【作者】 戴颖；

【导师】 王玉凤；

【作者基本信息】 华中师范大学 ， 动物学， 2008， 硕士

【摘要】 克氏原螯虾Procambarus clarkii(Girard)隶属于甲壳纲(Crustacea)、十足目(OrderDecapoda)、爬行亚目(Reptantia)、螯虾科(Cambaridae)、原螯虾属(Procambarus)。原产美国南部和墨西哥北部,后由美国移植到日本的本州,30年代末期由日本人引入我国南京附近,现已分布至十几个省市,成为归化于我国自然水体的一个种。最近十几年,种群发展很快,在有的湖泊和地区已成为优势种群,是重要的水产资源。由于克氏原螯虾喜欢打洞穴居,对农作物、池埂、堤坝有一定的破坏作用,在过去很长时间里,我国人民都把它当作敌害加以清除。前些年,随着克氏原螯虾消费量的不断增加,其经济利益逐渐被人们认识,克氏原螯虾又被狂捕滥捞。加上大多数人认为,克氏原螯虾繁殖快,是取之不尽的资源,因此广大渔民及农民,只顾眼前无本收利,对克氏原螯虾的开发利用缺乏长远的认识,导致克氏原螯虾的天然资源量锐减。目前克氏原螯虾基本上处于自然繁殖、人工捕捞的状况,还没有非常成功的人工繁殖育苗的养殖场,因此几乎所有经营克氏原螯虾出口业务的企业都面临着虾源严重不足的问题,从而导致克氏原螯虾的价格近几年一直在涨。克氏原螯虾人工养殖目前还没有现成的经验、模式与技术,可以说还处于探索阶段,虽然有些介绍养殖技术的资料,根据我们的观察,发现有的报道与与我们实验观察的不符,有的似乎只是参照其它虾类的养殖技术来写的,因此在参考时要谨慎对待。克氏原螯虾的人工繁殖与育苗技术,是人工养殖的基础。我们在前期实验室工作的基础上,对克氏原螯虾的繁殖生物学和胚胎发育,以及胚胎发育过程中主要消化酶活性的变化进行了研究,这不仅对克氏原螯虾亲虾人工饲料的研制、克氏原螯虾的人工繁殖和育苗技术的建立提供基础资料,而且对于保障国内和国际市场的需求,促进经济建设的发展具有重要的现实意义。不仅如此,在人工控制条件下繁殖和饲养的虾,避免了自然捕捞的虾可能体内有污染物的沉积或有寄生虫的危险,干净无污染,对于促进健康饲养技术、保障人民的身体健康也有着直接的社会效益。现将研究结果汇总如下:1.武汉地区克氏原螯虾的繁殖期的研究。关于克氏原螯虾的繁殖期,还没有一致的观点。我们采用室外调查、室内观察以及石蜡切片等方法,对武汉地区自然群体中克氏原螯虾雌雄成体的生殖腺进行了周年观察研究,结果表明:武汉地区成年克氏原螯虾的卵母细胞发育不同步,在4～5月以及9～10月的卵巢中都有大量成熟期的卵子,同时也含有少量卵黄发生前期或初期的卵母细胞。6-7月和11月都可见产后恢复期的卵巢,内含少量未产出的正在退化的过熟卵和一些卵黄发生前期或初期的卵母细胞。精巢发育的年周期变化没有卵巢的变化那么明显,但也可以看到,在4～6月和9～10月,含精子细胞和精子的精小管的比例大大增加,而在其他时期,含早期精细胞即精原细胞和精母细胞的精小管比例较多。这些结果表明,武汉地区克氏原螯虾一年有两个繁殖高峰期,一个在4～5月,另一个在9～10月。2.克氏原螯虾的胚胎发育过程的研究。结果表明:克氏原螯虾刚开始排出的所有卵子在早期被一层保护膜包住。胚胎发育过程中受精卵的颜色逐渐加深,表现为土灰色—灰色—灰褐色—棕褐色—棕色—黑色;胚胎发育过程可以分为7个主要阶段:受精卵期、卵裂期、囊胚期、原肠期、无节幼体期、复眼色素形成期、出膜前期;胚胎发育早期卵径无显著变化,仅在出膜前期卵径开始显著增大,增加了0.78mm:水温22-25℃左右时,抱卵的时间一般为25-33天;刚孵化出的幼体在形态结构上与成体有差异。3.克氏原螯虾胚胎发育时期消化酶活性变化的研究。采用酶学方法测定了克氏原螯虾胚胎发育各期主要消化酶(胃蛋白酶、胰蛋白酶、淀粉酶、脂肪酶)的比活力。结果显示:四种消化酶各自表现出不同的变化模式,胃蛋白酶的比活力受精卵期最高,晚期处于中等水平;胰蛋白酶的比活力无节幼体期最高,晚期也处于中等水平;淀粉酶的比活力的变化趋势呈倒“V”字形,原肠期最高;脂肪酶的比活力总体上很低,最高仅为0.028±0.0007 U/mgprot。可溶性蛋白含量随着胚胎的发育总体上呈逐渐下降的趋势。结果表明,消化酶的活力的高低随胚胎发育的进行有很大波动,消化酶的适时表达,为胚胎组织、器官和系统的形成以及未来仔虾的开口摄食提供物质保证。更多还原

【Abstract】 The red swamp crayfish Procambarus clarkii(Cirard)belongs to Decapoda, Reptantia,Cambaridae,Procambarus.It originally distributed in the north of Mexico and the south of America,and was introduced into China by Japanese in the 1930s.Now it distributes in more than 10 provinces of China.It has adverse effect to the plants,pools,dams because of its troglodytism,it has been treated as an pest for many years.But recently,with the improvement of people’s living standards,this swamp has become more and more popule because of its delicious taste and abundant nutrition.Now it has become one of the most important freshwater aquatic products in the cultivation. However,the natural resource of this crawfish has been decreased dramatically in recent several years because of its economic value and fishing without limit.Meanwhile,thers is no successful experiment or technology to support the artificial cultivation,leading this conomical aquatic animals could not meet the need of the consumption.So the artificial reproduction technique is imminently required to be developed for protecting the resource and for meet the need of the markets.In this study,we have investigated the reproductive biology and the changes of main digestive enzymes during embryonic development of the Procambarus clarkii Giard.The data may provide a base for developing the artificial reproductive technique.1.Investigation on the reproductive period of Procambarus clarkii.In order to provide the basic documents for developing the technique of artificial reproduction of this crayfish,the reproductive period of P.clarkii in Wuhan area was investigated by paraffin section in this paper.The asynchronism of oogenesis was observed in the sections of ovaries.The mature eggs appeared in the sections of the ovaries sampled in two periods.One period was from April to May,the other one was from September to October.The large eggs contained abundant yolk granules.In June to July and November, more previtellogenic and initial vitellogenic oocytes were observed in the ovaries,while there were a few eggs in degeneration,indicating that those periods might be after spawning and starting a new round of oogenesis.In testis of the crayfish,the proportion of the testicular tubules containing the spermatids and sperm increased dramatically in both periods of April to June and September to October,although there also appeared the spermatocytes during these two periods.Furthermore sperms contained in the vas deferens were frequently observed in these two periods.While the ratio of the testicular tubules containing spermatogonia and spermatocytes were higher in other periods during a year.These results suggest that in one year there are two periods of reproductive peak of P.clarkii in Wuhan area which are from April to May and from September to October, respectively.2.Investigation on the embryonic development of Procambarus clarkii.The results show that the colour of the eggs change garadually during the egg development:gray with yellow—gray—gray with brown—brown—tan—total black.The process of embryonic development could be divided into seven stages:fertilized eggs stage, cleavage stage,blastula stage,gastrula stage,egg-nauplius,embryo with compound eye pigments forming,prehatching stage.There were no significant difference in egg size at the early stages.However,the egg size increased about 0.78mm near the prehatching stage.Embryogenesis of this crawfish normally lasts 25-33 days at the water temperature of around 25℃.The whole eggs were around by protective coating in the early period of embryonic development,but the larval was similar to the adult from the morphology while it had just hatched.3.Investigation on the changes in main digestive enzymes(pepsin,trypsin,amylase, lipase)during embryonic development of Procambarus clarkii.The results showed that all four digestive enzymes display different activity pattern.Pepsin specific activities was the highest in the fertilized eggs stage,and it was in the middle level in last stage.Trypsin specific activities was the highest in the egg-nauplius stage,and also it was in the middle level in last stage.Amylase specific activity changed as upside-down "V" pattern,it reached irs high values in third stages.As a whole,lipase specific activities showed relatively low values,the highest point was only 0.028±0.0007 U/mgprot.The content of dissolvable protein had a decreased trend with the development of embryos.The results suggest that the vitality of digestive enzymes fluctuate with the embryonic development,The proper time expression of digestive enzymes is correlative with the formation of the tissues,organs and systems and also supports substances and energy for the feeding of larvae.更多还原