塑料袋包装充氧运输胁迫对四指马鲅幼鱼抗氧化系统的影响及抗应激剂的作用

为探究塑料袋包装充氧运输胁迫对四指马鲅(Eleutheronema tetradactylum)幼鱼肝、肌肉抗氧化系统的影响以及抗应激剂的生理作用。本研究设置了未经运输的幼鱼30尾作为对照组、不添加任何抗应激剂运输的幼鱼90尾作为空白组、添加维生素C(VC)运输的幼鱼90尾作为维生素C组以及添加谷氨酰胺(Gln)运输的幼鱼90尾作为谷氨酰胺组,在运输实验进行的2 h、6 h以及9 h采样,不同时间点每组各取30尾幼鱼分别采集肝、肌肉样品进行相关指标的测定。测定项目包括:超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、还原型谷胱甘肽(GSH)、丙二醛(MDA)以及总抗氧化能力(T-AOC)。结果显示,运输胁迫使空白组肝和肌肉中SOD活性最终显著(P0.05)高于对照组,而维生素C组和谷氨酰胺组由于抗应激剂的存在而使其最终活性低于对照组;运输胁迫使空白组和维生素C组肝以及肌肉中CAT活性显著(P0.05)升高,最终其活性均显著(P0.05)高于对照组,而谷氨酰胺组最终值与对照组无显著差异(P0.05);运输胁迫使空白组肝和肌肉MDA含量均显著(P0.05)升高,而抗应激剂维生素C和谷氨酰胺明显缓解了这一现象;GSH含量在空白组、维生素C组和谷氨酰胺组的肝与肌肉中均出现了不同的变化趋势,可能与这两种组织所承担的生理功能不同有关;运输胁迫后,空白组肝与肌肉T-AOC值均显著(P0.05)高于对照组,而维生素C组和谷氨酰胺组最终则略高于或等于对照组。本研究分析了运输胁迫下四指马鲅幼鱼抗氧化系统变化规律以及抗应激的作用效果,旨在为其养殖生产提供参考依据。     

四指马鲅视网膜早期发育的组织学研究

本文采用石蜡连续切片技术、H.E染色和显微测量法,对四指马鲅(Eleutheronema tetradactylum)早期发育过程中视网膜的结构、分化和形成过程以及视觉特性进行了研究。结果显示,受精后8 h54 min,视杯已经形成。初孵仔鱼视网膜没有分化。2日龄仔鱼可以清晰的辨认出色素上皮层、外核层、内核层和神经节细胞层。3日龄仔鱼内核层已经分化出水平细胞、双极细胞和无长突细胞。4日龄仔鱼视网膜10层结构完整。9日龄至14日龄,外核层胞核数目与神经节细胞数目的比值增大,视网膜会聚程度升高,是该鱼视觉特性发生变化的过渡期,这与其从浮游到浅海中下层和泥沙质海底活动的生态迁移相适应。在生长发育的早期阶段,其视网膜内核层水平细胞仅有1到2层,属于感光系统不甚发达的类型。该鱼在仔鱼浮游生活阶段,视敏度较高,视觉对其行为和摄食活动具有重要作用,适应生活于光照较充足的环境中,转入浅海中下层和泥沙质海底后,光敏度和视敏度均较差,视觉在其行为和摄食活动中不具有主要作用。     

Revision of the Indo-West Pacific polynemid fish genus <Emphasis Type="Italic">Eleutheronema</Emphasis> (Teleostei: Perciformes)

A taxonomic revision of the polynemid fish genus Eleutheronema, which is redefined, resulted in three species of the genus being regarded as valid: Eleutheronema rhadinum (Jordan and Evermann, 1902), having to date been treated as a junior synonym of E. tetradactylum (Shaw, 1804) and currently known only from East Asia (China and Japan) where it is endemic; E. tetradactylum, a senior synonym of both Polynemus teria Hamilton, 1822 and Polynemus coecus Macleay, 1878, being a widely distributed Indo-West Pacific species, which ranges from the Persian Gulf to Australia; and E. tridactylum (Bleeker, 1845), distributed in Southeast Asia (Thailand, Malaysia, and Indonesia). Eleutheronema tridactylum is easily distinguished from both E. rhadinum and E. tetradactylum owing to the vomer lacking tooth plates in the former [vs. vomer with 2 deciduous tooth plates (in specimens at least over ca. 70 mm SL) in the latter] and lower counts of pectoral filaments (free lower rays, 3 vs. 4) and gill rakers [mode 8 (range 4–10) vs. 12 (10–17) and 13 (6–18) in E. rhadinum and E. tetradactylum, respectively]. Eleutheronema rhadinum clearly differs from E. tetradactylum in having higher counts of pored lateral line scales [mode 95 (range 82–95) vs. 73 (71–80) in the latter] and higher scale counts above and below the lateral line [12 (11–14) and 16 (15–17), respectively, vs. 10 (9–12) and 14 (13–15), respectively]. Furthermore, E. rhadinum is distinguished from E. tetradactylum by having a dense black pectoral fin [vs. vivid yellow in life (except in specimens over ca. 350 mm SL, pectoral fin dusky-yellow) in the latter]. Intraspecific variations and morphological changes with growth of the three species are also discussed. Received: June 13, 2001 / Revised: October 11, 2001 / Accepted: October 17, 2001