pH值和Ca~（2＋）浓度对日本沼虾生长和能量收支的影响

本文报道了不同ｐＨ值（６．５、７．５和８．５）和不同Ｃａ２＋浓度（３８．８．６１．１和７８．８ｐｐｍ）对日本沼虾生长和能量收支的影响。实验结果表明，ｐＨ值对该虾的生长有一定的影响，Ｃａ２＋和ｐＨ值在影响其生长的过程中可能有一定的交互作用。ｐＨ值和Ｃａ２＋对该虾生长的影响主要是通过影响其能量摄入量实现的。本实验条件下，该虾摄入的能量平均有１５．８％用于生长，１．８％作为粪便排出体外，其余用于呼吸和排泄。     

水环境中Ca^2＋,Mg^2＋对中国对虾生存及生长的影响

通过单因子静态急性毒性试验和正交设计法，研究水环境中Ｃａ＾２＋、Ｍｇ＾２＋、Ｃａ＾２＋、Ｍｇ＾２＋总量及Ｃａ＾２＋／Ｍｇ＾２＋比值对中国对虾生存及生长的影响。结果表明：（１）中国对虾在水环境中能够生存的Ｃａ＾２＋、Ｍｇ＾２＋质量浓度范围分别为２４．９２￣２８０．６６ｍｇ／Ｌ、３４．５￣３４４．９ｍｇ／Ｌ；（２）Ｃａ＾２＋／Ｍｇ＾２＋比值为１：１０，对中国对虾的生存没有影响；（３）中国对虾的生长与Ｃ     

碳酸盐碱、pH对中国对虾幼虾的致毒效应

实验结果表明，ｐＨ为８．６、９．０、９．３和９．５时，中国对虾（Ｐｅｎａｅｕｓ ｃｈｉｎｅｎｓｉｓ）幼虾２４ｈ半致死碱度（ＬＣ５０）分别为２２．００、１１．６６、６．５７和３．２８ｍｍｏｌ／Ｌ；随着碱度、ｐＨ的升高，中国对虾幼虾的存活率下降。碱度和ｐＨ对幼虾的致毒效应应具综合作用，ｐＨ８。６～９．０时，ＨＣＯ３＾－、ＣＯ３＾２－共同影响幼虾的存活率；ｐＨ９．０～９．５时，ＯＨ＾－协同ＣＯ３＾２－影     

刀额新对虾的快速自溶技术

通过对刀额新对虾快速自溶影响因素的研究,为虾组织快速自溶技术提供了一个基本模式。结果表明：紫外线照射２０分种、Ｎａ＾＋对虾组织快速自溶有促进效果,而Ｋ＾＋、Ｃａ＾２对虾组织自溶基本无影响;ｐＨ７．０～７．５时,自溶效果最佳;采用４５～６０℃（５℃／ｍｉｎ）的梯度温度优于４５℃、５５℃、６５℃恒温反应的效果。虾组织自溶反应时间为３小时左右,蛋白质水解率可达８０％以上。     

pH和盐度对斑节对虾存活,生长和渗透调节能力的影响

斑节对虾幼虾（平均体重４．２－５．５ｇ）的ｐＨ低临界值使用盐酸醋化海水的静态生物测定的方法来求得。在盐度３２ｐｐｔ进其致死ｐＨ（即９６ｈＬＣ５０的ｐＨ）为３．７（９５％置信度是３．４和４．１）。最小可采用的ｐＨ（此ｐＨ在２３ｄ中使生长减少５％），在盐度为３０ｐｐｔ时估算为５．９。同ｐＨ７．８相比较，长期（２３ｄ）置于低ｐＨ（４．９），盐度为３０ｐｐｔ时，对虾于民分明显减少（Ｐ＜０．００１），而蜕皮     

条纹石鮨摄食强度与代谢及能量收支间的关系

设日摄食率为０．４％、１．５％、４．０％三种水平，分别测定条纹石鱼旨Ｍｏｒｏｎｅｓａｘａｔｉｌｉｓ幼鱼的代谢及能量的收支情况。处于饱食（日摄食率４．０％）及维持状态（日摄食率１．５％）下，该鱼代谢率增加的峰值分别于摄食后３ｈ及７ｈ内出现，为静止时代谢水平的２．１０倍和２．４６倍，ＳＤＡ（特殊动力作用）持续时间均为２１ｈ，ＳＤＡ总耗能量分别占摄入能的１３％和３５．８％。条纹石鱼旨在饱食时的转化效率Ｋ（湿重）为２０．８５％。三种摄食水平下条纹石鱼旨的能量收支方程分别为：饱食状态（日摄食率４．０％）时，１００Ｃ＝８．４Ｆ＋７．８Ｕ＋１３．０ＳＤＡ＋３６．９（Ｒｓ＋Ｒａ）＋３３．９Ｇ；维持状态（日摄食率１．５％）时，１００Ｃ＝７．８Ｆ＋４．１Ｕ＋３５．８ＳＤＡ＋５２．３（Ｒｓ＋Ｒａ），其中Ｇ＝０；减重状态（日摄食率０．４％）时，（Ｆ＋Ｕ＋Ｒ）／（Ｃ＋Ｐ１）＝６７．３％，其中Ｃ＋Ｐ１＝１４．４Ｃ＋８５．６Ｐ１，Ｆ＋Ｕ＋Ｒ＝１．８Ｆ＋８．１Ｕ＋５７．４Ｒ。     

二氧化氯改善养殖水环境效果的研究

使用二氧化氯化处理水养殖用水（实验室规模）测定水化学指标及水中细菌数量的变动，结果表明：（１）二氧化氯能够明显中水环境的溶氧（增氧量为５．８－２２．７％）减低水中ＣＯＤ和ＮＨ３－Ｎ值（ＣＯＤ降低幅度为２６．０－５８．８％，ＮＨ３－Ｎ清除率为１９．４－３８．５％）（２）二氧化氯浓度为０．２×１０＾－３ｍｏｌ／ｍ＾３及１．２×１０＾－３ｍｏｌ／ｍ＾３可有显降低海水中弧菌数及细菌总数，随着药物浓度增大，     

团头鲂配合饲料中锰和钴添加量的研究

试验按两因子三水平有重复试验设计，网箱养团头鲂。经９０天饲养结果表明，配合饲料中锰（Ｍｎ＾２＋）和钴（Ｃｏ＾２＋）的添加量分别为１２．９ｐｐｍ和２３．４ｐｐｍ时，团头鲂鱼种的生长效果相对最佳，饲料中添加适量的Ｃｏ＾２＋对团头鲂的生长有促进作用，且在０－２３．４ｐｐｍ范围内有递增趋势，当Ｍｎ＾２＋的添加量为２５．８ｐｐｍ时，其生长相对减慢。     

温流水养鱼系统对电厂冷却水影响的研究

对具有水处理设施的温流水养鱼系统的供水、养鱼水及回水进行了水质分析，结果：ＰＨ值、ＤＯ、ＡＬＫ、Ｃａ＾２＋和水温依次下降，经过集中水处理后的回水ＣＯＤ、ＢＯＤ５、ＴＨ、ＳＳ和Ｍｇ＾２＋的值有所下降，ＢＯＤ５去除率为５４．３８％，悬浮物去除率为６７．５４％；ＮＨ４＾＋－Ｎ和ＮＯ２＾－－Ｎ依次升高；电导率无明显变化；而ＮＯ３＾－－Ｎ供水略高于养鱼水，在此基础上讨论了温流水养鱼系统对电厂冷却水的正面影响     

甲基汞对鲤鱼血浆渗透压及鳃丝Na^＋—K^＋—ATPase活性的影响

以水体甲基汞不同浓度（μｇ／Ｌ）分别染毒鲤鱼２４小时和１周。实验结果表明：在浓度高于５０μｇ／Ｌ染毒２４小时和浓度２０μｇ／Ｌ染毒１周时，多数染毒鱼的血浆Ｋ＾＋和Ｍｇ＾２＋浓度增高，Ｎａ＾＋和Ｃｌ＾－浓度下降，ＰＯ４＾３－值变化不明显。血浆Ｃａ＾２＋浓度仅在２００μｇ／Ｌ染毒２４小时和高于４０μｇ／Ｌ染毒１周时，染毒鱼的血浆Ｃａ＾２＋出现极显著下降。甲基汞量高于１００μｇ／Ｌ染毒２４小时和８０μｇ     

The effects of different Ca2+ concentration fluctuation on the moulting,growth and energy budget of juvenile Litopenaeus vannamei (Boone)

A 40‐day experiment was conducted to investigate the effects of different Ca²⁺ concentration fluctuation on the moulting, growth and energy budget of juvenile Litopenaeus vannamei with an initial wet body weight of (1.20±0.01) g. The Ca²⁺ concentration of the control group C385 was 385 mg L^?1 throughout the experiment, while the Ca²⁺ concentration of the C591, C803, C1155 and C2380 groups periodically fluctuated from 385 to 591, 803, 1155 and 2380 mg L^?1 respectively. The moulting frequency (MF) of the shrimp in the Ca²⁺ concentration fluctuating groups was significantly higher than those in the control group (P<0.05). The specific growth rates (SGR_d) and feed intake of the shrimp in the C591 and C803 groups were significantly higher than those in other groups (P<0.05), but no significant differences in feed efficiency were found among all groups (P>0.05). The shrimp in C591 and C803 groups spent significantly less energy in respiration, while depositing significantly more energy for growth than those in other three groups (P<0.05). These results showed that proper Ca²⁺ concentration fluctuation could increase the MF and growth rate of the juvenile L. vannamei, and according to the regression formula made using SGR_d and range of Ca²⁺ concentration fluctuation, periodically enhanced Ca²⁺ concentration of 295 mg L^?1 in the seawater was suggested to be used in shrimp culture.     

Effects of constant Ca2+ concentration in salinity fluctuations on growth and energy budget of juvenile Litopenaeus vannamei

A 50-day experiment was conducted to investigate the effects of constant Ca²⁺ concentration in salinity fluctuations on growth and energy budget of juvenile Litopenaeus vannamei. The salinity and Ca²⁺ concentration of control group S0 were kept 30‰ and 385 mg l⁻¹, respectively throughout the experiment while the ranges of salinity fluctuations of the treatment groups S5 and S5C, S10 and S10C, S15 and S15C, S20 and S20C were 5, 10, 15, and 20‰, respectively. The Ca²⁺ concentration of the treatment groups S5, S10, S15, and S20 (salinity fluctuation groups) changed with salinities, while the Ca²⁺ concentration of the treatment groups S5C, S10C, S15C, and S20C (constant Ca²⁺ concentration groups) was kept 385 mg l⁻¹ during the experiment. The results were as follows: (1) There were no significant differences in SGR of shrimp in salinity fluctuation groups (P > 0.05); But shrimp in the groups S15C and S20C had significantly higher SGR than those in the groups S5C and S0 in constant Ca²⁺ concentration groups (P < 0.05); (2) Results of the t test showed that significant differences in SGR were also found between S15 and S15C (P = 0.012), and between S20 and S20C (P = 0.013); (3) The shrimp in groups S15C and S20C deposited significantly more energy for growth and spent significantly less energy in respiration than those in groups S15 and S20 (P < 0.05), respectively. These results showed that compared with constant salinity and fluctuating salinities, the growth performance of shrimp under constant Ca²⁺ concentration in large ranges of salinity fluctuations could be better.     

Effects of Na/K and Mg/Ca ratios in saline groundwaters on Na-K-ATPase activity, survival and growth of Marsupenaeus japonicus postlarvae

The effects of the Na⁺/K⁺ and Mg²⁺/Ca²⁺ ratios in saline groundwaters on Na⁺-K⁺-ATPase activity, survival and growth of Marsupenaeus japonicus postlarvae were investigated. The results indicate that the Na⁺-K⁺-ATPase activity, survival rate and weight gain of postlarvae were significantly affected by the Na⁺/K⁺ and Mg²⁺/Ca²⁺ ratios (P < 0.05). The Na⁺-K⁺-ATPase activity of postlarvae, in every treatment, changed corresponding to Na⁺/K⁺ and Mg²⁺/Ca²⁺ ratios, and came to a stable level after 24 h. There was a negative relation between Na⁺-K⁺-ATPase activity and Na⁺/K⁺ ratio, while there was a positive relation between Na⁺-K⁺-ATPase activity and Mg²⁺/Ca²⁺ ratio. Compared with seawater (the Na⁺/K⁺ and Mg²⁺/Ca²⁺ ratios are 27.8 and 4.64 respectively), the Na⁺-K⁺-ATPase activity of the Na⁺/K⁺ ratio 30 treatment showed no significant difference, while the Mg²⁺/Ca²⁺ ratio 4.5 treatment showed distinct difference. The survival rates and weight gain of postlarvae increased markedly when the suitable amount of K⁺ and Ca²⁺ was added to test water, and arrived at their maximum in the Na⁺/K⁺ ratio 20-30 or Mg²⁺/Ca²⁺ ratio 4.5 treatment, having no significant difference compared with normal seawater. Therefore, considering the Na⁺/K⁺, Mg²⁺/Ca²⁺ ratios and the absolute concentration of Mg²⁺, Ca²⁺ in the experimental saline groundwaters applied to Marsupenaeus japonicus farming, it should be modulated to around 30, 4.5 and 1312 mg/l, 291 mg/l, respectively.     

Effect of Cryoprotectants on Suppression of Protein Structure Deterioration Induced by Freeze-thaw Cycle in Pacific White Shrimp

This study aimed to elucidate the changes in Pacific white shrimp (Litopenaeus vannamei) myofibrillar protein as influenced by multiple freeze-thaw cycles as well as the stabilization effects of sucrose and trisodium citrate on shrimp myofibrils. Shrimp myofibrils in 0.1 M NaCl, 20 mM Tris-HCl (pH 7.5) were mixed individually with sucrose and citrate at concentrations of 0.05 M and were evaluated for Ca²⁺-ATPase activity, salt solubility, total and reactive sulfhydryl, and surface hydrophobicity during three freeze-thaw cycles. Sucrose and citrate had strong cryoprotective effects against freeze denaturation by retaining higher Ca²⁺-ATPase activity and salt-soluble myosin and actin, by slowing the reduction of reactive sulfhydryl (SH) and by exposing less hydrophobic groups at the surface of the protein compared with the no-additive sample. Results indicated that both cryoprotectants had suppressive effect against protein denaturation and helped stabilize white shrimp myofibrillar protein during the freeze-thaw process. This study suggests that sucrose and citrate stabilized the protein structure by retarding the unfolding of protein; thus, the native protein could be protected during frozen storage.     

Delivery of HUFA, probionts and biomedicine through bioencapsulated Artemia as a means to enhance the growth and survival and reduce the pathogenesity in shrimp Penaeus monodon postlarvae

One of the major problems in the shrimp culture industry is the difficulty in producing high-quality shrimp larvae. In larviculture, quality feeds containing a high content of highly unsaturated fatty acids (HUFA) and ingredients that stimulate stress and disease resistance are essential to produce healthy shrimp larvae. In the present study, Penaeus monodon postlarvae (PL15) were fed for 25 days on an unenriched Artemia diet (control; A) or on a diet of Artemia enriched with either HUFA-rich liver oil of the trash fish Odonus niger (B), probionts [Lactobacillus acidophilus (C1) or yeast-Saccharomyces cerevisiae (C2)] or biomedicinal herbal products (D) that have anti-stress, growth-promoting and anti-microbial characteristics. P. monodon postlarvae fed unenriched Artemia exhibited the lowest weight gain (227.9 ± 8.30 mg) and specific growth rate (9.95 ± 0.05%), while those fed the HUFA-enriched Artemia (B) exhibited the highest weight gain and specific growth rate (362.34 ± 12.56 mg and 11.77 ± 0.08%, respectively). At the end of the 25-day rearing experiment, the shrimp postlarvae (PL40) were subjected to a salinity stress study. At both low and high (0 and 50‰) salinities, the group fed the control diet (A) experienced the highest cumulative mortality indices (CMI) 935.7 ± 2.1 and 1270.7 ± 3.1, respectively. Those fed diet D showed the lowest stress-induced mortality, and CMI were reduced by 31.1 and 32.3% under conditions of low and high salinity stress, respectively. A 10-day disease challenge test was conducted with the P. monodon postlarvae (PL40–PL50) by inoculating the shrimp with the pathogen Vibrio harveyi at the rate of 10⁵–10⁷ CFU/ml in all rearing tanks. P. monodon postlarvae fed probiont-encapsulated Artemia diets (C1 and C2) exhibited the highest survival (94.3 and 82.3%, respectively) and lowest pathogen load (V. harveyi) in hepatopancreas (5.2 × 10² ± 9.0 × 10 and 4.6 × 10² ± 9.0 × 10 CFU g⁻¹, respectively) and muscle (2.0 × 10² ± 6 × 10 and 1.7 × 10² ± 8.6 × 10 CFU g⁻¹, respectively) tissues. The shrimp that were fed the unenriched Artemia (Control; A) showed the lowest survival (26.33%) and highest bacterial load in the hepatopancreas (1.0 × 10⁵ ± 5 × 10³ CFU g⁻¹) and muscle (3.6 × 10⁴ ± 6 × 10² CFU g⁻¹). The shrimp fed the herbal product (D)-enriched Artemia also exhibited enhanced survival and reduced V. harveyi load in the tissues tested compared to the control diet (A) group. The results are discussed in terms of developing a quality larval feed to produce healthy shrimp larvae.     

Effects of Decomposing Rhizophora apiculata Leaves on Larvae of the Shrimp Penaeus monodon

We studied the effects of different concentrations of decomposing Rhizophora apiculata leaves and their leachates on larvae of the shrimp Penaeus monodon under laboratory conditions. Shrimp mortality was highly dependent on the concentration of oxygen in the water, which in turn was strongly correlated to the amount of decomposing leaves in the same water. Shrimps died after 5 min when placed in water containing the highest concentration of mangrove leachates (15 g l⁻¹) tested in our experiments. Shrimp survival and biomass decreased significantly when the shrimp were cultured at the relatively higher concentrations of leaves and leachates (10 and 15 g l⁻¹); in contrast, moderate amounts of leaves or their leachates (2.5–5 g l⁻¹) had positive effects on shrimps. The survival and biomass of shrimps cultured with plastic leaves was lower than those of shrimps cultured with mangrove leaves, indicating that food derived from mangrove leaves contributed to a higher shrimp survival and biomass. These results have important implications for the culture of shrimps in extensive mangrove-shrimp systems. While litter may promote shrimp production, high leaf concentrations may have negative effects due to the drop in the oxygen concentration. Water circulation may help to prevent low oxygen conditions and reduce local accumulations of mangrove leaves.     

虾夷扇贝闭壳肌和外套膜肌原纤维蛋白的特性分析

为探索采捕后活品虾夷扇贝品质变化与其肌肉蛋白质生理特性变化间的关联,本研究以虾夷扇贝2个可食部肌肉为研究对象,以肌原纤维蛋白ATPase活性为指标(Ca²⁺-ATPase,Mg²⁺-ATPase),对扇贝肌原纤维蛋白(Mf)的稳定性进行了系统探索。首先,分别提取闭壳肌肌原纤维(A-Mf)和外套膜肌原纤维(M-Mf);然后,考察了不同因素(离子强度I、pH、温度)对Mf的ATPase活性的影响规律;对A-Mf及M-Mf的稳定性进行了探索;进一步比较了闭壳肌和外套膜肌原纤维蛋白ATPase的失活特性。研究结果表明:(1)虾夷扇贝闭壳肌与外套膜的Mf的理化性质相似,A-Mf与M-Mf的pI均在5.0附近,粘度分析发现A-Mf热稳定性高于M-Mf。(2)ATPase活性变化规律的结果发现,与脊椎动物中的鱼类一样,作为无脊椎动物的扇贝,与Mg²⁺-ATPase相比,Ca²⁺-ATPase更能准确地反映Mf的稳定性。(3)闭壳肌和外套膜二者的Mf的Ca²⁺-ATPase呈现出共同特性,在pH为中性时活性最高;A-Mf与M-Mf的差异性则表现为前者的Ca²⁺-ATPase在较低离子强度(I=0.2)下活性最高,后者则在较高离子强度(I=0.5)下活性最高;离子强度对A-Mf的热稳定性影响不明显,而M-Mf的热稳定性明显受到离子强度的影响,其在较低离子强度下表现出更好的稳定性。(4)Ca²⁺-ATPase失活速率的研究发现,无论是闭壳肌还是外套膜,其稳定性与离子强度I和温度均呈现显著正相关(R²=0.8181、0.8436和R²=0.9887、0.9557);二者在pH 7.0左右的稳定性最好,偏离中性会促使Ca²⁺-ATPase失活,与碱性条件相比,酸性对蛋白质稳定性的破坏更加明显。     

Effects of ambient ion concentrations on gill ATPases in fresh water eel,Anguilla anguilla

Branchial activities of Na⁺,K⁺-ATPase (ouabain sensitive), Mg²⁺ ATPase (ouabain insensitive) and kinetic analysis of high and low affinity Ca²⁺ ATPase were measured inAnguilla anguilla that had been acclimated to demineralized water (DW, Ca < 10 M), freshwater (FW, Ca = 2 mM), and Low calcium freshwater (L-Ca, Ca = 0.9 mM). Na⁺,K⁺-ATPase activity decreased while ouabain insensitive activity increased when ambient Ca²⁺ decreased. Two kinetic forms of Ca²⁺ ATPase could be resolved in each environmental condition. The stimulation coefficients of both sites or enzymes were not affected by ambient Ca²⁺ concentrations. The maximal velocity of both the high and the low affinity Ca²⁺ ATPase was increased when external Ca²⁺ was decreased during acclimation. The low affinity Ca²⁺ ATPase and the Mg²⁺ stimulated enzyme could be a non specific enzyme accepting either Ca²⁺ or Mg²⁺. Results are compared with previous results in the literature and in relation to the branchial morphology and ionic exchanges in fish.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.