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

A breeding program for Sydney rock oysters Saccostrea glomerata (Gould, 1850) has been selecting oysters for resistance to QX disease (Marteilia sydneyi) and winter mortality (Bonamia roughleyi) for three generations at three sites in Georges River, New South Wales, Australia. The experimental sites are located at the upper, middle and lower reaches of oyster growing areas in the estuary. QX disease mainly occurs in the middle and upper reaches and is most severe at the latter. Winter mortality on the other hand occurs mainly at the lower and middle reaches and is most severe at the former. Progeny of third‐generation Sydney rock oyster breeding lines were evaluated for resistance to both QX disease and winter mortality against a non‐selected control. Line 1, selected for QX disease resistance at the upper estuary site, had excellent resistance to one season of exposure to disease, but suffered high mortality during the second season of exposure. However, these oysters had already reached market size of 50 g whole weight, with low mortality at 2 years of age, before the second episode of QX disease. Line 2 showed good improvement in resistance to both diseases, whereas Line 3, was the most resistant to winter mortality. Selection for resistance to QX disease did not appear to confer resistance to winter mortality and the converse also applied.     

华南沿海牡蛎重金属含量特征及其风险评估

根据2009年对华南沿海部分海域的近江牡蛎和太平洋牡蛎的监测数据,对产品中重金属元素Cd、Cu、Pb、As、Hg和Zn的含量水平、分布与变化特征进行了分析讨论;采用点评估方法,计算Cd、Cu、Pb、As、Hg和Zn的膳食暴露量,对牡蛎产品的食用安全性进行风险评估。结果表明,调查海域牡蛎样品中Cu、Zn、Cd的含量较高,其值分别为92.0、268、1.32 mg/kg(湿重,下同);Hg、As、Pb的含量低,其值分别为9.21、0.11、0.26 mg/kg。不同海域、不同养殖季节的牡蛎产品中重金属元素的含量具有明显的差异。与无公害水产品质量标准的限量值相比,调查海域牡蛎产品中Cu、Zn、Pb、Hg、As的含量符合产品质量标准,Cd的含量超过产品限量标准值。由于元素间的相互作用,牡蛎产品Zn的含量高、Cd的含量低,Zn的可利用性阻止对Cd的吸收,牡蛎产品中的Cd不会对健康造成危害。风险评估的结果显示,每周食用适量的牡蛎,重金属的膳食摄入量低于世界卫生组织/联合国粮食和农业组织的食品添加剂联合专家委员会(JECFA)推荐的暂定每周耐受摄入量,处于安全范围内。     

Commercial assessment of growth and mortality of fifth-generation Sydney rock oysters Saccostrea glomerata (Gould, 1850) selectively bred for faster growth

The Sydney rock oyster Saccostrea glomerata (Gould, 1850) industry acquired hatchery-produced spat selected for faster growth for the first time in January 2004. Selectively bred and non-selected (Control) spat produced concurrently were used to compare performance when grown under commercial conditions. Spat were distributed to farmers in seven estuaries in New South Wales. Individual farmers cultivated these oysters using their own techniques and growth and mortality were recorded quarterly. At each site, the two oyster types were cultivated using the same culture method, location and density. Growth was compared when oysters were 27 months of age. At this time, selectively bred oysters were significantly larger and heavier than Control oysters. The same result was obtained when oysters were compared at the point in time when selectively bred oysters had reached 50 g at each site. No significant difference was found for cumulative mortality between the selectively bred oysters and Control oysters across all sites. However, the seven sites had significantly different levels of cumulative mortality. Overall, the performance of selectively bred oysters was superior to the Control oysters and selectively bred oysters reached the 50 g bench mark within 29.3 months when averaged across all sites.     

基于生食牡蛎HACCP计划的语义建模研究

为提高水产品加工中的质量安全风险信息化管理水平，以国标中的生食牡蛎HACCP 计划为例，提出了基于生食牡蛎加工HACCP计划的语义基础模型(HACCP semantic base model，HSBM)，用来实现知识的提取、表示、建模和推理。从HACCP计划中获取领域知识，构建生食牡蛎HACCP语义建模架构。在该架构指导下，构建知识表示模型，采用本体建模方法对生食牡蛎加工HACCP语义进行建模，并绘制生食牡蛎HACCP概念-关系结构图。然后，采用语义网规则语言SWRL描述业务逻辑规则，提高知识的自动推理能力。最后，利用HermiT推理机实现知识推理。结果表明，此模型可以较为完整地表述生食牡蛎HACCP计划覆盖的知识，丰富生食牡蛎本体知识库，为HACCP计划的数字化、智能化应用提供技术支持。