重金属对鱼类毒性的综合研究

鱼体重金属蓄积量的研究，同时取相应组织块进行病变的内在联系及重金属对鱼胚和鱼苗的毒性作用的研究，证实了温州市水产养殖场遭受到附近一家铅锌冶炼厂废水、废渣的污染。     

草鱼等8种淡水鱼血清凝集素作用的比较

选取8种常见养殖鱼：团头鲂、二龄草鱼与4～5月龄草鱼、加州鲈、银鲫、胡子鲇、鲢、鳙和黄鳝，采其血清，检测其对人和不同动物红细胞的凝集作用，并比较不同糖、酶、理化因素和脂溶剂等对鱼血清凝集兔红细胞的影响。试验显示，草鱼等8种常见养殖鱼血清对人和不同动物的红细胞均有一定的凝集作用，表明均存在血清凝集素。黄鳝、二龄草鱼血清凝集效价较高，二龄草鱼血清凝集效价远高于4～5月龄草鱼。兔红细胞经胰蛋白酶修饰后，不同鱼血清对其凝集效价显升高；甘露糖、半乳糖和乳糖对鱼血清凝集素凝集活性有较强的抑制作用；EDTA、巯基乙醇与胰蛋白酶等均能导致草鱼等血清凝集素凝集活性的下降。     

Improving the Quality of Silver Carp Fish Fillets by Gamma Irradiation and Coatings Containing Rosemary Oil

The objective of this work was to study the combined effect of gamma irradiation and coatings containing 0.5% rosemary (Rosmarinus officinalis) essential oil (RO) on the chemical, microbiological, and sensorial qualities of silver carp (Hypophthalmichthys molitrix) fish fillets (SFF) during cold storage (4°C). SFF were divided into three groups: uncoated (control), coated with edible coating (without additives), and γ-irradiated (0, 1, 3, and 5 kGy) coated with coating containing 0.5% rosemary. Gamma irradiation at 1, 3, and 5 kGy with coating reduced the initial total bacterial count, psychrophilic bacteria, and lactic acid bacteria and prolonged shelf life of the samples. Coated samples irradiated at 1 kGy reduced the counts of Enterobacteriaceae, Staphylococcus aureus, and Bacillus cereus, as well as eliminating Vibrio spp. and Salmonella spp., while coated samples irradiated at 3 and 5 kGy completely eliminated these bacteria. Combined treatment showed a slight increase in thiobarbituric acid-reactive substances postirradiation during cold storage but had no effect on the total volatile basic nitrogen and trimethylamine contents, while a gradual increase in these chemical quality indices was observed during cold storage. Combined treatment had no adverse effects on the sensory properties of SFF. The increase in the bacterial inhibitory effect is caused by both rosemary oil and irradiation.     

大伙房水库鲢鳙放养捕捞模型

用矩阵描述了放养和捕捞的一般数量关系,根据这个关系,用过去数年的放养数据和渔获物的年龄组成数据,可以求得回捕率;将１９９８年秋和１９９９年春测定的该水库放养鲢、鳙的回捕率代入该矩阵中,得出其放养－捕捞的数量方程。该方程可以作为指导水库制订放养和捕捞计划的依据。     

Gut contents of silver carp, Hypophthalmichthys molitrix, and the disruption of a centric diatom, Cyclotella, on passage through the esophagus and intestine

The digestibility of algae by stomachless filter-feeding fish has been debated for decades. Results from gut contents and digestive enzyme analysis suggest poor utilization, while the measurement of food assimilation using radiolabeled isotope techniques indicate reasonable assimilation efficiency. Phytoplankton in the gut contents of the planktivorous filter-feeding silver carp were studied during March–May. The fish were cultured in a large net cage in a shallow, hypertrophic subtropical Chinese lake, Lake Donghu. In terms of biomass, the dominant phytoplankton in the fore-gut contents were Cyclotella (average 77.8%, range 69.7–93.5%) and Cryptomonas (average 9.57%, range 0–20.4%). The Ivlev's electivity index E of silver carp was much higher for Cyclotella (1.54) than for Cryptomonas (0.56). The majority of the phytoplankton found in the intestines of silver carp were 8–20 μm, but they were also able to collect particles as small as 4.5–10 μm, smaller than their filtering net meshes, suggesting that the secretion of mucus may play an important role in collecting such small particles. We conclude that disruption of cell walls is principally by the pharyngeal teeth, explaining previous contradictory conclusions.     

鲢、鳙蛋白酶、淀粉酶的研究

运用酶动力学方法研究了鲢、鳙的蛋白酶和淀粉酶的活性分布。鲢、鳙的蛋白酶活性在肝胰脏中最强,脾脏中也较强,而在胆汁中未测出。该酶活性在肠粘膜的第Ⅱ段最大,第Ⅰ段向第Ⅱ段递增,第Ⅱ段向肠后端递减,但第Ⅴ段的该酶活性比前段要高些。鲢的淀粉酶活性分布规律与上述情况相似,但鳙的淀粉酶活性在肠粘膜各段中由前向后呈递减趋势,并以第Ⅰ段为最大。在相同的器官组织中,鳙蛋白酶活性高于鲢,但差异不显著（Ｐ＞０．０５）,而淀粉酶活性则相反。这两种鱼的蛋白酶活性适宜ｐＨ为８．０～８．５,淀粉酶活性在ｐＨ７．５时最适。在鲢的肠内容物中发现有纤维素酶活性,但在肠粘膜中未检出该酶。     

鲢鳙杂种亲本连锁图标记加密和共线性比较

鲢(Hypophthalmichthys molitrix)与鳙(Aristichthys nobilis)杂种的养殖性能优于亲本,在水产养殖中利用广泛.为促进鲢、鳙遗传资源管理、经济性状定位等研究,已构建了鲢鳙种间杂种亲本的遗传连锁图,但图谱以AFLP标记为主,利用范围有限.为提高图谱质量和可用性,本研究采用新开发的微卫星标记加密了鲢鳙杂种亲本连锁图.雌性亲本鲢的连锁图标记总数从153增加到288(包括新开发微卫星标记93个),雄性亲本鲢的连锁图标记总数从271增加到511(包括新开发微卫星标记136).鳙图谱总长度从852.0 cM增加到965.8 cM,鲢图谱总长度从952.2 cM增加到1049.6 cM.鲢、鳙图谱共线性比较甄别出22个同缘连锁群,标记排列只存在轻微重排现象.亲本间共享的76个微卫星标记界定的标记间隔总长度在亲本间无差异(雌:雄＝1:1),与鳞鲢种内杂种亲本共享微卫星标记界定间隔的总长度雌雄比(1:0.45)显著不同.与模拟自然受精(种内杂种)相比,混精受精(种间杂种)可增加雄性亲本基因组范围的重组率.鲢鳙形态相似,染色体组型相同,杂种可育,鲢鳙杂交对重组率没有影响或影响很小.根据研究结果,认为混精授精回避了精子竞争,强化了全基因组重排,不利于新形成的和已有的优良单倍型的保留,是鲢鳙养殖性能退化的原因之一.     

TG酶催化过程中鲢肌原纤维蛋白凝胶性能的变化

为探究转谷氨酰胺酶(TG酶)催化过程中,鲢肌原纤维蛋白凝胶性能的变化,进一步提升鲢鱼糜制品特性和营养价值。对不同催化时间(0、15、30、60 min)后鲢肌原纤维蛋白凝胶的交联度、凝胶强度、白度、持水性、微观结构及消化特性变化进行了分析。结果显示,TG酶诱导蛋白胶凝后,蛋白凝胶交联度显著提高。在TG酶催化过程中,随交联时间的延长,白度值增加、持水性提高。通过扫描电镜分析,发现凝胶网络孔径变小,结构变得更加致密。在催化时间30 min下,交联度、白度值及持水力显著提高,弛豫时间T22显著减小。TG酶催化后的蛋白凝胶在消化初始阶段水解程度较低,因为交联度提升,蛋白网络结构越来越致密,降低了胃蛋白酶对其水解位点的可及性。蛋白消化90 min后,网络遭到破坏,导致其水解速率明显提高。研究表明,在适当的交联时间下,有助于提升蛋白凝胶的凝胶特性。该研究为TG酶对鱼肉制品品质及消化特性的改善提供了实验依据。     

鳜和鲢肌肉蛋白质氨基酸组成及其蛋白质组成的比较分析

采用高压液相色谱和二维电泳方法,对鳜和鲢肌肉组织蛋白质组成成分以及肌肉蛋白质双向电泳分布图谱进行了比较研究。研究结果证明,鳜肌肉组织蛋白质干重为34.7％,而鲢肌肉干重为33.6%;鳜肌肉组织中必需氨基酸含量和鲜味氨基酸（天冬氨酸和甘氨酸）均高于鲢。同时,将两种鱼肌肉蛋白进行2D gel双向电泳分离,发现鳜和鲢肌肉蛋白质组成和分布也存在明显的差异。本研究将肌肉蛋白质组成成分和蛋白的双向电泳技术结合起来,进行蛋白质组分归类分析,可为进一步研究两种鱼肌肉肉质研究打下基础,为水产业提供有价值的参考,为鱼类的养殖和肉质的改良、利用提供一个指标。图3表3参24