• Volume 30,Issue 4,2006 Table of Contents
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    • Effects of dietary fish protein hydrolysate levels on growth, survival and body composition of larvae in Pseudosciaena crocea

      2006, 30(4):502-508. DOI: 10.3724/SP.J.1231

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      Abstract:A 30-day feeding experiment was conducted in tanks to investigate the effects of dietary fish protein hydrolysate (FPH) levels on the growth, survival and body composition of large yellow croaker (Pseudosciaena crocea Richardson) larvae [12 days after hatchery, with initial average weight (1.6±0.18) mg]. FPH was produced by hydrolyzing fish with two protease. Five practical diets were used in the present study. Four microdiets (MD), with FPH replacing 0%, 25%, 50% and 75% of fish meal protein, were formulated. The frozen copepods were used as a control diet. The results showed that dietary FPH levels significantly influenced the growth, survival and body composition of large yellow croaker larvae. With increasing dietary FPH, the specific growth rates (SGRs) and survival of large yellow croaker significantly decrease d (P<0.05). While the survival (32.6%) in fish fed the diet with 25% FPH replacing fish meal protein was significantly higher than other groups (P<0.05), but was not significantly different from that of the c ontrol diet group (P>0.05). The SGR (9.0% day-1) in fish fed the diet with 25% FPH replacing fish meal protein was not significantly different from the 0% FPH group. The body composition analysis showed that with increasing FPH, the whole body dry matter, crude protein and crude lipid significantly decreased (P<0.05). Analysis of whole body fatty acid showed that with increasing dietary FPH, DHA and EPA in fish body significantly decreased(P<0.05). Results from this study indicated that a proper replacement of fish meal with FPH in the microdiet of large yellow croaker larvae will improve survival, and excessive FPH will result in poor growth and low survival of the larvae.

    • Comparative pharmacokinetics of danofloxacin in healthy and Vibrio anguillarum infected flounder Paralichthys olivaceus

      2006, 30(4):509-514. DOI: 10.3724/SP.J.1231

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      Abstract:The founder Paralichthys olivaceus were divided into three groups randomly and the pharmacokinetics and bioavailability of danofloxacin were examined in healthy and Vibrio anguillarum infected founder Paralichthys olivaceus. Concentrations of dano floxacin were determined by the High Performance Liquid Chromatography and data were analyzed with the pharmacokinetic computer program MCP-KP. The results showed that blood concentration of danofloxacin in healthy P. olivaceus after intravascular administration (5 mg·kg-1 body weight) was described by a onecompartment open model with no absorption. The blood concentrationtime curves after oral administration (10 mg·kg-1 body weight) in healthy and infected P. olivaceus all could be described by a onecompartment open model with the first order absorption; whereas the liver and kidney were both fit to the twocompartmental open model with the first order absorption. Compared with the healthy P. olivaceus the pharmacokinetic parameters of danofloxacin in infected founder had great changes, such as the area under concentrationtime curve decreased from 256.07 mg·h-1·L-1 to 209.18 mg·h-1·L-1,the maximum drug concentration decreased from 5.699 μg·mL-1 to 2.932 μg·mL-1, the elimination halflife increased from 27.758 h to 46.195 h, and the bioavailability was 71.21% for healthy fish and 58.17% for infected fish.

    • The residues and pharmacokinetics of florphenicol in Trionyx sinensis following intramascular injection and oral administration

      2006, 30(4):515-519. DOI: 10.3724/SP.J.1231

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      Abstract:To study the residues and pharmacokinetics of florphenicol in Trionyx sinensis with different treatments, one hundred and sixty healthy T. sinensis were selected and followed by a single dose of florphenicol (30 mg·kg-1) with intramascular injection and oral administration respectively. Serial serum samples were obtained and assayed by reversedphase HPLC, and the corresponding pharmacokinetic parameters were calculated with 3p87. A onecompartment open model best fits the data. The major pharmacokinetic parameters were as follows: AUC=76.45 mg·L-1·h-1, T1/2ka=1.31 h, T1/2ke=4.48 h, and Cmax=7.09 mg·L-1 in intramascular injection group; while AUC =109.42 mg·L-1·h-1, T1/2ka=1.73 h, T1/2ke=3.63 h, and Cmax=10.64 mg·L-1 in oral administration one. It suggested that the assimilation of florphenicol was faster, the level of risidue concentration was higher, the maintain time was longer, and the bioavailability was higher in oral administration group as compared to intramascular injection. Florphenicol residue eliminated slowly in musculature.

    • Enzyme linked immunosorbent assay(ELISA) for the quantitative analysis of furazolidone residues in aquatic products

      2006, 30(4):520-524. DOI: 10.3724/SP.J.00001

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      Abstract:A method of ELISA for the determination of furazolidone metabolites residues in aquatic products is established in this paper. There were no literatures about determination of AOZ residues in aquatic products by Enzyme linked Immunosorbent assay (ELISA) at home. Samples were derivatived with 2nitrobenzaldehyde and extracted with ethyl acetate. Then they were purified with nhexane and determinated by ELISA. In the paper, effects of different disposal conditions including dilution factors, extraction times, illumination conditions and shelf time to recovery were researched. By determination on Eriocheir sinensis, Micropterus salmoides and Procambarus clarkii spiked with AOZ, recovery, precision and detection limit of the method were researched by single laboratory validation approach as well as between laboratory comparisons. Results show that there is a remarkable effect of dilution factors on the recovery while no such effect is displayed for extraction times by ethyl acetate, illumination conditions and shelf time. So the best disposal condition is that dilution factor and extraction time are both one. The average recoveries are 99.2%,96.0%and 100.0% respectively when the samples are spiked with 0.60 μg·kg-1,2.00 μg·kg-1 and 6.00 μg·kg-1 of AOZ. The detection limit is 0.3 μg·kg-1. The relative standard deviations(n=3) for intraassay are 1.76%-12.57% and coefficients of variation for interassay are 5.43%-8.58%. Three positive samples analyzed by ELISA are confirmed by LCMS and no false positive samples are found. The method is sensitive with a fairly good rep roducibility and suitable for the determination of furazolidone metabolites(AOZ) in aquatic products.

    • Separation and determination on virulence genes of Vibrio cholerae in Fugu obscurus

      2006, 30(4):525-530. DOI: 10.3724/SP.J.1231

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      Abstract:During the survey on diseases of Fugu obscurus from 2002 to 2004, two strains(J-1 and H-3) of pathogenic bacteria with typical symptoms were isolated from abdominal cavity and intestinal mucus of suffering Fugu obscurus. The two isolated strains were identified as non01strains of Vibrio cholerae through biochemical test and serotype identification. It could be inferred that they are pathogens of bacterial enteritis of Fugu obscurus since the results of artificial infection are the same as the natural infection. In order to testify the classification of the isolated strains, the isolated strains were amplified by polymerase chain reaction(PCR) with two primers designed according to the sequence of Vibrio. The PCR products were DNA sequence of 451 bp. The result showed that systematic status between J-1, H-3 and N92001, N16961 was close. Enterotoxin with active subunit A named ctxA is one of the primary infection agents of Vibrio cholerae. While the pathogenicity is related with ctxA, the test of gene of enterotoxin is the most important step of diagnosis. Using N16961 strains as positive control, the same PCR DNA sequence of 400 bp was obtained in the PCR analysis. By sequencing and alignment, this 407 bp sequence of H-3 strains is identical with ctxA, which indicated that J-1 strains and H-3 strains were the pathogenic bacteria of F. obscurus. Bacterial diseases are common and frequent in process of aquaculture especially the intensive aquiculture. This paper shows introduces how to combine common method and PCR to isolate, identify and study bacteria. The pollution of non01strains of V. cholerae in aquatic product reflects in some way the degree of environmental pollution. Thus the study of pathogenicity is meaningful to evaluate if bacteria would cause disease and to limit its prevalence, so as to study and control the zoonosis.

    • Purification and partial characterization of serum immunoglobulin in Acipenser sinensis, Acipenser schrenckii and Huso dauricus

      2006, 30(4):531-537. DOI: 10.3724/SP.J.00001

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      Abstract:Serum immunoglobulin (Ig) of Amur sturgeon Acipenser schrenckii, Chinese sturgeon, Acipenser sinesis and Huso sturgeon, Huso dauricus which were healthy and unimmuned, was first time respectively purified by using saturation ammonium sulfate precipitation followed by Sephadex G-200 gel column chromatography. Molecular weight and partial characterization of Ig and heavy chain and light chain of Ig were measured by polyacrylamide gel electrophoresis (PAGE), SDS polyacrylamide ge l electrophoresis (SDS-PAGE), Western blotting and Ouchterlony method. The results show that Ig molecular weight of Amur sturgeon, Chinese sturgeon and Huso sturgeon is 867 kD, 896 kD and 924 kD respectively. Heavy chain molecular weight of Ig in the three sturgeons' serum is all 88 kD and light chain of Amu r sturgeon and Chinese sturgeon is 29 kD, but there is an extra light chain of 26 kD in Huso sturgeon serum. The results of measurements and calculation show that Ig of sturgeon is tetramer. In Western blotting, Ig and Ig heavy chain of the sturgeons have the same antigenicity and can be detected by antibody of rabbit anti the sturgeon Ig respectively in colloxylin membrane while light chain cannot be detected. Serum and Ig in serum of the three sturgeons can react with serum of rabbit anti each of the three sturgeons' Ig, but cannot react with serum of rabbit anti Ig of carp Cyprynus carpio. The Ouchterlony results show that Ig of sturgeons are immune homologous in structure and sequence, but have little immune homologous characters compared with Ig of highclassification Osteichthyes such as carp.

    • Embryonic and postembryonic development of hybrid produced with frozen sperms of Paralichthys dentatus and eggs of Paralichthys olivaceus

      2006, 30(4):433-443. DOI: 10.3724/SP.J.00001

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      Abstract:In order to study hybrid offspring's embryonic development, postembryonic development and growth characteristics under different temperatures, crossing test was carried out using frozen sperms of summer flounder(Paralichthys dentatus) and eggs of Japanese flounder(Paralichthys olivaceus). The development of the hybrid embryos was successively observed and described under Olympus microscope. After 65 hours and 57 minutes the embryonic development finished, which contains cleavage stage, blastula stage, gastrula stage, closure stage of blastopore, somites stage, tail bud stage, heartbeating stage, and hatching stage. Then the embryos began postembryonic development. During the embryonic development the heart began to beat at 15 minutes after the embryos moved. Morphological characters and growth of the fries were also observed by Olympus dissecting microscope and recorded once every day. According to these, the postembryonic development was divided into four stages: yolksac absorption stage (1-6 days after hatching), premetamorphosis stage (7-25 days after hatching), metamorphosis stage (25-30 days after hatching) and growth stage after metamorphosis. The embryonic development at 16-17 ℃,18-19 ℃,20 ℃ and 22-23 ℃ was studied. Result showed that the hybrid embryos developed better at 16-20 ℃, and a great deal of the fries hatched at 22-23 ℃ died 2-3 days after hatching. Growth of the postlarva at 18-19 ℃, 20 ℃, 22 ℃ and 24 ℃ was also studied, result showed that the metamorphosis and the growth rate of metamorphosis stage postlarva were higher at 22-24 ℃ than that at 18-20 ℃.

    • Immunogenicity and immunoprotection of outer membrane proteins of Vibrio alginolyticus

      2006, 30(4):538-543. DOI: 10.3724/SP.J.1231

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      Abstract:Outer membrane protein (OMP) is the main member of outer membrane, which is the unique structure of Gramnegative bacterium and plays great role in life function of bacterium. However, few researches were reported about immunogenicity and immunoprotection of outer membrane proteins of Vibrio alginolyticus (Va-OMP). In this paper, we prepared four vaccines about V. alginolyticus (Va) and outer membrane protein of V. alginolyticus. Comparing active and passive immunoprotection of outer membrane protein of V. alginolyticus, 58 kD of outer membrane protein of V. alginolyticus (Va-OMP58), inactive V. alginolyticus and lipopolysaccharides of V. alginolyticus (Va-LPS) vaccine, the survival percentage of group Va-OMP and group Va-OMP58 was between 62.5%-86.7%. However, the survival percentage of group Va-LPS and group inactive Va was between 50%-62.5%. After being immunized with antiserum and challenged by Va, the survival percentage of group Va-OMP was 53.3% and 66.7%. It showed that Va-OMP vaccine and Va-OMP58 vaccine had higher immunogenicity than inactive vaccine and Va-LPS vaccine in mice. Moreover, outer membrane protein (OMP) can induce hypersensitivity reaction in mice by delayedtype hypersensitivity (DTH) test. All the results showed that VaOMP may be the protective antigen which is capable of inducing both humoral immunity and cellmediated immunity (CMI) in mice. The immunoprotection of OMP in Epinephelus fario is in process. The experiment provided the theory base for vaccine preparation of V. alginolyticus. It hopes that Va-OMP58 may be the protective antigen of V. alginolyticus and further be a candidate of the subunit vaccine.

    • The influence of salinity acclimation on activity of Na+/K+ATPase in branchial epithelium, concentration of ions and osmolarity in serum of Acipenser schrenckii

      2006, 30(4):444-449. DOI: 10.3724/SP.J.1231

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      Abstract:The activity of Na+/K+ ATPase in branchial epithelium, concentration of ions (Na+, K+, Cl-) and osmolarity in serum of Acipenser schrenckii, during salinity acclimation, were measured and analyzed in this paper, and the osmotic re gulation process was discussed. The activity of Na+/K+ATPase in different salinities (10,20,25) was significantly higher than that in control group, which increased by 2 or 2.5 times. Na+/K+ATPase activities under different salinities decreased in the beginning, and increased with the acclimated time elapsing, finally decreased again and tended to be stable. Osmolarity in serum was elevated with the rising salinities. The highest value was (328.77±26.78) mmol·kg-1 in salinity 10. Hereafter, the osmolarity decreased gradually and kept in about 290 mmol·kg-1. The value was a little higher than that in control group. In all acclimated salinities, the changes on activities of Na+/K+ ATPase and serum osmolarity showed the same trend. The concentration of K+ in 3 different salinities was rising, but the difference was not significant(P>0.05) than that in control. The average of K+ concentration kept between 3.0 and 3.20 mmol·L-1. The trend of Na+ and Cl- concentration changes in serum was similar. The concentrations of Na+ and Cl- were elevated under salinity 10, but the difference was not significant (P>0.05) than control. The concentration of Na+, Cl- in serum under 20 and 25 salinities were not significantly different. The osmotic regulation might be divided into 3 phases by analyzing the data in this paper. One is the stress. The obvious symptom is the decrease of Na+/K+ATPase activities. The second phase is active regulation, which is characterized by that the Na+/K+ ATPase is activated and its activity is elevated. The last phase is the adaptation. In this phase, the Na+/K+ ATPase activities decrease again and are inclined to be stable.

    • Detecting of an antigenic protein of lymphocystis disease virus (LCDV) using monoclonal antibodies

      2006, 30(4):544-548. DOI: 10.3724/SP.J.00001

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      Abstract:Lymphocystis disease (LCD) is a chronic disease characterized by papillomalike lesions typically on the skin, fins and tail. The causative agent of the lymphocystis disease, lymphocystis disease virus (LCDV), as been reported in over one hundred teleost species and it has a worldwide geographical distribution. In China LCD has resulted in a great economic loss in marine culture industry and become a factor restricting aquaculture development. In recent years, monoclonal antibody (Mab) technology has had an important impact on fish virus disease management. A large number of Mabs have been developed for fish viruses, In the present study, Mabs against LCDV were produced and characterized. In this experiment, LCDV was separated from lymphocystis nodules by cell disruption, differential centrifugation and density gradient centrifugation in sucrose. The purified virus preparation was used for mice immunizations, Western blotting and immunogold electron microscopy (IEM). Fourweek old Balb/c mice were immunized 4 times within 4 weeks with purified LCDV preparations. Three days after the last immunization, spleens of the immunized mice were dissected into cells and then fused with P3X63Ag8U1 myeloma cell line using polyethylene glycol (PEG) as fusongen. The fused cells were cultured in HATGIT selecting medium for about 2 weeks. The survival cells (hybridoma cells) were cultured in GIT. Mediums of hybridoma cells were detected by indirect immunofluorescence assay test (IFAT). Many positive hybridomas were found and 4 of them were cloned because of secreting high titer antibodies. As they were cloned 3 times continuously, it could be verified that the antibodies raised by these hybridoma cell lines were monoclonal. Then the monoclonal antibodies were used in IFAT, Western blotting and IEM. In the IFAT, cryosections were prepared from nodule tissues of diseased flounder. The specific fluorescence signals were granularm and observed only at the peripheral zone of hypertrophied cells cytoplasm where was the cytoplasmic inclusion bodies location and many of them formed ribbonshaped. Western-blotting analysis identified Mabs to the LCDV proteins. The Mabs demonstrated differences in their polypeptide binding patterns. Two Mabs (1D7, 2B6) react specifically with the 116 kD LCDV polypeptide. This result suggests that these Mabs target linear epitopes within the LCDV protein. However, the identity of the target antigen of two other Mabs (1A8, 2D11) could not be determined by Western blotting analysis. This observation suggests that these Mabs likely target conformational epitopes that are sensitive to the conditions employed in such analyses. Transmission electrton microscopy immunogold localization results showed that the high density gold particles were located at the outermost surface of freshly purified virus par ticles, but not the viral nucleocapsid or outside the virions. Very little ackg round labeling was observed. This study provided direct evidence that these four Mabs were antiLCDV and the epitopes recognized by these Mabs were located on the surface of the virion.In conclusion, four Mabs were produced and characterized for LCDV which recognize structurally different epitopes and confirmed the 116 kD polypeptide was viral proteins. It is anticipated that these Mabs will prove useful in understanding virus host cell interactions, and in tracing the transport of virusspecific proteins through the various cell and virusinduced compartment.

    • Extraction and the physical and chemical characterization of collagen in Stichopus japonicus

      2006, 30(4):549-553. DOI: 10.3724/SP.J.1231

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      Abstract:Sea cucumbers (Stichopus japonicus) belonging to the phylum Echinodermata are traditional tonic consumed by Chinese and Japanese. The major edible parts of sea cucumber are the body wall mainly consisting of collagen and mucopolysaccharides. More than 21 types of collagen have so far been identified in various tissues and their roles have been investigated. In invertebrate, at least 2 types of collagen, type Ⅰ and type Ⅴ are found to exist. There is little information about the collagen of sea cucumber except for few reports on S. japonicus and Cucumaria frondosa, respectively. However, results of the former findings were not consistent with that of the latter about the molecular composition of the sea cucumber collagen. In this paper, the intact collagens were isolated from the body wall of S. japonicus by a new method and their physical and chemical characterization were studied. The results showed that pepsinsolubilized collagens(PSC) without telopeptide could be prepared at low temperature. Through the ultraviolet scanning spectra from 190 to 400 nm, the PSC presented maximum absorption at 220 nm which was consistent with that of type Ⅰcollagen. The compositional features of the amino acid were with the high contents of glycine(329 residues/1000) and hydroxyproline(66 residues/1000), but with low contents of tyrosine, phenylalanine and histidine. No cysteine was detected. The ratio of hydroxyproline to proline was 0.69. It was conc luded that PSC was typical type Ⅰcollagen. This was the first report about the thermal stability temperature (Ts) of sea cucumber collagen which was 57 ℃ as measured by DSC, about 5 ℃ lower than that of type Ⅰcollagen of calf. The content of total polysaccharide determined with phenol sulfuric acid method was 0.61% and the glycosaminoglycan measured with cationic dye of methylene blue was 0.48%. The collagen could be separated from glycosaminoglycan by DEAE52. Based on SDS polyacrylamide gel electrophoresis(SDSPAGE), the purities of PSC were higher. Judging from their electrophoretic patterns, PSC contained β, α and a few γ chains, while α chain resembled α1 chain of typeⅠcollagen of vertebrate, however, the presence of (α1)3 trimers was evident.

    • Effects of 5-HT on excitability and secretion activity of MTXO cells in eyestalks of Eriocheir sinensis

      2006, 30(4):450-453. DOI: 10.3724/SP.J.1231

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      Abstract:The X-organ sinus gland is a major peptidergic neurosecretory system in crustacean, analogous to the vertebrate hypothalamoneurohypophyseal system. Chinese mittenhanded crab (Eriocheir sinensis) X-organ is located on the ventral surface of terminalia in the eyestalk, named MTXO. Three types of neurosecretory cell dissociated from MTXO had been identified on the basis of shape, size and outgrowth fashion. The cell type A and cell type B were immunoactive to antiCHH and antiMIH serum respectively. In the present paper, the wholecell patch clamp technique was used to examine the effect s of 5HT on the excitability and neurosecretion of MTXO cells. The epolariza tion was evoked from the cell type A and cell type B and hyperpolarization from cell type C in response to the rapid application of 5HT (50 μmol). The different frequency overshotting action potential could be recorded after depolarization in the cell type A and cell type B when the 5-HT had been washe d out. Under voltage clamp mode, the increase of cell capacitance was observe d in the cell type A and type B in response to the application of 5-HT. This su ggests that the excitability and releases of CHH and MIH could be induced by 5-HT in the cell type A and type B.

    • Counting and morphological changes in vitro of haemocytes in Eriocheir sinensis

      2006, 30(4):454-462. DOI: 10.3724/SP.J.1231

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      Abstract:The number of haemocytes per cubic milliliter haemolymph in Eriocheir sinensis was (13357±7196). The percentage of large granular cell (LGC) was 49.8% and its size was (16.6±1.1) μm×(10.2±0.6) μm; The percentage of large and small granular intermediate cell (LSGC) was 20.6% and its size was (13.1±1.2) μm×(8.4±0.5) μm; The percentage of small granular cell (SGC) was 29.3% and its size was (12.4±1.2) μm×(8.1±0.4) μm; The percentage of agranular cell (AGC) was 0.2% and its size was (11.3±1.3) μm×(8.9±1.1) μm. The complete coagulation time of haemolymph in Eriocheir sinensis was (9 7.7±25.3) s, during which only AGC and SGC displayed cytolysis. The main orpho logical and structural changes of AGC and SGC were that they and their nucleisw elled immediately after haemolymph leaving body, the ratio of nucleus to ytopla sm increased rapidly, membranes ruptured and the cytoplasm moved out from the inside of cell. After the complete coagulation of haemolymph, the main changes of AGC and SGC were that their mitochondria and endoplasmic reticulum ruptured, dissolved and disappeared gradually, the substance in the small granules of SGC moved out, the electron density in small granules decreased, the granules vacuolated and disappeared gradually, and nucleus became pyknosis. The cytolysis of LSGC and LGC started 5 min later after haemolymph leaving body and was slower than the cytolysis of AGC and SGC. The main morphological and structural changes of LSGC and LGC were that they and their nuclei swelled, membrane, mitochondria and end oplasmic reticulum ruptured, dissolved and disappeared gradually, large granules in LSGC and LGC vacuolated and disappeared gradually, and nucleus became pyknosis. From the characteristics of AGC and SGC morphological changes after haemolymph leaving body, it was inferred that they released some coagulative factors to get into the coagulative reactions which might be similar to that of vertebrate platelets.

    • >ROUNDUPS
    • Analysis of phenomena for frequent occurrences of red tides and bioremediation by seaweed cultivation

      2006, 30(4):554-561. DOI: 10.3724/SP.J.00001

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      Abstract:In this paper, the history, main events and present status of red tide (HAB, harmful algal blooms) along China coast in recent years were reviewed and presented. It showed that the HAB's frequency and scale, number of HAB spec ies, percentage of toxic HAB events and the degree of damages to marine environment and economy have sharply increased in China since 1960's. Eutrophication was key factor for high occurrence of red tide. In this paper, main causes of frequent HAB occurrence along China coast was discussed. Many factors might influence the occurrence of red tide, which included weather, climate, coastal current, tidal current, water temperature, salinity, hydrodynamic and nutrient conditions, trace metals and the variation of biological environment. Numerous evidences from all over the world revealed the linkage between the increases in nutrient loading and the occurrences of high biomass blooms. Eutrophication was one of the important causes that involved in high occurrence of HAB. The main sources of nutrients potentially stimulating HABs included terrestrial runoff, aquaculture selfpollution, atmospheric deposition, sea projects and other pollution events in the ocean. Studies showed that the input from land contaminations and the selfpollution of marine aquaculture accelerated eutrophication in coastal waters and were also important impact factors on red tide. Researches suggested that nutrient composition could affect the species composition of phytoplankton as well as the development of some HABs. The changes in nutrient supply ratios, primarily N∶P, often resulted in shifts in red tide species composition. The correlation between cysts and formation of HAB was discussed from the viewpoi nt of transformation of cyst and vegetative cell, the effects of trace elements and other organic substances on the occurrence of HAB were presented also. It indicated that the nutrient control could be an effective way to reduce the risk of red tide occurrence. Seaweed would play an important role for decreasing marine eutrophication. Among the different methods of red tide controlling studied, seaweed biomass has received much attention due to the cost saving, low sensitivity to environmental and impurity factors, the possible contaminant recovery from the biomaterial and its elevated adsorption capacity. Cultivated seaweeds have very high rates of productivity higher than that of seaweed in its natural habits and grow well in water bodies with higher nitrogen and other nutrients. Seaweeds are able to absorb large quantities of nitrogen, phosphorus and carbon dioxide, produce large quanti ties of oxygen, and have excellent effect on decreasing eutrophication. Large amounts of C, N and P are accumulated into seaweed tissues as they accumulate considerable biomass over a period of months or years depending on the cultivation season. When seaweeds are harvested, nutrients are removed from the sea area. An investigation was carried out for inorganic nitrogen and inorganic phosphorus concentration at Lusi Coast, Qidong County, Jiangsu Province in China, where there were about 270 hm2 for Porphyra yezoensis cultivation with eutrophic sea water in recent years. While during Porphyra yezoensis cultivation, from Sep 2003 to May 2004, the concentration of ammonium nitrogen declined form 0.511-0.778 mg·L-1 to 0.006-0.057 mg·L-1, nitrite nitrogen concentration declined from 0.010-0.040 mg·L-1 to 0.001-0.009 mg·L-1, and nitrate nitrogen concentration declined from 0.466-0.549 mg·L-1 to 0.286-0.0568 mg·L-1, the average concentration of inorganic phosphorus declined from 0.024 mg·L-1 to 0.019 mg·L-1. Furthermore, during five hours, the concentration of ammonium nitrogen in the seawater declined form 220.88 μmol·L-1 to 8.59 μmol·L-1 by cultivated Gracilaria lemanaiformis, and the concentration of ammonium nitrogen declined form 213.84 μmol·L-1 to zero by cultivated Enteromorpha clathrata. Other bioremediation mechanisms of seaweed inhibiting the red tide microalgae such as nutrients competition and allelopathic effects were also discussed.

    • >RESEARCH NOTES
    • The morphological character and karyotype of Oxyeleotris lineolatus

      2006, 30(4):562-565. DOI: 10.3724/SP.J.00001

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      Abstract:This paper reports the morphological character and karyotype of Oxyeleotris lineolatus. Oxyeleotris lineolatus is native in Australia and call ed sleepy cod. It belongs to Oxyeleotris, Eleotridae, Gobioidei, Perciformes in taxonomy. Recently, it was introduced to China and local people were not familiar with it. So we carried out this study. 30 individuals have been observed and some data were recorded. It has a large mouth that is in front and up. The mandible stands out and is longer than the up jaw. There are many rows of thin teeth in up and down jaws. The pelvie fins are located in chest and pectoral fins are large and fanlike. There are two dorsal fins. The tail fin is circular. Gill rakers are sparse and the number of gill rakers is 8-12+3-4. The gas bladder belongs to physoclistaus and its stomach is strong and I-like. The intestine is thick and short and no pyloric caecas. The length of the digestive path is 48.1%-80.3% of the length of body. Its liver has two lobes and the liver weight is 4.1%-7.2% of the body weight. The digestive organs characters are same as the trait of flesheater fish. Its scale belongs to ctenoid scale and its body surface shows several long lines. There is not lateral line in the body. The number of vertebra is 26-27 and it has 10-11 pairs rib. The number of diploid chromosome is 2n=46 and the karyotype formula is 2sm+8st+36t,NF=48. The relative length of chromosome is from 1.37% to 3.48% and it is continuity. No strange size chromosomes relation to sex was observed. The karyotype of Oxyeleotris lineolatus is similar to that of Oxyeletris marmoratus Bleeker from South East Asia and both of them belong to Oxyeleotri. It testifies the correctness of traditional classification on cytology.

    • >PAPERS
    • Sequence analysis of mitochondrial COI gene of Scylla spp. along coast of southeastern China

      2006, 30(4):463-468. DOI: 10.3724/SP.J.1231

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      Abstract:Culture of mud crab (genus Scylla) as precious seafood is growing rapidly in China recently. However, the taxonomy of mud crab in China is still in controversial. Mitochondrial cytochome oxidasesubunit I (COI) gene was used to identify species of genus Scylla resided along coast of southeastern China. A fragment of the COI gene was amplified and sequenced from 72 Scylla spp. individuals obtained from 5 regions along coast of southeastern China. 12 distinct haplotypes, which were identified among 72 COI sequences, were above 98% identical to the known S. paramamosain COI gene sequences, and showed 7.36%-15.54% difference from other 3 species. The average genetic distance of COI sequences between these individuals and S. paramamosain is only 0.00783 and this does not significantly differ from the intraspecific distance, while between these individuals and S. serrata, S. olivacea and S. tranquebarica is 0.11659, 0.17812 and 0.08423 respectively. The NJ tree shows that all four species formed reciprocal monophyletic groups, with the S. olivacea located in the base, and S. olivacea closely related to S. tranquebarica. Four species of Scylla are delineated as four well supported groups, with average levels of interspecific sequence difference (-12%) more than six times greater than that observed at the intraspecific level (-2%) and 12 haplotypes identified in this study cluster closely with the known COI sequences from S. paramamosain. The results of sequence characterization, genetic distance and phylogenetic analysis suggest that all samples investigated should belong to S. paramamosain and S. paramamosain should be one of the most common species in China. Caution is called for species identification when studying Scylla.

    • >RESEARCH NOTES
    • Cloning and expression of the major membrane protein gene of Aeromonas hydrophila strain isolated from Anguilla anguilla

      2006, 30(4):566-570. DOI: 10.3724/SP.J.00001

      Abstract (2732) HTML (0) PDF 0.00 Byte (2275) Comment (0) Favorites

      Abstract:A pair of primers were designed according to the published nucleotide sequence of a putative outer membrane protein gene (omp) of Aeromonas hydrophila . With the specific primers, a target fragment about 1.1 kb was amplified from Aeromonas hydrophila ML316 via PCR .The target fragment was inserted into the linearized pGEM-T easy vector. After enzyme restriction and sequencing analysis,the nucleotide data had been further analyzed by DNAman and ClutalW software. The analysis results showed that the cloned DNA fragment had a longest open reading frame (ORF) of 1035 nt,it predicted to be encoded a 344 aa protein with the molecular weight of 36 kD. Hydrophobicity analysis suggested that the protein was highly hydrophilic, especialy at the first 24 aminoacid, this region could function as signal peptide. The homologious comparison proved the cloned gene had 96% homology to the sequence of the omp gene, and the alignment of the amino acid sequence was 98% . The recombinant plasmid was constructed with the target gene and the expressing vector pGEX-4T-1 and then was transformed into E. coli BL21(DE3)by BamH and Sal I .The fusion protein was expressed under the IPTG inducing condition,and exhibited about 62 kD in size,very close to the predicted molecular weight of GSTMOMP, furthermore,the fusion protein was specifically recognized by antiserum which raised against the major outer membrane protein of AHML316. Considering all these together, it proved that the cloned gene represented the major outer membrane protein gene of AHML316, and the expressed gene products shared identical antigenicity with the natural main outer membrane protein,and also provided technical support for developing an advanced gene engineering vaccine against Aeromonas hydrophila.

    • >PAPERS
    • Study on genetic relationships of Sparidae by RAPD

      2006, 30(4):469-474. DOI: 10.3724/SP.J.1231

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      Abstract:Random amplified polymorphic DNA(RAPD) technique was applied to study genetic relationships of Sparidae, including Sparus macrocephalus, Parargyrops edita, Pagrosomus major, Rhabdosargus sarba and Sparus latus. Under predetermined optimal reaction conditions,amplifications with 29 random primers selected from 60 primers gave 200 reproducible and stable bands ranging from 200 to 2500 bp. Each species had its own unique bands used for species identification. The molecular phylogenetic trees constructed by UPGMA and NJ methods of MEGA2.1 indicated S. macrocephalus and S. latus that belonged to Sparus were the most related, while S. macrocephalus and P. edita Tanaka were the least; R. sarba was more related with P. major and P. edita than S. macrocephalus and S. latus. Both results were accordant. And they agreed with classical taxonomy based on morphological and biochemical characters. In the matrix of genetic distance resulted from the 40 individuals, the maximal value was 0.8916, and most of them were between 0.50-0.85. The results showed RAPD could be efficient for exploring genetic relationships to some extent.

    • >RESEARCH NOTES
    • Comparison of growth, body contents and feed utilization of Jian carp (Cyprinus carpio var.Jian) and allogynogeneticsilver crucian carp(Carassius auratus gibelio)

      2006, 30(4):571-576. DOI: 10.3724/SP.J.1231

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      Abstract:In order to investigate the difference in utilization of diets with different quality in Jian carp(Cyprinus carpio var. Jian)and allogynogenetic silver curcian carp(Carassius auratus gibelio), a 55 d growth trial was conducted and low quality diet (LQ-diet) and high quality diet (HQ diet) were tested. LQ-diet contained 33.91% dietary protein which is mainly from soybean meal while HQ-diet contained 45.59% dietary protein which is mainly from fish meal. The initial average body weights were from 5.58 g to 5.82 g for two fish strains. The trial was carried out in a system consisting of 12 self circulation 320 L tanks. During the experiment, the fish were fed to satiation twice a day (at 9: 00 and 15:00), and uneaten feed was collected 1 h after feeding and dried. Feces were collected twice a day (at 11:00 and 16:45) from the fecal traps and dried at 70 ℃. The results show that feed intake was higher in Jian carp than in allogynogenetic silver curcian carp when fed LQ diet, while there was no significant difference between weight gain, feed conversion efficiency, protein efficiency rate and apparent digestibility. When fed HQ diet, Jian carp showed a lower feed intake, but higher feed conversion efficiency and protein efficiency rate than allogynogenetic silver curcian carp while there was no significant difference in the weight gain and apparent digestibility of both species. For Jian carp, feed intake and protein efficiency rate for the fish fed HQ diet and LQ diet were not significantly different, while the fish fed HQ diet showed higher weight gain, feed conve rsion efficiency and apparent digestibility. For allogynogenetic silver curcian carp, the fish fed HQ diet showed significantly higher feed intake, apparent digestibility, weight gain, feed conversion efficiency and lower protein efficiency rate. For Jian carp, body contents of dry matter, protein, lipid and energy for the fish fed HQ diet and LQ diet were significantly higher. For allogynogenetic silver curcian carp, body contents of dry matter and protein was significantly higher, while body contents of lipid and energy were affected by diet qualities. Compared to Jian carp, allogynogenetic silver curcian carp showed better utilization when fed LQ diet while poorer utilization when fed HQ diet.

    • >PAPERS
    • Change of ecological environment of artificial reef waters in Haizhou Bay

      2006, 30(4):475-480. DOI: 10.3724/SP.J.00001

      Abstract (2513) HTML (0) PDF 0.00 Byte (2499) Comment (0) Favorites

      Abstract:Haizhou Bay, an open bay in the west coast of Yellow Sea, is of an area of 900 km2, with hundreds of species (such as fish, shrimp, crab etc.) colonizing in the waters. As one of the 8 greatest fishing grounds in history, Haizhou Bay had even seen the maximum fishery catches of 50 000 t during the period of 1980s. However, due to the overfishing and destruction of spawning grounds and other habitats, fishery resources in Haizhou Bay have been declining from 1990s, with traditional economic species, such as hairtail, snapper sea bream, large yellow croaker, small yellow croaker as well as slender shad etc, not forming their regular fishing seasons. In order to improve fish habit at environment, and conserve fishery resources, the local government carried out a project of “Artificial Reef Construction in Haizhou Bay” from the beginning of 2002. As the first phase of the project, different types of concrete artificial reefs and vesselreefs with a total volume of 13 000 cubic meters were deployed in the middle part of Haizhou Bay (119°28′-119°29′14″E,34°55′-34°57′N) during the middle term of July, 2003, resulting in a fishing ground of about 10 km2 area. So far, most studies on the habitat improvement function of artificial reefs have been qualitative, and very few quantitative researches have been reported. How to establish a certain quantitative relationship between building size of ARs and improvement degree of habitat is not only needed in evaluating artificial reef construction quantitatively, but also is one of the basic theories to decide scientifically the building size of artificial reefs in certain waters. As a trial of quantitative study on ecological benefits of artificial reefs, the variations of water quality, bottom mud as well as plankton etc was discussed. Between artificial reef area and near waters before and after the deployment of artificial reefs in comparative ways, according to the results of 4 surveys carried out in Haizhou Bay artificial reef area and near waters in 2003-2004. The survey result reveals that the upwelling produced by the deployment of ARs will bring nutritive salt such as nitrogen to upper levels, with the nitrogen content in bed mud in artificial reef area dropping to 85.7% of that before ARs deployment, while in the control area the content remains the same during the same season; at the same time, nutritional level indexes in AR area increase after ARs deployment, with 28.1% and 15.9% larger than that of the control area in autumn and winter respectively, therefore the water quality in AR area changes from nitrogen restriction (with an average P∶N value of 7.4) before to phosphorus restriction (average P∶N value of 20.9) after ARs deployment. As to plankton, the similarity index decreases from highly similar 0.963 before ARs deployment to 0.863 after 3 months of ARs deployment and 0.685 after 7 months of ARs deployment in AR area and control area. Community structure as well as habitat environment have changed a lot; at the same time, the individual weight of zooplankton has increase obviously by 5 times larger in AR area than in reference area, this is very good for proliferation of fishery resources. In conclusion, the amendment benefits of artificial reefs on ecological environment in certain waters have been proved quantitatively.

    • Study on the behavioral characteristics of fishes in the deep water sea cage

      2006, 30(4):481-488. DOI: 10.3724/SP.J.00001

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      Abstract:By using such methods as were used in fish ecology, behaviouristics and mariculture disciplines, a study on the behavioral characteristics of fishes in the deep water sea cages was done. Altogether fives fishes were studied, with results showing that the endurance ranking when exposing to the air was Sparus macrocephalus, Pagros major, Lateolabrax japonicus, Sciaenops ocellatus and Pseudosciaena crocea. P. crocea lived in the middle and lower water near cage net, schooling and didn't fight with each other. However, Sciaenops ocellatus fought with each other fiercely and schooled everywhere in the middle and lower waters. Lateolabrax japonicus also lived in the middle and lower waters, rarely schooled but fought fiercely. Lateolabrax japonicus distributed ne ar the ridge of lower waters and cage bottom, rarely schooled and also fought with others, so did Sparus macrocephalus. The five species took on obvious food taking rhythm and were of tidal regularity. There were two food taking peaks in the period of slack tide near at dawn and dusk. They had a selectivity to the food and strong tolerance to starvation. The lower the water temperature, the stronger the tolerance to starvation. The food taking intensity was related to feeding methods. It assumed to be a positive correlation to water temperatures, peaking in July and August and going to its valley in February. There was not apparent difference of activity whether in the day or not. When at swift water condition, almost all the fishes habited in the bottom and near bottom ridge; otherwise, they would swim everywhere. The ability concerning wind, flow and waveresistance were different, with S. ocellatus being best, Lateolabrax japonicus the second and so on with Pseudosciaena crocea, Sparus macrocephalus, Pagros major.

    • On the characteristics of Litopenaeus vannamei body length and weight growth at low salinity environment

      2006, 30(4):489-495. DOI: 10.3724/SP.J.00001

      Abstract (3178) HTML (0) PDF 0.00 Byte (2448) Comment (0) Favorites

      Abstract:Litopenaeus vannamei low salinity stocking was playing an important ro le and developed rapidly in southern parts and coastal areas of China in recent years. The stocking salinity level decreased gradually following the development of theory and techniques, the general level is at 1-8 ppt at present, and the characteristics of L. vannamei growth at the low salinity level had not yet been reported. The studies of the characteristics of L. vannamei growth at low salinity aim to provide more theory bases for desalination stocking. Experimental enclosures(l×b×d: 5 m×5 m×1.6 m) were set up in the shrimp pond, 2000 healthy shrimp larvae with body length(BL) 1 cm were reared for 85 days, the population density was 80 ind·m-2, water salinity was 6 ppt at early time, 3-4 ppt in the middle term and 2 ppt in final term, with desalination naturally and no water exchange in the course of experiment. The average of water temperature was 29.2-31.6 ℃, dissolved oxygen was 3.9-5.8 mg·L-1, value of pH was 7.8-8.8 and transparency was 20 cm throughout the experimental period. Data from five enclosures were analyzed and used in this paper.The results show that the a verage of shrimp body length growth rate (BLGR) is 1.398 mm·d-1( range at 1.353-1.435 mm·d-1) and that of the body weight growth rate (BWGR) is 0.169 g·d-1(the range at 0.156-0.176 g·d-1),the mean value of final BL and BW is 118.83 mm and 14.37 g, respectively. The results also show a period of 15 days for accommodation in early time, and the first 50 days mainly for BL growth and the final 35 days mostly for BW increase. There is a linear fast growth at 20-35 days for BLG and an accelerated increase at 50-60 days for BWG. As the results express as curve regression, the optimum model of BLG is Quadratic, L=7.843+2.297t-0.0105t2(R2>0.99),and that of the BWG is Boltzmann, W=16.541+(-0.621-16.541)/(1+e(t-54.809)/15.456(R2>0.99). The relationship between shrimp BL and BW fit to the power model W=aLbW=4.9×10-6L3.0716 (R2>0.99) (the parameter a value is from 4.9 to 9.0×10-6,and b is from 2.9495 to 3.0716).

    • Recovery of earth pond reared Pelteobagrus fulvidraco from transport stress in acclimatization of laboratory system

      2006, 30(4):495-501. DOI: 10.3724/SP.J.00001

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      Abstract:Earthpondreared adult yellow catfish (Pelteobagrus fulvidraco R.) were transported to the indoor laboratory recycle system. Feeding and responsiveness to daily management, blood cortisol and glucose, percentage and phagocytic function of circulating leukocytes of the fish were monitored immediately after transport (day 0) and in acclimatization of the laboratory system for a period of 35 days. Cessation of feeding was apparent during the first 4 to 7 days after transport. All fish resumed feeding by day 8 and adapted to daily management by day 15. Blood cortisol and glucose concentrat ions were significantly high at day 0, 1, 2 and 3. Elevated blood cortisol and glucose significantly decreased by day 7 and maintained at low levels at day 21, 28 and 35. No significant differences were found in circulating erythrocyte numbers. Compared to values of each parameter for circulating leukocytes at day 21, 28 and 35, lymphocytopenia was found at day 3 and 7, neutrophilia was detected at day 0, 1, 2 and 3, significantly decreased phagocytosis and phagocytic index of peripheral leukocytes were found at day 7 and 14. The results of the present study indicate (1) that transport induced characteristic stress responses in the adult yellow catfish, (2) that transport resulted in significant alterations in the percentage of circulating lymphocytes and neutrophils and suppression in the phagocytic function of circulating leukocytes in the adult yellow catfish, (3) that a minimum of three weeks needed for the earthpondreared adult yellow catfish to completely recover from transport stress in acclimatization of the laboratory system.

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