池塘主养斑点叉尾试验

在一面积为 5.4亩的池塘中 ,主养斑点叉尾 ,亩放养斑点叉尾冬片鱼种 730尾 ,规格 18.8克 /尾 ,经 2 70天养殖 ,取得亩产斑点叉尾成鱼 4 2 0kg ,规格 650克 /尾 ,成活率 88.5% ,亩产值8895元 ,亩效益 4 60 4 .8元的结果     

斑点叉尾中国养殖群体遗传多样性的AFLP 分析

采用AFLP 分子遗传标记技术,对来自福建和湖北的1984 年引进的斑点叉尾(Ictalurus punctatus ) 养殖群体(P1984)、来自福建和辽宁的1997 年引进的养殖群体(P1997)、来自湖南的2004 年引进的养殖群体(P2004) 和来自湖北的1984 年与1997 年引进养殖群体的杂交群体(P8497) 的遗传     

斑点叉尾鮰中国养殖群体遗传多样性的AFLP分析

采用AFLP分子遗传标记技术,对来自福建和湖北的1984年引进的斑点叉尾鲴(Ictalurus punctatus)养殖群体(P1984)、来自福建和辽宁的1997年引进的养殖群体(P1997)、来自湖南的2004年引进的养殖群体(P2004)和来自湖北的1984年与1997年引进养殖群体的杂交群体(P8497)的遗传多样性进行研究.用10对选择性引物共扩增出523个位点,其中,243个位点为多态位点,多态位点比例为46.46%;没有发现可以用于区分4个群体的特异性位点,但找到一些潜在的群体鉴别片段;P1984、P1997、P2004和P8497群体的多态位点比例(P)分别为28.93%、38.90%、31.02%和41.66%,Shannon多样性指数(I)分别为0.1439、0.208 1、0.1545和0.2373,平均杂合度(H)分别为0.078 1、0.0949、0.0803和0.1137.群体问的遗传分化系数(fst)值为0.1036;根据4个群体之间的基因分化系数(Gst)、遗传距离(D)、遗传相似度(S)以及UPGMA聚类分析发现,P2004和P1997亲缘关系最近,P2004和P1984亲缘关系最远.通过比较分析认为,4个养殖群体的遗传多样性水平均较低.     

斑点叉尾网箱养殖高产技术研究

进行了斑点叉尾鱼回鱼苗池塘强化培育、网箱养成鱼种、鱼种网箱越冬和商品鱼网箱养殖试验。鱼回鱼苗网箱培育当年个体重达 2 2 98g ,网箱越冬成活率 94 2 %。网箱养商品鱼回净产 5 1 3kg/m3 ,个体均重 34 1 9g ,饲料系数 1 70。     

斑点叉尾病毒病研究概述

简要介绍了斑点叉尾病毒病的临床症状、流行病学特征、诊断与防治方法以及病毒的生物学特性与检测技术等。     

斑点叉尾鮰基础群体生长和存活性状遗传参数估计

研究估计了斑点叉尾基础群体(G0)体质量、体长和存活性状的遗传参数,为制定育种目标、综合选择指数和选择方法提供基础参数。实验利用5个斑点叉尾引进群体,通过双列杂交和巢式交配设计,产生全同胞和半同胞家系。每个家系内的稚、幼鱼经过中间暂养、个体标记等阶段后,混合放入一个池塘进行生长和存活测试。利用两性状动物模型和公母畜阈模型分别估计生长和存活性状的方差组分和遗传参数。通过最佳线性无偏预测法估计所有个体生长和存活性状的育种值。斑点叉尾基础群体收获体质量和体长遗传力分别为0.41±0.074和0.32±0.064,属于高遗传力水平,并且统计检验显著(P<0.05)。尽管在两性状动物模型中设置标记体质量和标记体长作为协变量进行校正,但是由于加性遗传效应和共同环境效应混淆在一起无法剖分,遗传力估计值偏高。收获体质量和收获体长的表型和遗传相关系数分别为0.93和0.97,表现为高度线性正相关。存活性状的遗传力为0.037±0.016,表现为低遗传力,但统计检验仍达到显著水平(P<0.05)。家系生长(收获体质量和收获体长)和存活性状育种值间的相关系数分别为0.065和0.100,表现为低度线性遗传正相关,并且统计检验不显著(P>0.05)。因此在制定育种方案时,生长和存活性状都可纳入育种目标,利用多性状选择指数方法同时选择。     

斑点叉尾鲴线粒体DNA控制区结构和群体遗传多样性分析

经克隆测序获得了我国5个批次引进的40尾斑点叉尾鲴(Ictalurus punctatus)群体的线粒体控制区全序列,研究控制区序列结构和群体遗传变异.结果显示:比对长度包括906个位点,共有变异位点28个,简约信息位点21个.通过与GenBank中其它鱼类的mtDNA控制区序列进行结构分析,将斑点叉尾鲴的控制区分为终...     

HACCP体系在斑点叉尾人工繁殖中的应用

在江西峡江和赣州进行了HACCP(Hazard Analysis and Critical Control Point)体系在斑点叉尾(Ictaluruspunctatus)人工繁殖中的应用研究。应用HACCP的基本原理,对整个斑点叉尾人工繁殖过程进行危害分析,确立了亲鱼培育池的选择、亲鱼种质选择、亲鱼产卵池的选择、受精卵孵化、苗种培育、水质监测、饲料供应、日常管理等8个关键控制点,提出了相应的预防措施、关键限值、监控措施以及超过关键限值时的纠正措施,使各关键控制点处于人为控制之下。实现了斑点叉尾人工繁殖按无公害化、规范化、标准化生产。     

斑点叉尾胚胎及卵黄囊期仔鱼发育的观察

试验对斑点叉尾的胚胎及卵黄囊期仔鱼形态发育的过程进行观察、描述,研究了其发育特征。结果表明：斑点叉尾受精卵在水温24±1℃时,出膜时间（胚胎期）约为147h 30min。水温25±1℃时,斑点叉尾鮰卵黄囊期约为134h。     

斑点叉尾高密度流水养殖试验

斑点叉尾俗称美国鱼,因其肉质鲜美、无肌间刺、高蛋白且不饱和脂肪酸含量高而广受消费者欢迎。我站于1992年引进原种斑点叉尾亲鱼,并于1993年繁殖成功,在池塘养殖中得到大规模推广。为了满足广大消费者的需求,提高斑点叉尾的品质和养殖效益,我站进行了高密度流水养殖斑点叉尾试验。经过半年多     

Susceptibility of channel catfish (Ictalurus punctatus) fed with dietary sodium chloride to nitrite toxicity

Juvenile channel catfish (Ictalurus punctatus) were fed with nutritionally complete, basal diets supplemented with NaCl at 0, 10, 20 or 40 g kg^?1 diet (0, 1, 2, or 4%) to apparent satiation twice daily for 10 weeks. Catfish were exposed to nitrite after six (7.70 mg L^?1 nitrite‐N) and ten (7.18 mg L^?1 nitrite‐N) weeks of feeding to determine the effect of dietary NaCl supplementation on resistance to nitrite toxicity. Fish were sampled before (baseline, pre‐exposure) and after 24‐h nitrite exposure to determine the effects of dietary NaCl on haematology (haematocrit, haemoglobin and methaemoglobin) and plasma electrolyte dynamics (nitrite, chloride, sodium and potassium). Mortality from nitrite toxicity was also determined. Mortality from nitrite exposure tended to decrease with increasing NaCl in the diet at 6 weeks and was significantly lower in the 40 g kg^?1 NaCl group (12.5%) compared to the control group (57.5%). A similar trend in mortality occurred at 10 weeks as well; however, the differences among dietary treatments were not significant. The improvements in blood MetHb (non‐significant), chloride and nitrite levels in catfish may at least in part be responsible for the improved survival after nitrite exposure, which trended in support of the prevailing hypotheses for the positive effects of NaCl on nitrite toxicity.     

Effect of supplemental taurine on juvenile channel catfish Ictalurus punctatus growth performance

Juvenile channel catfish (5.6 g/fish) were fed a basal diet that contained major protein (soybean meal, cottonseed meal) and energy (ground corn grain, wheat middlings) ingredients that were derived from plant sources. The basal diet was supplemented with three levels of crystalline taurine to provide 1, 2 and 5 g/kg taurine. In addition, a fifth diet that contained 80 g/kg menhaden fishmeal formulated with the same plant‐source ingredients was included as the positive control diet. Fish were fed the five diets once daily for 12 weeks. Weight gain was highest in catfish fed taurine at 2 g/kg (47.8 g/fish) compared to catfish fed the control basal diet (40.8 g/fish) and 80 g/kg fishmeal diet (41.1 g/fish) (p < .05). Among the taurine‐supplemented diets, weight gain was lowest in catfish fed taurine at 5 g/kg. Feed conversion ratio (FCR) was significantly improved in fish fed diets supplemented with taurine at 2 g/kg compared to all other treatments (p < .01). Survival during the growth study ranged from 98.0 to 99.0% (p > .05) for all treatments. The results suggest taurine supplementation to juvenile channel catfish may improve weight gain and FCR.     

Effects of dorsal aorta cannulation on the stress response of channel catfish (Ictalurus punctatus)

The stress response to dorsal aorta cannulation and serial blood sampling was examined in the channel catfish Ictalurus punctatus. Channel catfish cannulated and repetitively sampled once a day for 7 days did not exhibit a change in response to surgery or to the 24h sample regime as measured by plasma cortisol, glucose, and chloride. In fish that were either serially bled (0, 1, 3, 6, 9, 12, 24, and 48h) immediately after surgery or allowed to recover 6 days before being serially bled, overall plasma cortisol levels were higher than those of fish bled every 24h. Catfish serially bled immediately after surgery had significantly higher plasma glucose levels compared with catfish allowed to recover from surgery 6 days before serial sampling. Although channel catfish recover from cannulation surgery in 24h, a longer recovery period may be needed prior to serial sampling if the samples are taken more frequently than every 24h.     

不同商品饲料对生长、体色及肝脏组织结构的影响

本试验评估了(Ictalurus punctatus)主产区4种商品颗粒饲料(分别记为S1、S2、S3和S4,其中S4为膨化饲料,其他均为颗粒饲料)和自行设计的颗粒饲料(记为S5)对试验阶段生长性能、体色变异、肝胰脏组织结构及形态指标的影响。7周的饲喂试验结果显示:饲料蛋白含量为38%的S4膨化饲料可明显的提高养殖鱼的体重,平均增重率为262.6%,但存活率较低,仅为72.3%;而喂养S5饲料组的增重率为168.89%,且存活率为92.4%,高于其他饲料组。养殖结束后,不同试验组的肥满度、脏体比有所差异,但均未达到显著性水平(P>0.05)。投喂S2饲料组养殖鱼体体色发白比较明显,体色异常比例高达91%;S4饲料组养殖后体色发白也比较明显,体色异常比例为72.3%;对背部黑色素扫描研究进一步证实饲喂S2饲料和S4饲料的黑色素细胞发生了变化,黑色素细胞边缘变得模糊,而自配S5饲料的黑色素细胞树突状分支较多;饲喂S4饲料组的背部斑点比例为12.15%,而S2饲料组的背部斑点比例为26.38%,自配S5饲料组的背部斑点比例为35.69%,S4饲料组的斑点比例明显较低。     

利用mtDNA控制区序列分析斑点叉尾(鮰)的遗传多样性

利用m tDNA控制区序列对1984、1997年引进的斑点叉尾鮰群体遗传多态性进行了分析。通过PCR产物测序法,测定了40尾斑点叉尾鮰线粒体DNA的一段包括部分Cytb基因、tRNAThr、tRNAPro、D-loop控制区和部分tRNAThe长度为1256 bp的核苷酸序列,经过比对分析得到7个序列单元型。7个单元型中共有13个碱基转换位点,全部发生在控制区,其序列相似度平均为99.58%。群体总的序列单元型多态性比例为17.5%,其中1997年群体的单元型多态性比例为35%,是1984年群体单元型多态性比例(15.0%)的2倍多。初步表明1984年引进的群体遗传多样性较低。