华南沿海近江牡蛎体中硫丹残留特征研究

为探讨种植业近年仍在使用的硫丹杀虫剂对沿岸海域的污染状况,以近江牡蛎(Crassostrea rivularis)作指示生物,用气相色谱-微电子捕获检测器测定其软组织中硫丹的含量(按μg·kg-1湿重计),分析硫丹含量的时空分布与组成特征。结果表明,华南沿岸海域牡蛎体中硫丹含量总体呈下降趋势,区域平均值相对高低依次为广东沿岸(2.13μg·kg-1湿重)海南沿岸(1.23μg·kg-1湿重)广西沿岸(0.76μg·kg-1湿重),且在23个观测站间存在不同程度的差异。按牡蛎体中硫丹异构体组成初步推测,近几年华南沿岸地区使用硫丹的可能性依次为广东广西海南岛。共观测样本115份,在检出硫丹的40份样本中,硫丹残留量在1.03~12.2μg·kg-1湿重程度范围内,其中2份略高于欧盟的限量,16份略超过日本的限量,但远低于澳大利亚、加拿大的限量和世界卫生组织评估的人体安全摄取量。     

The effect of temperature on physiological energetics of a fast‐growing selective strain and a hatchery population of the Pacific oyster (Crassostrea gigas)

Growth is an important aquaculture trait, which has been one of the most important traits for genetic improvement in aquatic species. Numerous fast‐growing domesticated aquaculture organisms are being cultured, but the physiological processes underlying growth remain largely unexplored. The Pacific oyster (Crassostrea gigas) is one of the most widely farmed bivalves. In order to improve the productivity traits, a fast‐growing selective strain of C. gigas was established. In this study, we compared physiological energetics of the fast‐growing selective strain and an unselected hatchery population of C. gigas under different conditions of temperature. Components of energy gain (clearance rates, ingestion rates, absorption efficiency and absorption rates), energy loss (metabolic rates) and resulting energy budget (scope for growth) were analysed at four temperatures (15, 20, 25 and 30°C). The results indicated that selective breeding oysters had a higher energy gain compared to unselected oysters, but the selected strain and hatchery population of oysters did not significantly differ in metabolic rates at all tested temperatures (p > 0.05). The enhanced energy gain resulted in almost two times higher scope for growth in selective breeding oysters compared with unselected oysters. Physiological characteristics of C. gigas were greatly affected by temperature and showed a fluctuation with the increase in temperatures. The selective breeding oysters outperformed those of hatchery population in growth performance by an increased energy gain along with a similar energy loss. This study provided insight into physiological energetics accounting for growth improvements in fast‐growing selective strain of C. gigas.     

Impacts of Lactobacillus plantarum in Depuration for Reducing Vibrio parahaemolyticus in Pacific Oysters (Crassostrea gigas)

This study investigated potential application of lactic acid bacteria (LAB) in depuration for reducing Vibrio parahaemolyticus in oysters. Lactobacillus plantarum ATCC 8014, which exhibited strong bactericidal effects against V. parahaemolyticus in vitro, was added to artificial seawater for depuration of Pacific oysters (Crassostrea gigas) inoculated with V. parahaemolyticus BE 98-2029 (O3:K6) to levels of about 10⁴ MPN/g at 15 ± 1 and 10 ± 1°C. Application of L. plantarum ATCC 8014 treatment (10⁷ CFU/mL) in oyster depuration did not enhance reductions of V. parahaemolyticus in oysters depurated at 15 ± 1°C but significantly decreased (p < 0.05) levels of V. parahaemolyticus in oysters depurated at 10 ± 1°C after 5 days (3.40 log reductions) when compared with controls (2.75 log reductions). It is not clear if a competitive exclusion by LABs to compete with V. parahaemolyticus binding sites in oyster tissues plays a role in the reduction of V. parahaemolyticus in the oysters. Further studies utilizing different types of LABs in oyster depuration might provide additional knowledge for application of LAB in depuration for decontaminating V. parahaemolyticus in oysters.     

Total Mercury Bioaccumulation in Tissues of Carnivorous Fish (Micropogonias furnieri and Cynoscion acoupa) and Oysters (Crassostrea brasiliana) from Sepetiba Bay,Brazil

Total mercury (Hg) levels were determined by cold vapor atomic absorption spectrophotometry (CVAAS) in tissues of two species of carnivorous fishes and in the soft tissue of oysters caught in Sepetiba Bay, Brazil. Hg was distributed unevenly in the organs and tissues of the fish; the mean Hg content was highest in the kidneys (0.048 μg/g wet weight) and lowest in the gills (0.004 μg/g w.w.). Mean Hg levels were higher in the oysters (0.052 μg/g w.w.) than in the fish (0.022 μg/g w.w). The total Hg concentration did not exceed the maximum concentration for food allowed by Brazilian legislation in any of the fish and oyster samples analyzed. Moreover, the Hg concentrations observed were all within the maximum level for fish recommended by the Food and Agriculture Organization (FAO; 0.5 μg/g w.w.).     

Evaluation of the progeny of the fourth‐generation Sydney rock oyster Saccostrea glomerata (Gould, 1850) breeding lines for resistance to QX disease (Marteilia sydneyi) and winter mortality (Bonamia roughleyi)

The Sydney rock oyster breeding programme began in 1990 and initially focused on faster growth and resistance to winter mortality disease (WM, Bonamia roughleyi) before including QX disease (QX, Marteilia sydneyi) resistance in 1997. Four generations of oysters have now been exposed to these diseases at three sites in the Georges River, NSW, Australia (Lime Kiln Bar, LKB; Woolooware Bay, WB; and, Quibray Bay, QB). Non‐selected control oysters and lines developed at each site (Line 1 – LKB, Line 2 – WB, Line 3 – QB) were placed at the three sites alongside a new QX‐resistant line (Line 4) bred from QX survivors in other NSW estuaries. Line 1 oysters grew to a marketable size (>50 g) in two years with minimal losses following QX disease outbreaks: 28% mortality compared with 97% in controls. Losses in Line 3 oysters selected for WM resistance at QB were reduced by more than half (23% versus 52%). Line 2 performed best at WB, but this line showed excellent resistance to QX at LKB and WM at QB, indicating that breeding for resistance to both diseases is effective. However, selection of oysters for QX did not confer resistance to WM and vice versa.     

5种常见珍珠贝的系统发育和遗传多样性分析

利用RAPD标记分析了珠母贝属常见的马氏珠母贝、大珠母贝、珠母贝、解氏珠母贝以及珍珠贝属常见企鹅珍珠贝的系统发育,同时分析了马氏珠母贝和大珠母贝不同地理种群的遗传多样性,并以邻接法（neighbor-joining,NJ）构建了种间及种群间的系统分支图。结果表明：（1）在珍珠贝5种9个种群中,大珠母贝的4个种群最早聚在一起分别成为2个姊妹群,这2个姊妹群聚合为1个单元群后,又与珠母贝聚在一起,然后才与马氏珠母贝姊妹群聚合成的单元群聚合,再与解氏珠母贝聚合,最后才与企鹅珍珠贝聚合;（2）珠母贝属4种珍珠贝进化程度由低到高的等级顺序为解氏珠母贝-马氏珠母贝-珠母贝-大珠母贝;解氏珠母贝是最晚形成的种类;（3）比较5种珍珠贝野生种群的Nei＇s多样性和Shannon多样性值为：马氏珠母贝（0.4111和0.5933）〉珠母贝（0.3971和0.5784）〉企鹅珠母贝（0.3831和0.5493）〉大珠母贝（0.3388和0.4999）〉解氏珠母贝（0.3016和0.4452）;（4）无论是马氏珠母贝,还是大珠母贝,野生种群的遗传多样性值均大于养殖种群。     

Short term effects of a commercial eastern oyster nursery upon nutrient and plankton dynamics of a coastal embayment: observations from mesocosm experiments

Two mesocosm experiments were conducted to study the interaction of a commercial oyster‐nursery system with the surrounding embayment, specifically, nutrient and plankton dynamics. The nursery was stocked with 80–200 L of oysters, sized 3–5 mm. Ambient water and the water passed through the oyster nursery were incubated in mesocosms, and nutrients and plankton were monitored over the course of 27‐h incubations. The first experiment conducted in July 2009 captured a phytoplankton community dominated by Peridinium quinquecorne, a rare dinoflagellate not previously reported in the northeastern USA. Dissolved nitrogen compounds in all mesocosms were depleted within the first 6 h. The second experiment was conducted in September 2009, when a more typical and diverse phytoplankton community was present. Unlike the first experiment, Nitrate plus nitrite in the mesocosms was not depleted. Both experiments indicated little difference between the water passed through the oyster nursery and the ambient water in terms of subsequent nutrient and plankton dynamics, indicating little ‘legacy effect’ of the oyster nursery upon nutrients and plankton in this embayment. This conclusion was reached under the specific operating conditions typical for this nursery system, as chosen by the commercial partner in the study; changes in oyster stocking or flow rate are likely to change the results.     

冷冻牡蛎加工工艺研究及模糊数学感官评价

[目的]优化冷冻牡蛎加工工艺。[方法]以牡蛎为主要原料制成冷冻牡蛎,研究了臭氧水浓度、三聚磷酸钠浓度、食盐和茉莉花茶复配物浓度和壳聚糖浓度对冷冻牡蛎感官质量、干耗和汁液损失率的影响,采用正交试验和模糊数学感官评价法对冷冻牡蛎的加工工艺进行优化。[结果]试验表明,选用臭氧水消毒、三聚磷酸钠漂洗、食盐和茉莉花茶复配物去腥和壳聚糖溶液进行镀冰衣处理,冷冻牡蛎的模糊综合评价总分均高于未处理的冷冻牡蛎,而干耗和汁液流失率均低于后者;应用模糊数学感官评价法优化的冷冻牡蛎最佳加工工艺条件为食盐和茉莉花茶复配物浓度3.0%、三聚磷酸钠浓度3.0 g/kg、壳聚糖浓度3.0%、臭氧水浓度2.0 mg/L。[结论]研究可为冷冻牡蛎工业化生产及质量安全控制提供理论基础。     

牡蛎养殖过程中副溶血弧菌与水质因子间的关系

为了研究牡蛎养殖过程中副溶血弧菌与水质因子之间的关系,2009年3月到11月从广东阳西某牡蛎养殖场采集牡蛎样品检测其副溶血弧菌的感染情况,并检测水体温度、盐度、pH和溶解氧。实验结果表明：副溶血弧菌总量的检出率为94.38%。水温和副溶血弧菌总量呈正相关,盐度和副溶血弧菌总量呈负相关,pH和溶解氧与副溶血弧菌总量的相关性不明显。对水温和盐度与副溶血弧菌总量的对数进行回归分析,水温和副溶血弧菌浓度的拟合回归方程为：lgVP= 0.093×T-0.685(R₂=0.336);盐度和副溶血弧菌浓度的拟合回归方程为：lgVP=1.199+0.116×S-0.004×S₂(R₂=0.217);水温和盐度对副溶血弧菌浓度的拟合回归方程为：lgVP=-1.941 0.116×T 0.058×S-0.001×S₂(R₂=0.414)。研究结果可为牡蛎养殖过程中副溶血弧菌的风险分析提供参考依据。