广西茅尾海的香港巨牡蛎(Crassostrea hongkongensis)在不同养殖区的性腺发育变化

为探究香港巨牡蛎(Crassostrea hongkongensis)的繁殖特性以及春季死亡原因,采用肉眼观察、活体镜检和组织切片方法研究了茅尾海沙井的香港巨牡蛎苗种吊养于大风江黄场的1龄牡蛎的性腺发育周年变化,并建立了快速判断香港巨牡蛎性腺发育程度的方法.对比分析了吊养在茅尾海沙井、大风江入海口内的黄场和入海口外的鑫丰场的2龄牡蛎性腺发育的启动和发展过程.结果显示,广西茅尾海的香港巨牡蛎每年只有1个繁殖周期,性腺发育过程可划分为未分化期(1-3月)、分化期(4月)、成熟排放期(5-10月)及休止期(11-12月)4个阶段;1龄和2龄牡蛎的性腺发育基本同步;大风江入海口外的牡蛎的性腺发育较入海口内的牡蛎提前约15d,而比茅尾海内海的牡蛎提前约30 d,入海口外的牡蛎的性腺4月即发育到成熟排放期,冬季饵料的丰富程度和温度、盐度等因素可能是造成这种差异的原因.研究还发现,高温少雨天气下,海水盐度高,抑制了牡蛎性细胞的排放,导致入海口外侧吊养牡蛎的大规模死亡,濒临死亡的牡蛎性腺处于退化和崩解状态.鉴于此,认为4月初即需密切监测吊养于入海口外的牡蛎性腺的发育状况和天气状况,及时收获性腺饱满的牡蛎,或将吊养牡蛎的蚝排放置在河流入海口内区域过冬.     

长牡蛎(Crassostrea gigas)壳宽快速生长选育群体遗传多样性及遗传结构的微卫星标记分析

为了监测长牡蛎(Crassostrea gigas)在选育过程中的遗传变异、分析选育对其遗传结构的影响,本研究以选育目标为壳宽快速生长的长牡蛎为实验材料,利用微卫星(Simple Sequence Repeats)标记技术,对长牡蛎基础群体(P0)和连续两代选育群体(F1和F2)进行遗传多样性评估。结果发现,所有微卫星位点在3个群体中都表现出了较高的多态性,P0、F1和F2代群体的平均等位基因数分别为16.5、12.2和12.8;P0、F1和F2代群体多态性信息含量(Pic)的平均数值分别为0.9068、0.8982和0.8836。所有群体10个位点的观测杂合度值(Ho)均小于期望杂合度值(He),观测杂合度平均值的大小范围为0.5775–0.6484,期望杂合度范围为0.8594–0.9279。哈迪-温伯格平衡(HWE)结果显示,3个群体在10个位点上有24个群体的位点组合显著偏离HWE(P<0.05),说明人工选育对选育群体的遗传结构有一定的影响。3个群体在10个位点上的Fis值均为正值,平均范围为0.1541–0.2341,表明群体内各位点上的杂合子比例有所下降;各群体间Fst值范围为0.0093–0.0245,遗传分化程度较弱。此研究表明,以壳宽快速生长为选育目的,长牡蛎连续选育群体仍具有很高遗传多样性,人工选育过程中保持一定选择压力,仍然会使长牡蛎的优良生长性状得到不断提高。     

Effect of ploidy on the mortality of Crassostrea gigas spat caused by OsHV‐1 in France using unselected and selected OsHV‐1 resistant oysters

The effect of ploidy on the mortality of Crassostrea gigas spat caused by the ostreid herpesvirus (OsHV‐1) genotype μVar was investigated at five sites along the Atlantic coast in France in 2011. Sibling diploids and triploids were produced using either unselected or selected OsHV‐1‐resistant oysters. No significant interactions were found between the factors of environment, genotype and ploidy at the endpoint dates. The mean mortality rates at the sites were 62% and 59% for diploids and triploids, respectively, and the two rates were not significantly different. The mean mortality rates were 33% and 32% for sibling diploids and triploids, respectively, when OsHV‐1‐resistant parents were used and 91% and 85%, respectively, when unselected parents were used. The results were confirmed through other broodstocks tested in 2013. Our study is the first to clearly show that mortality related to OsHV‐1 is similar between diploids and triploids in C. gigas when the same germplasm is used for both ploidy. Furthermore, OsHV‐1 resistance was not substantially altered by triploidization, indicating that the achieved selective breeding of diploid oysters for OsHV‐1 resistance can be translated into improved survival in triploids.     

长牡蛎壳金选育系F4与普通养殖群体摄食和呼吸的比较研究

为了从生理学角度探讨长牡蛎壳金选育系的快速生长机制,本研究以两种规格长牡蛎(Crassostrea gigas)第4代壳金选育系(简称金1和金2)和两种普通养殖群体(简称对照1和对照2)为材料,比较了不同温度(16℃、20℃、24℃、28℃、32℃)和盐度(15、20、25、30、35)条件下各实验组的滤水率(FR)和耗氧率(OCR)。结果显示:(1)摄食实验中,4个组长牡蛎的滤水率均随温度或盐度增加先上升后下降,在温度28℃时出现最大值;对照1的滤水率在盐度25时达到最大值,其他3组滤水率在盐度30时达到最大值;方差分析结果显示,温度、群体,盐度、群体对长牡蛎的滤水率均有显著性影响,长牡蛎壳金选育系的滤水率均显著大于普通养殖群体(P0.05)。(2)呼吸实验中,较大规格长牡蛎壳金选育系的耗氧率受温度或盐度变化的影响更小。方差分析结果显示,温度、群体,盐度、群体均对长牡蛎耗氧率有显著性影响。实验温度范围内,金1的耗氧率显著小于对照1,但金2的耗氧率显著大于对照2(P0.05)。实验盐度范围内,壳金选育系的耗氧率均显著大于普通群体(P0.05)。(3)同一壳色群体中,个体越大,单位软体部干重滤水率和耗氧率越低。研究表明,较大规格长牡蛎壳金选育系F4更能适应外部环境的变化,该选育系的快速生长可能是由其较高滤食行为导致的。     

Growth performance and biochemical composition of the oysters Crassostrea sikamea,Crassostrea angulata and their hybrids in southern China

The Kumamoto oyster (Crassostrea sikamea) and the Portuguese oyster (C. angulata) are important aquaculture species which naturally coexist along the southern coast of China. To understand the potential feasibility of hybridization between the two species, we conducted two‐by‐two factorial cross‐experiments in Beihai (Guangxi province), and also compared the survival and growth of the hybrids to that of the two parental progenies during the grow‐out period from July 2014 to July 2015. Genetic analysis confirmed that the hybrid spats were true hybrids. Additionally, the biochemical composition of the 1‐year‐old oyster progenies was determined. In July 2015, the mean shell height of the hybrids was 42.98 ± 6.29 mm, which was higher than that of the Kumamoto oyster progeny. The cumulative survival rate of the hybrids was 26.37 ± 1.32%, which was higher than that of the progeny of the Portuguese oyster. Mean lipid content of the hybrids was 13.65 ± 1.63% of dry weight, which showed obvious heterosis compared to those of the two parental progenies. Observation of gonads revealed that all hybrids were completely fertile. Furthermore, relative expression of the lipid homeostasis genes, SREBP (sterol regulatory element‐binding proteins), PPARα (peroxisome proliferator‐activated receptor) and INSIG (insulin‐induced gene) were found to vary between parental progenies and the hybrids, thus providing a possible reason for difference in the lipid contents of these experimental groups. Overall, the hybrids were viable, rich in lipid and completely fertile and thus could serve as a promising aquaculture stock for oyster breeding in southern China.     

5种壳色长牡蛎不同组织中金属元素的分析与评价

为评估不同壳色长牡蛎金属元素价值,实采用电感耦合等离子体原子发射光谱仪(ICP-OES)和近红外(NIR)分析模型对5种壳色(壳黑、壳紫、壳橙、壳金和壳白)长牡蛎4个组织(外套膜、鳃、闭壳肌和性腺—内脏团)中的Mg、Fe、Zn、Cu、Mn和Se元素含量进行检测分析,并比较与对照群体金属元素含量的差异以及5种壳色长牡蛎各组织间含量的差异。结果发现,在外套膜中,壳紫、壳橙和壳黑长牡蛎中Zn含量显著高于对照群体,壳紫长牡蛎Cu含量显著高于壳金和对照群体,壳金长牡蛎Mn含量显著高于壳紫和壳黑长牡蛎,其他元素在各群体中含量无显著差异;在鳃中,壳金长牡蛎Mn含量显著高于壳黑和对照群体,其他组份在6个群体无显著性差异;在闭壳肌中,壳橙和壳紫长牡蛎Zn的含量显著高于对照群体,其他组份在各群体中差异不显著;在性腺—内脏团中,壳橙长牡蛎Zn和Mn含量均显著高于对照群体,且Cu的含量显著高于壳金长牡蛎,其他元素在6个群体中含量无显著性差异。4个组织中各金属元素含量差异显著,其中闭壳肌内各金属元素含量显著低于鳃、外套膜和性腺—内脏团。研究表明,不同壳色长牡蛎之间以及不同壳色与对照群体之间在部分金属元素含量上已表现出分化,这为长牡蛎壳色新品系选育提供了重要的基础资料。     

溢油对贝类的毒害效应以及生态风险评价

通过磁力搅拌和超声波乳化等手段模拟海上溢油事故,采用常见的4种原油和4种燃料油开展对贝类的毒害效应以及生态风险评价。结果表明：根据8种油品对褶牡蛎的96h-LC50得出这8种油对褶牡蛎的整体上毒害作用的大小顺序是：F120=F180〉-20#〉F380〉TJ015〉TJ014〉TJ002〉TJ016;根据8种油品对缢蛏的96h-LC50得出这8种油对褶牡缢蛏蛎的整体上毒害作用的大小顺序是：F180〉F120〉-20#〉F380〉TJ002〉TJ015〉TJ014〉TJ016;根据8种油品对褶牡蛎的96h-LC50得出TJ016和TJ002对褶牡蛎属于低毒中风险,TJ015和TJ014对褶牡蛎属于低毒高风险,F380和-20#对褶牡蛎柴油属于中毒高风险,F180和F120对褶牡蛎属于高毒极高风险;根据8种油品对缢蛏的96h-LC50得出TJ016对缢蛏属于低毒中风险,TJ015、TJ014、TJ002和F380对缢蛏属于中毒高风险,-20#、F180和F120对缢蛏属于高毒极高风险。总之,对贝类而言,燃料油毒性比原油更大,缢蛏相对褶牡蛎对油品毒害作用更为敏感。     

Genetic parameters of growth and survival in the Pacific oyster Crassostrea gigas

The Pacific oyster Crassostrea gigas is a representative bivalve mollusc that is widely cultured in the world and is the largest molluscan group cultured in China. In order to assess the feasibility of improving survival of C. gigas through genetic selection, the heritability and genetic correlations for growth and survival traits between different life stages were examined. Genetic parameters were estimated based on intraclass correlations of 49 full‐sib families (29 half‐sib families) in larvae (4 and 20 days after fertilization) and spat (140 days after fertilization) stages. The heritability for growth traits in larvae and spat was 0.30–0.86 and 0.53–0.59, respectively, and varied with ages. The heritability of survival was low in larvae (0.13 ± 0.05 and 0.17 ± 0.04, respectively for 4 and 20 days after fertilization) but medium (0.39 ± 0.07) in spat, suggesting that selection for increasing spat survival was feasible. The genetic correlation between growth traits within age was medium to high and positive (ranging from 0.47 to 0.96, respectively, between shell length (SL) and shell height (SH) at 20 days and between SL and SH at 140 days after fertilization), suggesting that selection to improve single growth trait will cause positive response in another growth traits in C. gigas. The genetic correlations between survival and growth traits at 140 days were low but positive (ranging from 0.23 to 0.27, respectively, between survival and SH and between survival and SL at 140 days after fertilization), suggesting that selection for survival may not have a negative response in growth. Overall, this study suggests that survival traits should be taken as improving target of next selection breeding programme in C. gigas.     

关于我国农田福寿螺生物入侵需要加以研究的生态学问题

福寿螺已成为我国南方稻区主要的入侵生物之一,近年来,对水稻等农作物以及农业生物多样性和生态环境的危害日趋加重。本文对我国农田福寿螺的生物入侵危害状况进行了概述,提出了今后关于农田福寿螺生物入侵需要加以研究的生态学问题,包括农田福寿螺的生态适应性与耐性规律、农田福寿螺的种群暴发规律与预测预警、福寿螺的生态风险、农田福寿螺的综合防治与生态控制等。     

广东沿海近江牡蛎重金属含量特征及其风险分析

根据1997—2010年对广东沿海近江牡蛎(Crassostrea rivularis)的监测结果,对近江牡蛎体重金属元素镉(Cd)、铜(Cu)、铅(Pb)、锌(Zn)的含量水平、空间分布和时间变化进行了分析讨论,并对近江牡蛎这一经济水产品种的食用安全性进行了风险评估。结果表明,近江牡蛎Cd、Cu、Pb、Zn的含量分别为(1.31±1.43)、(72.3±89.7)、(0.26±0.22)、(203±178)mg.kg-1,不同元素的含量与近江牡蛎对其累积能力有关。1997—2010年,广东沿海近江牡蛎体重金属Cu、Cd、Pb、Zn的含量总体呈下降趋势;空间分布特征为中部沿海重金属元素含量高于东部和西部沿海。风险分析结果显示,近江牡蛎体Pb、Cd的暴露量低于世界卫生组织/联合国粮食和农业组织(WHO/FAO)的食品添加剂联合专家委员会(JECFA)的推荐值,处于安全范围内。