Treatment of the early life stages of scallop (Pecten maximus) with antimicrobial agents; searching for an alternative to chloramphenicol

High mortality rates are often observed in rearing the early stages of the great scallop, Pecten maximus. The addition of antibacterial agents has been necessary to improve larval survival. However, as one antibacterial agent, chloramphenicol, is banned in Norway and Europe the aim of this study is to investigate alternative antibacterial agents. The therapeutic agents investigated in this study were florfenicol, oxytetracycline, oxolinic acid, neomycin and Pyceze. The mean minimum inhibitory concentration (MIC) values were determined for oxytetracycline, oxolinic acid and Pyceze against bacteria isolated from scallop larvae. Two types of treatment regime were investigated on an intermediate scale (20 L). One regime involved continuous exposure of scallop larvae to the therapeutic agent while the other involved a short exposure lasting two hours. All intermediate scale treatments were performed in parallel to large-scale production (800 L) treatment with chloramphenicol. Of the therapeutants investigated, oxolinic acid was the most effective, although only at high concentrations. The short exposure of two hours was ineffective for all therapeutics.     

栉孔扇贝（Chlamys farreri）在模拟自然水环境中滤水率的测定

在模拟自然海区的生态环境的条件下，对桑沟湾内主要养殖种类栉孔扇贝的滤水率进行了测定，对其不同体长扇贝的滤水率进行了实验比较。在水温２４－２６℃。盐度３１－３２‰范围内，昼间光照５００Ｌｕｘ左右条件下，用叶绿素和颗粒有机物作为测定指标，结果表明，此种扇贝的滤水率随个体增大，单位个体的滤水率越大，而单位干组织重的滤水率越小；同一规格扇贝，密度越大，滤水率越低。在本实验过程中，昼夜间的滤水率变化不甚明显     

拟除虫菊酯和有机磷农药对三种扇贝稚贝的急性毒性效应

采用静水实验法测定拟除虫菊酯类和有机磷类农药对三种扇贝稚贝的急性毒性效应.结果表明:联苯菊酯对海湾扇贝、栉孔扇贝和虾夷扇贝稚贝24 h的LC50的分别为1.460、1.662和2.909 mg/L;辛琉磷对海湾扇贝、栉孔扇贝和虾夷扇贝稚贝24 h的LC50的分别44.598、182.167和39.334 μg/L;马拉...     

扇贝裙边氨基酸营养粉的制备工艺研究

为了对扇贝裙边进行综合利用,本文选择由中性蛋白酶、胰蛋白酶和复合蛋白酶3种酶组合成3对混合酶对扇贝裙边进行酶水解实验,以水解液中游离氨基酸态氮为考察指标,采用正交实验设计研究了加酶量、酶解时间、酶解温度及酶的种类对酶解效果的影响,从而优化了扇贝裙边的酶法水解工艺条件。以最佳水解工艺条件获得的酶解液经喷雾干燥制成的氨基酸营养粉,经检测,其粗蛋白含量为82.89%,粗脂肪含量为1.55%,总糖含量为6.82%。该氨基酸营养粉中氨基酸种类齐全,每100g粗蛋白中氨基酸总量达79.06%,其中游离氨基酸总量达51.53%。     

河北省扇贝养殖区河口区域石油类污染分析

在河北省扇贝养殖区7条主要人海河流河口区域设立监测站位,于2007年5月枯水期和8月丰水期对水样和沉积物样品中石油类含量进行监测.河口水样平均石油类含量丰水期为0.94 mg/L,超标18.8倍;枯水期为0.51 mg/L,超标10.2倍;丰水期明显高于枯水期.河口沉积物中石油类含量丰水期为473μg/g,为标准值的0.95倍;枯水期为777μg/g,为标准值的1.55倍;部分河口沉积物中石油类含量超标严重.河口区域水体石油类污染的主要原因是大陆径流.     

Evaluation of hemato-immunological parameters during the reproductive cycle of the scallop Nodipecten nodosus in association with a carotenoid-enriched diet

The cultivation of scallops Nodipecten nodosus is a promising activity emerging in Brazil. The purpose of this study was to characterize the immune system of N. nodosus and evaluate the modulation of some hemato-immunological parameters during the reproductive cycle, in association with an astaxanthin-enriched diet. It was hypothesized that a supplementation on astaxanthin could enhance scallop immune system and minimize stress of reproduction. Scallops were separated in different groups: juveniles (J), adults (A), sexually mature (M), and recently spawned (S) animals. The last two groups were fed standard (M and S) or astaxanthin-enriched (Ma and Sa) diets. Scallop hemolymph contained two hemocyte populations: hyaline (HH) and granular hemocytes (GH). Antimicrobial peptides, similar to mussel defensins and mytilins, were found by immunodetection within the GH granules, even though the scallop hemolymph did not exhibit significant antimicrobial activity against different bacteria, including marine vibrios. Scallop hemocytes were able to phagocytose zymosan and produce reactive oxygen intermediates (ROI–NBT reduction). The number of circulating hemocytes (Neubauer chamber) varied from 12 to 26.10⁶ cells mL^− 1, and the GH was always the predominant cell type (67–99%). The plasma of N. nodosus contained lectins, specific to galactose and sialoconjugates, and their agglutinating activity was partially calcium-dependent. A phenoloxidase (PO) activity (146–446 U min^− 1 mg^− 1) was observed in the scallop hemolymph. However, this activity was not induced by trypsin or components of microorganism surface, and was strongly enhanced by alkaline pH (≥ 8.5). The total protein concentration of the plasma varied from 240 to 660 μg mL^− 1. In general terms, all examined hemato-immunological parameters (hemograms, superoxide anion production, PO activity, lectin titers and total protein concentration) had a similar profile during all the scallop reproductive cycle. Their levels increased significantly from juveniles to adults (except PO activity), and declined markedly (immune depletion) in the sexually mature scallops. After spawning, the animals had a tendency to recover the standard levels of their immune parameters. Apparently, the astaxanthin-enriched diet had no effect on the tested immune parameters except for a slight influence on the scallop immune-oxidative reactions (ROI production). The results obtained in this study suggested the occurrence of a general immune depletion in the sexually mature scallops, confirming that the reproductive stage is a critical period in scallop life.     

基于重叠分片法的仿人研抛螺旋线轨迹规划

提出一种重叠分片算法，它可产生C^1连续的轨迹规划偏置环，依此给出仿人研抛螺旋线轨迹规划。用普通算法（非人工智能）模拟了人工研抛轨迹，消除了除工件边界外的所有刀具轨迹转折和棱角，产生的准螺旋线轨迹适用于高速铣削和研抛。给出加工重复率的定义，评估了加工效率并分析了适用的分片密度。本算法只需调节权因子w1就可连续调节加工重复率。全部算法通过了Matlab的仿真验证。     

扇贝亲贝配合饲料的研究

“配合饲料”以植物蛋白质和碳水化合物为主，加以适量各种添加剂，经科学调配混合组成。蛋白质含量２５－２６％，脂肪８４－１２９％，碳水化合物４３－５６％，并含有扇贝亲贝性腺成熟必需的微量元素和其他促进性腺成长发育的重要成分。经饲喂试验表明：亲贝性腺指数提高２０－３０％，亲贝成活率９８％，比对照提高２６％，亲贝产出优质精、卵，受精卵的孵化率９３％，饲料成本降低５０％，是一种完全可以代替单胞藻喂养扇贝亲贝的优良配合饲料。     

扇贝内脏团提取物对药物性肝损伤的保护作用

采用生化技术从扇贝内脏团中制备出具有药用价值的扇贝提取物。化学分析结果：牛磺酸含量占１．６％，糖原含量占８．２％，支链氨基酸（ＢＡＣＣ）含量占４０．７１％。支链氨基酸与芳香族氨基酸克分子比（ＢＣＡＡ／ＡＡＡ）为３４．７０。Ｄ—氨基半乳糖肝损伤和四氯化碳肝损伤动物模型试验结果表明，扇贝提取物能提高药物性肝损伤大鼠血清的ＢＣＡＡ／ＡＡＡ和肝组织中抗过氧化酶活性，有纠正血清氨基酸谱紊乱和增强机体抗氧化、清除活性氧自由基能力，对肝脏具有保护作用。     

日本扇贝加工废弃物中镉的脱除技术研究现状

扇贝是日本的重要水产品之一,其加工废弃物占总质量的30%左右,由于其废弃物中重金属含量超标,通常被焚烧处理,造成了环境污染和资源浪费,因此脱除扇贝加工废弃物中重金属的研究非常重要。日本对重金属脱除技术的研究比较重视,进行了大量的研究。综述了日本关于扇贝加工废弃物中镉的脱除方法,以期对我国水产品废弃物中的重金属脱除技术的研究及推广提供一定的借鉴。