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981.
To better understand the endocrine- and immune-response pattern during reproduction in a fish species having parental care behaviors and also to accumulate the endocrine- and immune-related data for future explanations of the low reproductive efficiency in seahorse species, the variations of immune factors and sex steroids in the plasma of the male lined seahorse Hippocampus erectus at different breeding stages, i.e., pre-pregnancy, pregnancy (early, middle, and late periods), and post-pregnancy, were investigated in the present study. The immune factors included monocytes/leucocytes (M/L), leucocyte phagocytic rate (LPR), immunoglobulin M (Ig M), interleukin-2 (IL-2), interferon-α (IFN-α), and lysozyme (LZM). The sex steroids included testosterone (T), 11-ketotestosterone (11-KT), 11β-hydroxytestosterone (11β-OHT), 17α-methyltestosterone (17α-MT), 17β-estradiol (E2), and 17α-hydroxy-20β-dihydroprogesterone (17α-20β-P). Moreover, the immune metabolic activity of epithelium cells in the brood pouch at different breeding stages was also analyzed through ultrastructural observations of the abundance of cytoplasmic granules, mitochondria, endoplasmic reticulum, lysosomes, and exocytosis. The results show that a higher immune level was observed during pregnancy, particularly in the early and middle periods, and a lower immune level was noted during pre-pregnancy. Correspondingly, the epithelium cells in the brood pouch also showed a stronger immune metabolic activity during pregnancy and weaker activity during pre-pregnancy. Four sex steroids of T, 11β-OHT, 17α-MT, and E2 were higher during pre-pregnancy and lower during post-pregnancy, whereas 11-KT and 17α-20β-P, which were positively correlated with part immune factors, were higher during pregnancy. No negative correlations between sex steroids and immune factors were observed. In conclusion, the higher immune competence during pregnancy may indicate that parental care could improve immunity, which may be the major factor for no immunosuppressive effect of sex steroids during reproduction in the seahorse H. erectus, unlike noncaregiving fishes in which inhibitions of sex steroids on immunity are frequently observed. Moreover, higher 11-KT and 17α-20β-P during pregnancy than during pre-pregnancy and post-pregnancy may suggest that these two steroids are also involved in parental care regulation.  相似文献   
982.
RAPD技术在鱼类研究中的应用   总被引:3,自引:0,他引:3  
刘辰莹 《淡水渔业》2005,35(5):59-61,64
RAPD(Random Amplified Polymorphic DNA, 随机引物扩增多态DNA)技术是1990年由Williams和Welsh两个研究小组同时发展起来的一项DNA多态检测技术.RAPD技术与其他分子标记技术相比具有独特的优势,在生物种群遗传结构分析、遗传多样性检测、物种亲缘进化关系鉴定、基因连锁图谱的构建和基因定位与分离等得到了广泛应用,在鱼类研究中也有了一定应用,并取得相应成果,主要表现在以下方面.  相似文献   
983.
鳗鲡仔,幼鱼年龄生长的研究   总被引:3,自引:0,他引:3  
辽东半岛黄海北部沿岸河口4—6月溯河的白仔鳗,全长53.5—64.5毫米,平均58.83毫米,体长频率高峰位于57.1—59.0 毫米体长组,其体长体重呈直线相关。白仔鳗与幼鳗群体的体长、体重则是指数相关,其方程为W=1.136×10~(-7) L~(3.3871)。12尾白仔鳗耳石平均日轮数为146.3,据此对其产卵期进行了推测,观察证实,在不同生态条件下生活过的幼鳗耳石的环纹有过渡带存在。  相似文献   
984.
斑节对虾GLUT1基因cDNA的克隆与表达分析   总被引:1,自引:0,他引:1  
该研究利用RACE技术克隆获得了斑节对虾(Penaeus monodon) GLUT1 (glucose transporter type 1)的cDNA全长序列;采用实时荧光定量的方法研究了PmGLUT1在斑节对虾幼体发育过程中、各个组织中及低盐胁迫下的差异表达情况。该基因cDNA开放阅读框(ORF)全长1 476 bp,可编码491个氨基酸。检测PmGLUT1基因从受精卵至仔虾期发育过程的表达情况,结果显示,PmGLUT1在幼体发育各期的表达量有所波动,但总体呈现上升趋势。组织表达分析发现,PmGLUT1在鳃组织中的表达量最高,肝胰腺次之,在卵巢中的表达量最低。急性低盐胁迫后,PmGLUT1在肝胰腺中的表达水平显著高于对照组(P<0.05),但在鳃中的表达水平显著低于对照组(P<0.05)。研究结果表明,Pm GLUT1可能在斑节对虾幼体发育及机体应对低盐胁迫过程中具有重要作用,这为进一步研究葡萄糖转运蛋白基因在斑节对虾幼体发育调控和耐低盐胁迫应答中的分子机制提供了理论依据。  相似文献   
985.
An 8‐week feeding trial was conducted to investigate the effect of dietary selenium (Se) on feed intake, weight gain and antioxidant activity in juvenile grass carp (11.2 ± 0.03 g). Six Se levels (0.13, 0.41, 0.56, 1.12, 2.18 and 4.31 mg/kg) of semi‐purified diets were assayed in triplicate. The maximum weight gain, specific growth rate and feed intake were obtained in fish fed with 1.12 mg Se/kg diet. Hepatic glutathione peroxidase activity was markedly increased when dietary Se ≤1.12 mg/kg diet and reached a plateau when dietary Se ≥1.12 mg/kg diet. Hepatic superoxide dismutase and serum catalase activities in juvenile grass carp fed with 0.56, 1.12 and 2.18 mg Se/kg diets were all significantly higher than those in the other groups. The malondialdehyde content in liver and serum was firstly decreased and then increased with increasing dietary Se content, and the lowest content was observed in fish fed with 1.12 mg Se/kg diet. With the increase in Se level, the activities of serum alanine aminotransferase and aspartate aminotransferase were reduced. In addition, serum alkaline phosphatase activity and albumin content were highest in fish fed with 1.12 mg Se/kg diet. This study indicated that both the Se deficiency and excess of Se caused negative effect on the oxidative stress in juvenile grass carp and suggested that the health‐giving concentration of dietary inorganic Se was 1.12 mg/kg diet. Moreover, based on the broken‐line regression analysis of weight gain, the optimal concentration of dietary inorganic Se was 0.83 mg/kg for juvenile grass carp.  相似文献   
986.
野生牙鲆亲鱼摄食驯化技术   总被引:5,自引:0,他引:5  
刘悦  木云雷 《水产科学》1999,18(3):30-32
以活鱼为诱饵对捕获的3批野生牙鲆亲鱼进行摄食驯化培育,解决了野生牙鲆捕后在人工培育条件下拒食的难题,并利用牙鲆摄食的诱导性、使后期捕获的野生鱼在已驯化了的亲鱼带动下主动摄食人工投喂的鲜铒。  相似文献   
987.
从自然感染发病的美洲鲥肝脏、肾脏和肠道中分离出1株细菌,经革兰染色镜检及PCR鉴定,确定为维氏气单胞菌(Aeromonas veronii)。用该菌株接种健康美洲鲥,鉴定其致病力,从人工感染50 g左右的健康美洲鲥发现,菌株具有很强的致病力,试验鱼在感染后72 h内全部死亡,且患病症状与自然发病的鱼症状一致。进一步采用药敏纸片法测定分离菌株对多种抗生素的敏感性,结果发现:维氏气单胞菌对恩诺沙星、氧氟沙星、头孢噻吩三种药物极为敏感,对红霉素、头孢唑啉中度敏感,对青霉素、氨苄西林、阿莫西林、四环素、链霉素不敏感。  相似文献   
988.
Effects of cysteamine (CS) on growth hormone (GH) mRNA, two types of growth hormone receptor (GHR) mRNAs and growth rate in orange-spotted grouper (Epinephelus coioides) were investigated. CS could cause a modification in the structure of somatostatin, which is the most important neuroendocrine inhibitor of basal and stimulated growth hormone synthesis and release, and renders it nonimmunoreactive probably through interaction with the disulfide bonds. In the present study, cysteamine hydrochloride (CSH) enhanced the level of pituitary GH mRNA in a dose-dependent manner through attenuating or deleting the inhibiting action of somatostatin on GH mRNA expression. CSH at relatively low doses (from 1 to 3 mg/g diet) enhanced the levels of two types of GHR mRNAs in dose-dependent manner, whereas the stimulation induced by CSH declined from the peak at higher dose of CSH (4 mg/g diet). It might be attributed to the variation in GH-induced up-regulation of GHRs at different doses of GH. Feeding of CSH could induce remarkable enhancement of growth rate in orange-spotted grouper. In addition, the stimulatory effect of CSH could be potentiated by the additive effect of luteinizing hormone-releasing hormone analog (LHRH-A). Compared with individual treatments, combined feeding of CSH and LHRH-A caused more efficient elevation of growth rate after 8 weeks of feeding. CSH and LHRH-A individually and in combination remarkably increased the levels of GH and GHR mRNAs compared with the control. The combined administration of CSH and LHRH-A in diet was most effective to enhance the level of GH and GHR1 mRNA. The morphological characteristics of the experimental fish were evaluated. Compared with control, the ratios of muscle RNA/DNA, condition factors (CF) and feed conversion efficiency (FCE) were significantly enhanced in the treated groups, while the highest values were observed in the combined treatment. All the results suggested that CSH (1–3 mg/g diet) is an effective, economical and feasible feed additive in orange-spotted grouper culture.  相似文献   
989.
为了解脊尾白虾(Exopalaemon carinicauda)在不同发育期线粒体基因组(mtDNA)拷贝数的变化特征,本研究共采集其8个时期(受精卵期、溞状幼体Ⅰ期、溞状幼体Ⅱ期、溞状幼体Ⅲ期、溞状幼体Ⅳ期、溞状幼体Ⅴ期、仔虾期和成虾期)的DNA样品,利用TaqMan实时荧光定量PCR技术,对上述各发育期单个细胞中的mtDNA拷贝数进行了测定。检测结果显示,脊尾白虾受精卵期、溞状幼体Ⅰ期、溞状幼体Ⅱ期、溞状幼体Ⅲ期、溞状幼体Ⅳ期、溞状幼体Ⅴ期、仔虾期和成虾期的mtDNA拷贝数的均值分别为2366、2648、2644、2873、3559、9948、6452和8872。进一步统计分析结果显示,mtDNA拷贝数与发育时间存在正相关性,相关系数为0.83。研究表明,随着脊尾白虾不断生长,其单个细胞中mtDNA拷贝数总体呈上升趋势。  相似文献   
990.
微孢子虫是专性细胞内寄生的真核生物,有着广泛的宿主。中华绒螯蟹微孢子虫可以引起中华绒螯蟹微孢子虫病,因此而受到重视。本文简要综述了中华绒螯蟹微孢子虫的生物学特性,检测方法以及中华绒螯蟹微孢子虫病的研究现状,以期为有效防治河蟹微孢子虫病提供参考。  相似文献   
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