栉孔扇贝对环境变化适应性研究－温度对存活、呼吸、摄食及消化的影响

取体长分别为 ３和 ５ ｃｍ 栉孔扇贝（Ｃｈｌｙｍｙｓ ｆａｒｒｅｒｉ）置室内水泥池流水暂养 １周后进行实验。结果表明，栉孔扇贝 ９６ ｈ的半致死温度为 ２７～２８℃，导致其耗氧率突然升高和滤水率急剧下降的温度为 ２６℃，体内淀粉酶活性下降的温度为２７℃。因此确定，栉孔扇贝的适宜极限高温为２７℃。在水温２７℃持续９６ ｈ后，扇贝呼吸量迅速增大，随后减弱，摄食和消化能力逐渐降低；在 ２７℃持续 ５ ｄ，死亡率为 ５０％， ７ ｄ时全部死亡；在相同温度下，个体小的较个体大的耐高温程度要强一些。     

盐度变化对栉孔扇贝钙化与呼吸的影响

通过碱度异常技术( Alkalinity anomaly technique)方法测定了栉孔扇贝(Chlamys farreri)在不同盐度条件下的钙化率和呼吸率,发现栉孔扇贝的钙化和呼吸活动受盐度影响显著(P＜0.5).在海水盐度为15～25时,钙化率随盐度提高呈上升趋势,后随盐度降低而下降.在盐度为15 ～ 25,呼吸率随盐度提高而增大,盐度为25 ～ 35,呼吸率下降.钙化率与呼吸率均在盐度25时达到最高值,分别为0.33±0.02 μmol/( FW g·h)(钙化率)、(2.32±0.10) μmol/(FW g·h)(碳呼吸)、2.87±0.14 μmol/(FW g·h)(氧呼吸),此时钙化和呼吸活动向环境释放CO2也最强烈.     

栉孔扇贝（Chlamys farreri）在模拟自然水环境中滤水率的测定

在模拟自然海区的生态环境的条件下，对桑沟湾内主要养殖种类栉孔扇贝的滤水率进行了测定，对其不同体长扇贝的滤水率进行了实验比较。在水温２４－２６℃。盐度３１－３２‰范围内，昼间光照５００Ｌｕｘ左右条件下，用叶绿素和颗粒有机物作为测定指标，结果表明，此种扇贝的滤水率随个体增大，单位个体的滤水率越大，而单位干组织重的滤水率越小；同一规格扇贝，密度越大，滤水率越低。在本实验过程中，昼夜间的滤水率变化不甚明显     

栉孔扇贝生殖活动前后的滤食和生长

在桑沟湾用模拟现场流水法对栉孔扇贝的摄食生理进行了比较研究。结果表明，栉孔扇贝在进行生殖活动前后滤水率无明显的差异，但进行生殖活动前的摄食量较大。尽管栉孔扇贝的滤水率和摄食量随着个体的增大而增加，它的吸收率却与个体大小无关。在３００￣６００ｍｌ／ｍｉｎ的水流范围内栉孔扇贝的滤水率没有明显的变化，水流小于３００ｍｌ／ｍｉｎ时扇贝的滤水率则明显降低。根据实验数据，用计算机模拟得出了栉孔扇贝在生殖活动前     

栉孔扇贝对环境变化适应性研究一温度对存活,呼吸,摄食及消化？…

取体长分别为３和５ｃｍ栉孔扇贝（Ｃｈｌｙｍｙｓ ｆａｒｒｅｒｉ）置室内水泥池流水暂养１周后进行实验。结果表明，栉孔扇贝９６ｈ的半致死温度为２７～２８℃，导致其耗氧率突然升高和滤水率急剧下降的温度为２６℃，体内淀粉酶活性下和的温度为２７℃。因此确定，栉孔扇贝的适宜极限高温为２７℃。在水温２７℃持续９６ｈ后，扇贝呼吸量迅速增大，随后减弱，摄食和消化能力逐渐降低；在２７℃持续５ｄ，死亡率为５０％，７ｄ时     

海洋酸化对栉孔扇贝钙化、呼吸以及能量代谢的影响

通过Alkalinity anomaly technique测定了栉孔扇贝Chlamys farreri在不同酸度条件下的钙化率和呼吸率,发现栉孔扇贝的钙化和呼吸活动受酸化影响显著,均随着酸化的加剧出现了明显下降。当pH降低到7.9时,栉孔扇贝的钙化率将会下降33%左右;当pH降到7.3左右时,栉孔扇贝的钙化率将趋近于0,栉孔扇贝无法产生贝壳,而此时栉孔扇贝碳呼吸率(RC)与耗氧率(RO)也分别下降了14%和11%。随着酸化的加剧,栉孔扇贝的能量代谢方式也会发生改变。这些变化都可能影响到栉孔扇贝的生存。     

栉孔扇贝生理能量学研究

在室内实验条件和现场模拟条件下对栉孔扇贝的耗氧率、排泄率、摄食率、同化率和能量收支进行了较为系统的研究。结果显示 ,在适宜的温度范围内 ,栉孔扇贝的耗氧率、排氨率和摄食率均与温度成正比 ,与体重成幂函数关系 ,体重与耗氧率、排氨率和摄食率的关系均可用幂函数关系式Y=aWb表示。在 8～ 2 8℃温度范围内栉孔扇贝的耗氧率、排氨率和摄食率均随温度的升高而增大 ,2 3℃时耗氧率和摄食率达到最高值 ,2 8℃时下降 ,而排氨率则呈持续升高的趋势 ,其变化幅度分别为 0 4 8～ 9 0 9mg/ g·h、0 0 5～ 1 0 1mg/ g·h和 1 0 7～ 11 6 6mg/ g·h。栉孔扇贝的摄食率随藻类密度的增加而增加 ,符合关系式 :IR =4 78C0 36 6 (R2 =0 97,P <0 0 5 )。栉孔扇贝的同化率与饵料密度呈负相关关系 ,而与饵料质量呈正相关关系 ,其相关关系分别为 :AE =4 7 6 5C- 0 30 9(R2 =0 96 )和AE =5 1 6 8lnX - 112 38(R2 =0 97)。栉孔扇贝的个体大小是影响能量收支各组分比例的主要因素 ,随个体增大呼吸能增大 ,生长能减小。在能量收支方程中 ,呼吸能占总摄食能的 4 4 2 %～5 1 7% ,排粪能为 31 4 %～ 36 8% ,生长能为 12 7%～ 2 1 7% ,排泄能小于 2 %。     

盐度和饵料密度对栉孔扇贝稚贝滤水率的影响

采用静水法研究了恒定温度(24±0.5℃)、饵料密度(3.0×104cell/ml)、不同盐度(20、25、30和35)和恒定温度(24℃±0.5℃)、盐度30、不同饵料密度梯度(3.0×104、4.5×104和 6.0×104cell/ml)对栉孔扇贝稚贝(壳长1.177～2.017 mm)滤水率的影响.结果表明,栉孔扇贝稚贝的滤水率(FRS)开始随着盐度的升高而升高,在25～30之间存在最大值,然后随盐度的升高而下降,与盐度(S)间的相关关系为FRS ＝-30.893S2+1 691.5S-19 610 (r =0.847,以整体干重计算)或FRS＝-0.022S2+1.223 6S-14.522 (r = 0.928,以个体数量计), 通过公式推算在盐度27.8时FRS达到最大值,为3.54L/g*dw*h(2.49×10-3 L/ h*ind);投饵密度(Q)对栉孔扇贝稚贝的滤水率(FRQ)有显著影响(P< 0.05),二者之间的相关关系为FRQ=-0.069 3Q2+0.648 4Q-1.083 5(r = 0.722),其变化趋势亦呈现先升高后下降的抛物线趋势,推算金藻密度为4.7×104cell/ml时滤水率最大,为0.43×10-3 L/ h*ind.     

栉孔扇贝面盘幼虫和稚贝的滤水率昼夜节律

采用静水法研究了在水温18±0.5℃、饵料密度1.0×104 cell/ml下栉孔扇贝面盘幼虫滤水率的昼夜节律；在水温24℃±0.5℃、饵料密度3.0×104 cell/ml下栉孔扇贝稚贝(壳长1.177～2.017 mm)滤水率的昼夜节律.栉孔扇贝面盘幼虫和稚贝的滤水率分别于17:00、21:00、01:00、05:00、09:00和13:00测定.栉孔扇贝面盘幼虫和稚贝的滤水率均具有明显的昼夜节律,且二者相似.在白天滤水率较低,最低值出现在09:00～13:00,幼虫为0.002 6 ml/h · ind,稚贝为0.1231 ml/h·ind；在夜间有较高的滤水率,最大值出现在凌晨21:00～01:00,幼虫达0.025 8 ml/h·ind,稚贝达0.509 6 ml/h·ind.统计分析表明,栉孔扇贝稚贝和面盘幼虫的滤水率昼夜差异显著(P＜0.01).     

低温对栉孔扇贝能量收支的影响

研究低温下栉孔扇贝 (Chlamysfarreri)摄食、呼吸代谢、排泄及能量分配情况 ,为栉孔扇贝的反季节养殖提供生物学依据。在实验室条件下采用静水法 ,测定 3、5和 8℃时栉孔扇贝的能量收支。结果显示 ,在 3～ 8℃时 ,栉孔扇贝的耗氧率、排氨率、摄食率及生长率 (净生长率、毛生长率 )随温度的升高而增大 ;3℃时 ,栉孔扇贝虽然能摄食 ,但是生长率却很低 ;温度对能量分配影响较大 ,生长、排泄分配率随温度的升高而增大 ,呼吸、排粪的分配率与温度呈负相关。在能量收支方程中 ,生长能所占比例变化较大 ,为 17.61%～ 5 3 .2 7% ,代谢能为 2 1.4 8%～3 5 .91% ,排粪能为 2 2 .5 2 %～ 4 5 .99% ,排泄能所占的比例最小 ,低于 3 %。     

Effect of Salinity on Embryonic Development,Hatchability, and Growth of African Catfish,Clarias gariepinus,Eggs and Larvae

Abstract

Effects of salinity on embryonic development and growth of African catfish, Clarias gariepinus, eggs and larvae were studied. Eggs were incubated at 27-29°C in 2,4,6,8, and 10 ppt sodium chloride. Rate of embryonic development was delayed in all salt solutions by 15, 15,28 and 30 minutes, in 2,4,6, and 8 ppt sodium chloride, respectively, when compared with the control group (0% salt); total mortality occurred at 12 hours after gastrula stage in the 10 ppt concentration. Percentage hatching was 45.1,47.7, 59.5,49.2, and 26.6% while percentage deformity was 10.4, 16.1, 52.0, 28.6, and 71.6% in 0, 2, 4, 6, 8, and 10 ppt salt treatments, respectively. There were significant differences (P <0.05) in the hatching percentage and in deformity percentage between 4, 6, and 8 ppt. Rate of yolk absorption was significantly faster in the control and 2 ppt salt treatments, but slower in 4, 6, and 8 ppt. Rate of increase in length was slower with increasing salinity. The optimum salinity for African catfish eggs and was between 0-2 ppt and acceptable up to 6 ppt. The results suggest that increasing salinity delayed hatching and development of African catfish eggs and larvae, respectively, as well as increased the deformity of the larvae.     

Influence of season, initial size, depth, gear type and stocking density on the growth rates and recovery of sea scallop, Placopecten magellancius, on a farm-based nursery

Hatchery-reared sea scallop (Placopecten magellanicus) spat weremonitored for growth and recovery in three experiments to determine themost suitable system for nursery culture. In Experiment I, four size classesof nursery-sized spat held at two depths from October to July exhibiteddeclining growth rates over the winter period and increased growth ratesin the spring. Overall, season, depth and initial size had a significantinfluence on the absolute and specific growth rates of scallops. Recovery,defined as number of scallops remaining after mortality and loss of spatthrough gear mesh, was influenced by season and initial size, but notdepth. Scallops in the 3.0 mm⁺ size class had higher growth rates andrecovery than those in the 1.4–1.6 mm, 1.7–1.9 mm and 2.0–2.9 mm sizeclasses. In Experiment II, two gear types containing similar size spat werecompared. Growth rates were significantly higher in 3.0 mm pearl nets thanin 3.0 mm collector bags, although recovery was similar between the twoequipment types. Experiment III, two stocking densities of nursery-sizedspat were compared in collector bags. Neither growth rate nor recoverywere significantly different for the two densities (2600 and 5200spat/collector bag) tested. Overall, these studies indicated that importantparameters for optimizing the growth and recovery of scallops in a farm-based nursery system include season, initial spat size, deployment depthand gear type.     

响应面法研究温度、盐度、pH及磷酸盐、硝氮、氨氮对副溶血弧菌生长的影响

副溶血弧菌(Vibrio parahaemolyticus，VP)在海洋环境中普遍存在，是能够引起人类中毒的重要食源性病原菌之一，研究其生长受环境因子的影响规律对科研和社会生活都具有重要意义。本研究采用响应面法研究温度、盐度、pH、磷酸盐、硝氮和氨氮对VP的生长影响，以探讨、评估这6种理化因子的综合作用结果。首先用Design-Expert软件中的Box Behnken中心组合原则设计三因素三水平响应面实验，再进行响应面分析，以培养基光密度(OD600 nm)值为生长状态参数，获得该菌的最佳培养参数：温度为34.5℃，盐度为3%，酸碱度pH为8.0。在此基础上，考察NaNO3、NH4Cl和Na3PO4对VP生长的影响并建立模型。回归方程决定系数R2=0.9217，校正系数R2=0.8211，回归模型F=9.16, P=0.004，表明该模型具有较好的准确性。实验所得实测值与模型演算理论值拟合良好，皆表明磷酸盐、硝氮和氨氮对VP的生长都具有抑制作用。     

Studies on activity, distribution, and zymogram of protease, α-amylase, and lipase in the paddlefish Polyodon spathula

A series of biochemical determination and electrophoretic observations have been conducted to analyze the activities and characteristics of protease, α-amylase, and lipase of paddlefish Polyodon spathula. The results obtained have been compared with those of bighead carp (Aristichthys nobilis) and hybrid sturgeon (Huso dauricus ♀?×?Acipenser schrenki Brandt ♂), in order to increase available knowledge of the physiological characteristics of this sturgeon species and to gain information with regard to its nutrition. Further, a comparative study of enzymatic activity, distribution, and characterization between commercial feed-reared paddlefish (CG) and natural live food-reared (NG) paddlefish was conducted. Results showed that higher proteolytic activity was observed in the pH range 2.5-3.0 and at a pH of 7.0 for paddlefish. Levels of acid protease activity of paddlefish were similar to that of hybrid sturgeon, and significantly higher than that of bighead carp. The inhibition assay of paddlefish showed that the rate of inhibition of tosyl-phenylalanine chloromethyl ketone was approximately 2.6-fold that of tosyl-lysine chloromethyl ketone. There was no significant difference observed for acid protease activity between PG and CG groups, whereas the activity of alkaline protease, α-amylase, and lipase in the PG group were significantly lower than those in the CG group. The substrate sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis further showed that there were certain types of enzymes, especially α-amylase, with similar molecular mass in the paddlefish and hybrid sturgeon. It can be inferred that acid digestion was main mechanism for protein hydrolysis in paddlefish, as reported for other fishes with a stomach. This indicates that the paddlefish requires higher alkaline protease, α-amylase, and lipase activity to digest natural live food.     

盐化幅度、速度及方式对凡纳滨对虾仔虾生长和存活率的影响

本研究测定了盐化幅度(3/d、6/d、9/d、12/d和15/d)、盐化速度(1、3、6、12和18 h/次)和盐化方式(前期盐化、中期盐化、后期盐化和间隔盐化)与凡纳滨对虾(Litopenaeus vannamei)仔虾生长发育、活力和存活率的关系。研究结果显示，不同盐化幅度、盐化速度和盐化方式均显著影响盐化标粗过程中仔虾的生长发育、活力和存活率(P<0.05)。综合考虑生长性能、苗种活力和存活率等因素，最适盐化幅度为3~6/d，在该盐化幅度范围内，仔虾存活率可达74.07%~78.83%；盐化幅度超过9/d时，仔虾存活率显著下降(P<0.05)，其中，盐化幅度达到15/d时，存活率仅为43.37%。过快的盐化速度导致存活率和活力显著下降，盐化速度>1 h/次时，仔虾死亡率接近50%；随着盐化速度的放缓，仔虾生长速度加快，盐化速度为6~18 h/次时，生长速度维持稳定，日增重量为1.48~1.51 mg。在盐化方式方面，后期盐化和间隔盐化时，苗种的质量和存活率优于前期盐化和中期盐化，仔虾活力表现为间隔盐化>后期盐化>中期盐化>前期盐化。综合考虑，仔虾的最适盐化幅度为3~6/d，最佳盐化速度为6~12 h/次，后期盐化和间隔盐化更有助于仔虾保持较好活力和较高存活率。本研究通过探讨凡纳滨对虾苗种盐化标粗的最适盐化幅度、盐化速度和盐化方式，丰富了凡纳滨对虾高盐环境抗逆性研究，为凡纳滨对虾苗种的盐化标粗生产实践提供了理论支持。     

Effect of salinity on growth,survival, and serum osmolality of red snapper,Lutjanus campechanus

Fish Physiology and Biochemistry - Three trials were conducted to evaluate the performances of red snapper, Lutjanus campechanus, in low salinities. The median lethal concentration (96&nbsp;h...     

Effects of levamisole,echinacea, and thyme oral administration on growth factors,blood parameters,and immunity in beluga,Huso huso

A total of 180 fish (95.50 g) were fed with 0.1% levamisole, 0.5% thyme, and 0.5% echinacea crude extract for 60 days. The control group received no stimulant. The results of growth parameters indicated a significant positive effect of levamisole in comparison with the control group, though it was not significantly different from echinacea and thyme treatments (P > 0.05). No mortalities were observed in the treatments. Feed conversion ratio and protein efficiency ratio did not differ significantly between the treatments. The highest numbers of white and red blood cells and the greatest amounts of hemoglobin and hematocrit were detected in the levamisole treatment, showing significant differences with the other groups in the percentage of hemoglobin only (P < 0.05). The highest levels of MCH and MCHC were also measured in the levamisole treatment. Differential count of white blood cells revealed no significant differences in neutrophil and lymphocyte levels with the control. There was a significant increase in the percentage of eosinophil in the levamisole treatment alone. No significant differences were recorded in total protein, albumin, and aspartate aminotransferase and alanine aminotransferase enzymes. Levamisole treatment displayed the highest activities of glutathione peroxidase and lysozyme as well as the greatest amount of immunoglobulin. So 0.1 levamisole yielded better results in the growth, blood, and immunity parameters and can be used as a stimulant without injuring body organs.     

Effect of Temperature on Growth,Energy Budget,and Physiological Performance of Green,White, and Purple Color Morphs of Sea Cucumber,Apostichopus japonicus

As an intertidal species, Apostichopus japonicus is subject to diel and seasonal temperature fluctuations. Color variation is a distinct characteristic of A. japonicus, and a new color morph, purple A. japonicus, was recently found on the coast of Rushan, Weihai City. This study was conducted to compare the performance of green, white, and purple color morphs of A. japonicus at different water temperatures to help improving aquaculture technology and management. In this study, green, white, and purple color morphs of juvenile A. japonicus (1.5 ± 0.1 g) were cultured at 10, 14, 18, 22, and 26 C for 60 d, according to the suitable temperature range for sea cucumber growth. Temperature was shown to have a significant effect on growth, energy budget, and physiology of sea cucumbers (P < 0.05). Specific growth rates, feed conversion efficiencies, and the proportion of energy allocated to growth of all three color morphs were optimal at 18 C. Activities of the enzymes related with oxidative stress, immune response, and digestion were determined. Superoxide dismutase (SOD) and trypsin activities generally reached a maximum in all three color morphs at 18 C. The purple color morph of A. japonicus was higher in growth rate, food conversion efficiency, and proportion of energy allocated to growth than green and white color morphs at 18 and 22 C, consistent with its higher trypsin and SOD activity, indicating the mutual effect of growth and physiology. At 18, 22, and 26 C, the green color morph had the highest level of lysozyme activity and purple color morph had the lowest, indicating possible infection by external pathogens of green color morph, which might be caused by high temperature. These results suggested that the optimum temperature for culture of the three color morphs was approximately 18 C, the purple had a better adaption to high temperature, and the green and white color morphs may be more susceptible to thermal stress than the purple color morph.     

温度、盐度、pH和饵料密度对皱肋文蛤清滤率的影响

采用实验生态学方法研究了温度、盐度、pH和饵料密度对皱肋文蛤清滤率的影响,旨在为该贝养殖容量、摄食行为和能量学研究提供基础数据,以及为该贝在我国南方海域的健康养殖和推广提供依据。实验结果表明,皱肋文蛤清滤率随温度(13~33℃)、盐度(13~33)、pH(7~9)和饵料密度(2.5×104~10×104cell/ml)的变化而呈现峰值变化,各种环境因子对3种规格皱肋文蛤清滤率均具有极显著性影响(P<0.01)。当温度、盐度、pH和饵料密度分别为28℃、23、8和10×104cell/ml时,大、中、小规格皱肋文蛤清滤率均达到最大值,分别为1.06、1.78和2.42 L/g.h,0.35、0.65和1.05 L/g.h,1.26、1.67和2.02 L/g.h,1.29、2.07和2.29 L/g.h,表明温度为28℃、盐度为23、pH为8、饵料密度为10×104cell/ml是皱肋文蛤最适宜的摄食环境条件。大、中、小规格皱肋文蛤清滤率对温度、盐度、pH和饵料密度敏感性均表现为大规格<中规格<小规格,揭示皱肋文蛤在适宜的环境条件下,中、小规格个体摄食活动频繁,生长旺盛。     

Effects of stocking density on survival, growth, size variation, and production of Tilapia fry

In aquaculture, controls of size (length and weight) and production of fish are two important tasks to meet the market demands, and increasing the stocking density is a way of dealing with the problem of land shortage. In this study, tilapia fry were stocked at the densities of 0.1, 0.2, 0.4, 0.8, 1.6 and 3.2 fry I^?1 for an experimental period of 10 weeks. The size, size variation, percentage survival and production were found to be significantly affected by stocking density, but not for condition factor. The simple linear regression model, after the logarithmic transformation, was appropriate for the relationship between size and experimental period. The percentage survivals at all stocking densities were high (> 95%), especially at the stocking density of 0.4 fry I^?1 and less (100%). At the higher densities, percentage survival and experimental periods were anti-logistically related. At the end of the experiment, there was a negative relationship between the logarithms of size and the logarithms of stocking density, but a positive relationship between the logarithms of production and the logarithms of stocking density.