Measuring density effects on growth and survival of two size classes of juvenile sea urchins (Strongylocentrotus droebachiensis) held in sea‐based holding systems and impacts on holding system design and management

Assessing density in intensive sea urchin culture systems by measuring the percentage coverage of available surface area is an effective means of calculating the available space within a holding system, the proximity of the animals in the system to each other and the probable effects of the stocking density. The results of this study show that density plays a critical role in regard to both somatic growth (increase in test diameter measured in millimetres) as well as mortality of juvenile sea urchins ranging in size from 5 mm to 26 mm test diameter (the size range tested in the current experiments). These effects appear to be greater for smaller urchins. The critical percentage coverage densities are in the order of 50%‐60% coverage for juvenile sea urchins, and the authors advise farmers growing Strongylocentrotus droebachiensis to maintain stocking densities below this point and to reduce the stocking densities as and when stocks reach these critical density points. Percentage cover must be constantly monitored as the results from this study indicate that the growth rates of juvenile urchins can alter percentage coverage rapidly and reductions in density may be required as frequently as every 3‐4 months at the early juvenile stage. Holding system design should take these factors into account and incorporate a method of rapidly reducing stocking densities with minimal stress and handling of sea urchin stocks.     

饲料脂肪水平对中间球海胆幼胆生长、消化酶和热胁迫后抗氧化酶活力的影响

为了确定中间球海胆Strongylocentrotus intermedius幼胆饲料中适宜的脂肪水平,采用摄食生长试验探讨了饲料中脂肪水平(3%、6%、9%、12%和15%)对海胆幼胆存活、生长、消化酶和热胁迫后抗氧化酶活力的影响,试验共进行96 d。结果表明:试验结束时,6%饲料脂肪水平组海胆增重率最高,显著高于15%脂肪组(P0.05);随着饲料脂肪水平的升高,中间球海胆消化道中脂肪酶活力显著升高(P0.05),淀粉酶活力显著下降(P0.05),胃蛋白酶活力有下降趋势(P0.05);饲料脂肪水平显著影响热胁迫后海胆体腔液中抗氧化酶活力,其中热胁迫2 h后,12%脂肪组超氧化物歧化酶(SOD)活力最高,显著高于15%脂肪组(P0.05);热胁迫6 h后,海胆体腔液过氧化氢酶(CAT)活力最高值出现在6%脂肪组,且高于12%和15%脂肪组。研究表明,6%饲料脂肪水平时中间球海胆幼胆的生长速率最快,6%~12%饲料脂肪水平能够显著提高热胁迫后海胆的抗氧化能力。     

模拟海底水流和光照条件下光棘球海胆行为特征及其聚礁效果的初步研究

为观察光棘球海胆Strongylocentrotus nudus在饱食、饥饿和饥饿再投喂状态下的行为特征,及其对水泥、PVC两种材质模型礁的聚集特性,在实验室中模拟光棘球海胆栖息海域底层的昼夜水流速度和光照强度进行试验。结果表明:当光照强度达到560 lx、水流速度达到20 cm/s(9:00)时,均匀分布的光棘球海胆有90%向模型礁附近区域移动;当光照强度和水流速度下降时,光棘球海胆向模型礁附近区域外移动;运动趋势明显的光棘球海胆在饱食、饥饿和饥饿再投喂3种状态下的平均移动速度分别为0.039、0.041、0.052 cm/s,3种状态下光棘球海胆顺、逆水流运动次数的比值依次为饥饿状态(1.63)饱食状态(1.18)饥饿再投喂状态(0.73),饥饿再投喂状态下光棘球海胆的活跃程度高于饱食和饥饿状态;鱼礁材质也影响光棘球海胆的聚集行为,光棘球海胆在饱食、饥饿和饥饿再投喂状态下对水泥模型礁的平均聚集率分别为25%、17%、24%,对PVC模型礁的平均聚集率分别为16%、7%、12%,光棘球海胆对两种模型礁的聚集效果均为饱食状态饥饿再投喂状态饥饿状态。研究表明,光棘球海胆在饱食和饥饿再投喂状态下对两种模型礁的聚集效果较好,而水泥材质的模型礁比PVC材质的模型礁聚集效果更好。     

岩栖蝮蛇毒纤溶酶基因克隆、序列分析及真核表达载体的构建与鉴定

克隆岩栖蝮蛇(Gloydius saxatilis)纤维溶解酶(Fibrinolytic enzyme,FLE)基因,分析基因序列并对该基因的功能进行分析;构建真核表达载体并鉴定.从岩栖蝮蛇毒腺细胞中提取总RNA,通过RT-PCR法扩增纤溶酶基因,与pMDl8-T载体连接进行TA克隆,再进行序列的测定并且对该序列进行分...     

虾夷马粪海胆群体的遗传多样性及微卫星标记与生长性状的相关性分析

为了明确性腺性状和分子标记之间的关系,在海胆选育工作中提高性腺性状,利用微卫星标记对海胆各生长性状及性腺颜色进行相关分析。选用28个虾夷马粪海胆多态性微卫星分子标记对虾夷马粪海胆自交F1代家系群体的进行了检测分析,结果表明:共检测到80个等位基因,平均等位基因数为2.857 1个;平均有效等位基因数为0.827 0个; 观测杂合度平均值0.515 0,期望杂合度平均值为0.530 4;平均多态信息含量（PIC）为0.402 6,卡方检验显示其中有9个位点发生了偏离(P<0.01)。采用一般线性模型(GLM)进行连锁显著性检验,发现与壳高、体重和体积显著相关（P<0.05）的微卫星标记各1个,分别为TS131、TS38和TS105；与海胆颜色L*值（暗-亮）显著和极显著相关的微卫星标记分别为4个 (TS38、TS85、TS105、TS108)和1个(TS41)；与海胆颜色a*值（绿-红）显著和极显著相关的微卫星标记各1个(TS101 TS41)；与海胆颜色b*值（蓝-黄）显著相关的微卫星标记3个(TS41、TS114和TS128)；与海胆口器重显著和极显著相关的微卫星标记各1个(TS114和TS46)。该研究结果可以为虾夷马粪海胆的相关性状进一步QTL定位提供参考数据,并为虾夷马粪海胆的养殖和选育提供理论指导。     

Estimates of heritabilities and genetic correlations for growth and gonad traits in the sea urchin Strongylocentrotus intermedius

The present study is the first estimate for the sea urchin, Strongylocentrotus intermedius, of genetic parameters for growth and gonad traits during the entire reproductive period. 2165–5764 sea urchins were sampled from 74 to 120 families at six different growth stages. Six hundred individuals were sampled from 20 randomly chosen families at harvest. Coefficients of variation for most growth and gonad traits were high (18.08–78.66%) suggesting a good variation foundation for breeding. Point estimate for heritabilities based on the sire components of variance were moderate to high for test height (0.24–0.39), test diameter (0.21–0.48) and body weight (0.16–0.49). Heritabilities of gonad wet weight, gonad index and gonad moisture at harvest were 0.17, 0.41 and 0.50 respectively (moderate or high). Gonad colour parameters, L^* (lightness) and a^* (redness) have a heritability of 0, while b^* (yellowness) and colour difference ΔE₁ and ΔE₂ have very similar heritabilities of 0.2, 0.18 and 0.21 respectively. Heritabilities of β‐carotene concentration and content were 0.89 and 0.44 respectively. The genetic correlations between the two measured traits ranged from ?0.984 to 0.999. Gonad wet weight, L^*, b^*, β‐carotene concentration and β‐carotene content had significant positive genetic correlations with all the growth traits. However, gonad index, gonad moisture and colour differences ΔE₁ and ΔE₂ had significant negative genetic correlations with growth traits. The present study indicates that growth, gonad yield and most gonad quality traits could be improved by selection with moderate to high potential. Indirect selection should be applied on gonad traits using growth traits as secondary traits. The present study provides important theoretical guidance for future selective breeding programmes for S. intermedius.     

Isolation and characterization of bacteria associated with a syndrome disease of sea urchin Strongylocentrotus intermedius in North China

Sea urchin, Strongylocentrotus intermedius, transplanted from Japan in 1989, has been widely cultured along the coasts of Liaoning and Shandong Provinces and has become the dominant and most economically important maricultured species in North China. However, a lesion syndrome symptom of S. intermedius broke out frequently these years, showing lethargy in activities, blackish peristomial membrane and body well lesions, and brought about high mortality eventually. Six representative prominent bacterial strains were isolated from diseased sea urchin from September 2009 to January 2010. By means of API 20NE and 16S rRNA gene sequences analysis, isolates were identified as Shewanella aquimarina, Pseudoalteromonas tetraodonis, Vibrio shilonii, V. harveyi, V. fortis and V. splendidus. Bacterial challenge tests showed that their representative isolates were virulent to S. intermedius with LD₅₀ values ranging from 9.2 × 10⁴ to 3.4 × 10⁶ CFU/g body weight, among which S. aquimarina , V. fortis and P. tetraodonis were highly virulent, and the other three isolates showed moderate virulence. The results indicated that a variety of bacteria including Shewanella, Pseudoalteromonas and Vibrio were involved in the mortality of S. intermedius, and the six isolates were opportunistic pathogens of sea urchins. All isolates reported herein were sensitive to ampicillin, enrofloxacin, ofloxacin, doxycycline and florfenicol.     

中间球海胆幼体及稚海胆生长性状的遗传参数估计

为估计中间球海胆Strongylocentrotus intermedius幼体及稚海胆生长性状的遗传参数,采用巢式不平衡设计方法建立了44个中间球海胆全同胞家系,并测量了各家系海胆四腕幼体、六腕幼体和八腕幼体等各期浮游幼体的体长以及受精后30 d的稚海胆壳径,采用动物模型和约束性最大似然法(REML)估计了中间球海胆幼体和稚海胆生长性状的遗传参数。结果表明:中间球海胆四腕幼体和八腕幼体体长的遗传力分别为0.705±0.373和0.538±0.444,为高度遗传力,六腕幼体体长和稚海胆壳径的遗传力均接近于0,为低度遗传力;各阶段幼体体长和稚海胆壳径的共同环境效应为0.048~0.352;各阶段幼体体长间遗传相关为正相关(0.300~0.518),各阶段幼体体长与稚海胆壳径间的遗传相关为负相关(-0.152~-0.435)。本研究结果可为制定中间球海胆的早期选择和间接选择选育方案提供参考依据。     

Inhibitory effect of 2,4-dibromophenol and 2,4,6-tribromophenol on larval survival and metamorphosis of the sea urchin <Emphasis Type="Italic">Strongylocentrotus nudus</Emphasis>

ABSTRACT:   As a possible factor leading to the low recruitment level of sea urchins in kelp forests, the inhibitory effect of 2,4-dibromophenol (DBP) and 2,4,6-tribromophenol (TBP) released from the large perennial brown algae Ecklonia kurome and Eisenia bicyclis on survival and metamorphosis of eight-armed larvae of the sea urchin Strongylocentrotus nudus was examined. The percentage of larvae that underwent metamorphosis in filtered sea water after 1 h exposure to one-half dilution of saturated dibromomethane solution (∼60 ppm) as a chemical inducer reached approximately 100% after 1 h, while that in filtered sea water containing 1 ppm TBP was reduced to 73%. This was further reduced to less than 40% in the presence of 10 and 20 ppm TBP after 2 h. In filtered sea water containing 1 and 10 ppm DBP, the proportion of metamorphosed larvae was reduced markedly to 43 and 5% after 2 h, respectively. All larvae exposed to 50 ppm TBP and to 20 and 50 ppm DBP died after 1 h. These findings suggest that DBP is more toxic than TBP for sea urchin larvae, strongly inhibiting their metamorphosis.     

中间球海胆性腺氨基酸组成研究

试验结果表明,中间球海胆鲜味氨基酸含量占总氨基酸含量的43%以上,尤其是含有较高的甘氨酸、谷氨酸.雄性性腺鲜味氨基酸含量高于雌性,因此,雄性味更美.在生产中采集中间球海胆时期最好选在早期成熟阶段,在海胆成熟后期自然排放之前采收完毕.