Environmental concentration of ammonia nitrogen induced marked changes in proteome of clam Ruditapes philippinarum in dose-and time-dependent manner

Previous studies have revealed that ammonia nitrogen has several adverse effects on clam Ruditapes philippinarum.However,knowledge is lacking regarding the related proteins involved in the toxicological responses,which is vital to elucidate the underlying mechanism of ammonia nitrogen.In this study,clams R.philippinarum were exposed to ammonia nitrogen for 21 d at two environmentally relevant concentrations.The tandem mass tags approach(TMT)was applied to assay the differentially expressed proteins(DEPs)in clam gill tissues on the 3 rd and 21 st day.Finally,a total of 7263 proteins were identified.Bioinformatics analyses revealed that clam protein profiles changed in dose-and time dependent manner after ammonia nitrogen exposure.We inferred that the clams may face heavy challenges after ammonia exposure,such as unbalanced gender ratio,lysosomal disease,energy lack,neurological disorders,altered glutamine metabolism,increased lipid synthesis,and impaired immunity.Variation profiles of enzyme activities of glutaminase and glutamine synthase provided direct evidence to verify the related inference from proteome data.Most of the inferred toxic effects merit further study.This study identified important proteins related to ammonia nitrogen toxicity in the clam and indicated the severe stress of marine ammonia pollution on the healthy development of mollusc aquaculture.

pH胁迫对菲律宾蛤仔(Ruditapes philippinarum)耗氧率、排氨率、免疫和抗氧化酶活性以及组织形态的影响

随着人类工业迅速发展,CO_(2)大量排放,引起了海洋的酸化效应,不仅导致了全球气候变暖,也严重危害了海洋生物的生态健康。以菲律宾蛤仔(Ruditapes philippinarum)为研究对象,研究pH变化对菲律宾蛤仔耗氧率、排氨率、鳃组织结构以及鳃和内脏团的免疫、抗氧化酶活性的影响。将菲律宾蛤仔置于酸化海水(pH 6.4、7.1和7.7)中,以自然海水(pH 8.1)为对照。结果表明:耗氧率和排氨率随着pH的升高或降低而降低,在pH=8时达到最大值;6.4酸化组蛤仔鳃组织结构损伤严重,鳃丝间距扩大,纤毛黏合;鳃组织碱性磷酸酶(AKP)第42天所有酸化组活性显著高于对照组(P<0.05),所有酸化组溶菌酶(LZM)和酸性磷酸酶(ACP)活性显著低于对照组(P<0.05),7.7酸化组超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活性和总抗氧化能力(T-AOC)显著高于对照组(P<0.05),所有酸化组丙二醛(MDA)含量显著低于对照组(P<0.05);内脏团7.1和7.7酸化组LZM活性显著高于对照组(P<0.05),所有酸化组T-AOC和SOD活性显著高于对照组(P<0.05),7.1和7.7酸化组MDA含量显著低于对照组(P<0.05)。酸化致使菲律宾蛤仔耗氧率和排氨率降低,减缓其生理活动,降低鳃组织的免疫和抗氧化酶活性,打破蛤仔原有的代谢水平,会增加蛤仔患病的可能性。

AFLP analysis revealed differences in genetic diversity of four natural populations of Manila clam (Ruditapes philippinarum) in China

The amplified fragment length polymorphism （AFLP） technology was used to analyze the genetic diversities in four natural populations of Manila clam （ Ruditapes philippinarum）, distributed in four sea areas of China, i.e. , the Bohai Sea, the Huanghai Sea, the East China Sea and the South China Sea. Two hundred and sixty-four AFLP loci were analysed in 195 individuals and revealed high levels of genetic diversity. The percentage of polymorphic loci ranged from 92.13% to 96.06% and the Shannon＇ s information index was from 0.256 8 to 0. 275 6. By analyzing molecular variance （ AMOVA）, it was found that there were high levels of genetic differentiation between populations of Qingdao and the other three sea areas. Cluster analysis by Nei＇ s pairwise distances grouped specimens by geographical origin, except the population of Qingdao. A conclusion can be drawn that there are high genetic diversities in the four natural populations of Manila clam in China and some distinct differences existed among and between the four populations. The results also indicated that human cultivation activities will have great influence on the genetic structure of the population of Qingdao.

The influence of salinity on toxicological effects of arsenic in digestive gland of clam Ruditapes philippinarum using metabolomics

Ruditapes philippinarum,a clam that thrives in intertidal zones of various salinities,is a useful biomonitor to marine contaminants.We investigated the influence of dilution to 75% and 50% of normal seawater salinity(31.1) on the responses of the digestive gland of R.philippinarum to arsenic exposure(20 μg/L),using nuclear magnetic resonance(NMR)-based metabolomics.After acute arsenic exposure for 48 h,salinity-dependent differential metabolic responses were detected.In normal seawater,arsenic exposure increased the concentrations of branched-chain amino acids,and of threonine,proline,phosphocholine and adenosine,and it decreased the levels of alanine,hypotaurine,glucose,glycogen and ATP in the digestive glands.Differential changes in metabolic biomarkers observed at lower salinity(～23.3) included elevation of succinate,taurine and ATP,and depletion of branched-chain amino acids,threonine and glutamine.Unique effects of arsenic at the lowest salinity(～15.6) included down-regulation of glutamate,succinate and ADP,and up-regulation of phosphocholine.We conclude that salinity influences the metabolic responses of this clam to arsenic.

Isozyme Analysis on the Populations of Ruditapes philippinarum

Horizontal starch gel electrophoresis was used to investigate the genetic structure of six populations of Ruditapes philippinarum in the coast of China. Seven enzymes revealed eleven putative loci, and seven of them were polymorphic, PGM^＊, MDH-1^ ＊, MDH-3^＊, LAP-1^＊, LAP-2^＊, MPI-1^＊ and MPI-2^＊. The proportions of polymorphic loci of R. philippinarum populations varied from 0.454 5 to 0.636 4. The values of observed and expected heterozygosities were from 0.039 4 to 0.154 5 and from 0.111 1 to 0.238 5, respectively. Nei＇s genetic distance varied from 0.003 3 to 0.025 3 with an average of 0.013 5. It is suggested that the genetic diversity of R. philippinarum was high.

Annual Variations of Biogenic Element Contents of Manila Clam(Ruditapes philippinarum) Bottom-Cultivated in Jiaozhou Bay, China

Manila clam （Ruditapes philippinarum） was monthly sampled from its benthic aquaculture area in Jiaozhou Bay from May 2009 to June 2010.The annual variations of major elemental composition,organic content,fatness and element ratio of Manila clam were examined.The element removal effect of clam farming in Jiaozhou Bay was analyzed based on natural mortality and clam harvest.The results indicated that the variation trend of carbon content in shell （Cshell） was similar to that in clam （Cclam）.Such a variation was higher in summer and autumn than in other seasons,which ranged from 9.10±0.13 to 10.38 ± 0.09 mmol g^-1 and from 11.28 ±0.29 to 12.36±0.06 mmol g 1,respectively.Carbon content of flesh （Cflnesh） showed an opposite variation trend to that of shell in most months,varying from 29.42 ± 0.05 to 33.64 ± 0.62 mmol g^-1.Nitrogen content of shell （Nshell） and flesh （Nflesh） changed seasonally,which was relatively low in spring and summer.Nshell and Nflesh varied from 0.07 ±0.009 to 0.14±0.009 mmol g^-1 and from 5.46 ± 0.12 to 7.39 ± 0.43 mmol g^-1,respectively.Total nitrogen content of clam ranged from 0.50 ± 0.003 to 0.76 ± 0.10 mmol g^-1 with a falling tend except for a high value in March 2010.Phosphorus content of clam （Nclam） fluctuated largely,while phosphorus content of shell （Pshell） was less varied than that of flesh （Pflesh）.Pshell varied from 0.006±0.001 to 0.016±0.001 mmol g^-1; while Pflesh fluctuated between 0.058±0.017 and 0.293±0.029mmolg^-1.Pclam ranged from 0.015±0.002 to 0.041 ±0.006mmolg^-1.Carbon and nitrogen content were slightly affected by shell length,width or height.Elemental contents were closely related to the reproduction cycle.The removal amounts of carbon,nitrogen and phosphorus from clam harvest and natural death in Jiaozhou Bay were 2.92× 10^4t,1420t and 145 t,respectively.The nutrient removal may aid to reduce the concentrations of nitrogen and phosphorus,the main causes of eutrophication,and to maintain the ecosystem health of Jiaozhou Bay.

Observations on shell growth and morphology of the bivalve Ruditapes philippinarum

The bivalve Ruditapes philippinarum is not only one of the main mollusc species in the west Pacific Ocean, but also one of the main species for aquaculture in China. Knowledge of growth of the R. philippinarum shell will improve our understanding of the shell as an environmental archive. It is also useful for the aquaculture of R. philippinarum. In this research, a hanging box culture method was introduced in the culture of R. philippinarum. The bivalves were cultured for 126 days, from March 31 to August 3, 2002. The average growth rates of shell width, height, and thickness were 0.069, 0.046, and 0.032 mm/d, respectively. The mean increase of average individual wet mass was 0.028 g/d. The largest growth rates of both shell and average individual wet mass occurred in June, indicating that water temperature and bivalve reproduction were 2 important factors. The shell morphology underwent significant changes with shell growth. The ratio of height to thickness (value of B/C) shifted 1.58 in the first 60 days to 1.54 in the last 30 days, which was resulted from the change in major shell growth direction. Periodic changes in the B/C ratio led to corrugated shell form, which could be used to determine the age of the shell.

Impact of seawater acidification on shell property of the Manila clam Ruditapes philippinarum grown within and without sediment

Although the impact of ocean acidification on marine bivalves has been previously investigated under mainly controlled laboratory conditions,it is still unclear whether the impact of acidification on sediment-burrowing species differs between those within or without sediment.In order to fill this gap in our knowledge,we compared shell properties of the infaunal Manila clam(Ruditapes philippinarum)exposed to three pH concentrations(7.4,7.7,and 8.0),within and without sediments.In the first experiment(140 d),clams were exposed to seawater in an acidification system without sediment.A decrease in shell weight corresponding to the increase in dissolution rate was observed in the group ofpH 7.4,at which shell color disappeared or whitened.SEM observations confirmed the changes of the external shell surface.In the second experiment(170 d),sediment was placed at the bottom of each exposure chamber.The effects were found obvious in shell dissolution rate and shell color in the shell specimens exposed to overlying seawater but not found in the shell specimens exposed to sediment.Although the experimental period was longer in the second experiment,shell specimens in the first experiment were more seriously damaged than those in the second experiment under acidic seawater conditions.Our results,in relation to the defense function of the shell,show that marine bivalves in burrowing behavior are more adaptable to seawater acidification than those who do not burrow into sediment.

Seawater acidification affects the immune enzyme activities of the Manila clam Ruditapes philippinarum

Ocean acidification leads to changes in physiological and immune responses of bivalves, but the eff ect on the immune enzyme activities of the Manila clam, R uditapes philippinarum, when the pH is lower than the normal value has not been studied in detail. In this study, experiments were conducted to determine how pH(7.4, 7.7, 8.0) affects the immune enzyme activities in the gill and hemocytes of the Manila clam. Membrane stability and phagocytosis increased with decrease of pH from 8.0 to 7.7 and then decreased at pH 7.4. The total protein content in the hemocytes and gills decreased with decreasing pH. Lysozyme content in the hemocytes increased with decreasing pH, and the diff erences were significant among the different pH groups(P < 0.05). Adenosine triphosphatase activity at pH 7.4 was significantly higher than in the other two groups, but no significant diff erence was observed between pH 7.7 and 8.0. Catalase activity decreased from pH 8.0 to 7.7 and then increased at pH 7.4, and the dif ferences were significant among the experimental groups( P < 0.05). These findings provide valuable information about the immune response of R. philippinarum to reduced water pH and insights for future research investigating exposure of bivalves to elevated CO_2 conditions.

mRNA differential display on gene expression in settlement metamorphosis process of Ruditapes philippinarum larvae

The mRNA differential display (DDRT-PCR) technique was adopted to find out the genes related tosettlement metamorphosis development process of Ruditapes philippinarum larvae.In this study,we haveobtained three hundred and forty-six amplification bands in total from pediveliger larvae,veliger larvae,eye spot larvae and post-larvae.Sixty-five out of three hundred and forty-six bands are distinctly differen-tial display from band pattern,which can be put into four groups,standing for different expression char-acters.Sixteen differential display bands were cloned,sequenced and analyzed and nine different se-quences are obtained in the study.Three sequences have higher similarity to the cDNAs deposited indatabase and three are very similar to the rDNA of other species,considered as the rDNA of Ruditapesphilippinarum.The rest three sequences are found to be novel sequences after analyzed.Their accessionnumbers are AY916799,AY916798,and AY916797 respectively.We thought the novel sequences arepossibly relevant to the early embryo development of Ruditapes philippinarum larvae and can provide somefundamental understandings that are helpful for the improvement of scallop seed raising industry.

Gametogenic Cycle, the Spawning Season, First Sexual Maturity, and the Biological Minimum Size in Male Ruditapes philippinarum （Bivalvia： Veneridae） in Western Korea

The male gametogenic cycle, spawning season, first sexual maturity, and the biological minimum size in male Ruditapes philippinarum were investigated by qualitative and quantitative reproductive analyses. In the study of the male gametogenic cycle by qualitative histological analysis, the gametogenic cycle in male individuals can be classified into five successive stages： （1） early active stage, （2） late active stage, （3） ripe stage, （4） partially spawned stage, and （5） spent and inactive stage. Monthly changes in the gonad index in males measured by qualitative analysis showed a similar pattern to the male gametogenic cycle. In the study of the male gametogenic cycle by quantitative statistical analysis, monthly changes in the portions （%） of areas occupied by the testis areas to total tissue areas showed a rapid increase in March, and reached the maximum in May-June. And also monthly changes in the portions （%） of areas occupied by the spermatogenic stages to the testis area showed a maximum in May and gradually decreased from June to October. Therefore, this species showed a unimodal gametogenic cycle during the year, and the number of spawning seasons occurred once per year, from June to October, with a peak spawning between July and August. The percentage at the first sexual maturity of male clams ranging from 15.1-20.0 mm in shell length was 64.7%, and that of all individuals ranging from over 25.1 mm in shell length was 100%. The biological minimum size （shell lengths at 50% of sexual maturity （RMs0）） of male mature clams that was fitted to an exponential equation was 17.16 mm （considered to be 1 year old）. Because harvesting clams less than 17.16 mm in shell length could potentially cause a drastic reduction in recruitment, a measure indicating a prohibitory fishing size should be enacted for adequate fisheries management.

Action Mechanism of Antibacterial Hydrolysate from Ruditapes philippinarum

[Objectives] The antibacterial mechanism of protein hydrolysate from Ruditapes philippinarum（ named RPPH） was studied in this article. [Methods]The integrity of bacteria＇s wall and membrane was determined by some traditional ways. [Results]The growth of Staphylococcus aureus and Bacillus subtilis were inhibited by RPPH in the logarithmic phase. The activity of alkaline phosphatase could be detected in the culture solution. The results showed that the protein content and the conductivity of two kinds of bacteria increased with the extension of incubation time. The results of scanning electron microscope revealed that it emerged the phenomenon of agglomeration with the extension of response time in the culture solution of S. aureus,and the cell shape became irregular,a large number of cells stuck together,afterwards intracellular material was released from bacteria,and the boundaries among cells completely disappeared. The cell surface of B. subtilis became rough,the cells began to adhere,intercellular boundaries became blurred,subsequently cells broke,and then intracellular material leaked out after treating for 9 h. The form of B. subtilis could be roughly identified from the remnants of the bacterial debris,and most of the bacteria had been completely cracked and died. Transmission electron microscope results showed that the surface of S. aureus became rough,with uneven distribution of cytoplasm,and darker substances appeared in the middle,followed by leakage of large numbers of intracellular material. Massive cells became dead when treating for 9 h. B. subtilis cells began to shrink,and cytoplasm was distributed unevenly. The significant phenomenon of plasmolysis and rupture of cell wall could be observed. Afterwards,intracellular material spilled out,only the residual and ambiguity nucleoplasm area could be seen,and cells were killed. [Conclusions] Therefore,it was speculated that the RPPH could destroy cell wall and membrane of the two kinds of bacteria,change the permeability of cells membrane,result in the leakage of intracellular substances and enter within the bacterial cells to affect their normal physiological metabolism which led to death.

Use of antioxidant enzymes of clam Ruditapesphilippinarum as biomarker to polycyclic aromatic hydrocarbon pollution

The typical organic pollutant polycyclic aromatic hydrocarbon(PAH) anthracene was selected as a contaminant to investigate its eff ects on the activities of superoxide dismutase(SOD), catalase(CAT) and glutathione peroxidase(GSH-Px) in the clam Ruditapes philippinarum. The results show that SOD, CAT and GSH-Px had diff erent induction and inhibition reactions to anthracene stress, and that three diff erent organs in R. philippinarum(visceral mass, muscle tissue and mantle) had diff erent sensitivities to anthracene stress. This study suggest that SOD activities of the visceral mass, CAT activitities of the mantle and the visceral mass, and GSH-Px activity of the muscle tissue could be used as sensitive indicators of anthracene stress in R. philippinarum.

Bioaccumulation and function analysis of glutathione S-transferase isoforms in Manila clam Ruditapes philippinarum exposed to different kinds of PAHs

This study analyzed the function of different glutathione S-transferase(GST)isoforms and detoxification metabolism responses in Manila clam,Ruditapes philippinarum,exposed to 4 kinds of polycyclic aromatic hydrocarbons(PAHs)single,and their mixtures for 15 days under laboratory conditions.13 kinds of GSTs in R.philippinarum were classified,and the results of tissue distribution indicated that 12 kinds of GSTs(except GST sigma 3)expressed most in digestive glands.We detected the m RNA expression levels of aryl hydrocarbon receptor signaling pathway,and detoxification system in digestive glands of clams exposed to benzo[a]pyrene(Ba P),chrysene(CHR),benzo[a]anthracene(Ba A),benzo[b]fluoranthene(Bb F),and Ba P+CHR+Ba A+Bb F,respectively.Among these genes,we selected GST-sigma,GST-omega and GST-pi as potential indicators to Ba P;GST-sigma,GST-A and GST-rho to CHR;GST-pi,GST-sigma,GST-A,GST-rho and GST-microsomal to Ba A;GST-theta and GST-mu to Bb F;while GST-pi and GST-mu to the mixture of Ba P,CHR,Ba A and Bb F.Additionally,the bioaccumulation of PAHs in tissues increased remarkably over time,and showed an obvious doseeffect.Under the same concentration,the bioaccumulation in single exposure group was higher than that in mixture group,and the bioaccumulation of PAHs in tissues with different concentrations of stress was irregular.The results revealed the metabolic differences and bioaccumulation rules in clams exposed to four kinds of PAHs,and provided more valuable information for the PAHs risk assessment.

四种消毒剂对菲律宾蛤仔的急性毒性研究

为获得4种消毒剂对菲律宾蛤仔(Ruditapes philippinarum)成贝的安全浓度,为菲律宾蛤仔人工催产前消毒处理提供理论依据,采用静态急性毒性试验法,检测了高锰酸钾、聚维酮碘、二氧化氯和甲醛4种消毒剂对菲律宾蛤仔的急性毒性。结果表明,4种消毒剂的安全浓度分别为高锰酸钾(0.24 mg/L)、聚维酮碘(11.04 mg/L)、二氧化氯(0.68 mg/L)、甲醛(1.87 mg/L),4种消毒剂对菲律宾蛤仔的毒性大小为高锰酸钾>二氧化氯>甲醛>聚维酮碘。在菲律宾蛤仔的催产育苗和养殖过程中宜选用聚维酮碘进行消毒。

LPS胁迫下五个群体菲律宾蛤仔TYR基因在鳃和肝胰腺中表达特性研究

为了解TYR基因与蛤仔免疫的关系,本实验利用荧光定量PCR技术研究了菲律宾蛤仔五个群体(白蛤、白斑马蛤、斑马蛤、养殖和野生群体)的鳃组织和肝胰腺组织在LPS胁迫下TYR基因在不同时间(0 h、3 h、12 h、24 h、48 h)的表达特性。结果表明,在LPS注射后鳃组织中TYR6基因表达水平在白蛤和白斑马蛤3 h、6 h、12 h,野生蛤仔3 h,斑马蛤3 h、6 h,养殖群体6 h、12 h显著上调(P<0.05),3h野生蛤仔和斑马蛤达到峰值, 6 h白蛤、白斑马蛤、养殖群体达到峰值(P<0.05);在肝胰腺中,养殖群体和白斑马蛤6 h,白蛤6 h、24 h,野生群体24 h,斑马蛤3 h显著上调, 3 h野生蛤仔和斑马蛤达到峰值,6h养殖群体、白蛤、白斑马达到峰值(P<0.05);鳃组织中TYR10基因表达水平在白蛤、野生群体和白斑马蛤3 h,养殖群体3 h、6 h,斑马蛤3 h、12 h显著上调(P<0.05),肝胰腺组织中TYR10基因表达水平在白蛤3 h,野生群体3 h、6 h、12 h,斑马蛤、养殖群体6 h显著上调(P<0.05),推测TYR基因在五个菲律宾蛤仔群体的鳃和肝胰腺中参与了免疫应答。通过对TYR基因的氨基酸序列进行二级结构分析和系统发育树分析,找到两个铜离子结合位点和6个组氨酸残基,并发现TYR6基因和长牡蛎同源性最高,为39.43%, TYR10基因和大珠母贝同源性最高,为51.04%。本文首次探讨在LPS胁迫下菲律宾蛤仔TYR基因的表达特性,为进一步探究TYR基因与菲律宾蛤仔免疫应答机制提供参考。

Larval and Juvenile Growth Performance of Manila Clam Hybrids of Two Full-Sib Families

In order to determine whether growth performance could be improved by hybridizing full-sib families of Manila clam （Ruditapes philippinarum）, crosses between two full-sib families including self and reciprocal crosses were carried out. The effects of heterosis, combining ability and interaction on the growth of shell length were estimated. The results showed that the growth of hybrid larvae was intermediate between parents on days 6 and 9. Heterosis on shell length was observed, which varied at juvenile stage. The cross of ♂A×♀B （Hp varied between 10.41% and 68.27%） displayed larger heterosis than ♂A×♀B （Hp varied between 1.89% and 32.33%） did, suggesting that ♂A×♀B was an ideal hatchery method of improving the growth performance of Manila clam. The variances of general combining ability （GCA）, special combining ability （SCA） and interaction （I） were significant in shell length （P〈 0.05）, indicating that both additive and non-additive genetic factors were important contributors to the growth of larvae and juveniles. The GCA for shell length of ♂A×♀B was higher than that of ♂A×♀B at both larval and juvenile stages. This con- firmed that the cross between ♂A and ♀B showed great growth in shell length. In summary, the growth of Manila clam seeds could be improved by hybridizing selected parents from large numbers of full-sib families.

Effect of Epinephrine on the Settlement and Metamorphosis of Manila Clam Larvae

Chemical inducement and DDRT-PCR （differential display reverse transcription PCR） are adopted to investigate the effect of epinephrine （EPI） on the settlement and metamorphosis of Manila clam larvae. Chemical inducement shows that EPI has an effect to some extent on the metamorphosis of Manila clam larvae at all concentrations and in all treatments designed. The most significant result of inducement is obtained at the concentration of 10^-6 tool L^-1 and for 4 h. DDRT-PCR using six primer pairs shows that the gene expression pattern is quite different between EPI treatment and the control. Three hundred and forty-three amplification bands are obtained in total, among which, 67 （19.53%） are differentially appeared. Therefore, EPI has an effect on the gene expression of the eye spot larval Manila clam. It can be hypothesized that EPI is a settlement and metamorphosis inducer for Manila clam. EPI may lead to larvae settlement and metamorphosis by binding to the receptors on the membrane and then changing the gene expression of larvae cells.

碱蓬-黑鲷-菲律宾蛤仔生态混养模式探究

为探究一种海水生态混养模式,以碱蓬(Suaeda glauca Bunge)、黑鲷(Sparus macrophslus)和菲律宾蛤仔(Ruditapes philippinarum)为养殖对象,通过设置碱蓬-菲律宾蛤仔、碱蓬-黑鲷、碱蓬-黑鲷-菲律宾蛤仔、黑鲷-菲律宾蛤仔4种混养模式(黑鲷鱼苗养殖密度为155尾/m3、菲律宾蛤仔养殖密度为75 ind./m^(2)),在养殖过程中监测各体系水质指标以及养殖对象生长指标。结果表明,碱蓬-黑鲷体系、碱蓬-菲律宾蛤仔养殖体系具有较强的水体自净能力,水体氨氮、总磷、亚硝酸盐氮含量在养殖后期均呈现下降趋势,两种体系呈现较好的稳定性,而菲律宾蛤仔与黑鲷混养的两种体系水质指标较差,养殖对象死亡率高,系统缺乏稳定性。在黑鲷鱼苗155尾/m^(3)、菲律宾蛤仔75 ind./m^(2)密度条件下适宜建立碱蓬-黑鲷或碱蓬-菲律宾蛤仔混养模式,体系中碱蓬不仅可以净化水质,而且可以增加养殖水体溶解氧含量、稳定养殖水体pH。

红鳍东方鲀-日本对虾-菲律宾蛤仔的池塘生态立体养殖试验

为探索出适合河北省海水池塘的高效养殖技术新模式,开展“红鳍东方鲀—日本对虾—菲律宾蛤仔”混养试验,菲律宾蛤仔(Ruditapes philippinarum)投放密度为1500 kg/hm^(2),日本对虾(Penaeus Japonicus)放养密度为45000尾/hm^(2),红鳍东方鲀(Takifugu rubripes)投放密度分高、中、低三个梯度进行养殖对比。养殖试验结果表明,池塘生态立体养殖中红鳍东方鲀投放密度为1200尾/hm^(2)时,红鳍东方鲀成活率约为95%,成鱼产出规格1.09 kg/尾,产量约1250 kg/hm^(2),鱼虾合计产量约1500 kg/hm^(2),有利于提高池塘的生产能力。