黑蝶贝苗种中间培育技术的初步研究

以黑蝶贝野生群体人工繁育苗种为研究材料,探索了大、小两种规格和不同吊养深度对黑蝶贝苗海区中间培育的影响。将壳长、体质量分别为(4.12±0.019)mm、(0.07±0.008)g,(2.02±0.012)mm、(0.03±0.005)g两种规格黑蝶贝吊养于2m、4m、5m区,每组黑蝶贝500枚,养殖水温23.09~29.77℃,养殖海区水深8~10m。每隔30d随机抽取50枚贝苗测量壳高、壳长、壳宽、体质量。经180d中间培育,壳长(4.12±0.019)mm的黑蝶贝生长速度明显大于壳长(2.02±0.012)mm的黑蝶贝,表明壳长(4.12±0.019)mm的黑蝶贝出池移入海区养殖较理想。同一规格贝苗在2m、4m、5m养殖水层的成活率差异不显著(P0.05),而3个不同养殖水层中不同规格贝苗养殖成活率差异显著(P0.05)。该研究结果为进一步开展黑蝶贝苗种人工繁育提供了重要参考。     

马氏珠母贝微胶囊饲料的适用性研究

本研究测定了自主研发的马氏珠母贝(Pinctada martensii)微胶囊饲料的粒径范围、悬浮性和稳定性;并以室内投喂微胶囊饲料的马氏珠母贝为实验组,自然海区养殖的马氏珠母贝为对照组,养殖45 d后比较实验组与对照组成活率、生长率、软体部生化成分、肝胰脏形态与消化酶的差异。结果表明:(1)该饲料粒径均小于48μm,其中约80%饲料颗粒粒径在28~48μm;(2)该饲料分散性良好,静置状态下,在盐度为35的Na Cl溶液中的沉降速度是(2.74±0.21)mm/s;(3)饲料的氮保留率(NRR)较高,25℃浸泡120 min后、35℃浸泡60 min后NRR分别为(79.10±0.15)%和(80.85±0.72)%;(4)实验组和对照组的成活率没有显著差异(P0.05);实验组壳长、壳宽、壳高和总重的绝对增长率和相对生长率均显著低于对照组(P0.05);(5)实验组软体部脂肪含量显著大于对照组(P0.05),碳水化合物、蛋白质和灰分含量无显著差异(P0.05);(6)实验组肝胰脏为橘黄色,淀粉酶活力显著大于对照组(P0.05),纤维素酶、蛋白酶活力差异不显著(P0.05)。研究结果表明,该微胶囊饲料粒径小、稳定性较好,能被马氏珠母贝消化与吸收,但需要继续改进饲料配方、完善室内养殖技术方案,为马氏珠母贝工厂化养殖条件的优化提供科学依据。     

Pearl formation in the Japanese pearl oyster (Pinctada fucata) by CaCO3 polymorphs: Pearl quality‐specific biomineralization processes and their similarity to shell regeneration

Pearl oyster shell consists of two layers: a calcite prismatic layer (outer layer) and an aragonite nacreous layer (inner layer). Calcite and aragonite are CaCO₃ polymorphs, and their formations are controlled by shell‐forming tissue called mantle. Pearl sacs originating in the mantle form cultured pearls. Therefore, it has been widely accepted that pearl and shell are produced by the same process. However, this idea has been called into question by some recent mineralogical studies indicating microstructural and crystal‐polymorphic diversity in pearls. The pearl biomineralization process is still not fully understood in detail. Thus, in this study, we focused on the diversity of CaCO₃ polymorphism of non‐nacreous structures (NNSs) underlying the nacreous layer in pearl and regenerated shell, to reveal the biomineralization process of the Japanese pearl oyster (Pinctada fucata). Using Meigen's stain and scanning electron microscope‐energy dispersive X‐ray (SEM‐EDX), NNSs polymorphs in valuable and valueless pearls, in addition to regenerated shell, were compared. Aragonite was exclusively observed in the NNSs of valuable pearls, whereas calcite was dominant in those of valueless pearls. The same analysis of NNSs of regenerated shells was carried out. As in valueless pearls, almost all regenerated shell NNSs consisted of calcite, but one NNS was composed of aragonite. Accordingly, it seems that pearls are formed by the same biomineralization process as shell regeneration rather than shell formation.     

限食对合浦珠母贝幼虫生长、成活及变态的影响

自2009年4月27日至2009年5月25日,在不同投饵条件下研究了限食对合浦珠母贝（Pinctada fucata）幼虫生长、成活和变态的影响。结果显示,试验初期对照组幼虫的壳长、壳高日增长率逐渐升高,自第20天开始迅速下降;试验一组（隔天投喂）和二组（隔2d投喂）幼虫的壳长、壳高日增长率缓慢升高,且与对照组同期幼虫的日增长率差异显著,这表明饵料是否充足直接影响马氏珠母贝幼虫的生长。试验期间,对照组幼虫的成活率逐渐降低,畸形率无显著性变化,而试验一组和二组幼虫的成活率显著低于对照组,试验二组幼虫的畸形率高于同期对照组和试验一组幼虫的畸形率,表明在食物匮乏的情况下,幼虫的发育受到影响。对照组幼虫在第20天时开始变态,随后变态率逐渐升高,试验一组幼虫在第30天时开始变态,而试验二组幼虫在试验期间一直没有变态,表明该组幼虫的营养状况不足以支持其变态附着。     

两个马氏珠母贝养殖群体遗传多样性微卫星分析

以两个马氏珠母贝(Pinctada martensii Dunker)养殖群体为对象,采用微卫星分子标记技术对两个群体的遗传结构进行了研究,分析了各群体内的遗传多样性和两个群体间的遗传分化.结果表明,在广东养殖贝和三亚养殖贝群体中,分别获得232和230条扩增片段,两群体的平均观测杂合度分别为0.28和0.29,平均多态信息含量分别为0.44和0.46,平均有效等位基因数分别为2.25和2.13,显示两个群体的群体遗传多样性水平相差较小(p<0.05),两群体间遗传变异性小,其遗传多样性处于中等水平.两个养殖群体的基因分化系数(GST)为0.0448,群体之间属于轻度偏中度分化水平.     

马氏珠母贝鳃组织抗菌活性的研究

用纸片琼脂扩散法和微量测定法对制备的马氏珠母贝鳃组织匀浆物进行抗菌活性分析.结果表明,马氏珠母贝鳃组织匀浆物具有抗革兰氏阴性菌-副溶血弧菌、河流弧菌、嗜水气单胞菌、大肠杆菌、绿脓杆菌活性;对革兰氏阳性菌-金黄葡萄球菌具一定抑制活性,但对枯草芽孢杆菌无抑制活性.利用胰蛋白酶对马氏珠母贝鳃组织匀浆物水解后,其抗菌活性消失,表明其中抗菌成分为蛋白质.将马氏珠母贝鳃组织匀浆物在不同温度(37～95 ℃)和不同pH(2.5～5)保温,发现其抗菌活性成分对热及酸耐受性较强.马氏珠母贝鳃组织匀浆物在低浓度无溶血活性.该抗菌组分在马氏珠母贝的免疫防御中具有一定的作用.     

合浦珠母贝章鱼胺受体(OAR)基因的克隆与表达分析

章鱼胺受体(octopamine receptor,OAR)广泛存在于无脊椎动物中,具有调节神经肌源性节奏收缩、调节c AMP水平、参与磷酸化途径等多种重要功能,但其在贝类中的研究却很少。该研究克隆了合浦珠母贝(Pinctada fucata)OAR基因(pf OAR)的c DNA全长序列,比较分析了氨基酸序列的同源性,并采用荧光定量PCR技术检测了该基因在不同组织和幼体不同发育阶段的表达差异以及贝壳损伤后该基因在外套膜中表达水平的变化。结果显示:pf OAR的c DNA全长1 890 bp,开放阅读框1 659 bp,编码552个氨基酸,有7个跨膜结构域,具有G蛋白偶联受体的共性。pf OAR在6个被检测的组织中均有表达,且在外套膜中的表达水平显著高于其他组织;幼体发育过程中pf OAR表达水平逐渐升高,变态期的表达水平显著高于其他时期;人为损伤贝壳36 h后,pf OAR的表达水平显著升高。这些结果表明pf OAR在合浦珠母贝中可能具有多样化的功能,参与了贝壳的形成和修复,为进一步开展pf OAR的功能研究奠定了重要基础。     

马氏珠母贝磺基转移酶基因的克隆及功能

硫酸角质素具有丰富的携带大量负电荷的磺酸基团,参与生物矿化的成核过程。磺基转移酶催化磺酸基团的转移,对硫酸角质素的生物合成起决定性作用。本研究利用RACE技术克隆马氏珠母贝磺基转移酶PmCHST1a全长,并通过RNA干扰技术检测PmCHST1a对硫酸角质素合成及贝壳珍珠层形成的影响。结果显示,PmCHST1a基因全长1385 bp,编码366个氨基酸;含有磺基转移酶结构域,具有跨膜结构和信号肽,定位于高尔基体上。组织差异表达分析发现,PmCHST1a在中央膜显著高表达。注射PmCHST1a的RNAi探针后,PmCHST1a在中央膜的表达量显著下调,并且外套膜外液中硫酸角质素的浓度显著降低;SEM检测发现珍珠层结构紊乱。综上所述,PmCHST1a可能通过影响外套膜外液中硫酸角质素的合成,参与珍珠层的形成。本研究为进一步探讨磺基转移酶及其参与合成的糖胺聚糖硫酸角质素在马氏珠母贝生物矿化中的作用提供依据。     

Macro‐geographical differences influenced by family‐based expression on cultured pearl grade,shape and colour in the black‐lip ‘pearl oyster’ Pinctada margaritifera: a preliminary bi‐local case study in French Polynesia

In French Polynesia, the aquaculture of Pinctada margaritifera is carried out in numerous grow‐out sites, located over three archipelagos (Gambier, Society and Tuamotu). To evaluate the impact of macro‐geographical effects of these growing sites on pearl quality traits, five hatcheries produced families were used as homogeneous donor oysters in an experimental graft. The molluscs were then reared in two commercial locations: Tahaa Island (Society) and Rangiroa atoll (Tuamotu). At harvest, eight pearl quality traits were recorded and compared: surface defects, lustre, grade, circles, shape categories, darkness level, body and secondary colour and visual colour categories. Overall inter‐site comparison revealed that: (1) all traits were affected by grow‐out location except for lustre and round shape, and (2) a higher mean rate of valuable pearls was produced in Rangiroa. Indeed, for pearl grade, Rangiroa showed twice as many A‐B and less reject samples than Tahaa. This was related to the number of surface defects (grade component): in Rangiroa, twice as many pearls had no defects and less pearls had up to 10 defects. Concerning pearl shape, more circled and baroque pearls were found in Tahaa (+10%). For colour variation, 10% more pearls have an attractive green overtone in Rangiroa than in Tahaa, where more grey body colour were harvested. Lustre does not seem to be affected by these two culture site (except at a family scale). This is the first time P. margaritifera donor family have been shown to vary in the quality of pearls they produce depending on their grow‐out location.     

栅栏技术优化即食调味珍珠贝肉工艺的研究

文章运用栅栏效应的理论,确定了高水分型即食调味珍珠贝肉食品的制作工艺,分析了各种常见栅栏因子对制品感官品质及微生物的影响,优化前处理、烘干工艺、杀菌工艺、pH、水分活度（activity water,Aw）和低温处理等多种栅栏因子,形成有效防止制品腐败变质的栅栏模式。试验结果表明,原料前处理需用3％的食盐进行了清洗;采用0．15％柠檬酸溶液调节pH为5．6～5．7;贝肉调味后需经烫煮;产品水分含量45％～50％,Aw为0．88～0．90;产品真空包装,低温处理24h,再采用巴氏杀菌（80～85℃、30min）,能较好地保持产品的品质和风味,延长保存期,保持珍珠贝肉特有的鲜味和营养价值,促进珍珠贝肉的开发利用。