Persian sturgeon Acipenser persicus, Stetates sturgeon A. stellatus and great sturgeon Huso huso) included 44 Persian sturgeon, 13 stellate sturgeon and 8 great sturgeon specimens. Fifty eggs were randomly collected from each broodfish and the micropyle number of totally 3250 eggs was determined. Out of 44 Persian sturgeon used, 14 specimens were collected from the south-east Caspian region (Golestan Province, Shaid Marjani Center) and 30 were from the south-west Caspian region (Guilan Province, Shahid Dr. Beheshti Center). The stellate sturgeon specimens were taken from the south-west and the great sturgeon specimens from the south-east Caspian region. The obtained result showed that the mean micropyle number in Persian sturgeon caught from the south-east Caspian region was 8 whereas in those caught from the south-west region was 9. There was no significant difference (p>0.95) in the micropyle number of Persian sturgeon collected from the south-east and south-west regions. The mean micropyle number determined for stellate and great sturgeon was 5. The outer diameter of the micropyle in the Persian, stellate, and great sturgeon were 22 μm, 17 μm and 19 μm respectively.