施氏鲟鱼鳍营养成分的分析

对人工养殖的施氏鲟鱼鳍的营养成分综合分析的结果表明:施氏鲟鱼鳍的水分平均含量58.70%;灰分含量16.00%;总脂肪的平均含量0.70%;总糖含量0.53%;粗蛋白含量24.70%;纯蛋白含量15.90%。施氏鲟鱼鳍还含有丰富的氨基酸,其中必需氨基酸占氨基酸总量的22.50%,蛋白质营养价高。鲟鱼鳍的矿物质含量丰富,特别是钠元素、锌元素和硒元素的含量,分别达到了154.4mg/kg、49.1mg/kg和0.21mg/kg,可作为富硒食品。因此施氏鲟鱼鳍具有较高的营养价值和开发产品的潜力。     

利用鳍条组织进行流式细胞实验的可行性研究

流式细胞术能快速检测生物细胞的DNA含量和细胞周期,在鱼类遗传育种方面已得到广泛运用。目前的研究多基于鱼类血液和生殖细胞开展实验,存在周期性和操作难度的限制。该研究利用草鱼(Ctenopharyngodon idellus)不同组织进行流式分析,在鳍条组织中得到了明显的峰图,并在4种鱼类的重复实验中得到了稳定结果,且不同鱼类的鳍条组织均存在细胞周期,大部分细胞停留在G_0/G_1期。利用斑马鱼(Danio rerio)作为内标测定出团头鲂(Megalobrama amblycephala)鳍条组织的相对DNA含量(C值)为(1.25±0.07)pg,与相关研究结果基本吻合,认为利用鳍条组织作为血液和生殖细胞的替代材料进行流式细胞实验是科学可行的。     

Standardised removal and sectioning locations for shovelnose sturgeon fin rays

Abstract  Fin rays are a common structure used in age and growth analyses, but many inconsistencies exist regarding removal and processing methodology. The purpose of this study was to evaluate precision of age estimates obtained from shovelnose sturgeon, Scaphirhynchus platorynchus (Rafinesque) fin rays sectioned at different locations. Fin rays were examined from 203 shovelnose sturgeon sampled from Pools 9, 13 and 14 of the Mississippi River. Three readers provided age estimates for sections acquired from five locations along fin rays to determine the optimum location for removing and sectioning fin rays. Precision and readability were generally greater for fin ray sections close to the articulating process on the fin ray (i.e. proximal) and decreased as sections approached the tip (i.e. distal). Based on these results, it is recommended that scientists remove shovelnose sturgeon fin rays at the articulating process and section immediately distal to the conspicuous curve in the fin ray close to the articulating process of the ray.     

Establishment of a novel fin cell line from Brown-marbled grouper, Epinephelus fuscoguttatus (Forsskål), and evaluation of its viral susceptibility

To lay a solid foundation of in vitro investigations of fish viral diseases, cytotechnology and cytotoxicology, a novel fin cell line from brown-marbled grouper, Epinephelus fuscoguttatus , was established and its viral susceptibility was evaluated. The fin tissues, digested with hyaluronidase and collagenase II, were used to initiate primary culture at 24 °C by using 20% foetal bovine serum-Dulbecco's modified Eagle medium/F12 medium, which was further supplemented with carboxymethyl–chitooligosaccharide, basic fibroblast growth factor and insulin-like growth factor-I. The fibroblastic fin cells grew at a steady rate during subsequent subculture and had a population doubling time of 50.6 h at passage 60. The modal diploid chromosome number was 48. A brown-marbled grouper fin cell line (bmGF-1) has been established and subcultured to passage 75 by now. Viral susceptibilities revealed that typical cytopathic effects of bmGF-1 cells emerged after being infected by turbot reddish-body iridovirus (TRBIV) or lymphocystis disease virus (LCDV). However, a large number of TRBIV and LCDV particles were also found in infected bmGF-1 cells. All these indicate that the bmGF-1 cell line has good susceptibility to TRBIV and LCDV, which may serve as a valuable tool for studies of cell–virus interactions and have potential applications in fish virus propagation and vaccine development.     

Differential viral haemorrhagic septicaemia virus genotype IVb infection in fin fibroblast and epithelial cell lines from walleye,Sander vitreus (Mitchill), at cold temperatures

A cell line, WE‐cfin11e, with an epithelial‐like morphology was developed from a caudal fin of walleye, Sander vitreus (Mitchill), characterized as distinct from the established walleye caudal fin fibroblast‐like cell line, WE‐cfin11f, and compared with WE‐cfin11f for susceptibility to VHSV IVb. Immunocytochemistry and confocal microscopy were used to localize the intermediate filament protein, vimentin, the tight junction protein, zonula occludens‐1 (ZO‐1), the extracellular matrix protein, collagen I, and the viral protein, G. Although both cell lines contained vimentin, only WE‐cfin11e stained for ZO‐1 and only WE‐cfin11f stained for collagen I. Ascorbic acid increased the accumulation of collagen I and caused the appearance of collagen fibres only in WE‐cfin11f cultures. At 14 °C, both cell lines produced VHSV IVb, but the infection developed more rapidly in WE‐cfin11f. At 4 °C, both cell lines became infected with VHSV IVb as judged by the expression of viral proteins, N and G, but only WE‐cfin11f produced virus. The results suggest that cold temperatures can modulate viral tropism.     

Non‐lethal sampling of walleye for stable isotope analysis: a comparison of three tissues

Abstract Stable isotope analysis of fishes is often performed using muscle or organ tissues that require sacrificing animals. Non‐lethal sampling provides an alternative for evaluating isotopic composition for species of concern or individuals of exceptional value. Stable isotope values of white muscle (lethal) were compared with those from fins and scales (non‐lethal) in walleye, Sander vitreus (Mitchill), from multiple systems, size classes and across a range of isotopic values. Isotopic variability was also compared among populations to determine the potential of non‐lethal tissues for diet‐variability analyses. Muscle‐derived isotope values were enriched compared with fins and depleted relative to scales. A split‐sample validation technique and linear regression found that isotopic composition of walleye fins and scales was significantly related to that in muscle tissue for both δ¹³C and δ¹⁵N (r² = 0.79–0.93). However, isotopic variability was significantly different between tissue types in two of six populations for δ¹⁵N and three of six populations for δ¹³C. Although species and population specific, these findings indicate that isotopic measures obtained from non‐lethal tissues are indicative of those obtained from muscle.     

基于单位体积热能准则的肋片传热拓扑优化设计

基于渐进结构优化(ESO)思想,以删除单位体积热能低的单元为优化准则,建立了肋片传热优化数学模型。采用基于选择逻辑的方法,利用ANSYS中的APDL命令开发了数值求解程序。数值算例分析表明:模型具有很好的可行性和通用性。     

翅片结构对航空活塞式风冷发动机缸体强度与传热性能的影响

航空活塞式风冷发动机由于结构紧凑、体积小、质量轻等优势,在通用航空、农业等领域得到广泛运用。针对航空活塞式风冷发动机热负荷问题,该研究以某水平对置四缸四冲程航空活塞风冷汽油机为研究对象,试验测试了标定功率工况下发动机缸内压力,结合缸压试验数据与风冷发动机缸体的结构与传热特性,搭建一维仿真模型,计算获得了缸内燃气侧边界条件。采用热电偶法测试了标定功率工况下缸体关键区域的工作温度,结合缸体温度测试数据与缸内各位置的温度和传热系数,建立流固耦合仿真模型。选择翅片厚度、翅片间距、翅片长度3个主要结构参数分析其对缸体结构强度及传热性能的影响。结果表明,翅片结构对缸体的强度及传热性能影响较大,翅片厚度增大使得温度最大下降19.8℃、应力最大下降33.0 MPa。以翅片厚度、翅片间距、翅片长度3个翅片主要结构参数为因素设计正交试验,计算结果表明,翅片长度变化对缸体温度影响最大;选取最优值优化后与原机相比温度最大下降18.2℃。翅片厚度对翅片强度影响最大,选取最优值优化后与原机相比热应力最大下降50.1 MPa。研究结果可为航空活塞风冷发动机散热翅片的设计与优化提供参考依据。     

Deformity of agglutinated pelvic fin membrane in hatchery-reared black rockfish Sebastes inermis and its application for stock separation study

ABSTRACT:   This study is the first to report on the high occurrence of agglutinated pelvic fin membrane deformities in hatchery-reared black rockfish Sebastes inermis . For 5 years, this symptom was marked in hatchery-reared fish, with 58.7% of fish deformed on average (varying between 46.7 and 72.0%). The deformity was a peculiarity in hatchery-reared fish, but is negated in wild fish, and was not related to whether the fish broodstock originated from the wild or from a hatchery. Mark–release experiments showed that deformed fish were almost the same as normal hatchery-reared fish in growth and survival rates, and, theoretically, the recapture numbers of hatchery-stocked fish, estimated by deformity, almost coincided with actual recapture numbers, confirmed by otolith tagging. The results of the present study indicate that deformity in hatchery-reared black rockfish is useful as a stock separation tool.