不同盐度和驯养时间中华鲟子二代幼鱼鳃的显微结构变化

采用光学显微镜和组织切片方法,研究了不同盐度和驯养时间中华鲟幼鱼鳃及鳃中泌氯细胞的结构变化特征。试验用鱼为1+龄中华鲟子二代,平均全长50.7 cm,平均体重约441.9 g。试验前在养殖池中暂养1周。试验设2个盐度梯度(10、15)组和1个对照组(淡水)。盐度驯养为将中华鲟子二代从暂养池转入盐度10海水中驯养,分别取驯养1、3、6、9、12、24、48、72、96、120、144、168、192、216、240和264 h的幼鱼各1尾用于试验;将剩下的鱼再转入盐度15海水中驯养,分别取驯养24、48、72 h的幼鱼各1尾用于试验。结果显示,在淡水组中,中华鲟子二代幼鱼鳃丝发达,细胞饱满,鳃小片宽且长。鳃丝上皮的泌氯细胞数量较少,通常靠近鳃小片基部,呈近椭圆状。与淡水组相比,盐度10组的幼鱼鳃丝主干部明显变窄,鳃小片基部区域及鳃小片上泌氯细胞的数量略有增加,胞体变大,且随驯养时间的延长,出现了明显的细胞膜间隙。幼鱼在盐度15组中鳃丝主干明显变窄变短,鳃小片也显著缩短,鳃泌氯细胞数量显著增加,主要分布在鳃小片基部,有明显的分泌腔。中华鲟子二代幼鱼能够快速适应外界水体盐度的变化,这与鳃及鳃上皮中调节渗透压功能细胞的数量和结构变化相适应。     

马氏珠母贝精子的超低温保存

采用光镜和透射电镜方法，研究了不同盐度驯化下施氏鲟幼鱼鳃中泌氯细胞的分布和结构特征。结果显示，在淡水中，施氏鲟幼鱼鳃中的泌氯细胞数量较少，且主要分布在近鳃小片基部，胞体与核均较大而明显，胞内含大量线粒体；泌氯细胞中有网管和囊管，但网管欠发达，囊管分布面积小，细胞表面有顶隐窝。表现为典型的淡水型泌氯细胞（freshwater-type chloride cells）特征。与淡水组相比，盐度10组鳃泌氯细胞的分布和结构变化均不明显，仅数量略有增加，胞体变大。幼鱼在盐度25海水中驯化65d，鳃丝和鳃小片上泌氯细胞数量明显增加，泌氯细胞集中分布在鳃小片基部；超微结构显示，细胞内线粒体数量明显增加，胞质中网管颇为发达，囊管丰富，顶隐窝扩大，表面有微绒毛，表现为α-型（α-subtype）泌氯细胞特征。泌氯细胞具有分泌体内过多Na^＋、Cl-以及调节体液渗透平衡的功能，其数量和结构变化与幼鱼所处的高渗环境相适应。     

盐度对花鲈幼鱼鳃、脾及肌肉组织结构的影响

为了探究不同盐度对花鲈(Lateolabrax maculatus)幼鱼组织结构的影响，用组织学方法对不同盐度条件下(0、10、15、20、30)花鲈幼鱼的鳃、脾及肌肉组织结构进行研究。结果显示，盐度为0时，花鲈幼鱼鳃丝排列紧密，顶端膨大呈棒状，鳃小片细胞饱满，有少量泌氯细胞。花鲈幼鱼鳃丝宽度随盐度的升高而缩小，鳃小片间距则逐渐增大，差异显著(P<0.05)；盐度为20时，部分鳃小片变形脱落，鳃丝上的泌氯细胞明显增多增大；盐度为30时，鳃丝宽度较大，出现断裂脱落，鳃丝上细胞排列疏松，泌氯细胞明显膨大，有溶解现象。脾脏在淡水条件下(盐度为0)，淋巴细胞数目较少，血细胞较多；在低盐环境中(盐度为10、15)，淋巴细胞增大，数量增多，黑色素巨噬细胞中心数量增加；在高盐度下(盐度为30)，脾细胞和部分淋巴细胞出现肿大、空泡化现象，细胞排列疏松。盐度为0时，花鲈幼鱼肌纤维排列较为疏松，多角形或长椭圆形，长径和短径较大、密度较小；盐度为15时，肌纤维短径变小、密度增大，与0、10盐度组均差异显著，盐度为30时，肌纤维长径增大、密度减小；随着盐度的增加，肌纤维长径和短径均有先减小后增加的趋势，单位面积肌纤维数量则先增加后减小，差异显著(P<0.05)。结果表明，花鲈幼鱼鳃、脾及肌肉组织结构变化特征与其所处的环境盐度有关。     

中华鲟幼鱼渗透调节器官组织结构在海水条件下的适应性调整

本研究以淡水养殖中华鲟(Acipenser sinensis)幼鱼为研究对象,采用连续升盐的方式实施海水驯化实验,对驯化过程中不同盐度下中华鲟幼鱼渗透调节器官鳃、肾和肠组织结构进行比较研究,以期了解各器官在渗透调节过程中的适应性变化。结果显示,中华鲟幼鱼在海水条件下存活率达100%;海水驯化过程中,随着盐度的升高,中华鲟幼鱼鳃小片宽度显著减小(P<0.05),相邻鳃小片间距、泌氯细胞直径显著增加(P<0.05),表明中华鲟幼鱼从淡水环境逐渐向海水环境适应过程中,通过改变鳃小片宽度及相邻间距,加快机体与外界水氧交换量,增加泌氯细胞大小,提高细胞代谢水平,以应对海水环境的高渗透压。同时,中华鲟幼鱼肾小球长径在海水驯化过程中显著减小(P<0.05),同时数量也略有减少,表明中华鲟幼鱼通过降低肾脏的滤过功能减少机体水分丧失,以适应外界环境渗透压的变化。肠道组织结构未观察到明显变化。研究表明,中华鲟幼鱼具有较强的海水适应能力,渗透调节器官主要通过改变鳃小片宽度和间距、泌氯细胞大小及肾小球大小和数量来适应海水盐度变化。     

南海北部黄鳍金枪鱼幼鱼和成鱼鳃的组织学比较研究

本研究运用光学显微镜、扫描电镜以及透射电镜技术研究了南海北部黄鳍金枪鱼(Thunnus albacares)幼鱼和成鱼鳃的显微组织结构、鳃表面超微结构和鳃小片内部超微结构特点。结果表明, 黄鳍金枪鱼鳃丝顶端弯曲, 鳃弓、 鳃丝和鳃耙表面具有不同类型的细胞。表面超微结构研究显示黄鳍金枪鱼的鳃具有高的片层密度、独特的斜向血流模式以及鳃的融合特性, 幼鱼和成鱼鳃结构之间存在显著不同。鳃小片内部超微结构研究显示鳃扁平上皮细胞覆盖于鳃丝和鳃小片表面, 顶端存在微绒毛或微脊结构, 相对幼鱼, 成鱼具有高的细胞质密度; 离子细胞主要分布于鳃小片以及鳃小片基部, 幼鱼离子细胞顶端开口为微绒毛, 成鱼为小坑状。本研究阐明了黄鳍金枪鱼幼鱼和成鱼鳃的组织结构, 丰富了黄鳍金枪鱼鳃的基础生物学资料, 为研究高速游泳鱼类鳃的形态特征与其高速游泳习性之间的关系提供了参考。     

黄鳍鲷和尼罗罗非鱼鳃丝表面结构扫描电镜观察

黄鳍鲷Sarus latus和尼罗罗非鱼Oreochromis nilotica鳃丝和鳃小片表面都具有规则或不规则分布的环形微嵴、沟状或坑状凹陷及孔洞等结构.黄鳍鲷的鳃丝表面一部分鳃丝表皮凹凸不平,另一部分鳃丝表皮较为平坦.黄鳍鲷和尼罗罗非鱼鳃上皮几种细胞的形态结构及数量分布存在细微的差异.黄鳍鲷的扁平上皮细胞表面观以不规则的六边形为主,或类似菱形的四边形,细胞间界限清楚,而尼罗罗非鱼鳃丝细胞表面的微嵴以形成密集指纹状回路,隆起的微嵴两侧有细小的横突,扁平上皮细胞间排列凹凸不平,形成深沟或凹坑,成为细胞间明确的界线.黄鳍鲷鳃丝表面的氯细胞和粘液细胞数量较多,尼罗罗非鱼鳃丝表面基本上没有观察到氯细胞,粘液细胞很少.黄鳍鲷鳃小片的厚度比尼罗罗非鱼鳃小片的厚.     

苏氏鲢鲶鳃超微结构观察

对苏氏鲢鲶鳃结构进行扫描和透射电镜观察.鲢鲶鳃丝末端膨大呈杓状结构,每一鳃丝两侧具许多呈褶状的鳃小片,相邻两鳃丝上的鳃小片紧密镶嵌排列.鳃弓和鳃耙表面分布众多味蕾.鳃丝呼吸面上皮细胞薄,高度血管化,形成呼吸面隆起;非呼吸面由微脊细胞彼此相连,间缝具分泌细胞开口.鳃小片由单层或数层外上皮细胞和由基膜相隔的柱状细胞及其围在血管腔的凸缘构成,氯细胞多分布在鳃小片基部,并有开口通外.还探讨了鲢鲶鳃丝和鳃小片特殊的结构与功能.     

红笛鲷和卵形鲳鲹鳃的扫描电镜观察与功能探讨

对两种鲈形目鱼类红笛鲷Lutjanus erythopterus和卵形鲳(鱼参) Trachinotus ovatus的鳃结构进行扫描电镜观察。结果表明,红笛鲷和卵形鲳(鱼参)鳃的表面结构和微细结构与其他硬骨鱼类基本相似,鳃丝表面都具有规则或不规则分布的环形微嵴、沟、坑、孔等结构。红笛鲷的中部鳃丝表面一部分较为平坦,基部鳃丝表面则凹凸不平。红笛鲷的鳃小片高度要较卵形鲳(鱼参)鳃小片高。红笛鲷和卵形鲳(鱼参)鳃上皮的几种细胞的形态结构及数量分布存在细微的差异。红笛鲷鳃上的扁平上皮细胞界限清楚,而卵形鲳(鱼参)鳃上扁平上皮细胞表面遍布不规则的微嵴,细胞界限模糊。红笛鲷鳃丝表面的氯细胞数量多于卵形鲳(鱼参),这可能与两种鱼对生活环境、生活习性的长期演变相关。     

红笛鲷和卵形鲳鳗鳃的扫描电镜观察与功能探讨

对两种鲈形目鱼类红笛鲷Lutjanus erythopterus和卵形鲳碜Trachinotus ovatus的鳃结构进行扫描电镜观察。结果表明，红笛鲷和卵形鲳够鳃的表面结构和微细结构与其他硬骨鱼类基本相似，鳃丝表面都具有规则或不规则分布的环形微嵴、沟、坑、孔等结构。红笛鲷的中部鳃丝表面一部分较为平坦，基部鳃丝表面则凹凸不平。红笛鲷的鳃小片高度要较卵形鲳够鳃小片高。红笛鲷和卵形鲳够鳃上皮的几种细胞的形态结构及数量分布存在细微的差异。红笛鲷鳃上的扁平上皮细胞界限清楚，而卵形鲳够鳃上扁平上皮细胞表面遍布不规则的微嵴，细胞界限模糊。红笛鲷鳃丝表面的氯细胞数量多于卵形鲳够，这可能与两种鱼对生活环境、生活习性的长期演变相关。     

不同盐度对斜带石斑鱼幼鱼血清离子浓度和激素水平的影响及其与鳃MRCs渗透调节功能的关系

为探究不同盐度对斜带石斑鱼幼鱼血清离子浓度和激素水平的影响及其与鳃线粒体丰富细胞(MRCs)渗透调节功能关系,实验将暂养于盐度为30的水体中的斜带石斑鱼幼鱼直接转移至盐度分别为5、10、20和30(对照组)的水体中,于7和15 d分别检测血清Na~+、K~+、Cl~–浓度和血清皮质醇(COR)水平,并于第15天观察幼鱼鳃MRCs分布和结构的变化。结果显示,随盐度升高,幼鱼血清Na~+、Cl~–浓度显著上升,而K~+浓度无显著变化;COR水平在盐度5和10实验组显著高于盐度20和对照组;随盐度上升,鳃MRCs体积增大,数量增多,且盐度20和对照组鳃MRCs体积显著大于盐度5和10实验组;鳃MRCs表面存在一个特殊的顶膜结构,在不同盐度下呈现不同形态:盐度5和10实验组中鳃MRCs顶膜开口较大,且其表面存在大量的微绒,而盐度20实验组和对照组中鳃MRCs的顶膜向内深陷形成了一个顶隐窝,开口较小,且其表面没有微绒毛。研究表明,斜带石斑鱼幼鱼鳃MRCs在盐度5的水体中可以很好地发挥渗透调节功能,使幼鱼在盐度5的水体中存活。     

Effects of low environmental salinity on the cellular profiles and expression of Na+, K+-ATPase and Na+, K+, 2Cl? cotransporter 1 of branchial mitochondrion-rich cells in the juvenile marine fish Monodactylus argenteus

The goal of this study was to determine the osmoregulatory ability of a juvenile marine fish, silver moony (Monodactylus argenteus), for the purpose of developing a new experimental species for ecophysiological research. In this study, M. argenteus was acclimated to freshwater (FW), brackish water (BW), or seawater (SW). The salinity tolerance of this euryhaline species was effective, and the fish survived well upon osmotic challenges. The largest apical surface of mitochondrion-rich cells was found in the FW individuals. Immunohistochemical staining revealed that Na(+), K(+)-ATPase immunoreactive (NKA-IR) cells were distributed in the interlamellar region of the gill filaments of the silver moony in all experimental groups. In addition to the filaments, NKA-IR cells were also found in the lamellae of the FW individuals. The number of NKA-IR cells in the gills of the FW individuals exceeded that of the BW and SW individuals. The NKA-IR cells of FW and SW individuals exhibited bigger size than that of BW fish. The NKA activities and protein expression of the NKA α-subunit in the gills of the FW individuals were significantly higher than in the BW and SW groups. Additionally, the relative amounts of Na(+), K(+), 2Cl(-) cotransporter 1 (NKCC1) were salinity-dependent in the gills. Immunofluorescent signals of NKCC1 were localized to the basolateral membrane of NKA-IR cells in all groups. In the gills of the FW individuals, however, some NKA-IR cells did not exhibit a basolateral NKCC1 signal. In conclusion, the present study illustrated the osmoregulatory mechanisms of this easy- and economic-to-rear marine teleost with euryhaline capacity and proved the silver moony to be a good experimental animal.     

Acclimation of brackish water pearl spot (Etroplus suratensis) to various salinities: relative changes in abundance of branchial Na+/K+-ATPase and Na+/K+/2Cl− co-transporter in relation to osmoregulatory parameters

The present study was conducted to elucidate the osmoregulatory ability of the fish pearl spot (Etroplus suratensis) to know the scope of this species for aquaculture under various salinities. Juvenile pearl spot were divided into three groups and acclimated to freshwater (FW), brackish water (BW) or seawater (SW) for 15 days. The fish exhibited effective salinity tolerance under osmotic challenges. Although the plasma osmolality and Na⁺, K⁺ and Cl^? levels increased with the increasing salinities, the parameters remained within the physiological range. The muscle water contents were constant among FW-, BW- and SW-acclimated fish. Two Na+/K+-ATPase α-isoforms (NKA α) were expressed in gills during acclimation in FW, BW and SW. Abundance of one isoform was up-regulated in response to seawater acclimation, suggesting its role in ion secretion similar to NKA α1b, while expression of another isoform was simultaneously up-regulated in response to both FW and SW acclimation, suggesting the presence of isoforms switching phenomenon during acclimation to different salinities. Nevertheless, NKA enzyme activities in the gills of the SW and FW individuals were higher (p < 0.05) than in BW counterparts. Immunohistochemistry revealed that Na⁺/K⁺-ATPase immunoreactive (NKA-IR) cells were mainly distributed in the interlamellar region of the gill filaments in FW groups and in the apical portion of the filaments in BW and SW groups. The number of NKA-IR cells in the gills of the FW-acclimated fish was almost similar to that of SW individuals, which exceeded that of the BW individuals. The NKA-IR cells of BW and SW were bigger in size than their FW counterparts. Besides, the relative abundance of branchial Na⁺/K⁺/2Cl^? co-transporter showed stronger evidence in favor of involvement of this protein in hypo-osmoregulation, requiring ion secretion by the chloride cells. To the best of our knowledge, this is the first study reporting the wide salinity tolerance of E. suratensis involving differential activation of ion transporters and thereby suggesting its potential as candidate for fish farming under different external salinities.     

长江口中华鲟幼鱼的生长特性

2004年5~8月中华鲟幼鱼降河洄游途中在长江口聚集期间,收集到196ind幼鱼样本,分析研究了其生长特点。结果显示,中华鲟幼鱼在长江口逗留期间生长迅速,体长和体重分别从5月下旬刚到达长江口时的16.68±3.27cm和28.69±16.06g增加到8月份入海时的31.90±7.77cm和236.77±176.64g,体长增长1.91倍,体重增加8.25倍。中华鲟幼鱼体重与体长呈幂函数关系,其幂指数b值在5月和8月小于3,此时表现出异速生长。b值在6月和7月接近于3,呈等速生长。6月和7月的肥满度也高于5月和8月。表明6月和7月的生长情况要好于5月和8月。这一现象可能是中华鲟幼鱼在5月和8月有2次生活环境改变和食性变化所导致。     

大规格中华绒螯蟹亲本子代大眼幼体在微山湖地区的池塘扣蟹培育试验

为探究大规格中华绒螯蟹(Eriocheir sinensis)亲本子代大眼幼体在山东微山湖地区的池塘养殖效果,2019年在微山湖扣蟹基地将2种大规格河蟹亲本(规格Ⅰ:雌190~210 g、雄280~300 g;规格Ⅱ:雌240~260 g、雄330~350 g)所产的大眼幼体饲养至扣蟹,并比较各组扣蟹的生长情况、养殖性能、规格分布和经济效益。试验结果:(1)在相同的养殖管理下,规格Ⅰ组扣蟹在8—10月期间的平均规格稍低于规格Ⅱ组,但2组扣蟹的最终规格并无明显差异(P>0.05);(2)两组大眼幼体在扣蟹阶段的最终养殖性能无显著差异,大眼幼体到扣蟹阶段的成活率约为22%,非早熟扣蟹产量约为300 g/m²,饲料系数为2.1,饲料成本约为13元/kg;(3)从非早熟扣蟹的体质量分布看,规格Ⅰ组中体质量在4.00~5.99 g和8.00~9.99 g的比例显著高于规格Ⅱ组,规格Ⅱ组中体质量<4.00 g、6.00~7.99 g和>10.00 g的扣蟹比例高于规格Ⅰ组,2组扣蟹体质量占比最高的均为4.00~5.99 g;(4)就养殖成本而言,规格Ⅱ组购买大眼幼体的费用高于规格Ⅰ组,饲料、苗种、池塘租金和人工费用为4项主要的投入成本,占总投入的80%以上,但规格Ⅱ组扣蟹的销售价格高于规格Ⅰ组,因此其最终利润及投入产出比都高于规格Ⅰ组。试验结果表明,通过科学的养殖管理,微山湖地区开展大规格亲本子一代大眼幼体的扣蟹池塘养殖可以获得较好的养殖效果和经济效益。     

Morphological changes in gill mitochondria-rich cells in cultured Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis> acclimated to a wide range of environmental salinity

Morphological changes in gill mitochondria-rich (MR) cells were examined in cultured Japanese eel acclimated to deionized freshwater (DFW), freshwater (FW), 30%-diluted seawater (DSW), and seawater (SW). The gill Na⁺/K⁺-ATPase activity was higher in SW-acclimated eel than in those acclimated to DFW, FW, and DSW. Immunocytochemical observations revealed that MR cells in the gill filaments were most developed in SW, whereas MR cells in the lamellae were preferentially observed in DFW, suggesting that filament and lamellar MR cells are responsible for ion secretion and absorption, respectively. In scanning electron microscopic observations, the apical membrane of lamellar MR cells appeared as a flat or slightly projecting disk with a mesh-like structure on its surface. In contrast, the apical membrane of filament MR cells showed a slightly concave surface. Whole-mount immunocytochemistry revealed that most MR cells showed cystic fibrosis transmembrane conductance regulator immunoreaction in their apical region in fish in DSW and SW, but not in those in DFW and FW, indicating that MR cells developed in DSW and SW function as an ion-secreting site. In addition to MR cells, distinct Na⁺/K⁺-ATPase immunoreaction was observed in the outermost layer of gill epithelia, suggesting that pavement cells are an additional site of ion uptake in the gills.     

中国养殖斑石鲷(Oplegnathus puncatus)上皮囊肿病的发现及显微观察

2015年,山东省某养殖场工厂化养殖的斑石鲷(Oplegnathus puncatus)幼鱼(全长为15 cm左右)因病陆续死亡,15d内累积死亡率达40％以上.现场调查发现,发病池水温为21℃,盐度为30.患病鱼群散开、不聚集.病鱼身体侧偏,活力差,常贴底或者贴壁,严重者随着水流漂流.病鱼呼吸困难,口部持续张开,鳃盖开合频繁,对投喂的食物无反应.但病鱼反应灵敏,难以捕捉.临床检查和剖检可见病鱼鳃表面覆盖着大量黏液,鳃丝有损伤,肠道无食物.取病鱼鳃丝制成水浸片,在光学显微镜下观察,鳃丝上可见到许多直径约为30-70 μm的囊肿物,外观圆形或卵圆形,呈浅黄棕色.在苏木精-伊红染色的石蜡切片中,病鱼次级鳃丝末端粘连,许多上皮细胞膨大呈囊肿状.囊肿嗜碱性,内部均质化.在扫描电子显微镜下观察,病鱼鳃丝呈棍棒化,鳃小片被大量黏液覆盖,表面光滑的囊肿细胞镶嵌其间.通过上述疾病现场调查、病鱼的临床检查、鳃组织的光学显微镜和扫描电子显微镜病理观察,可以初步确定该病为斑石鲷上皮囊肿病.这是上皮囊肿病在中国养殖斑石鲷中首次被发现和记载.     

Salinity effects on osmoregulation and gill morphology in juvenile Persian sturgeon (<Emphasis Type="Italic">Acipenser persicus</Emphasis>)

The effect of abrupt and 5-day gradual salinity transfers from freshwater (FW) to 11 ‰ Caspian Sea brackish water (BW) was investigated in juvenile Persian sturgeon Acipenser persicus with three different weight groups: 1–2 g (1.62 ± 0.27 g), 2–3 g (2.55 ± 0.41 g) and 3–5 g (4.28 ± 0.76 g). Mortality rates, blood osmotic pressure, gill morphology and branchial Na⁺, K⁺-ATPase (NKA) activity were measured 4 and 10 days after abrupt transfer and 9 and 15 days after the initial gradual transfer (i.e. 4 and 10 days after reaching Caspian Sea salinity). Fish under 3 g could not survive increased salinity, and the blood osmotic pressure of the remaining surviving fish increased and remained elevated. However, heavier fish were able to survive and successfully acclimate, even to rapid salinity change with osmotic pressure reduced to Caspian Sea osmolality levels. At the gill level, the developmental increase in chloride cell volume and a higher NKA content most probably allow juveniles weighing more than 2 g to sharply increase NKA activity if the fish are transferred to BW. The rapid chloride cell proliferation occurring with increased salinity should strengthen this acclimation response. Therefore, a drastic physiological change occurs when fish weigh more than 2 g that allows migration to higher salinities. The triggering signal on chloride cells must be further investigated in order to optimize this functional step.