物理处理鱼体内华支睾吸虫囊蚴感染兔实验观察

为研究钴-60辐照和-18℃～-20℃冷冻对鱼肉中华支睾吸虫囊蚴感染的影响，设立A、B2个实验组。一组用0．05、0．10、0．15、0．20、0．25kGy钴-60对含华支睾吸虫囊蚴的鱼肉进行辐照；另一组将感染了华支睾吸虫囊蚴的鱼肉于-18～-20℃冷冻3、7、14、2l、28d。用两组处理过囊蚴的鱼肉灌喂家兔，用粪检虫卵和解剖动物检查虫体的方法判定结果。囊蚴感染家兔45d后解剖，0．15、0．20、0．25kGy组及冷冻组鱼肉饲喂的动物内均未找到华支睾吸虫成虫、童虫、和虫卵。肝胆器官未见病变。鱼肉中的华支睾吸虫囊蚴经钴-600．15kGv以上剂量辐照或存放于-18℃～-20℃冷冻3d以上，便失去感染力。     

Seventy years of food-web change in South Bay,Lake Huron

Though aquatic ecosystems (and the Laurentian Great Lakes in particular) have faced many stressors over the past century, including fisheries collapses and species invasions, rarely are data available to evaluate the long-term impacts of these stressors on food web structure. Stable isotopes of fish scales from the 1940s to the 2010s in South Bay, Lake Huron were used to quantify trophic position and resource utilization for fishes from offshore (alewife, cisco, lake trout, lake whitefish, rainbow smelt) and nearshore (rock bass, smallmouth bass, white sucker, yellow perch) habitats, providing one of the longest continuous characterizations of food webs in the Laurentian Great Lakes. Mean δ¹⁵N and δ¹³C values for each species were compared across twenty-year time periods. Using directional statistics, no significant community-wide changes were detected between time periods from 1947 to 1999. In contrast, a significant change was detected between 1980-1999 and 2000–2017, with all species showing increased reliance on nearshore resources. The increase in nearshore resource reliance for lake whitefish between these time periods was the greatest in magnitude compared with any other species between any two adjacent time periods. Besides lake whitefish, the increased reliance on nearshore resources was more pronounced for nearshore compared to offshore species. The timing of these shifts coincided with the invasion of dreissenid mussels and round goby, and declines in offshore productivity and prey densities. These results show the unprecedented magnitude of recent food-web change in Lake Huron after 50 years of relative stability.     

渤海鱼类及几种畜禽肌肉中的无机元素含量

测定渤海的8种鱼类的以及4种家畜家禽肌肉中的2 2种无机元素的含量,并进行比较     

秉传统之精华 造观鱼之佳境——福州西湖公园《鉴湖慕鱼》造园艺术

分析西湖历史沿革,西湖名胜景点,从景点布局、建筑、植物等方面论述“鉴湖慕鱼”景点的造园特色。     

Determination of methylmercury in fish and seafood using optimized digestion and derivatization followed by gas chromatography with atomic emission detection

Mercury is an environmental contaminant that appears in different chemical forms. Organic forms of mercury, such as methylmercury, can occur in marine organisms like fish and shellfish and are far more toxic than the inorganic form. It is therefore vital to have refined analytical methods for the different mercuric species in order to evaluate the potential risk for seafood consumers. The aim of our investigations was to develop a simple, robust and valid method for differentiation of the mercury species in marine organisms. Different alkaline and acidic digestion procedures were evaluated. The best performing methodology consisted of digestion of 0.5 g sample in methanolic potassium hydroxide solution. After derivatization with sodium tetraethylborate and extraction of the ethylated mercury species using n-hexane, a quantitative determination of the extract using gas chromatography, combined with atomic emission detection, was possible. The procedure was shown to be selective and sensitive with a limit of detection of 6.1 μg/kg for methylmercury. The average recovery for the full procedure was 91 ± 19%. A preliminary survey of seafoods confirmed the previous observation that the proportion of methylmercury in the total mercury can vary widely, up to a complete occurrence as methylmercury.     

一起疑似食用养殖鲶鱼引起的食物中毒

2004年10月11日,浙江省湖州地区发生一起疑似因食用养殖鲶鱼导致食物中毒事件。共有5户19人食用鲶鱼,4户在烧制过程中未除去鱼卵,一户不能确定是否除去了鱼卵。共有13人发病(男性7人,女性6人),年龄最长74岁,最小20岁,发病呈家庭聚集性。推算每人食用鱼卵36g,鱼肉250g。患者发病潜伏期短,病情发展迅速,症状重,主要表现为恶心、呕吐、抽搐和昏迷。除对重症者血透治疗外,对其他患者采取对症治疗,无死亡。经流行病调查、病人临床表现和实验室分析,认为该食物中毒可能与食用养殖革胡子鲶鱼卵有关。     

浙江省369份淡、海水鱼香港海鸥型菌污染状况研究

目的 掌握浙江省淡、海水鱼中香港海鸥型菌污染状况，为防止食源性香港海鸥型菌痛的发生和流行提供科学依据。方法 用改良头孢哌酮麦康凯琼脂分离，API20NE鉴定香港海鸥型菌。K-B纸片扩散法作耐药性测定。通用引物扩增16S rDNA并与香港海鸥型菌HKU1株开展同源性比较。结果 369份样品检出香港海鸥型菌18株。阳性率为4．88％，其中，鲤鱼检出率为25．00％，草鱼的阳性率为10．26％，海水鱼以及鲫鱼、鲢鱼、扁鱼等淡水鱼中未分离出。分离的香港海鸥型菌16SrDNA序列与HKU1株仅相差1～2个碱基，同源性在99．6％～100．0％之间；18株菌对头孢拉定、万古霉素、甲硝唑、克林霉素、头孢哌酮完全耐药，对红霉素、亚胺培南、克拉霉素、氨曲南、庆大霉素、丁胺卡那霉素、三甲氧苄氨嘧啶、四环素、氯霉素、多粘菌素B、环丙沙星完全敏感，对头孢噻吩、胺苄西林、头孢曲松的耐药性分别为83．33％、61．11％和5，56％。结论浙江省存在香港海鸥型菌污染源，建议相关监督部门应加大这类产品的管理力度。防止香港海鸥型菌病在我省的发生和传播。     

Conservation of fish species diversity in navigable waterways

Nineteen waterways in the German lowlands were surveyed between 1992 and 1997 to evaluate their fishes conservation capacity. From 277 sites a total of 84 821 fish of 31 species was collected. Number of species in various waterways ranged from 6 to 26 with a mean±standarddeviation of 15.4±5.4. Mean species diversity was H′=1.61±0.29 (range 1.02–2.20), and corresponding evenness 0.61±0.09 (0.51–0.76). Fish communities of waterways were dominated by perch and roach, both contributing in mean 68.5±12.5% to the total catch. The mean relative abundance of threatened fish listed in “Red Data Books” of Germany or Europe was 7.83±4.82%.Percentage of artificial shoreline structures like riprap or sheet pile wall was inversely correlated to species number, species diversity and abundance of intolerant species. This study was a first approach to estimate the percentage of habitat restoration required to increase species diversity. Even the restoration of one-fifth of the river banks, the restoration of natural shoreline structures from close 0 to 20% of the bankline should result in substantial improvement of fish diversity, and significantly contribute to species conservation and persistence of viable populations of threatened fishes in waterways. In regard to such relatively low restoration effort, biodiversity conservation in waterways is compatible with long-term resource use, navigation and human needs. Even though heavily modified, waterways are also recommended for conservation issues by their large area covered as well as their substantial number of fish species.     

Proposal of new analytical procedures for heavy metal determinations in mussels, clams and fishes

New analytical procedures and sample mineralizations for the determination of copper, lead, cadmium, zinc and mercury in matrices such as mussels, clams and fishes are proposed. An H₂SO₄ HNO₃ acidic mixture was used for the determination of copper, lead, cadmium and zinc. In the case of mercury, the sample digestion was performed using a concentrated supra pure H₂SO₄ K₂Cr₂O₇ mixture and the results compared with those from other conventional methods. Differential pulse anodic stripping voltammetry (DPASV) was employed for simultaneously determining copper, lead, cadmium and zinc, while the mercury determination was carried out by cold vapour atomic absorption spectrometry (CV-AAS) with reduction with SnC₂, using an innovative method for sample dissolution. The analytical quality control procedures have been verified on three reference standard materials: Oyster Tissue NIST 1566, Mussel Tissue BCR-CRM 278 and Cod Muscle BCR-CRM 422. For all the elements in the certified matrices, the precision, expressed as relative standard deviation (s_r     

Fatty Acids in Liver,Muscle and Gonad of three Tropical Rays including Non-Methylene-Interrupted Dienoic Fatty Acids

Scientific investigation of lipids in Elasmobranchs has been conducted mainly on shark species. Because rays seem to be neglected, this study was performed to examine the complete fatty acid (FA) composition with a particular interest for long-chain polyunsaturated FA (PUFA) content in different tissues of three ray species including parts usually discarded. The total FA and PUFA profiles of total lipids were determined in muscle, liver, and gonad of Rhinobatos cemiculus, Rhinoptera marginata, and Dasyatis marmorata, the most often caught ray species from the East Tropical Atlantic Ocean. Fifty FA were characterized as methyl esters and N-acyl pyrrolidides by gas chromatography/mass spectrometry, showing significant levels of 20:5n-3 (EPA) (up to 5.3%) and 22:5n-3 (DPA) (up to 7.3%), high levels of 20:4n-6 arachidonic (ARA) (4.8–8.6% of total FA) and 22:6n-3 (DHA) (up to 20.0%). The results show that muscle, liver and gonad of rays can provide high amounts of essential PUFA, specially DHA, for direct human nutrition or the food processing industry. High proportions of DHA were particularly found in all samples of R. cemiculus (11.6–20.0%), and in muscle and liver of D. marmorata (11.1–16.1%). Regarding the high amounts of (n-3) PUFA, this study shows that these rays deserve a better up-grading, including the normally discarded parts, and describes the occurrence of unusual NMID FA in all tissues studied. Five non-methylene-interrupted dienoic fatty acids (NMID FA) (0–3.4%) were reported, including previously known isomers, namely 20:2 Δ7,13, 20:2 Δ7,15, 22:2 Δ7,13, 22:2 Δ7,15, and new 22:2 Δ6,14. These acids are quite unusual in fish and unprecedented in rays. The 22:2 Δ6,14 acid occurred in gonads of male specimens of R. cemiculus at 2.9%.