Repellent activities of some Labiatae plant essential oils against the saltmarsh mosquito Ochlerotatus caspius (Pallas, 1771) (Diptera: Culicidae)

The repellent activities of the essential oils of two Thymus (Thymus sipyleus Boiss. subsp. sipyleus and Thymus revolutus Celak) and two Mentha (Mentha spicata L. subsp. spicata and Mentha longifolia L.) species against Ochlerotatus caspius (Pallas, 1771) (Diptera: Culicidae) are presented. The essential oils were obtained by hydrodistillation of the aerial parts of the plants in flowering period and repellency tests were done with a Y-tube olfactometer. All essential oils showed repellency in varying degrees and exhibited no significant time-dependent repellent activities. When all test oils compared for repellent activities there was no significant activity detected within 15 min exposure period. Mentha essential oils had better activity than Thymus essential oils, producing high repellency (73.8-84.2%) at 30th min on Oc. caspius. Mentha longifolia has the best mosquito repellent activity among the plants tested at the 25th min. Th. sipyleus subsp. sipyleus essential oil produced >85% repellent activity at the 15th min, but the effect decreased noticeably to 63.1% and 68% at 25th and 30th min, respectively.     

Effects of ghrelin on some plasma hormonal changes in juvenile Persian sturgeon (Acipenser persicus)

The functions of ghrelin, a novel weight-regulatory peptide, have not been intensively investigated in primitive fish. This experiment was conducted to determine whether ghrelin has a specific effect on growth hormone (GH), prolactin and cortisol levels in Persian sturgeon (Acipenser persicus). Juvenile Persian sturgeons with a mean body weight of 320?±?30?g were given a single injection of ghrelin at three doses of 0.1, 1 and 10?ng/g body weight. Control animals were injected with vehicle (sterile saline) only. Blood samples were collected at 0, 2, 4, 8, 24, 48 and 72?h after injection. The level of plasma hormones were determined by ELISA kit. As expected, ghrelin injection significantly elevated plasma GH (P?<?0.05), whereas prolactin levels did not significantly change after injection (P?>?0.05). Plasma cortisol levels decreased in fish injected with high doses of ghrelin (P?<?0.05). Ghrelin at 10?ng/g body weight had the most influence on GH release, and 1?ng/g ghrelin injection caused the lowest level of cortisol. These results show for the first time that ghrelin induces some plasma hormonal changes in sturgeon fish, as lower vertebrates, but more investigations are needed in this area.     

Selected biochemical parameters in plasma of blood and semen of Persian sturgeon,Acipenser persicus

The investigation of blood and seminal plasma biochemical parameters is essential for fish stock conservation and development of artificial propagation methods via extender improvement. In this research, comparison of blood and seminal plasma compounds and their relationship in Persian sturgeon, Acipenser persicus, were studied. Seminal plasma contained 59.53?±?2.56 mEq/l sodium (Na⁺), 4.72?±?0.31 mEq/l potassium (K⁺), 1.45?±?0.075 mEq/l chloride (Cl^?), 9.1?±?1.42 mEq/l calcium (Ca²⁺), 0.7?±?0.072 mEq/l magnesium (Mg²⁺), 0.11?±?0.021 g/dl total protein, 6.67?±?1.04 mg/dl cholesterol, 15.2?±?0.65 mg/dl triacylglycerol, and 18.22?±?4.16 mg/dl glucose. Also, blood biochemical values were determined (mean?±?SEM) for Na⁺ (123.2?±?1.31 mEq/l), K⁺ (2.77?±?0.088 mEq/l), Cl^? (97.18?±?1.23 mEq/l), Ca²⁺ (6.67?±?0.24 mEq/l), Mg²⁺ (1.29?±?0.074 mEq/l), glucose (198.49?±?18.03 mg/dl), triacylglycerol (214.22?±?13.38 mg/dl), total protein (3.62?±?0.23 g/dl), and cholesterol (127.11?±?6.94 mg/dl). The mean blood and seminal osmolality values were 244.62?±?3.66 and 86.9?±?4.22 mOsm/kg, respectively. Results of the comparison between biochemical parameters of seminal and blood plasma indicated that the concentrations of all parameters of blood plasma were significantly (P?++ and Na⁺ of the seminal plasma (P?P?相似文献   

Cadmium accumulation and biochemical parameters in juvenile Persian sturgeon, Acipenser persicus, upon sublethal cadmium exposure

The purpose of the present study was to evaluate the effects of exposure to waterborne sublethal cadmium (Cd) concentration on juvenile Persian sturgeon, Acipenser persicus. Fish were exposed to 0.68 mg/l of Cd for 1, 7, and 14 days, and metal bioaccumulations, biochemical responses, and gill ions were investigated. There were significant differences (p?<?0.05) in the kidney (1, 7, and 14) and gills (7 and 14) for Cd concentrations between the control and treatment groups. Also, kidney Cd concentrations were significantly higher (p?<?0.05) at metal treatments on day 14 in comparison to day 1. Results showed that there were significant differences (p?<?0.05) in plasma glucose and cortisol concentrations between the experimental and control groups on day 1 only, and at metal treatments, a significant decrease (p?<?0.05) was observed on days 7 and 14 compared to day 1. No significant alterations were observed in plasma and liver protein contents during the course of the study. Neither triiodothyronine or thyroxine levels nor liver catalase or glutathione-S-transferase activities changed significantly with sublethal dose and with the time. In contrast, liver superoxide dismutase activities were significantly decreased (p?<?0.05) at Cd treatments both over the control group and during Cd exposure on days 7 and 14. Finally, a comparison between the groups revealed no differences in gill ion levels for 2 weeks. This study demonstrated that sublethal dose of Cd was stressful for Persian sturgeon and resulted in rapid changes in some of the biochemical parameters.     

Comparative analysis of steroid levels in blood serum of female Persian sturgeon,Acipenser persicus,induced by hormonal treatment

The aim of this study was to measure sex steroid levels before and after induction of ovulation using luteinizing hormone-releasing hormone analog (LH-RH-A)₂ in female Persian sturgeons. A total of ten females were induced by LH-RH-A₂ hormone. Seven females were ovulated successfully, and rest of breeders did not respond to hormonal treatment (non-ovulated fish). The serum cortisol (C), testosterone (T), oestradiol-17b (E₂), progesterone (P4), testosterone (T), FSH, and LH concentrations were measured by radioimmunoassay. In ovulated and non-ovulated females, C and P4 levels tended to increase after LH-RH-A₂ injection. Serum E₂ levels in ovulated and non-ovulated females decreased dramatically after LH-RH-A₂ injection. Following hormonal treatment, T levels increased slightly in ovulated and non-ovulated females, but values were not statistically different. An increase was observed in FSH levels of ovulated fish, but this trend was not observed in non-ovulated females. The data clearly illustrated that induction of ovulation in female Persian sturgeons using LH-RH-A₂ led to change in steroid hormones. Also, the rise in C levels may indicate an interaction between corticosteroids and gamete maturation in Persian sturgeon.     

Effect of sperm pH and density on fertilization success in Persian sturgeon Acipenser persicus (Borodin, 1897)

The objectives of the present study were to determine the relationships between sperm characteristics (density and pH) and fertilization capacity (hatching rate) for Persian sturgeon during their reproductive season. Eleven males were used in this study. The luteinizing hormone releasing hormone analog was used to induce spermiation following which semen samples were stripped. Statistical analysis revealed positive correlations between hatching rate and sperm pH (P?<?0.05, r?=?0.711) and between sperm pH and fertilization rate (P?<?0.05, r?=?0.633). Highly negative relationships were found between sperm density and hatching rate (P?>?0.01, r?=??0.745). We suggest that understanding these correlations is critical in the evaluation of sperm quality and for the composition of media (extender) to be used in the dilution of semen to improve sperm motility/fertility parameters of Persian sturgeon.     

Relationships between sex steroids of the seminal fluid and milt quality parameters of Persian sturgeon, Acipenser persicus Borodin, 1897

To investigate the role of sex steroids of the seminal fluid on sperm quality, the relationships between sex steroids and milt quality parameters (sperm motility and sperm production) were investigated in the Persian sturgeon. The seminal fluid levels of 17α,20β,21-trihydroxy-4-pregnen-3-one (20βs), and 11-ketotestosterone (11-KT) had positive relationships with sperm motility characteristics (percentage and duration of motility) and sperm density. Also, no relationships were found between other sex steroids including: Testosterone (T), progesterone (P), 17α-hydroxyprogesterone (OHP), and milt quality parameters. The good correlation of 20βs and 11-KT of the seminal fluid with sperm motility and sperm density suggests that these steroids may be important hormones involving in final maturation of the Persian sturgeon spermatozoa.     

Determination of normal blood biochemistry (electrolytes and non-electrolytes) values in mature Huso huso in spring

Knowledge of fish haematology can provide information supportive of a wide variety of uses. These studies have generally been used as an effective and sensitive index to monitor physiological and pathological changes in fish, especially in the management of endangered species such as Huso huso. In this study, 12 biochemical parameters in mature H. huso were measured. Serum samples of 40 H. huso (20 males and 20 females) were analysed, and their serum parameter values were determined as median (percentiles) in males and females, respectively: Na, 162.70 (160–164.75) and 141.10 (156–144.9 mmol/l); K, 3.2 (2.75–3.35) and 3.1 (2.75–3.85 mmol/l); Ca, 9.6 (7.8–11) and 9.7 (8.6–10.9 mg/dl); P, 14.7 (12.65–15.65) and 12.1 (11.25–13.95 mg/dl); glucose, 176 (124.5–234.5) and 173 (147.5–212 mg/dl); triglyceride, 770 (607.5–872) and 750 (664.5–842 mg/dl); bilirubin, 0.67 (0.575–0.825) and 0.61 (0.525–0.745 mg/dl); TOP, 3.2 (2.85–3.45) and 3.6 (3–3.8 g/dl); albumin, 1.4 (1.3–1.6) and 1.6 (1.2–1.85 g/dl); cholesterol, 286 (202–289.5) and 239 (202–308 mg/dl); creatinine, 0.13 (0.11–0.14) and 0.11 (0.9–0.15 mg/dl) and BUN, 15.2 (12.3–17.6) and 17.7 (15.7–19.55 mg/dl). The concentration of P was significantly higher (P < 0.05) in males than in females and levels of BUN and TOP in females was significantly higher (P < 0.05) than in male fish.     

Variability of the immunoglobulin light chain in the Siberian sturgeon, Acipenser baeri

All sturgeon VL segments isolated in this study belong to a single family, VLI, which can be divided into two subfamilies. Of the 79 cDNA clones isolated, 76 belong to the larger subfamily, VLIa, and only 3 clones constitute the smaller subfamily, VLIb. To evaluate variability, the Shannon entropy was estimated for each individual amino acid position, and to facilitate comparisons of variability between species the mean entropy of the CDR regions was calculated. In such a comparison, the sturgeon was found to have CDR1 and CDR3 variability approaching those found in mouse and clawed frog, but showed very low variability for CDR2. Amino acid position 50 does however display variability in the range of mouse and clawed frog. It is further confirmed that the sturgeon has numerous J segments, but that the junctional diversity does not contribute greatly to the diversity of the light chain. Comparisons of cDNA clones and a genomic VL segment indicate that the VL undergoes changes, particularly in the CDR regions, in a manner that can be explained by somatic hypermutation and/or gene conversion.     

Effects of different dietary prebiotic inulin levels on blood serum enzymes, hematologic, and biochemical parameters of great sturgeon (Huso huso) juveniles

An 8-week growth trial was carried out in freshwater fiberglass tanks to investigate the effects of different dietary prebiotic inulin levels on hematologic and biochemical parameters and some blood serum enzymes in juvenile great sturgeon (Huso huso). Four experimental diets were formulated to contain different prebiotic inulin levels (0.0%, 1.0%, 2.0%, and 3.0%, respectively). Triplicate groups of fish (50 fish per tank with an average body weight of 16.14 ± 0.38 g) were assigned to each diet. Blood samples were taken from the caudal vein of 60 apparently healthy fish at the end of the trial. No significant differences were observed in serum enzymes between the treatment groups (P > 0.05). The results show that with the increase in supplementation level of inulin, the mean values of alkaline phosphatase decreased but the mean value of other enzymes increased. white blood cell count increased significantly in group treated with 1% inulin compared with the other groups (P < 0.05). No significant difference between the treatment groups was observed in some hematologic and biochemical parameters such as red blood cell count, mean corpuscular hemoglobin (MCH), and glucose (P > 0.05). With the increase supplementation level of inulin, the mean values of cholesterol, MCH, and MCH concentration increased, but the mean value of glucose, white blood cell count, red blood cell count, hematocrit, hemoglobin, and mean corpuscular volume decreased.     

Hematological, serum biochemical parameters, and physiological responses to acute stress of Beluga sturgeon (Huso huso, Linnaeus 1785) juveniles fed dietary nucleotide

The present study aimed to investigate the effects of dietary nucleotide on serum biochemical and hematological parameters as well as stress response in Beluga sturgeon Huso huso juveniles. Fish (12.6?±?0.5?g) were fed diets containing 0%, 0.15%, 0.25%, 0.35%, and 0.50% nucleotide over a 62-day period. The experiment was carried out in 600-L tanks with 30 fish per tank. Fish were fed five times a day until apparent satiation. At the end of the experiment, blood samples were collected from treatments for investigation of biochemical and hematological parameters. Then, fish were subjected to an acute stress. Blood samples were collected at 0 and 6?h post stress, and plasma cortisol and glucose levels were determined. The results showed that total protein, cholesterol, triglycerides, albumin, and globulin were not affected by dietary nucleotide (P?>?0.05). Hematocrit and hemoglobin values were significantly higher in the 0.35% treatment compared to those of the control (P?<?0.05). Beluga juveniles fed 0.5% dietary nucleotide had a significantly lower hemoglobin value (P?<?0.05). Lymphocyte proportion was significantly higher in the 0.25 and 0.35 nucleotide groups than in the control group (P?<?0.05). Cortisol and glucose levels in all groups were significantly affected by time; nevertheless, in fish fed nucleotides, stress-induced cortisol elevation was lower compared to that of the control group (P?<?0.05). The results indicated that dietary nucleotide supplementation was capable of affecting hematological parameters and physiological stress responses of Beluga juveniles.     

Coding of sound direction in the auditory periphery of the lake sturgeon, Acipenser fulvescens

The lake sturgeon, Acipenser fulvescens, belongs to one of the few extant nonteleost ray-finned fishes and diverged from the main vertebrate lineage about 250 million years ago. The aim of this study was to use this species to explore the peripheral neural coding strategies for sound direction and compare these results to modern bony fishes (teleosts). Extracellular recordings were made from afferent neurons innervating the saccule and lagena of the inner ear while the fish was stimulated using a shaker system. Afferents were highly directional and strongly phase locked to the stimulus. Directional response profiles resembled cosine functions, and directional preferences occurred at a wide range of stimulus intensities (spanning at least 60 dB re 1 nm displacement). Seventy-six percent of afferents were directionally selective for stimuli in the vertical plane near 90° (up down) and did not respond to horizontal stimulation. Sixty-two percent of afferents responsive to horizontal stimulation had their best axis in azimuths near 0° (front back). These findings suggest that in the lake sturgeon, in contrast to teleosts, the saccule and lagena may convey more limited information about the direction of a sound source, raising the possibility that this species uses a different mechanism for localizing sound. For azimuth, a mechanism could involve the utricle or perhaps the computation of arrival time differences. For elevation, behavioral strategies such as directing the head to maximize input to the area of best sensitivity may be used. Alternatively, the lake sturgeon may have a more limited ability for sound source localization compared with teleosts.     

Effect of photoperiod on blood parameters of young beluga sturgeon (Huso huso Linnaeus, 1758)

This study investigated the effect of manipulated photoperiod on haematological parameter in beluga sturgeon (Huso huso). One hundred eight fish (24-month old) were randomly allocated into 18 tanks. Each tank received one of six photoperiod regimes for 73 days: natural photoperiod, 24Light (L):0Dark (D), 16L:8D, 12L:12D, 8L:16D and 0L:24D. Different photoperiods had no significant effects on hormonal and cytological features of blood in young beluga sturgeon.     

Study of some haematological parameters in Barbus grypus, 1843 (Osteichthyes: Cyprinidae)

Values of some haematological indices were assessed in 30 Barbus grypus (mean length, 22.88?±?4.16?cm; mean weight, 101.01?±?58.50?g). The fishes were randomly selected from ponds of Dashte Azadegan Aquaculture Centre. The blood samples were collected from the caudal vein after adaptation to laboratory conditions. The values of the haematological parameter were measured using standardized and approved methods. The following values (mean±SD) were recorded. Packed cell volume (PCV), 46?±?5.71%; haemoglobin (Hb), 9.5?±?4.58?g/dL; white blood cell, 3,196.6?±?716.54 in each mm³; red blood cell, 1,378,667?±?195,408.2 in mm³, mean corpuscular haemoglobin concentration, 34.68?±?20.23%; mean corpuscular haemoglobin 12.53?±?70.02 (pg); mean corpuscular volume, 7.58?±?34.1 (fl); neutrophils, 25.40?±?6.04%; lymphocytes, 72.2?±?4.58%; monocytes 1.13?±?0.97% and eosinophil 0.6?±?0.67%. A significant (p?<?0.05) interaction was found between total length, weight and PCV as PCV value increases with increasing weight and length. Data obtained from this study will serve as baseline haematological parameters for use in monitoring of health and productivity of B. grypus regarding the increasing interest in this fish for aquaculture purposes.     

The structure of the conus arteriosus of the sturgeon (Acipenser naccarii) heart: II. The myocardium,the subepicardium,and the conus-aorta transition

Sturgeons constitute a family of living "fossil" fish whose heart is related to that of other ancient fish and the elasmobranches. We have undertaken a systematic study of the structure of the sturgeon heart aimed at unraveling the relationship between the heart structure and the adaptive evolutionary changes. In a related paper, data were presented on the conus valves and the subendocardium. Here, the structure of the conus myocardium, the subepicardial tissue, and the conus-aorta transition were studied by conventional light, transmission, and scanning electron microscopy. In addition, actin localization by fluorescent phalloidin was used. The conus myocardium is organized into bundles whose spatial organization changes along the conus length. The variable orientation of the myocardial cell bundles may be effective in emptying the conus lumen during contraction and in preventing reflux of blood. Myocardial cell bundles are separated by loose connective tissue that contains collagen and elastin fibers, vessels, and extremely flat cells separating the cell bundles and enclosing blood vessels and collagen fibers. The ultrastructure of the myocardial cells was found to be very similar to that of other fish groups, suggesting that it is largely conservative. The subepicardium is characterized by the presence of nodular structures that contain lympho-hemopoietic (thymus-like) tissue in the young sturgeons and a large number of lymphocytes after the sturgeons reach sexual maturity. This tissue is likely implicated in the establishment and maintenance of the immune responses. The intrapericardial ventral aorta shows a middle layer of circumferentially oriented cells and internal and external layers with cells oriented longitudinally. Elastin fibers completely surround each smooth muscle cell, and the spaces between the different layers are occupied by randomly arranged collagen bundles. The intrapericardial segment of the ventral aorta is a true transitional segment whose structural characteristics are different from those of both the conus subendocardium and the rest of the ventral aorta.     

Effects of rearing temperature on hematological and biochemical parameters of great sturgeon (Huso huso Linnaeus, 1758) juvenile

The effect of environmental temperature changes on hematological and biochemical parameters of Huso huso juveniles was studied. Six-month-old juveniles with mean body weight of 69.2 ± 4.1 g were subjected to different temperatures (9–14°C, 15–20°C, and 21–26°C, respectively). The hematological parameters, ion Ca2+, glucose, and the cortisol concentrations were assessed after a period of 21 days rearing at these temperatures. The results show that hematocrit, Ca²⁺, and eosinophil were affected by different temperatures. Increasing temperature led to a significant increase (P < 0.05) in the hematocrit, Ca²⁺, and eosinophil, but white blood cell count, lymphocyte, cortisol, and glucose concentrations were decreased slightly (P > 0.05). The rest of the parameters showed no significant effect with increase in environmental temperature (P > 0.05). These data show significant effect of temperature on the blood parameters of great sturgeon.