基于Gibbs抽样的贝叶斯方法估计大菱鲆生长和耐高温性状的遗传参数

为了开展大菱鲆耐高温选育工作,对其进行耐高温性状及其相关生长性状的遗传评估是非常必要的。以来源于英国、法国、丹麦和挪威4个国家的不同群体构建大菱鲆选育家系,利用F₁的20个和F₂的22个耐高温选育家系进行耐高温实验,统计耐高温评估指标（UTT）和相应的实验鱼体重（每个家系选取40-50尾实验鱼）。基于Gibbs抽样的贝叶斯方法,采用包含母性效应和不包含母性效应的两种动物模型,对大菱鲆耐高温（UTT）和生长性状的遗传力以及这两个性状间的遗传相关和表型相关进行分析。结果表明,基于不包含母性效应的动物模型估计的体重和耐高温性状的遗传力以及这两个性状之间的表型相关和遗传相关分别为0.239±0.141,0.111±0.080,0.075±0.026和-0.019±0.011。基于包含母性效应的动物模型估计的这4个值分别为0.203±0.115,0.055±0.026,0.047±0.034和-0.024±0.028,体重和耐高温性状的母性效应分别为0.050±0.017和0.013±0.004。母性效应对这两个性状的遗传评估有一定的影响。本文的研究结论为制订合理的大菱鲆耐高温育种规划提供了理论依据。     

大菱鲆(Scophthalmus maximus)幼鱼生长性状的遗传力及其相关性分析

以4种不同地理群体大菱鲆为亲本,采用巢式设计方法和人工采卵授精技术,按照1雄配2雌的原则,构建了28个父系半同胞家系和56个母系全同胞家系,分别测定了每个母系生长到6月龄的全同胞个体60个后代的体长、全长、体高、体重,应用数量遗传学原理,利用全同胞资料,采用方差、协方差分析的方法,研究了大菱鲆6月龄生长性状的遗传力及性状间的遗传相关和表型相关。对性状遗传力研究结果表明,雌性遗传方差组分均大于雄性遗传方差组分,雌性遗传方差组分存在显著的母性效应。基于父系半同胞组内相关法估计的遗传力是大菱鲆体长、全长、体高、体重遗传力的无偏估计值,估计的遗传力准确可靠,估计值分别为0．282、0．251、0．283、0．450,为中高等遗传力,显示对大菱鲆生长性状进行选择育种具有很大的潜力。对性状间相关性分析结果表明,依据父系半同胞遗传协方差组分和表型协方差分别估计体长．全长、体长一体高、体长．体重、全长。体高、全长一体重、体高一体重间的遗传相关和表型相关,遗传相关在0．888-0．985,表型相关在0．864—0．957,各性状间遗传相关和表型相关经t检验均达到极显著水平（P〈0．01）。     

大菱鲆(Scophrhalmus maximus)不同生长阶段体重的遗传参数和育种值估计

采用非求导约束最大似然法(DFREML)进行了大菱鲆不同生长阶段体重的遗传参数和育种值研究,每一生长阶段分别对4种不同动物模型估计遗传参数的差异进了比较.不同模型中对全同胞家系效应和日龄协变量作了不同的考虑:模型A,不考虑全同胞家系效应和日龄协变量:模型AD,仅考虑日龄协变量;模型AE仅考虑全同胞家系效应;模型AFD,同时考虑全同胞家系效应和日龄协变量.结果表明,6月龄利用模型AF,3月龄、9月龄、12月龄、15月龄利用模型AFD对遗传参数和育种值进行估计较为适合.利用育种值选择和表型值选择两种方法分别进行了家系选择和个体选择的效率比较,结果表明,在每一生长阶段依据育种值选择的效率均高于表型值选择的效率.利用不同生长阶段的家系育种值以及亲本育种值分别进行了家系选择比较和亲本选择比较,结果表明,在不同生长阶段,按家系、父本和母本的育种值分别排序,前50%的相同率和育种值的相关系数均为9-12月龄较6-9月龄的提高幅度比其它相邻阶段显著增加,推测家系提前筛选的时间以及父本和母本选择的时期均不低于9月龄.     

大菱鲆（Scophthalmus maximus）不同生长阶段体重的遗传参数和育种值估计

采用非求导约束最大似然法（DFREML）进行了大菱鲆不同生长阶段体重的遗传参数和育种值研究,每一生长阶段分别对4种不同动物模型估计遗传参数的差异进了比较。不同模型中对全同胞家系效应和日龄协变量作了不同的考虑：模型A,不考虑全同胞家系效应和日龄协变量;模型AD,仅考虑日龄协变量;模型AF,仅考虑全同胞家系效应;模型AFD,同时考虑全同胞家系效应和日龄协变量。结果表明,6月龄利用模型AF,3月龄、9月龄、12月龄、15月龄利用模型AFD对遗传参数和育种值进行估计较为适合。利用育种值选择和表型值选择两种方法分别进行了家系选择和个体选择的效率比较,结果表明,在每一生长阶段依据育种值选择的效率均高于表型值选择的效率。利用不同生长阶段的家系育种值以及亲本育种值分别进行了家系选择比较和亲本选择比较,结果表明,在不同生长阶段,按家系、父本和母本的育种值分别排序,前50％的相同率和育种值的相关系数均为9-12月龄较6—9月龄的提高幅度比其它相邻阶段显著增加,推测家系提前筛选的时间以及父本和母本选择的时期均不低于9月龄。     

大菱鲆体重性状遗传参数及选育遗传进展研究

本研究估计了大菱鲆收获体重性状的遗传参数和选育遗传进展。数据共包括3个世代（G0,G1,G2）的508个全同胞家系10952尾个体。G0,G1,G2的体重估计遗传力分别为0.11±0.08,0.18±0.09,0.17±0.07;世代间估计遗传力为0.19±0.04。每一世代母本和共同环境效应分别为0.10±0.04,0.14±0.04,0.13±0.03;世代间为0.12±0.01。G0和G1世代选择差分别为,18.24g和21.19g。对应的G1和G2世代的遗传进展为22.06g,11.93g;百分比表示分别为6.36%,3.52%。连续两代选择之后总遗传进展为10.10%。以上结果说明针对大菱鲆体重性状的选育项目是成功的。     

利用限制性最大似然方法和贝叶斯方法估计大菱鲆生长性状的遗传参数。

Bayesian and restricted maximum likelihood(REML) approaches were used to estimate the genetic parameters in a cultured turbot Scophthalmus maximus stock. The data set consisted of harvest body weight from 2 462progenies(17 months old) from 28 families that were produced through artificial insemination using 39 parent fish. An animal model was applied to partition each weight value into a fixed effect, an additive genetic effect, and a residual effect. The average body weight of each family, which was measured at 110 days post-hatching, was considered as a covariate. For Bayesian analysis, heritability and breeding values were estimated using both the posterior mean and mode from the joint posterior conditional distribution. The results revealed that for additive genetic variance, the posterior mean estimate( δ_a~2=9 320) was highest but with the smallest residual variance,REML estimates( δ_a~2=8 088) came second and the posterior mode estimate( δ_a~2=7 849) was lowest. The corresponding three heritability estimates followed the same trend as additive genetic variance and they were all high. The Pearson correlations between each pair of the three estimates of breeding values were all high,particularly that between the posterior mean and REML estimates(0.996 9). These results reveal that the differences between Bayesian and REML methods in terms of estimation of heritability and breeding values were small. This study provides another feasible method of genetic parameter estimation in selective breeding programs of turbot.     

大菱鲆体重和形态性状的遗传动态分析

In order to elucidate the genetic mechanism of growth traits in turbot during ontogeny, developmental genetic analysis of the body weights, total lengths, standard lengths and body heights of turbots was conducted by mixed genetic models with additive-dominance effects, based on complete diallel crosses with four different strains of Scophthalmus maximus from Denmark, Norway, Britain, and France. Unconditional genetic analysis revealed that the unconditional additive effects for the four traits were more significant than unconditional dominance effects, meanwhile, the alternative expressions were also observed between the additive and dominant effects for body weights, total lengths and standard lengths. Conditional analysis showed that the developmental periods with active gene expression for body weights, total lengths, standard lengths and body heights were 15–18, 15 and 21–24, 15 and 24, and 21 and 27 months of age, respectively. The proportions of unconditional/conditional variances indicated that the narrow-sense heritabilities of body weights, total lengths and standard lengths were all increased systematically. The accumulative effects of genes controlling the four quantitative traits were mainly additive effects, suggesting that the selection is more efficient for the genetic improvement of turbots. The conditional genetic procedure is a useful tool to understand the expression of genes controlling developmental quantitative traits at a specific developmental period(t-1→t) during ontogeny. It is also important to determine the appropriate developmental period(t-1→t) for trait measurement in developmental quantitative genetic analysis in fish.     

利用父母本微卫星标记估计大菱鲆(Scophthalmus maximus L.)幼鱼生长性状的遗传参数

The estimation of genetic parameters has played an important role in animal selective breeding for growth traits.Recently studies show that molecular markers can be incorporated into genetic evaluations. In order to improve the performance of an incomplete pedigree(i.e, only parents are known) in the genetic evaluations, 12 microsatellite markers have been applied in the estimation of the genetic parameters for body weight in a farmed population(n=1 890) of juvenile turbot(Scophthalmus maximus L.). A new relatedness called parental molecular relatedness(PMR) is estimated based on results of genotyping of 48 parents(31 males, 17 females) with microsatellites markers. The feasibility of PMR in estimation of genetic parameters is verified by comparison with pedigree related(PR) which is obtained from a complete pedigree. The results demonstrate that a high correlation(0.872) between them is found. Heritabilities are estimated using the PMR(0.52±0.13) and PR(0.55±0.22) with the same animal model. A cross-validation shows that the predictive abilities of models using the PMR and the PR are identical(0.81). From that, a conclusion can be made that PMR and PR predicted genetic values equally well in a population of juvenile turbot. Therefore PMR can be applied as an alternative of the PR when only parents are known. However, for a better performance, more markers and more families should be included in a further study.     

泥蚶(Tegillarca granosa)主要经济性状遗传参数的估算

采用巢式设计和人工控制授精方法构建了19个半同胞和41个全同胞泥蚶家系,研究了泥蚶各发育阶段生长性状遗传力及性状间遗传相关和表型相关。结果表明,泥蚶家系间各个阶段生长性状均存在一定变异,总体表现生长早期家系间变异较大,发育至后期家系间变异明显降低。在遗传力参数上,表现为体尺性状遗传力大于体重性状,如11月龄壳长、壳高、壳宽遗传力分别为0.298、0.313和0.257,而湿重遗传力仅为0.138;在体尺性状中,则表现为壳长、壳高的遗传力高于壳宽,如4月龄壳长、壳高遗传力分别达到0.378和0.357,而壳宽为0.312。各性状之间表型相关和遗传相关分析表明,不同发育阶段各性状表型相关系数都达到了极显著水平,而在遗传相关上,早期稚贝遗传相关系数均达极显著水平,发育至后期遗传相关系数变小。     

长牡蛎壳橙品系幼虫和稚贝的生长性状遗传参数评估

为查清长牡蛎(Crassostrea gigas)壳橙品系在不同生长阶段各生长性状的遗传力、遗传相关和表型相关,本实验通过平衡巢式设计和人工授精的方法,建立了30个全同胞家系,利用个体动物模型计算了长牡蛎壳橙品系幼虫期和稚贝期的壳高、壳长、壳宽和湿重的遗传参数。研究发现:幼虫在1～21日龄时壳高和壳长的遗传力分别为0.19±0.08～0.36±0.11和0.17±0.08～0.28±0.10,均为中等遗传力;稚贝在90～270日龄时壳高和壳长的遗传力分别为0.13±0.07～0.40±0.12和0.11±0.06～0.37±0.12,在270日龄时壳宽和湿重的遗传力分别为0.17±0.08和0.22±0.09。在不同生长阶段,各性状之间的遗传相关和表型相关均为正相关,其中壳高和湿重与其它性状间的遗传相关相对更高(分别为0.35±0.30～0.99±0.08和0.72±0.17～0.93±0.06),表明对这两个性状的直接选育将对其它生长性状起到间接促进作用。本研究获得了长牡蛎壳橙品系不同生长阶段的遗传参数,这些参数将为制定适宜的选育技术路线提供基础资料。     

大菱鲆不同家系生长性能的比较

为培育优良的大菱鲆养殖新品种,收集了4个不同地理群体的大菱鲆作亲本,根据巢式设计,采用人工受精技术,在群体间和群体内构建了全同胞和半同胞家系,对其不同生长时期(生长阶段)全同胞家系的生长性能进行了比较.综合不同生长时期家系的体质量差异分析和不同生长阶段家系的生长速度分析,结果表明:来自英国和法国的群体间和群体内家系的生...     

Rearing in intermediate salinity enhances immunity and disease-resistance of turbot (Scophthalmus maximus L.)

Studies were conducted to investigate the non-specific immune responses and disease-resistance of juvenile turbot Scophthalmus maximus,cultured at four different salinities(8,20,32 and 40) . Three concentrations(3.75 × 10 7,3.75 × 10 8 and 3.75 × 10 9 CFU/ml) of Vibrio anguillarum suspension were employed at each salinity to determine the 4-day LD 50 . The serum lysozyme activity,the alternative complement pathway activity(ACH50) and the phagocytosis percentage of head kidney in turbot were tested at 24,48 and 72 h post-challenge of V. anguillarum(1.1 × 10 8 CFU/ml,0.1 ml) ,respectively,to evaluate the non-specific immune responses at the selected rearing salinities. Fish reared at salinity 20 had the lowest mortality,namely,the highest 4-day LD 50 value(8.88 ± 0.17) . Besides,the lysozyme activity,ACH50 and the phagocytosis of turbot were the highest at the salinity 20,but with the lowest at the salinity 40 treatment regardless of sampling time. In addition,the non-specific immune activities kept increasing within 72 h post-challenge of V. anguillarum,except that the lysozyme activity increased from 24 to 48 h,and then decreased from 48 to 72 h at 40 significantly. These results together indicate that rearing in intermediate salinity(20) was able to enhance the immunity and disease-resistance of turbot.     

大菱鲆CD55负调控补体激活及其广谱细菌结合能力

CD55蛋白在哺乳动物中是一种补体调控因子,但其在鱼类中的功能未知。本研究探索了大菱鲆(Scophthalmus maximus) CD55(SmCD55)蛋白的功能。结果表明,SmCD55蛋白由344个氨基酸残基构成,含有一个N端信号肽和3个补体调控蛋白(CCP)功能域。SmCD55基因在大菱鲆多种组织中均有表达,其中,在肌肉中表达量最低,在脑组织的表达量最高。通过原核表达获得了重组的SmCD55(rSmCD55)蛋白,发现rSmCD55蛋白能够抑制大菱鲆血清的溶血活性和杀菌活性,表明其负调控补体系统的激活。此外,本研究还发现rSmCD55蛋白可以结合包括重要水产病原菌迟缓爱德华氏菌(Edwardsiella tarda)、荧光假单胞杆菌(Pseudomonas fluorescens)、鳗弧菌(Vibrio anguilla­rum)、哈维氏弧菌(Vibrio harveyi)和海豚链球菌(Strep­tococcus iniae)在内的多种细菌,其中与哈维氏弧菌的结合能力最强。以上这些研究结果丰富了鱼类补体系统的理论知识,加深了对鱼类补体激活调控的了解。     

养殖密度对循环水系统中大菱鲆生长和蛋白质代谢的影响

在工厂化循环水养殖系统中,将初始体质量为186 g±2.0 g的大菱鲆(Scophthalmus maximus)放养于低(9.4 kg/m~2±0.2 kg/m~2)、中(13.6 kg/m~2±0.8 kg/m~2)、高(19.1 kg/m~2±1.3 kg/m~2)3个养殖密度,以研究不同养殖密度对大菱鲆生长、消化酶和蛋白质代谢的影响。养殖120 d后,低、中、高试验组养殖密度分别增长至26.1 kg/m~2±1.2 kg/m~2、38.2 kg/m~2±2.5 kg/m~2、52.3 kg/m~2±3.6 kg/m~2。结果表明:低密度组和中密度组中大菱鲆增质量率、特定生长率、肥满度和蛋白质效率均显著(P0.05)高于高密度组;而饲料系数显著低于高密度组(P0.05)。低密度组和中密度组大菱鲆总蛋白酶和淀粉酶活力显著低于高密度组(P0.05);但脂肪酶活力在3个密度组之间无显著性差异。与低密度组相比,高密度组显著提高了谷氨酸脱氢酶活力,同时降低了谷草转氨酶和亮氨酸氨肽酶活力(P0.05),而对谷丙转氨酶活力无任何影响。综上所述,在工厂化循环水系统中,增加养殖密度能提高养殖的产量,但过高的养殖密度会对大菱鲆生长、消化酶活力以及蛋白质代谢产生不利的影响。     

大菱鲆精子运动特征与精液pH的相关性研究

为探究大菱鲆(Scophthalmus maximus)精液质量与pH的关系及甘油对大菱鲆精子激活的影响,本研究通过计算机辅助精子分析系统分析检测了威海和烟台4家大菱鲆育苗场(A、B、C、D)的精子质量。研究发现,不同育苗场的大菱鲆精子活力存在显著的差异,A2A1DCB,精子预测寿命分别为11.7、7.1、6.8、4.6、3.3 min,所取精子的质量的存在显著差异。研究结果发现,大菱鲆精子运动特性与精子活化率相关性显著,其中精子活化率与平均曲线运动速度、平均直线运动速度、平均路径速度、精子头侧摆幅度、精子平均鞭打频率呈显著正相关(P0.05),与运动直线性、运动摆动性、运动前向性等参数无显著相关性;大菱鲆精子运动特性受pH影响显著,精液pH与平均曲线运动速度、平均直线运动速度、平均路径速度、精子头侧摆幅度、精子平均鞭打频率呈显著正相关(P0.05),而与运动直线性、运动摆动性、运动前向性等参数无显著相关性。同时还发现,精子活化率高、寿命长的大菱鲆精液pH偏弱碱性(pH=8.0),即大菱鲆精子适宜在弱碱性环境中活动。除此之外,向激活海水中加入梯度甘油(0.1、1、10、100、500、1 000 mmol/L),发现可以显著提高大菱鲆精子寿命,其中甘油浓度为100 mmol/L时,精子寿命延长至15.17 min±0.29 min,推测甘油在精子激活后可能被精子吸收并氧化分解提供能量。     

几种益生菌对大菱鲆幼鱼生长及消化酶活性的影响

作者以初体质量为(4.80±0.11)g 的大菱鲆(Scophthalmus maximus)为研究对象,在循环水水族箱中进行60 d 饲喂实验,研究饵料中添加单一益生菌和复合益生菌对大菱鲆生长及消化道酶活性的影响.以基础饲料为对照组,在基础饲料中分别添加枯草芽孢杆菌(Bacillus subtilis)、地衣芽孢杆菌...     

Genetic parameter estimation for juvenile growth and upper thermal tolerance in turbot (Scophthalmus maximus Linnaeus)

Twenty-six half-sib groups(53 full-sib families) of turbot, Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring(40–50 individuals/family) and subjected them to a thermal tolerance challenge over a period of 34 d. There was no significant difference in daily mortality(range: 0.580%–1.391%) between Days 1–13 during the thermal tolerance challenge. However, daily cumulative mortality increased rapidly between Days 14 and 29, especially on Days 15 and 16(20.232% and 34.377%, respectively). Mortality was highest on Day 16(14.145%). We estimated the genetic parameters using the average information restricted maximum likelihood method. We used a likelihood ratio test to evaluate the significance of effects in models with and without identity as an effect, and compared the final log-likelihoods(maximum log L). Lastly, we estimated phenotypic and genetic correlation between the upper thermal tolerance limit(UTT) and body weight(BW). In this study, the positive phenotypic correlation was low between UTT and BW(0.093±0.029). The genetic correlation between UTT and BW was negative(-0.044±0.239). The heritability for upper thermal tolerance was low(0.087±0.032), which is of approximately moderate heritability. The heritability for body weight was high(0.303±0.074). Our results suggest there is significant potential for improvement in the culture of turbot by selective breeding.     

急性热应激对大菱鲆血液生化指标的影响

为探讨大菱鲆(Scophthalmusmaximus)大规格幼鱼热耐受性和热应激过程中敏感指标的变化,本研究设定18℃、21℃、24℃和27℃4个温度梯度,采用1℃/h的升温速率,对驯化温度为18±1℃的苗种进行96 h急性胁迫实验,统计各温度组96 h成活率和测定血浆部分生化指标的变化情况。结果表明,在pH 7.85、盐度29.5和溶解氧高于6.5 mg/L的环境条件下,平均体质量183.65±15.99 g的大菱鲆幼鱼96h高起始致死温度(UILT50)为28.05℃;温度和胁迫时间对血浆肾上腺素(EPI)、皮质醇(Cortisol)、血糖(GLU)、还原型谷胱甘肽(GSH)、超氧化物歧化酶(SOD)和碱性磷酸酶(AKP)含量/活性都存在显著影响,除GSH外,温度和胁迫时间存在显著的交互影响作用;热应激组血浆EPI含量随胁迫时间延长呈逐渐上升趋势,同一胁迫时间以21℃组含量最高;热应激组Cortisol含量的响应时间随温度升高相应提前、随胁迫时间呈先升后降的趋势,均在48 h达最高值; 24℃和27℃组GLU含量随胁迫时间呈先升后降趋势,胁迫3h～6h即达最高值,上升幅度与温度正相...     

饵料中添加益生菌对大菱鲆幼鱼肠道菌群及部分免疫指标的影响

作者以初体质量为(4.80±0.11)g的大菱鲆(Scophthalmus maximus)为研究对象,在循环水水族箱中进行60 d饲喂实验,研究饲料中添加单一益生菌和复合益生菌对大菱鲆肠道菌群及部分血液免疫指标的影响。以基础饲料为对照组,在基础饲料中分别添加枯草芽孢杆菌(Bacillus subtilis)、地衣芽孢杆菌(Bacillus licheniformis)、枯草芽孢杆菌+地衣芽孢杆菌(1:1)、嗜酸乳酸菌(Lactobacillus acidophi-lus)、双歧杆菌(Bifidobacterium inopinatum)、嗜酸乳酸菌+双歧杆菌(1:1)、枯草芽孢杆菌+地衣芽孢杆菌+嗜酸乳酸菌+双歧杆菌(1:1:1:1),每克饲料约含菌3.0×109个/g干质量,共配制7种实验饲料。实验结果显示,饲料中添加益生菌对肠道中总菌数无显著影响,但显著降低了肠道弧菌数(P<0.05),显著提高了大菱鲆酚氧化酶活力、溶菌酶活性和总抗氧化力。添加不同的益生菌对血细胞数、血清蛋白浓度及超氧化物歧化酶的影响不同,例如添加的益生菌中含有乳酸菌能显著提高大菱鲆血清蛋白浓度(P<0.05),而添加芽孢杆菌无此效果。上述实验结果表明,与添加单一益生菌相比,在饲料中添加复合益生菌对降低大菱鲆肠道弧菌总数,提高机体免疫力具有更好的促进作用。