Optimal dietary taurine level for growth of juvenile Japanese flounder Paralichthys olivaceus

The requirement for taurine in juvenile Japanese flounder Paralichthys olivaceus was determined by feeding diets containing various levels of taurine and cystine. Test diets supplemented with 0.5, 1.0 and 1.5% of taurine or with 0.5, 1.0 and 1.5% of L -cystine were prepared. The basal diet contained 55% protein from white fish meal. These diets were fed to juvenile Japanese flounder with an initial mean bodyweight of 0.9 g (total length (TL) 48 mm) for 5 weeks. Approximately 1.4% taurine content in the diet was required for optimum growth of juvenile flounder. A positive linear relationship was noted between the content of taurine accumulated in the muscle, liver and brain and the level of taurine in the diet. However, there was no increased taurine content in tissues of fish fed the cystine-supplemented diet. In contrast, the fish fed control and cystine-supplemented diets showed higher contents of cystathionine in the tissues. The concentration of cystathionine in tissues rapidly decreased with an increase of taurine in the diet. It was also observed that for each of the dietary groups, a trace amount of taurine was excreted. These results suggest that the taurine content in the diet affects the sulfur amino acid metabolism of juvenile Japanese flounder, and indicate that juvenile flounder are unable to biosynthesize taurine from cystine.     

基于无线传感网络的海参苗养殖环境监测系统的研究

本文通过分析海参苗养殖现状,设计了一种基于无线传感网络的海参苗养殖环境监测系统。通过在监测区域部署传感器节点,监测养殖池中的的温度、盐度、溶解氧及水位等环境参数。将检测到的数据无线发射到远程监测软件,监测软件将分析结果反馈给末端执行机构,实现对养殖池环境的实时监控。本文从系统结构和数据传输等方面进行了阐述,对海参苗养殖的自动化生产提供了一种有效可行、成本较低的解决方案。     

Hg↑（2+）、Zn↑（2+）、Cr↑（6+）对黄姑鱼幼鱼的急性致毒效应

2004年8月，在浙江省舟山市定海区小沙镇浙江华兴海水种苗有限公司以日龄为56d的黄姑鱼（Nibeaalbiflora）幼鱼作为实验动物，开展Hg^2＋、Zn^2＋、Cr^6＋对黄姑鱼幼鱼的急性毒性和加和等毒性强度联合毒性试验。结果表明，Hg^2＋对黄姑鱼幼鱼24h、48h、72h、96h的半致死质量浓度分别为0．7523mg／L、0．6616mg／L、0．5618mg／L、0．4959mg／L；Zn^2＋对黄姑鱼幼鱼24h、48h、72h、96h的半致死质量浓度分别为22．9908mg／L、18．4576mg／L、14．5306mg／L、11．5833mg／L；Cr^6＋对黄姑鱼幼鱼24h、48h、72h、96h的半致死质量浓度分别为18．7654mg／L、16．7415mg／L、15．4521mg／L、13．1276mg／L。黄姑鱼幼鱼对Cr6’、Zn^2＋、Hg^2＋96h安全质量浓度分别为1．31mg／L、1．16mg／L和0．050mg／L。各重金属离子毒性由大到小依次为Hg^2＋、Zn^2＋、Cr^6＋,Hg^2＋-Zn^2＋、Hg^2＋,Cr^6＋对黄姑鱼幼鱼的96h联合急性毒性表现为协同作用。Zn^2＋-Cr^6＋对黄姑鱼幼鱼的96h联合急性毒性表现为，低毒性强度的Zn^2＋对Cr^6＋具拮抗作用Cr^6＋毒性强度略高于Zn^2＋时表现为相互独立作用，当Zn^2＋毒性强度高于Cr^6＋时则表现为协同作用。并就Hg^2＋、Zn^2＋、Cr^6＋对黄姑鱼幼鱼的急性致毒效应特征，黄姑鱼幼鱼对Hg^2＋、Zn^2＋、Cr^6＋的安全浓度以及Cr^6＋-Zn^2＋、Cr^6＋-Hg^2＋与Zn^2＋-Hg^2＋对黄姑鱼幼鱼的联合毒性效应机理进行了探讨。     

Effect of taurine supplemented practical diet on growth performance and taurine contents in whole body and tissues of juvenile Japanese flounder <Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>

ABSTRACT:   The effect of dietary taurine on juvenile Japanese flounder was determined by feeding three taurine-supplemented experimental diets (TAU) and a commercial diet (CD) to evaluate a practical diet for juvenile Japanese flounder. Juvenile Japanese flounder were reared on the three experimental diets supplemented with taurine at 0, 0.5, 1.0% and CD. These diets were fed to juvenile Japanese flounder of an initial mean body weight of 0.2 g for 6 weeks at 20°C and the taurine contents of the whole body and tissues were analyzed. The final average body weight of juvenile Japanese flounder fed the 1.0% TAU was significantly higher than that of the other groups. Taurine contents in the whole body and tissues increased with the increase in dietary taurine level. These results indicate that juvenile Japanese flounder require at least 15 mg/g taurine in the diet, even though a combined mix of fish, krill and squid meal was the main protein source in the experimental diets.     

Delineating foraging grounds of a loggerhead turtle population through satellite tracking of juveniles

1. Tracking of juvenile sea turtles is a research priority to inform the protection of relevant habitats and ensure sustainable rates of recruitment into adult populations. Based on satellite tracking, mixed stock analysis, and mark–recapture studies, Drini Bay in the South Adriatic Sea, Central Mediterranean, has been confirmed as an important foraging site used by loggerhead turtles from all major rookeries in the Mediterranean subpopulation.
2. Three juvenile loggerhead turtles (Caretta caretta) from Drini Bay were tracked for 763, 364, and 211 days respectively. All turtles exhibited different movement patterns.
3. The two smaller turtles ranged widely beyond the bay. One of these (69.5 cm curved‐carapace length; CCL) used the coldest region of the Mediterranean during the first winter of tracking where mean weekly temperatures dipped below 12°C but moved southwards to warmer waters during the second winter. In comparison, the other (66 cm CCL) individual moved south to winter in warmer waters from the outset. Both individuals returned to Drini Bay during summer, demonstrating fidelity to the study site. The third turtle, which was larger (76 cm CCL), remained in Drini Bay for the duration of tracking. These results support the findings of other mark–recapture studies at Drini Bay, which have suggested that the foraging site is being used in a transient way by immature turtles.
4. All three turtles preferentially used the shallow waters (<30 m) in the south of Drini Bay. The study demonstrates a high degree of overlap between the habitat use of the three tracked turtles and that of adult turtles tracked from nesting sites, and although based on a small sample size, contributes to a growing knowledge base regarding the wider habitat use of the Mediterranean loggerhead population.

     

充分发挥图书馆服务功能预防青少年犯罪

近年来,我国青少年犯罪呈上升趋势,成为社会各界关注的焦点问题。图书馆的组织者、管理人员应针对青少年犯罪的重点群体采取相应的有效措施,强化图书馆服务职能、优化图书馆环境,在预防青少年犯罪方面作出新贡献。     

Prey‐type‐dependent foraging of young‐of‐the‐year fish in turbid and humic environments

Abstract – Fish, which are generally visual foragers, experiences reduced reaction distance in visually degraded environments, which has consequences for encounter rates with prey. Small prey is detected at shorter distances than larger prey, and piscivores are therefore predicted to be more strongly affected by visual degradation. In experiments, roach (Rutilus rutilus) were fed two plankton prey types and pike (Esox lucius) were fed Daphnia and larval roach, in clear water, algal turbid water and water coloured brown by dissolved organic matter (DOM). Planktivorous foraging in roach was not affected by visual degradation, while pike foraging on both Daphnia and larval roach was. Pike showed increased reaction distance to Daphnia in visually degraded water, while it was severely reduced with roach as prey even if the visual range was not reduced below pike reaction distances in clear water. Pike foraging on Daphnia was not affected, but when foraging on roach, the reduced search efficiency was counteracted by increased attack rates. However, there was no increase in movement and no difference between turbid and DOM treatments. Effects on piscivores will likely become more pronounced at later life stages as prey size and the reliance on long‐distance detection increases at the same time as changing climatic conditions may further deteriorate the visual conditions in future.     

中华鲟幼鲟饲料中适宜动植物蛋白比的研究

按单因子梯度设计的原理 ,以鱼粉和豆粕作为蛋白源 ,设计出5种不同蛋白质水平的饲料配方 ,通过5周饲养试验和2周消化试验 ,以研究中华鲟幼鲟饲料中适宜的动植物蛋白比。结果表明 ,中华鲟饲料中动植物蛋白比为1:1时 ,幼鲟的生长就能达到较好的效果 ;当动植物蛋白比达3:1时 ,既能发挥中华鲟生长迅速的潜力 ,又可获得良好的经济效益     

Interpopulation comparison of size and age at smolting of white-spotted charr, Salvelinus leucomaenis

Abstract – The relationships between size and age at smolting and juvenile growth rates were examined for 13 populations of white-spotted charr ( Salvelinus leucomaenis ). Mean smolt length (ranging 142–210 mm in fork length) and smolt age (2.4–3.7 years) varied significantly among populations and there was a significant negative relationship between smolt length and age. Mean smolt length was positively correlated with mean specific growth rate from age 0 to 1 year, whereas mean smolt age was negatively correlated with specific growth rate. The present study shows that the freshwater environment conditions operating on juvenile growth are important for moulding the phenotypic characteristics of size and age at smolting.     

Effect of dietary supplementation with taurine, β-alanine andGABA on the growth of juvenile and fingerling Japanese flounder Paralichthysolivaceus

ABSTRACT:   Three diets supplemented with taurine, β-alanine andGABA and a control diet were fed to juvenile and fingerling Japaneseflounder to investigate the effects of the diets on growth and metabolicchanges of free amino acids in whole body and tissues. In experimentI, three diets supplemented with 1% each of taurine, β-alanineand GABA and a control diet were fed to juvenile Japanese flounderwith an initial mean body weight of 0.4 g for 4 weeks at20°C. In experiment II, the taurine-supplemented diet anda control diet were fed to fingerling Japanese flounder with an initialmean body weight of 15 g for 4 weeks at 20°C.Only supplementation of taurine in the diet of juvenile flounderimproved their growth performance in experiment I, but fingerlinggrowth performance of experiment II was not significantly relatedto taurine supplementation in the experimental diet. These resultssuggest that there is a greater requirement for taurine for thegrowth of juvenile Japanese flounder than fingerling Japanese flounder.