【作者】 何小燕；

【导师】 刘小林； 白俊杰；

【作者基本信息】 西北农林科技大学 ， 水生生物学， 2009， 硕士

【摘要】 大口黑鲈（Micropterus salmoides）俗名加州鲈,自上世纪70年代由美国引入我国台湾,80年代又从台湾引入广东。因其生长快,肉质鲜美等优点,已成为我国重要的淡水养殖品种,现已在全国各地都有养殖。经过20多年的养殖,因缺乏定向选育,加上繁殖生产过程中不注重亲本所需遵循的操作规程,已使大口黑鲈出现种质退化现象。为保证大口黑鲈养殖业的可持续发展,有必要展开大口黑鲈良种选育。目前已运用群体选育和家系选育展开大口黑鲈良种选育工作。为保证选育工作能高效进行,本研究对大口黑鲈早期生长发育和微卫星DNA标记在选育后代亲权鉴定中应用进行了研究,该研究可为大口黑鲈选择育种和日常生产管理提供可靠的理论依据,具体研究内容如下:1、大口黑鲈早期生长规律研究为了解大口黑鲈早期生长发育规律,选用8个全同胞家系,每月从每个家系随机选取30～40尾对其体重和体长进行测量。运用Gompertz、Logistic和Von Bertalanfly 3种非线性模型对大口黑鲈体重和体长的生长进行了曲线拟合分析,还利用幂函数研究大口黑鲈体重和体长的生长关系。结果显示,3种非线性模型均能较好的模拟大口黑鲈体重和体长的生长,但Logistic模型拟合效果更佳;进一步分析,体重和体长的最佳拟合参数,发现体重和体长的拐点月龄分别为5.77月龄和4.95月龄,拐点体重和拐点体长分别为146.35g,13.75cm。幂指数亦能很好的拟合大口黑鲈体重和体长的相互关系,其方程为W=0.076L^2.650（R²=0.998）。研究结果为及时了解大口黑鲈的早期生长规律和自然生长条件下大口黑鲈的饲养管理提供了参考。2、大口黑鲈形态性状对体重的影响效果分析对大口黑鲈全长、体长、体高、体宽、眼间距、头长、吻长、尾柄长、尾柄高和体重共10个性状进行测定,运用相关分析、通径分析和多元回归分析,剔除与体长存在显著共线性的全长、体高、头长,尾柄高及回归方程中不显著的吻长和尾柄长。计算以体宽、体长、眼间距3个形态性状为自变量,体重为依变量的相关系数、通径系数、决定系数及相关指数,定量分析大口黑鲈形态性状对体重的影响效果。结果显示:3个形态性状与体重的相关系数（0.942,0.979,0.928）均达到极显著水平（P＜0.01）;通径分析中,3个形态性状对体重的通径系数亦达到极显著水平（P＜0.01）,它们是直接影响体重的重要指标,其中体宽（P₄=0.599）对体重的直接影响最大。所选形态性状与体重的相关指数R²=0.980,说明所选性状是影响体重的主要形态性状。应用逐步多元回归分析建立了以体重为依变量（Y）、体宽（X₄）、体长（X₂）和眼间距（X₅）为自变量的回归方程:lgY=1.065+0.765 lgX₂+1.441 lgX₄+0.543 lgX₅。以上形态性状对体重影响效果相关数据的获得为大口黑鲈选育测量指标的确定提供了理论依据。3、微卫星DNA标记在大口黑鲈亲权鉴定中的应用为了解微卫星DNA标记在大口黑鲈亲权鉴定中的可行性,为大口黑鲈家系选育的系谱精确鉴定和选育效果评价提供依据,选择12个多态信息含量较高的微卫星DNA位点,以人工选育建立大口黑鲈（Micropterus salmoides）的5个全同胞家系（总共102个个体）为试验材料,采用Cervus3.0进行亲权分析,并根据家系内个体间的遗传距离进行UPGMA聚类分析。结果显示,所选的12个微卫星DNA多态位点在102个子代中的平均等位基因数A为3,平均观测杂合度Ho为0.594 8,平均期望杂合度He为0.545 7,平均多态性息含量PIC为0.475 9。Cervus3.0亲权分析表明,置信度95%,使用12个和10个位点,模拟和实际分析的判别成功率分别为96%和98%,87%和91%;而置信度99%,分别为78%和92%、64%和86%;在置信度99%和95%时,判别准确率皆在90%以上。从12个位点中挑选10个多态性息含量最高的微卫星DNA位点即可将102个子代完全准确的聚为5个群体。亲权分析和聚类分析结果一致。所选用的12个微卫星位点可用于大口黑鲈亲权鉴定研究,其判定成功率和准确率高,结果可靠。4、大口黑鲈群体选育效果初步研究2005年从四个不同地区选择体型标准、健康、体重均大于0.65 kg的大口黑鲈各300尾建立群体选育基础群,混合后均匀的分到不同的两个选育养殖场,雌雄各半。选择率为5%～12%。至2008年,群体选育系已产生第三代。为及时了解大口黑鲈群体选育后代的生长情况,本研究以2组群体选育大口黑鲈为选育组,未选育组作为对照组。每组随机测量50～60尾,测量了112、144、168和207日龄的体重、全长、体长、头长、体高、尾柄长和尾柄高共7个性状,并进行多重比较。结果显示,除112日龄时,选育组体重介于对照组之间,在144日龄、168日龄和207日龄时,大口黑鲈选育组体重极显著高于对照组;选育组全长、体长和尾柄长亦高于对照组,头长、体高和尾柄高在168日龄时极显著高于对照组,在207日龄时,差异不显著,在112日龄和144日龄时,呈现不规律的显著性差异水平。结果表明,以增加大口黑鲈体重为目标的群体选育是可行的。更多还原

【Abstract】 The largemouth bass （Micropterus salmoides） has been introduced into Taiwan from the United States since 1970s, and then introduced to Guang dong Provience in 1980s. Now the largemouth bass has been an important aquaculture species in China. Because of its fast-growing, good quality, it was cultured throughout in China. But it lacked directional selection and did not pay attention to the rules which must be followed in the production process in 20-year breeding. It had led to emergence of germplasm degradation in largemouth bass breeding. To ensure the sustainable development of the largemouth bass, the selected breeding program must be carried out in time. In the present study, we focused on the growth and development of largemouth bass in early stages and microsatelliate marker in parentage determination, in order to make the work can be highly effective. The specific studies are as follows:1、The growth and development of largemouth bass in early stagesIn order to study the growth and development rules of largemouth bass, 8 full-sib families of the largemouth bass were selected , body weight and standard length of randomly sampled 30 to 40 individuals from each family were measured per month （from 1 month to 7 months）. The growth data were analyzed and fitted with three kinds of nonlinear models （Gompertz, Logistic, Von Bertalanffy）. Further, the power growth model was performed to find the relationship between body weight and standard length. Results indicate that the growth curves were appropriately fitted with three models, but the Logistic had the best goodness-of-fit of growth curve. Analyzing the fitting parameters of the Logistic, we found the inflection point month of body weight and standard length were 5.77 and 4.95 respectively, the inflection point of weight and standard length were 146.35g and 13.75cm respectively. The power growth model also had a better effection on fitting the relationship between body weight and standard length W = 0.076 L^2.650 （R² = 0.998） . This research will help us to kown the early growth and development rules of largemouth bass and supply guideline for feeding and selected breeding.2、Mathematical analysis of effects of morphometric attribute on body weightThe effects of morphometric attributes on body weight of Largemouth bass were analyzed. Data of total length （X₁）,standard length（X₂）,body depth （X₃）,body width （X₄）,interorbital distance （X₅）,head length （X₆）,snout length （X₇）,caudal peduncle length （X₈）,caudal peduncle depth （X₉） and body weight （ Y ）were collected from culture pond in this study. Correlation analysis, path analysis and multiple regressions were used. The correlation coefficients among the morphometric attributes were calculated, then the total length、body depth、head length and caudal peduncle depth were eliminated from the variable data, because all of them were co-linear with standard length. Snout length and caudal peduncle length were also kicked out from the variable data because of no significance in multiple regression equation. The three morphometric attributes （ X₂, X₄, X₅） were used as independent variables, and body weight （Y） was used as a dependent variable for path analysis. Path coefficients (P_y.x) , determination coefficients (d_y.x) and correlation index （R²） were calculated in path analysis. The results showed that the three independent variables significantly effect body weight with correlation coefficient 0.942 , 0.979 , 0.928 （p<0.01 ） respectively. The path coefficients (P_y.x ) of the body width, standard length, Interorbital distance to the body weight have all reached a level of significance. These attributes were very indicative of determining the body weight, among them the body width weighted the most （P₄ = 0.599） to the body weight, it is a key effective factor, standard length and interorbital distance weighted the second and the third （P₂ = 0.231, P₅ = 0.189 ）. Judging from the result of high correlation index （ R² = 0.980 ）, the main variables （X₂, X₄, X₅） have been selected. We have obtained the multiple regression equation to estimate the body weight as lgY = 1.065 + 0.765 lgX₂+1.441 lgX₄ +0.543 lgX₅ This paper provides theoretical evidence and perfect measure target for selective breeding of Largemouth bass.3、microsatellite marker in parentage determinationThis study was initiated to assess the feasibility of parentage determination by microsatellites in order to giving help for family accuracy determination and estimating the results of selective breeding in aquaculture populations for largemouth bass （Micropterus salmoides）. The genotypes of 12 the most polymorphic microsatellites loci were detected in 5 full-sib families of selected largemouth bass （Micropterus salmoides） and the parentage determination was done by using the software package Cervus3.0. the UPGMA dendrogram was constructed according to genetic distance among 102 individual of 5 families.The Result indicated that: The basic genetic parameters of the 12 microsatellite polymorphic loci in offspring population were: the average number of alleles A = 3, Mean observed heterozygosity Ho = 0.5948, Mean expected heterozygosity He = 0.5457, Mean polymorphic information content PIC = 0.4759. Simulations based on allele frequency data from the population demonstrated that 10 loci were required to assign 64% and 86% of offspring with 99% confidence, 87% and 91% of offspring with 95% confidence in simulation and actual simulation analysis, respectively. When marker data from 12 loci were used, the assignment rate of offspring to their true parental couple （including 7 males and 7 females） increased to 78% and 92% with 99% confidence, 96% and 98% with 95% confidence in simulation and actual simulation analysis, respectively. The power of microsatellite loci was not only estimated by the assignment success rate, but also judged by assignment accuracy rate. When 10 microsatellites were used, the assignment accuracy rate was more than 90%; when all loci were used, the assignment accuracy rate was nearly to 100%. The UPGMA tree demonstrated that when only 10 most polymorphic loci were selected, the results were consistent with parentage determination and the records of the 5 families. The results of this study revealed that the microsatellite markers could be used in the parentage determination of largemouth bass with high assignment rate and accuracy.4、the preliminary study about the results of mass selectionIn 2005, 300 largemouth bass with body weight above 0.65 kg were selected from 4 different regions as broodstocks respectively which were divided into 2 hatcheries （sire : dam = 1:1）, selected rate was 5%～12%. Till to 2008, three generations had been produced. In order to kown growth of offspring in mass selection in time, two mass selection groups were chosed as selected groups and unselected group as control group. We randomly sampled 50～60 individuals from each group at the age of 122, 144, 168 and 207days respectively. The body weight, total length, standard length, head length, body height, caudal peduncle length and caudal peduncle depth were measured. Then the means were compared among selected groups and control group using LSD. Results indicated that the body weight of selected groups were above that of control group with significant except at the age of 112days; The means of total length, standard length and caudal peduncle length were also above those of control group; The means of head length, body height and caudal peduncle depth of selected were high than those of control group with significant at the age of 168 days, but there were no significant difference among selected groups and control group at the age of 207 days, the significant difference and no significant difference were not always the same when at another two stages; The results suggusted that mass selection applied in largemouth was possible.更多还原