【作者】 彭刚；

【导师】 俞菊华；

【作者基本信息】 南京农业大学 ， 渔业， 2010， 硕士

【摘要】 克氏原螯虾原产于美国中南部和墨西哥东北部,1929年由日本引入中国后,很快遍布长江流域,甚至在一些江河湖泊成为优势物种。随着克氏原鳌虾产业规模的逐渐扩大,对其饲料的研发特别是饲料组分中适宜蛋白含量的研究逐渐成为热点之一。此外,目前主要养殖模式的苗种来源仍主要依赖于采捕天然苗种,规模化人工育苗技术尚未成熟,加上环境污染等原因,野生资源量大大减少,因此函需对现存的野生群体遗传结构进行分析。本研究设置了不同蛋白水平饲料对克氏原螯虾生长及免疫的影响试验,对饲料适宜蛋白含量进行了探讨,为克氏原螯虾饲料的科学配方积累基础资料；另外利用微卫星标记技术(SSR)对兴化养殖群体和长江游流域三个克氏原螯虾野生群体遗传结构进行了调查,对克氏原螯虾的种质资源的保护和利用提供了依据。主要研究结果如下：1、蛋白水平对克氏原螯虾存活率影响极显著(P<0.01),最高存活率为74%出现在5%蛋白组,最低存活率为56%出现在45%蛋白组,其他各组存活率均在70%以上。45%蛋白组与其他组均有显著性差异,其余四组间差异不显著(P>0.05)。不同蛋白组间试验虾末期总体规格存在显著性差异(P<0.05)。实验末残肢虾最大体长与该组实验虾的众数体长较为一致,最小体长则与实验虾的最小体长较为一致。克氏原螯虾的增重率和特定生长率随蛋白水平的提高而增加,饲料系数不断降低.当蛋白含量为43.45%时,其饲料系数最小。以增重率和特定生长率为指标,通过回归分析得出当蛋白含量在41.22%时,增重率最大,当蛋白含量在41.57%时,特定生长率最大。本研究中克氏原螯虾(平均体重为0.0238士0.0014g)适宜蛋白含量在41.22%～41.57%之间。2、适宜蛋白含量对克氏原螯虾胃蛋白酶活力的增加有诱导作用,胃蛋白酶活力随饲料中蛋白含量的增加而呈逐渐上升的趋势,其中当饲料蛋白水平从5%增加到35%时,胃蛋白酶活力不断增加,当蛋白含量高于该值时,胃蛋白酶活力反而下降,但未达显著水平。胃蛋白酶活力与增重率随蛋白含量的变化趋势一致,成正相关。饲料不同蛋白质水平对克氏原螯虾碱性磷酸酶(ALP)活性有显著影响(P<0.05),但对酚氧化物(POD)、酸性磷酸酶(ACP)和超氧化物歧化酶(SOD)活力无显著性影响(P>0.05),表明蛋白含量对免疫力有一定的影响。3、利用7对微卫星引物对分布于我国长江流域的三个克氏原鳌虾野生群体洪泽湖(HZH)、巢湖(CH)及鄱阳湖(PYH)群体进行遗传多样性分析结果表明：3个群体的平均观测杂合度为0.5762 (HZH)-0.6190 (CH);平均期望杂合度为0.6113(HZH)-0.7399 (CH);平均多态信息含量为0.5316 (HZH)-0.6788(CH),表明长江中下游地区的3个克氏原螯虾野生群体的遗传多样性处于较高水平,其中巢湖群体遗传多样性最高,洪泽湖群体最低。兴化(XH)养殖群体的观测杂合度为0.5714,养殖群体的遗传多样性略低。群体间的遗传分化指数值表明群体间遗传分化程度较弱,CH与PYH群体间遗传分化最弱仅为1.11%。分子变异分析表明,野生群体间变异占总变异的1.11%-6.61%,表明目前我国克氏原螯虾野生群体间遗传分化很微弱,绝大部分变异来自群体内部。PYH群体与HZH群体之间的遗传距离最大(DA=0.2793),与巢湖群体遗传距离最小(DA=0.0375),以群体间遗传距离为依据,用UPGMA分析方法进行聚类分析结果表明,四个群体聚为两类,遗传距离最近的PYH与CH群体聚为一类,HZH野生群体与XH养殖群体聚为一类,聚类结果基本符合四个群体的地域分布。更多还原

【Abstract】 The red swamp crayfish, Procambarus clarkii, a kind of native species in the south-central of United States and the northeastern part of Mexico, has been a dominant species after induced into China from Japan since 1929.With the scale of crayfish industry gradually expand, the study on formula feed, especially the appropriate protein content of feed components has become one of the hotspots.In addition, the main source of seed breeding mode depends on the capture of natural seed, but the large-scale artificial breeding technology is not yet mature, coupled with environmental pollution and other reasons, a significant reduction in the amount of wild resources, so we need to do research on the genetic structure of existing wild population of Procambarus clarkii.In this study, we studied on the appropriate protein content of formula feed on the growth and immunity of Procambarus clarkii. In addition, seven microsatellite markers were applied to investigate the genetic diversity among three wild geographic stocks, comparing with one cultured stock. The main results were as follows:1. There was significant difference Shrimps fed 45% had the lowest survival rate valued 56%, the 5%group had the highest valued74%.The others were all above 70%,and there were no significant difference when the protein level was above 35%.At the end of the experiment, there was significant difference of average total size between the different protein levels on (P<0.05),the maximal body length of stump shrimp is similar with the total size of mode, the minimum body length of stump has the same size as the total size of the shortest in the end.Growth rate and specific growth rate increased with increasing protein level, feed conversion ratio is decreasing. Shrimps fed 41.22% dietary protein had the maximal special growth rate and fed 43.45% dietary protein had the minimal feed conversion, the protein content valued 41.57% had the maximal special growth rate. In this study, the appropriate protein content of Procambarus clarkii (average weight of 0.0238±0.0014g) was between 41.22% and 41.57%.2. When the dietary protein level valued from 5% to 35%, pepsin activity increased gradually by the protein content of formula feed. When the protein content is higher than the 35%, the pepsin activity decreased, but not significant. The change law of Pepsin activity was accord with the growth rate.In order to find out the effect of protein levels on immune-related enzyme activities, acid phosphates (ACP), alkaline phosphates (ALP), Superoxide dismutase (SOD) and peroxides (POD) in muscle were monitored. The dietary protein levels had significant effects on the activity of ALP in the muscle (P<0.05) and had not significant effects on the activities of ACP, SOD and POD in the muscle (P>0.05).3. The genetic diversity of wild population of Procambarus clarkii in the Yangtze River Basin was studied by using seven polymorphic microsatellite markers. The three wild populations were collected in Hongze Lake (HZH), Chaohu Lake (CH)and Poyang Lake (PYH).The cultured population was collected from Xinghua county (XH).The polymorphic information contents (PIC), the expected heterozygosity (He) and the observed heterozygosity (Ho) were ranged from 0.5316 to 0.6788,0.6113 to 0.7399 and 0.5762 to 0.619,respectively.Observed heterozygosity (Ho) of cultured population was only 0.5714.Obviously, the data above showed that the genetic diversity of wild population was a little higher than the cultured population.The results showed genetic differentiation coefficient estimated by Nei’s index between populations was low.There were only 1.11% between CH and PYH population. Coefficient of genetic differentiation was 1.11%～6.61% on average and the majority of genetic variation occurred within population.According to the genetic similarity and distance, PYH and CH population were shortest, while between PYH and HZH population were longest. Cluster’s analysis showed that the first group contained PYH and CH populations;the second group contained HZH and XH populations; The result of cluster’s analysis accorded with it’s region distribution.更多还原