动物分子育种及其在鱼类育种中的应用

随着生物技术的迅速发展,动物的育种技术也在更新换代,新型的分子育种正在越来越广泛地被应用于各种动植物育种中,但在鱼类中起步较晚,然而发展却迅速,如目前已在遗传图谱构建、QTL定位、分子标记辅助育种等方面广泛应用.本文综述了分子育种的研究内容并结合当前科研动态介绍了其在鱼类育种中的应用现状.     

鳜鱼养殖技术之一鳜鱼人工繁殖技术

近几年,江苏省南通市在发展鳜鱼人工养殖的过程中,受苗种全部从外地引进的制约发展不快。为此,笔者在2001年进行鳜鱼人工繁殖小试的基础上,2002年在江苏省海门市国营水产养殖场承担实施了南通市科技局下达的《鳜鱼人工繁殖技术研究》课题,共催产亲鱼15组,产苗61.7万尾,育成2cm左右的苗种7.26万尾。现将有关技术介绍如     

略论我国海水鱼类苗种繁育和种质改良的研究

种苗是海洋生物养殖产业的源头和必需的物质基础,种质是海洋养殖业的核心问题。海水养殖产业"种子工程"包括"健康苗种繁殖"和"优良种质创制"两个部分,前者以实现原种和良种的人工繁殖为中心目标,还包括与之相匹配的设施设备等建设,对鱼类原种开发、种子扩繁和产业发展起到支撑作用;后者强调应用现代生物技术,以不断改进和优化原种种质为目标,是增加产量的有效途径,是实现海水养殖业健康和可持续发展的有效保证。本文以海水鱼类为例,分析了"种子工程"两个方面的研究发展历程、研究中心目标及其内在既有联系又相对独立的研究特点,基于研究和产业平衡发展的共同需要,应坚持二者并列、并重的研究方向。文中还对当前海水养殖鱼类原种开发、种质改良和良种选育等研究领域提出了初步看法和设想。     

鱼类环境耐受性与抗逆性育种研究进展

随着高密度集约化水产养殖业的发展,溶解氧、水温和氨氮等水环境因子胁迫已成为制约渔业高质量发展的限制性因素,抗逆水产新品种的培育成为重要的解决途径之一。本文综述了鱼类对温度、低氧、氨氮、亚硝态氮、盐碱胁迫的响应机制,以及环境耐受性鱼类新品种的育种现状,提出充分利用第一次全国水产养殖种质资源系统调查结果发掘优异种质资源,建立高通量表型和基因型精准鉴定技术,深入解析鱼类响应环境因子胁迫的机制,利用分子标记辅助育种、全基因组选择育种、基因编辑育种和分子设计育种等现代分子育种技术进行高效精准抗逆新品种的培育,为鱼类抗逆性新品种培育提供参考。     

观赏鱼的健康养殖

随着物质生活水平的提高,各地已兴起一股观赏鱼饲养热.观赏鱼品种丰富,有金鱼、锦鲤、龙鱼、热带鱼及其他观赏鱼.发展观赏渔业,是提高渔业附加值的一个途径.观赏渔业已成为渔业发展的一个新领域,下面从三方面讨论观赏鱼的健康养殖.     

Flesh quality improvement in fish through breeding

In salmonids, which are fat fish, phenotypic and genetic parameters in flesh quality traits have been studied in several investigations while little has been done in other fish species. For traits like fat percentage, area of fat depot, and flesh colour in salmonids, relatively large genetic variation has been found. There is an unfavourable genetic correlation between body weight and the traits fat percentage and area of fat depot. The expected response to selection in quality traits, considering single trait selection, varies between 5 and 15% per generation. Quality traits can usually be recorded only on dead animals, and therefore family selection mush be practised in a breeding programme.     

遗传连锁图谱及其在鱼类遗传育种中的应用

基因组图谱的构建 ,是遗传学研究的一个重要领域 ,它是对基因组进行系统性研究的基础 ,也是动植物遗传育种和人类遗传病诊断的依据 ,它将使标记辅助选择技术的应用成为现实 ,从而可能从根本上改变传统的育种方法 ,进一步改良畜禽品种和大幅度提高畜禽生产效率。因此 ,从 1 91 3年 ,ＡＨＳｔｕｒｔｅｖａｎｔ在果蝇的性染色体上确定了 6个性连锁位点 ,构建了第 1张连锁图至今 ,科学家已经在人类及动植物的基因图谱构建方面做了大量的工作。近年来 ,许多国家投入大量的人力、物力 ,对陆生农业经济作物及牛、猪、鸡等畜禽进行了遗传图谱的构建…     

养鱼塘用循环水泵的优化选用

针对达州养鱼塘循环水泵的选用现状,分析了选用ZW自吸排污泵、WQ污水污物潜水电泵的不足,提出了在缺少三相电源的水产养殖场,选用HFD自吸塑料泵作为循环水泵最为适宜,通过实际应用证实:HFD自吸塑料泵使用效果好、使用寿命长、节资节能。     

大口黑鲈生长性状的遗传参数和育种值估计

采用最佳线性无偏差预测法(BLUP法)对大口黑鲈(Micropterus salmoides)体质量、体长和体高的遗传参数和育种值进行估计.4月龄和6月龄的体质量遗传力分别为0.29±0.08和0.28±0.10、体长遗传力分别为0.31±0.08和0.26±0.10,6月龄的体高遗传力为0.29±0.10.这些性状的传力都属于中度遗传力(P＜0.01),表明在加性效应控制下,大口黑鲈生长性状具有较大的遗传改良潜力.6月龄的体质量与体长、体质量与体高及体长与体高的遗传相关分别为0.790±0.094、0.820±0.081和0.990±0.001,这些性状之间均表现为高的正遗传相关性(P＜0.01),说明在对体质量进行选择的同时,其他生长性状也可以获得相应的间接选择反应.从不同评定方法的秩相关来看,6月龄时综合育种值与体质量育种值、体长育种值以及体质量育种值与体长育种值的秩相关系数均达到了极显著(P＜0.01),分别为0.998、0.914和0.890,用综合育种值对大口黑鲈的评定名次排序与用单性状育种值排序的差异不大.本研究对大口黑鲈生长性状的遗传参数和育种值进行确定与分析,旨在为该物种的人工选育提供理论依据和技术参考.     

网箱培育军曹鱼亲鱼及人工育苗研究

12月底从海上网箱挑选14尾1 5龄以上,健康、外表无伤的军曹鱼(Rachycentron cana dum),移至陆地盖有顶棚的大水泥池进行强化培育。经过4个月左右的培养,结果显示,亲鱼在陆地强化培育比在海区网箱提前约7 d成熟并自然产卵。受精卵在室内育苗池进行人工育苗,在海水比重为1. 020±0. 5,pH 8 1~8 4,水温在27. 0、29. 2 ℃时,仔鱼孵出时间分别为26、24 h,孵化率为88 .8%~93 .5%。孵出后的仔鱼在第7~9天为死亡高峰期,第11天左右的仔鱼体色有明显的变化,由棕红色变为黑色。经过1个月的培养,仔鱼的成活率约为9%。     

我国养殖鱼类育种技术概况

我国渔业产量和养殖规模近年来一直居世界首位,但依然缺少高效、优质、抗病力强的养殖品种.如何通过传统育种和生物技术对鱼类进行品种选育和遗传改良,以获得优良性状的苗种,将对促进水产养殖业向高产、优质、持续、健康方向发展具有重要的意义.本文就我国养殖鱼类育种技术研究作一扼要的概述.     

Genetic and phenotypic comparison of Nocardia seriolae isolated from fish in Japan

The phenotypic and genetic characterizations of 58 isolates of the fish pathogen Nocardia seriolae , from amberjack, Seriolae dumerili , yellowtail, Seriola quinqueradiata , Japanese flounder, Paralichthys olivaceus , and chub mackerel, Scomber japonicus, in Japan from 1970–2005, were examined to investigate the epidemiological relationship between isolates. The phenotypic and genetic characterizations were determined by α-glucosidase activity and biased sinusoidal field gel electrophoresis (BSFGE) analysis, respectively. There was no α-glucosidase activity in strains isolated from 2000–05 ( n  = 50) with a few exceptions ( n  = 3), while all strains isolated from 1970–90 ( n  = 8) were positive. In BSFGE analysis, digestions with restriction enzymes Xba  I and Ase  I produced 15 and 16 restriction patterns, respectively. All restriction patterns obtained from 50 strains isolated during 2000–05 were unrelated to those obtained from eight strains isolated during 1970–90, with the exception of two strains isolated during recent outbreaks. Based on the phenotypic and genetic characterizations, recent outbreaks of nocardiosis in Japan are suggested to be epidemiologically unrelated to earlier outbreaks in Japan. Although a low genetic relationship was observed in the restriction pattern between recent and earlier isolates, identity was confirmed between these groups of isolates because five representative strains showed 99.9% homology with N. seriolae ATCC43993^T in the 16S rRNA sequence.     

丁引种控温繁育与养殖技术

欧洲丁(Tincatinca)引种北方控温繁育与规范化养殖技术研究项目,由锦州市海洋与渔业科学研究所于2006-2009年完成。控温繁育催产率达95%,孵化率70%,鱼苗成活率90%。共计生产丁水花鱼苗6 000万尾,鱼种10万kg,产值847万元,效益535.42万元。应用推广试验点辐射辽宁省7个市区,商品鱼养成面积135 hm2,产值2 118万元,利润850万元,推广技术养成效益明显。     

鱼类应激应对策略及其在抗逆育种中的应用

发展现代水产种业,引领水产养殖绿色发展,成为未来水产养殖业可持续发展的保障。应鼓励产业选育推广优质、高效、多抗、安全的水产养殖新品种,由单纯高产品种转向适宜生态化、集约化养殖模式的优质高效、节料节药、抗逆性强、适应性广的品种。本文分析了当前水产种业存在的一些问题,剖析了优质、高效、多抗水产养殖品种的耐应激本质,围绕应激反应、应激恢复、应激应对方式在畜禽种业中的应用案例等,提出了环境限制育种理念和未来综合性抗逆育种技术发展方向,助推水产养殖业的可持续发展。     

Fat or lean? The quantitative genetic basis for selection strategies of muscle and body composition traits in breeding schemes of rainbow trout (Oncorhynchus mykiss)

Quantitative genetic analyses of fish composition have been strongly biased towards lipid deposition, rather than protein deposition. This is partly at odds with desires of the modern aquaculture industry, to improve the efficiency of lean growth. Using a quantitative genetic approach, we examined the selection potential in both protein and lipid components of wet weight growth in rainbow trout over a two-year growth period. Two diet treatments were applied to test the hypothesis that an experimental, high protein, low lipid diet (HP) would enhance selection potential compared to the current modern, normal protein, high lipid diet (NP). We found that lipid traits (lipid body weight, percent muscle and body lipid; h² = 0.40) were more heritable than corresponding protein traits (protein body weight, percent muscle and body protein; h² = 0.18), indicating a higher selection potential for lipid traits. The results revealed further that breeding for improved lipid composition over the whole growth period is easier than for protein composition. This was shown by the high favourable genetic correlations between differently aged fish for lipid traits. In contrast, the respective correlations for protein traits were low or even negative. Similarly, the genetic correlations between muscle and body composition were higher for lipid than for protein, enhancing selection efforts to change lipid traits. Heritabilities increased with age, implying that selection practiced on old (> 800 g) rather than young (< 60 g) fish should be more effective in achieving a compositional response. Although the diet had a significant effect on the composition traits, there was no general trend for diet differences in heritabilities of either protein or lipid traits. Thus, the hypothesis of increased selection potential on HP diet was not supported. In conclusion, lipid traits are both more variable and exhibit more favourable genetic architecture for selection compared to protein traits.     

Markers for selection of disease resistance in fish: a review

Aquaculture is the fastest growing food producing sector in the world. However, diseases result in a major loss in production. Among the several management techniques, selective breeding for resistant trait is one of the most reliable methods and provides long-term control over disease problems. Field survival or challenge survival records provide initial information of resistant stocks. However, selection programmes demand a proper marker which can identify the resistant stock easily with much accuracy. Several immunological indicators associated with resistance to a particular disease have been reported. These include positively correlated markers such as level of natural and specific antibody, respiratory burst activity of phagocytes and level of acute-phase ceruloplasmin protein and negatively correlated markers such as serum lysozyme, haemolytic and haemagglutination activities. However, for few fish species and pathogen-specific markers viz., myeloperoxidase activity, cortisol and glucose levels, macrophage aggregation and the level of plasma proteins, a confined conclusion of association has not been established. Besides immunological markers, molecular markers are in use because of their reliable screening methods. Genome can be scanned for molecular markers which provide the full linkage map of a species or stock. Association of these molecular markers with resistant traits gives rise to quantitative trait loci (QTL) for resistance to a particular pathogen. Screening of resistant stock can be carried out using these markers. Among the several marker systems, amplified fragment length polymorphism, microsatellites and single-nucleotide polymorphism play a major role in the process of selection for disease resistance. With the use of these marker techniques, we can avoid challenge testing where a huge number of animals were being killed. Multiple trait selection can also be possible with multiple QTL identification for resistance to two or more diseases simultaneously.     

Mate selection in aquaculture breeding using differential evolution algorithm

An algorithm to perform mate selection in aquaculture breeding using a computational optimization procedure called “differential evolution” (DE) was applied under optimum contribution selection and mate selection scenarios, to assess its efficiency in maximizing the genetic merit while controlling inbreeding. Real aquaculture data sets with 8,782 Nile tilapias from five generations and 79,144 coho salmon from eight generations were used to optimize objective functions accounting for coancestry of parents and expected genetic merit and inbreeding of the future progeny. The mate selection results were compared with those from the realized scenario (real mates), truncation selection and optimum contribution selection method. Mate selection allowed reducing inbreeding up to 73% for Nile tilapia, compared with truncation selection, and up to 20% for coho salmon, compared with realized scenario. There was evidence that mate selection outperformed optimum contribution selection followed by minimum inbreeding mating in controlling inbreeding under the same expected genetic gain. The developed algorithm was computationally efficient in maximizing the objective functions and flexible for practical application in aquaculture breeding.     

草鱼生长性状的遗传参数和育种值估计

利用草鱼(Ctenopharyngodon idellus)生长性状选育核心群亲本,采用人工授精方式构建21个全同胞家系,并选用动物模型对16月龄草鱼生长性状进行遗传参数和育种值估计。结果显示,草鱼选育种群的生长性状存在丰富变异。采用约束极大似然法估计方差组分,发现草鱼体重、体长和体高性状的遗传力分别为0.39,0.47,0.21,属于中高遗传力;肥满度性状遗传力为0.11,属于低遗传力;4个性状的共同环境效应值相近且较小,范围为0.07~0.17。采用两性状动物模型分析相关性,发现体重、体长和体高性状间表型和遗传相关系数均达到高度正相关(r=0.88~0.97),而肥满度性状与三者间相关系数接近零,只与体高性状存在一定遗传正相关(r=0.43)。结合各性状遗传变异系数和相对遗传进度,分析表明,以体重为目标性状可便捷有效地改良草鱼生长性能。采用最佳线性无偏估计法预测个体育种值,发现4个性状育种值与表型值的相关系数范围为0.77~0.93。基于单性状育种值和表型值分别进行个体选择,按10%留种率,各性状选留个体相同率为68.75%~81.82%,秩相关系数范围为0.19~0.81,两种选择方式显示出较大差异,且差异大小与性状遗传力成反比例。本研究为草鱼生长性状选择育种提供了理论依据和技术支撑。     

耐盐罗非鱼育种回交效应评估

对罗非鱼2种回交子代、2种正反交子代(回交鱼的母本)、2种原始种(回交鱼的祖父、母本),共6种遗传型的生长特性、耐盐特性及遗传特征进行了研究.结果表明:(1)在盐度15、20及25时,2种回交子代的日均增重率皆比母本提高了30%～45%,差异显著(P=0.023).(2)SSR分析发现,2种回交子代接受尼罗罗非鱼(Oreochromis niloticus)的遗传特征带分别为87.5%和79.2%,接受萨罗罗非鱼(Sarotherodon melanotheron)的分别为35.2%和41.2%;而2种正反杂交子代接受尼罗罗非鱼的分别为66.7%和41.7%,接受萨罗罗非鱼的分别为47.1%和88.2%.(3)回交子代与原始亲本尼罗罗非鱼的遗传距离较近,同正反交子代相比,回交子代生长性能有所进步,耐盐性能基本保持,扩增的特异性条带数目较少,表明遗传多样性走低和基因型纯合性走强的趋势.(4)两种回交子代间有一定差异,萨尼♀[萨罗罗非鱼♀×尼罗罗非鱼(♀)(F2)]×尼罗罗非鱼(♂)生长快5%,有效等位基因数、平均杂合度、多态信息含量等遗传指标较高,是优选的对象.     

Modelling fish growth: Model selection,multi-model inference and model selection uncertainty

Model selection based on information theory is a relatively new paradigm in biological sciences with several advantages over the classical approaches. The aim of the present study was to apply information theory in the area of modelling fish growth and to show how model selection uncertainty may be taken into account when estimating growth parameters. The methodology was applied for length–age data of four species of fish, taken from the literature. Five-candidate models were fitted to each dataset: von Bertalanffy growth model (VBGM), generalized VBGM, Gompertz growth model, Schnute–Richards growth model, and logistic. In each case, the ‘best’ model was selected by minimizing the small-sample, bias-corrected form of the Akaike information criterion (AIC). To quantify the plausibility of each model, given the data and the set of five models, the ‘Akaike weight’ $w_i$ of each model was calculated. The average model was estimated for each case based on $w_i$. Following a multi-model inference (MMI) approach, the model-averaged asymptotic length ${\overline{L}}_{\infty }$ for each species was estimated, using all five models, by model-averaging estimations of L_∞ and weighting the prediction of each model by $w_i$. In the examples of this study, model selection uncertainty caused a magnification of the standard error of the asymptotic length of the best model (up to 3.9 times) and thus in all four cases estimating L_∞ from just the best model would have caused overestimation of precision of the asymptotic length. The VBGM, when used for inference, without being the best model, could cause biased point estimation and false evaluation of precision. Model selection uncertainty should not be ignored even if VBGM is the best model. Multi-model inference by model-averaging, based on Akaike weights, is recommended for making robust parameter estimations and for dealing with uncertainty in model selection.