Effect of DNA damage caused by cryopreservation of spermatozoa using a modified Single cell gell electrophoresis in the freshwater catfish Pangasianodon hypophthalmus(Fowler,1936)

Objective:To detect the integrity of sperm DNA in the catfish Pangasianodon hypophthalmus cryopreserved with Hanks balanced salt solution,5%-30%dimethyl acetamide(DMA)using the single-cell gel electrophoresis in order to test how sperm cryopreservation affected nuclear DNA stability.Methods:Electrophoresis was conducted for 60 min at 130 mA and 15 V.The comet images were analyzed using software CometScore 1.5,and parameters such as comet length,tail length and percentage DNA in the tail were obtained.Then the comet rate and damage coefficient were calculated.Results:There were no significant differences in motility,comet rate and damage coefficient between fresh sperm and cryopreserved sperm stored in 5%,10%,15%and 20%DMA,while the sperm cryopreserved with 25%and 30%DMA had lower motility,higher comet length and damage coefficients than those of fresh sperm.Conclusions:There was positive correlation between comet rate of cryopreserved sperm and the concentration of DMA.The toxicity of cryoprotectant is the main factor for DNA damage in cryopreserved sperm.

巴沙鱼低眼巨鲶胚胎和仔稚鱼发育观察及其生长模型的确定

为研究巴沙鱼低眼巨鲶(Pangasianodon hypophthalmus)(亲鱼体质量为4.0~8.0 kg)胚胎发育和仔稚鱼发育特点,采用干法授精获得受精卵,观察其胚胎发育和仔稚鱼发育时序特征,并在生化培养箱(SPM-50)进行了不同盐度、温度对其胚胎发育的影响试验。结果表明:低眼巨鲶卵为黏性卵、透明,卵径为(1.60±0.23)mm;在水温为(30±0.5)℃时,其胚胎历经受精卵期、卵裂期、囊胚期、原肠期、神经胚期、器官形成期和孵出期7个阶段(共23个发育时期),22 h开始孵出仔鱼,28 h后全部孵出,初孵仔鱼全长为(4.38±0.23)mm;在不同温度和盐度下的孵化试验显示,最佳孵化水温为27~30℃,在此温度下的孵化率最高(49.35%~44.33%),最适盐度为0,在此盐度下的孵化率最高(54.33%),随着盐度的升高,孵化率逐渐降低;在水温为(30±0.5)℃条件下,初孵仔鱼的生长发育历经前期仔鱼(0~2 d)、后期仔鱼(3~16 d)、稚鱼期(17~29 d)和幼鱼期(30 d);初孵仔鱼出膜后第3天卵黄囊完全消失。研究表明,低眼巨鲶孵化期短,最佳孵化温度为27~30℃,最适盐度为0,是典型的热水性淡水鱼类;仔鱼前期生长较慢,20 d后开始增速,属于快速生长的鱼类。

巴沙鱼养殖与开发研究进展

简述了巴沙鱼生物学特性、养殖及繁育状况,介绍了巴沙鱼病害及防治方法,对其鱼肉、鱼皮的营养价值及用途进行了分析。指出,巴沙鱼作为外来淡水经济鱼类,其养殖业近年来在我国发展迅速,不但可提供营养丰富、深受欢迎的食用巴沙鱼肉,在医药、饲料、化工等领域也有所开拓,是具有极大开发潜力的养殖品种。提出,目前国内在养殖巴沙鱼方面已经积累了一定的经验,但对其结构、生理、代谢、免疫、病害、繁育等方面还有待进一步深入研究,以促进巴沙鱼产业链的发展。

斑点叉尾鮰、半滑舌鳎和低眼无齿巨鲶实时荧光RPA快速检测方法研究

斑点叉尾鮰、半滑舌鳎和低眼无齿巨鲶在肉质和产品形态上十分相似,相互难以区分,市场上商品名称混乱,进出口货物中标签和实物不符等现象屡有发生。本实验根据3种鱼的保守基因序列,设计并筛选出3对特异性重组酶聚合酶扩增(recombinase polymerase amplification,RPA)的引物和探针,建立了基于实时荧光RPA技术的斑点叉尾鮰、半滑舌鳎和低眼无齿巨鲶的物种成分快速检测方法,并对方法进行特异性和灵敏性分析。结果表明,建立的实时荧光RPA检测方法具有较好的特异性和灵敏性,且简单、快速,整个扩增时间仅需20 min,为相关产品的物种成分鉴定提供了快捷、准确的检测依据。